J. DRUG EDUCATION, Vol. 43(2) 155-172, 2013
CROSS-NATIONAL STUDY ON FACTORS THAT INFLUENCE PARENTS’ KNOWLEDGE ABOUT THEIR CHILDREN’S ALCOHOL USE*
JOSE-RAMON FERNANDEZ-HERMIDA, PH.D. University of Oviedo, Spain AMADOR CALAFAT, M.D. Irefrea – European Institute of Studies on Prevention, Spain ELISARDO BECOÑA, PH.D. University of Santiago de Compostela, Spain ROBERTO SECADES-VILLA, PH.D. University of Oviedo, Spain MONTSE JUAN, PH.D. Irefrea – European Institute of Studies on Prevention, Spain HARRY SUMNALL, PH.D. Liverpool John Moores University, United Kingdom
ABSTRACT
Previous research has shown that parents underestimate their children’s substance use. The aim of the present work was to analyze parental estimation of their children’s use of alcohol in five countries from northern, central, and southern Europe, and to explore the variables that influenced this perceptual
*This article was partially funded by the European Commission, Directorate General for Justice, which supports the project JLS/DPIP/2008-2/112, European Family Empowerment; and also by the Spanish Delegación del Gobierno para el Plan Nacional sobre Drogas (Government Delegation for the National Drug Plan), Order 12 July 2013). 155 Ó 2013, Baywood Publishing Co., Inc. doi: http://dx.doi.org/10.2190/DE.43.2.d http://baywood.com
156 / FERNANDEZ-HERMIDA ET AL.
bias. The sample comprised 1181 parent-children dyads living in Sweden, Slovenia, the Czech Republic, Spain, and Portugal. In accordance with the findings of previous studies, we found high parental underestimation of substance use, which was greater for more frequent alcohol use or the use of illegal drugs. This underestimation appears to be subject to some degree of sociocultural influence, and is also influenced by the severity of the children’s use.
Parental knowledge about their children’s substance use is usually imprecise, with a marked tendency for underestimation (Fernandez Hermida, Secades-Villa, Vallejo Seco, & Errasti Perez, 2003; Stanton, Li, Galbraith, Cornick, Feigelman, Kaljee, et al., 2000; Williams, McDermitt, Bertrand, & Davis, 2003). This is important because this information deficit has been linked to greater likelihood of childhood substance use or delinquent behavior and conduct problems (Bailey, Hill, Oesterle, & Hawkins, 2009; DiClemente, Wingood, Crosby, Sionean, Cobb, Harrington, et al., 2001; Laird, Criss, Pettit, Dodge, & Bates, 2008; Laird & Marrero, 2011; Racz & McMahon, 2011) and to changes in patterns of parental intervention (O’Donnell, Stueve, Duran, Myint, Agronick, San Doval, et al., 2008). There is a large body of research analyzing the factors that potentially influence underestimation. Parents’ perception of control over their children is one of these. In a large-scale study of Spanish parent-children dyads it was found that parents whose children used alcohol or other drugs underestimated use and overestimated the control they had over their children (Fernandez Hermida et al., 2003). Specifically, 41.7% underestimated cigarette smoking and 46.7% alcohol use, while only 9% of parents with children who used cannabis knew that their child was using it. As has been seen in other studies, this relation between overestimation of control and underestimation of use is neither uncommon nor spurious (Kerr, Stattin, & Burk, 2010). Related to perceived control, another variable whose influence has been analyzed is the degree of monitoring and level of parent-child communication perceived by parents. In a study with a sample of 985 Canadian adolescents and parents, it was found that the percentage of parents who underestimated their children’s substance use was 61% in the case of tobacco, 66% in that of alcohol, and 89% in that of illegal drugs (Williams et al., 2003). Interestingly, parental knowledge about their children’s substance use was associated with children’s reports of high levels of family communication and parental reports of low levels. This seemingly paradoxical finding is probably related to how family communication is assessed, with children’s voluntary reporting of their activities being a greater component of disclosure than parental monitoring (Stattin & Kerr, 200). Accordingly, children perceive a high level of family communication, so that it may be they are also more willing to talk about their levels of substance use.
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE /
157
However, as parents may perceive child substance use as a form of failure of internal family communication (Williams et al., 2003), even parents with accurate information on child behavior may feel a subjective sense of failure. If this interpretation is correct, and the flow of information between parents and children were high, the results of the following study are in total accordance. A sample of 754 dyads of African-American parents-adolescents were analyzed, again suggesting high underestimation of risk behaviors, with a rate ranging from 53 to 86% (Yang, Stanton, Cottrel, Kaljee, Galbraith, Li, et al., 2006). Specifically, 72% underestimated marijuana and alcohol use, and 50% cigarette smoking. However, the conclusions drawn from this research were surprising. Indeed, such underestimation appeared to be strongly associated with higher levels of monitoring and open communication, with adolescents with better school results and who participated more in religious services, and with lower likelihood of the adolescent being involved in risk behaviors. This same result that associates high perceived monitoring and greater parental underestimation can be found in another, more recent study (Green, Bekman, Miller, Perrott, Brown, & Aarons, 2011). It emerges as especially paradoxical that greater family communication and perceived control, which should involve better knowledge of the children’s substance use, leads to greater underestimation. It cannot be ruled out that this greater parental underestimation was focused on experimental adolescent behaviors, which are often of relatively low frequency and duration. It would therefore make sense for a higher rate of underestimation to be associated both with protective factors and with lower probability of the children being involved in risk behaviors. Overestimation, in contrast, would be more likely in adolescents who were more at risk or who were in contexts conducive to risk behaviors. In such cases, overestimation might work as a type of self-fulfilling prophecy, which could lead to parents’ disengagement from supportive child rearing strategies, given their poor expectations of success. In other cases, researchers have studied children’s age as an important factor; the result is always that the younger the child, the greater the underestimation. Parents made better estimates of their children’s alcohol or tobacco use where children were older or had better school results in the Canadian study mentioned above (Williams et al., 2003). This is also the principal conclusion of a study with 935 parent-child dyads in England (Morleo, Cook, Elliott, & Phillips-Howard, 2013). In accordance with these results, it might be thought that parents always tend to believe that their children do not use substances, especially the younger the children are. The percentage of parents who consider the possibility that their children use substances increases as the child gets older, so that underestimation starts to decrease. This hypothesis can also be confirmed in one of the studies already referred to (Green et al., 2011), where 985 young people (and their parents) considered “high risk” and receiving professional support through a range of public services (judicial, social, health, school, etc.) in San Diego, California, were interviewed to determine the accuracy of parental estimates of
158 / FERNANDEZ-HERMIDA ET AL.
children’s substance use, as well as to identify possible factors that predict parental knowledge of this risk behavior and of related problems. As with previous research, parents tended to underestimate their children’s substance use. The accuracy of parents’ estimates was higher when their children were abstinent, but the error increased where children reported use of substances. A significant percentage of the parents were unaware of their children’s problems associated with the use of alcohol (30%) and other substances (50%). It also emerges clearly from a study (Elliott, Morleo, Harkins, Cook, & Phillips-Howard, 2011) carried out in the UK with a sample of 964 parent-children dyads that a minority of the parents (9%) mistakenly believed that their children had not tried alcohol. In 53% of cases, the parents were correct in reporting that their children had never tried alcohol, while the reports of 33% correctly judged that their children reported at least some previous use. Furthermore, 17% of parents with children who drank underestimated this behavior in the previous month, while 72% were correct in estimating that their child had not been drunk in the last month. This study yielded low figures for underestimation, as the majority of the children sampled did not use alcohol, or if they did, not in problematic fashion. Once again, it seems that the results for underestimation are linked to the prevalence of use. Type of drug also appears to play a role. Parents tend to believe that their children do not use substances, and agreement figures were higher for cannabis than for sedatives, and lower for problems related to alcohol than for those related to drugs (Green et al., 2011). It would seem once more that young people’s frequency of use is what determines the probability of underestimation. The higher the prevalence of use, the more likely it is that parents who generally believe that their children do not use substances are mistaken. Other factors that may have an influence (Green et al., 2011) are race (better knowledge in Whites than in Hispanics), level of parental depression (the higher the depression level, the lower the knowledge), and the child’s functional impairment as perceived by the parents (the more the perceived impairment, the more the knowledge). In the case of other substances, the predictors were race (the same as for alcohol), sex (better knowledge in the case of males), and functional impairment as perceived by the parents (the greater the perceived impairment, the greater the knowledge). The above-cited studies have two limitations that may reduce the significance of the results obtained. First of all, the research was carried out in just one country, the majority of it in the United States. To the best of our knowledge, there has been no cross-national research on the possible relationship between cultural and sociodemographic factors and parental knowledge of children’s substance use. Second, these studies did not use a uniform concept of underestimation that permits identification of the most significant cases. Most of the cited studies classify as underestimator parents both those who are unaware of the child’s sporadic use (e.g., a single occasion) and those who are ignorant of regular use. With such a criterion, it is no surprise that the rates of underestimation yielded are
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE /
159
high, especially when it is found that parents generally tend to believe their children do not drink. However, such a wide concept of underestimation includes, in the same classification, on the one hand, parents who have a good rapport with their children and knowledge of their drug use, but who are unaware that they have used alcohol sporadically, and on the other, those who are unaware that their children drink more frequently and problematically. Moreover, the present study also examines the relation between certain characteristics of parenting style (warmth and control) and underestimation, with the aim of clarifying the relationship between these variables and cultural factors. We describe an international study including samples with different cultural traditions, and which applies a more precise criterion on defining underestimation. This data would be useful for understanding the mechanisms of underestimation and, hence, for developing strategies to maximize parents’ interest in preventive and early intervention initiatives. METHOD Objective The present study falls within the framework of a broader European research project aimed at exploring and developing preventive options for European families in relation to their children’s substance use. The specific objective of this work was to determine whether sociodemographic factors such as country of origin, age, and sex of the adolescents, persons with whom they live, socioeconomic or educational level of the parents, and so on, are related to accuracy of parents’ knowledge about their children’s use of alcohol, tobacco, or illegal drugs. Furthermore, the research also sought to corroborate the influence of variables such as perceived warmth and control, which affect parenting style, on the accuracy of parental information about frequency of use and access to alcohol. Sample and Procedure A survey was carried out between October 2010 and February 2011 in five European locations (Coimbra in Portugal, Ljubljana in Slovenia, Mallorca in Spain, Prague in the Czech Republic, and Stockholm in Sweden), with samples of school students aged 11 to 19. A total of 69 schools participated, with the aim of including around 1,000 students per region. The type of sampling was incidental. The final sample consisted of 10,652 participants (3,587 adults and 7,065 children), and was stratified by type and size of school and geographical location. With the sample size employed, and given the test variances and confidence level of 95%, the maximum error of the estimations made with the sample of parents is .0007, and in the case of the children, .35 (Henry, 1990; Smith, 2001).
160 / FERNANDEZ-HERMIDA ET AL.
A common survey methodology was used in all the countries. The survey was delivered to the students in their classrooms by specially-trained researchers who followed an established procedure. Data were collected using a self-administered paper-and-pencil questionnaire. The procedure for obtaining consent from participants differed between countries. Participants’ anonymity and confidentiality were guaranteed, and institutional ethical research approval, licenses, and authorizations for undertaking the survey were obtained in each country. Parents received their questionnaires via their children. In general, the parents returned the completed questionnaire directly to the school or by post. In cases in which the parents had more than one child at the school who had completed the survey, they were instructed to refer only to the eldest of them. Reminders were issued to parents in order to improve rates of questionnaire return. Even so, in Slovenia, Sweden, and the Czech Republic, fewer parental questionnaires than expected were collected. A quasi-anonymous code was generated in order to allow matching across dyads. The code included in the child and parent surveys was made up of the first three letters of the mother’s name, child’s birthday date (number), the first three letters of his her name, and the birth month number. In a few cases (about 3%), the code was wrong and matching was not feasible. In total, 10,652 surveys, 3,587 from adults (33.7%) and 7,065 (66.3%) from children, were included in the analysis, with 2,509 (23.55% of the total number of surveys) parent-child pairs providing sufficient information to allow for matching of adult-child dyads. Given that the aim was to determine whether the parents were aware of their children’s use, we excluded from the analyses those dyads in which the children had never used alcohol. Consequently, the sample used in this study is reduced to 1,181 cases of youngsters aged 11 to 19 who have used alcohol on at least one occasion. Measures The information was obtained via ad-hoc questionnaires. For the purposes of this article, the following variables were assessed in the children: Sociodemographic Data
Age, sex, education, parent characteristics (i.e., both, single, step-parents), number of siblings, country of birth, ethnicity, and number of times moved house in the previous 5 years was ascertained. Substance Use (Alcohol, Tobacco and Cannabis) in Parents and Children
Substance use was assessed via questions that enquired about the prevalence and frequency of use of alcohol, tobacco, and illegal drugs (e.g., “How often do you use alcohol?”). Alcohol use frequency was coded as: Never, Less than once
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE /
161
a month, Once a month, Once a week, Two to four times a week, and Daily. Tobacco use was assessed according to current smoking status (never smoked, single lifetime episode, former regular use, infrequent current user, regularly smoke between one and six cigarettes per week, regularly smoke more than six cigarettes per week). Frequency of illicit drug use was assessed through questions on period prevalence (lifetime, last year, and last month use). Illegal substances were cannabis, cocaine, ecstasy, amphetamines, heroin, and mephedrone. Semeron was included as a verification of false reporting of illegal drug use. We also asked about the quantity of alcohol used and the number of (selfdefined) drunken episodes in the last month. Furthermore, there were questions on the preferred place for drinking and where the alcohol was obtained from, as well as about the estimated proportion of friends who used alcohol (coded “none of them” to “all of them”). This last question was also asked with respect to tobacco (smoking) and illegal drugs. Also, in the case of illegal drugs, the questionnaire assessed perceived difficulty of access to each substance. Parents were asked to estimate their children’s alcohol use using the same response categories, but unlike the children’s questionnaire, tobacco and illicit drug use were assessed via a dichotomous scale (uses, does not use). Moreover, parents were required to report their own drinking and smoking, and (if relevant) those of their partner. Finally, they were also asked to state whether they had used any illegal drug in their lifetime, indicating the frequency (i.e., lifetime, last year, last month). Parental Control and Affect
Control and affect were assessed by means of children’s scores on two subscales of the Parental Acceptance-Rejection Questionnaire, PARQ (Rohner, 1990). In Spain, the PARQ© has been applied previously, providing a reliable measure of the extent to which youngsters perceive these aspects in their parents (García & Gracia, 2010). The WAS (Warmth/Affection Scale) is made up of eight items (e.g., “He/She says nice things about me”) and is a reliable measure of the extent to which the adolescent perceives his or her parents as loving, responsive, and involved. The Parental Control Scale (PCS) is made up of 13 items (e.g., “He/She makes sure that I know exactly what I can and can’t do”). The PCS assesses the extent to which the adolescent perceives strict parental control. Cronbach’s alpha for Control Scale mother’s version was .646, and for father’s version, .731. Cronbach’s alpha for the Warmth Scale mother’s version was .899, and for the father’s version, .929. Analyses Descriptive analyses were initially undertaken to explore the discrepancies between substance use reported by the children and parental estimates. Discrepancies in estimation for the three different types of substance (alcohol, tobacco,
162 / FERNANDEZ-HERMIDA ET AL.
and illegal drugs) were categorized as underestimation (parents think their children do not use, or estimate use as less frequent than their child’s report), agreement (frequency of children’s use reported by parents and the children themselves is identical), or overestimation (parents estimate substance use frequency to be greater than the child reports), for each type of substance use. Subsequently, prior to carrying out bivariate and multivariate analyses, the parents were divided into two groups according to their degree of underestimation of their children’s alcohol use. The first group was made up of parents who accurately estimated, or who only slightly underestimated their children’s use, and to whom we refer as “non-underestimators” (representing 72.4% of the sample). It is important to point out that, in this case, we adopted a restricted definition of alcohol underestimation. Where children reported use less frequently than monthly, and parents believed that their child abstained, we did not class these parents as “underestimators” (50.7% of the sample). This was because brief episodic or experimental use of alcohol is likely to be non-problematic, and underestimation of this behavior is unlikely to relate to poor parental monitoring. The second group (27.6%) is made up of parents who significantly underestimate. Once the groups had been constituted, bivariate correlation analysis was carried out on the variables that best predicted the dyad’s group membership, selecting those which emerged as statistically significant. Finally, binary logistic regression was carried out, including those variables identified as significant in the bivariate study as predictors of accuracy of parental estimates of children’s substance use. All statistical analysis was carried out using SPSS v20. RESULTS Substance Use The discrepancies between parental estimates and children’s reported substance use are shown in Table 1. The percentage of discrepancy was calculated by comparing the score given by the parents with that given by the children in each variable. In the case of tobacco and illegal drugs, only those cases in which the children reported use of the substance evaluated are included, and these were compared against parental estimates of alcohol use. As shown in Table 1, there were discrepancies between the children’s reported use of substances and their parents’ estimates. The percentages of parents who correctly estimated their children’s use decreased considerably as the frequency of child alcohol use increased (see ratio A/B in Table 1). Overall, 79.1% of parents underestimated their children’s alcohol use. Similar patterns emerged for parental estimates of drunken episodes in the last month or use of tobacco and illegal drugs. With respect to tobacco and illegal drugs, the data obtained from parents did not reveal whether or not there was overestimation, as the response format was dichotomous (uses/does not use).
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE /
163
Table 1. Parental Estimation of Children’s Use of Alcohol or Other Substances
Variable Alcohol use < 1 time per month
% according to % according to parents who children who acknowledge acknowledge this frequency this frequency or higher (B) or higher (A) 100a
% discrepancy: Parents who underestimate or overestimate use Ratio A/B
38.6
2.59
Monthly alcohol use
43.3
12.8
3.38
Weekly alcohol use
17.1
4.7
3.63
Use 2/4 times per week
3.6
.5
7.2
Daily alcohol use
1.2
.1
At least one drunken episode in the last month
24.0
5.3
UnderOverestimate estimate
79.1
4.1
4.53
19.9
1.9
12
At least one cigarette per week (260 cases, 22% of the total)
100
23.4
4.27
76.6
NA
Lifetime prevalence of illegal drug use (273 cases, 23.1% of the total)
100
17.1
5.85
82.9
NA
aWe excluded from the sample those dyads in which the children reported not having used alcohol.
164 / FERNANDEZ-HERMIDA ET AL.
Source of Alcohol and Location of Use These variables indicate parents’ knowledge about where their children drink alcohol and where they had obtained it. The results can be seen in Tables 2 and 3. Many parents appear not to have a clear idea about either the source of their children’s alcohol, or its location of use. The data indicated that parents most
Table 2. Parents’ Knowledge about Where Their Children Drink Alcohol Percentage (frequency) of adolescents who report drinking in each location
Percentage (frequency) of parental concordance with children’s report
Home
22.6 (267)
17.2 (46)
Public places (parks, street, beach)
28.9 (341)
14.4 (49)
Friends’ houses
40.1 (474)
22.6 (107)
Relatives’ houses
11.7 (138)
23.2 (32)
Bar/pub/club/disco
56.1 (662)
28.4 (188)
Drinking location
Table 3. Parents’ Knowledge about the Source of the Alcohol Their Children Drink
Source of alcohol Parents
Percentage (frequency) of adolescents who report each source
Percentage (frequency) of parental concordance with child’s report
13.5 (160)
12.5 (20)
Siblings
9.5 (112)
5.4 (6)
Friends
39.0 (460)
23.3 (107)
Friends’ parents
8.7 (103)
6.8 (7)
Other adults
9.9 (117)
12.8 (15)
Stolen from home
7.2 (85)
5.9 (5)
Bar/pub/club/disco
44.7 (528)
40.2 (212)
Shop/supermarket
30.4 (359)
19.5 (70)
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE /
165
easily identified bars as the places where their children obtained and drank alcohol. Given that, in general, parents tended to report that their children did not drink, it was not surprising that when they were asked about the source and location of use of the alcohol, the majority were also ignorant of them. Substance Use by Friends A total of 31% of the adolescents report that their friends use some type of illegal drug. In contrast, just 13.3% of the parents correctly reported this, rising to 19.2% if the question referred specifically to classmates. Difficulty of Access to Illegal Drugs On a scale of 1 (very difficult) to 4 (very easy), parents score a mean of 1.92 (SD = .83), and children a mean of 1.74 (SD = .69), indicating that parents perceived it as somewhat easier for children to obtain such substances, though a majority still believed that it was very difficult or quite difficult. Factors that were associated with the accuracy of parents’ knowledge about their children’s substance use are shown in Table 4. Significant variables were then entered into a binary regression model and used to predict estimation category, in relation to the grouping variable of underestimators and non-underestimators. The regression equation correctly classified 76.9% of the 733 cases subjected to analysis. The capacity for correct classification was better in the case of non-underestimators (93.1%) than in that of underestimators (32%). The predictive power of the variables entered, in order from highest to lowest, was: country, for the value corresponding to the Czech Republic (OR: 3.749, p < 0.05); estimation of partner’s alcohol use, for the value of “never” (OR: 3.229, p < 0.01); child’s sex, for the value of “boy” (OR: 1.559, p < 0.05); parental estimate amount of alcohol used by the child in the last 30 days (OR.: 1.116, p < 0.001); and disagreement about the source of the alcohol (OR: .981, p < 0.05). DISCUSSION In this study we defined parental underestimation as the tendency to estimate children’s substance use at lower levels than reported by the child. Our data suggest that the majority of parents underestimate substance use in their children (around 80%). More accurate estimates of children’s substance use were reported by approximately 20% of parents, but even this group tended to overestimate. These results are in accordance with those obtained in other research to date (Fernandez Hermida et al., 2003; Green et al., 2011; Yang et al., 2006). However, this high proportion of “underestimating” parents derives from the fact that parents with children who use substances in an experimental manner (i.e., low frequency) are often unaware of such alcohol or drug use. Such patterns
.000
.000
.000
.009
.008
.000
Test used Xnon-underestimator = 15.38 (s = 1.61), Xunderestimator = 15.82 (s = 1.47), t(628) = –4.487 c2 = 12.511 (with continuity correction) c2 = 25.098
c2 = 6.838 (with continuity correction) c2 = 13.790
Xnon-underestimator = 7.64 (s = 3.74), Xunderestimator = 10.22 (s = 5.15), t = –8.185
Variable
Age of child
Sex of child
Country of origin
Family structure
Parental educational level
Amount of alcohol drunk by the child in the last 30 days
Statistical significance (2-tailed) Comments
Cohen’s The quantity of alcohol used in the last 30 d = .62 days by the children of underestimators is markedly higher.
Cramer’s Parents who underestimate tend to have V = .110 medium educational levels, underestimation being less likely both from those with only basic education and those with university education.
Cramer’s The children of underestimators are more V = .079 likely to live with the mother only.
Cramer’s There is a slight tendency to underestimate in V = .147 Spain and the Czech Republic. The opposite is the case in Portugal, Sweden, and Slovenia.
Cramer’s Children of underestimators are more likely V = .106 to be male.
Cohen’s The children of parents who underestimate d = .28 are older.
Effect size
Table 4. Analysis of Factors with a Statistically Significant Relation (p < .05) to Parental Underestimation
166 / FERNANDEZ-HERMIDA ET AL.
Cramer’s The children of underestimators are more V = .249 likely to report having friends who use alcohol.
Cohen’s Underestimators are more likely to be d = .52 mistaken about the source of the alcohol their children drink.
Cohen’s Underestimators are less likely to know where d = .28 their children normally drink the alcohol.
Cramer’s It is more likely for the children of underV = .260 estimators to have used illegal drugs.
Cohen’s The children of underestimators report easier d = .43 access to illegal drugs.
.000
.000
.000
.000
.000
c2 = 71.346
Xnon-underestimator = 82.08 (s = 12.92), Xunderestimator = 75.19 (s = 14.51), t = 7.848
Xnon-underestimator = 76.13 (s = 21.20), Xunderestimator = 69.86 (s = 25.25), t = 3.948
c2 = 74.688 (with continuity correction)
Xnon-underestimator = 1.65 (s = .65), Xunderestimator = 1.94 (s = .76), t(445) = –5.585
Proportion of children’s friends who use alcohol
Parental concordance with child’s report source of alcohol
Parental concordance with child’s report of location of alcohol use
Use of illegal drugs by the child
Child’s perceived access to illegal drugs
Cohen’s The children of underestimators are more d = .58 likely to report one or more drunken episodes in the last month.
.000
Xnon-underestimator = .17 (s = .38), Xunderestimator = .41 (s = .49), t(469) = –7.766
Number of drunken episodes in last month according to the child
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE / 167
Cramer’s The children of parents who underestimate V = .256 their alcohol use are more likely to be current cigarette smokers. Cohen’s The partners of underestimators drink less. d = .92
Cohen’s Non-underestimator fathers score higher than d = .23 underestimator fathers in emotional warmth.
.000
.022
.001
c2 = 74.131 (with continuity correction)
Xnon-underestimator = 3.48 (s = 1.48), Xunderestimator = 3.19 (s = 1.72), t(932) = 2.288 Xnon-underestimator = 3.14 (s = .73), Xunderestimator = 2.97 (s = .80), t(1064) = 3.299
Partner’s use of alcohol
Warmth/Affection father
Comments
Child’s current use of tobacco (smoking)
Effect size
Test used
Variable
Statistical significance (2-tailed)
Table 4. (Cont’d.)
168 / FERNANDEZ-HERMIDA ET AL.
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE /
169
of use, although they may still warrant concern, are less likely to result in problematic outcomes. Therefore, in this study we adopted a stricter criterion for defining underestimation in order to detect underestimation of more frequent, and hence potentially more problematic, substance use. Using this criterion, the number of underestimating parents fell to 27.6%. The results of the binary analyses suggested that parental underestimation was associated with higher alcohol use and frequency, as well as with greater likelihood of the child’s reporting illegal drug use. Children of underestimators were more likely to be older and male, to have used more alcohol in the last month and to report more drunken episodes in the same period, to perceive greater alcohol use by their friends, to use illegal drugs, and to perceive access to illegal drugs as easier. This finding of an association between parental underestimation and greater use by children is not a novel one (Fisher, Bucholz, Reich, Fox, Kuperman, Kramer, et al., 2006), and suggests that parents whose children may be in more need of prevention activities are those with the poorest knowledge of their actual level of use, and who are probably more difficult to involve in any type of preventive or therapeutic activity (Alhalabí-Diaz, Secades-Villa, Perez, Fernandez-Hermida, García-Rodriguez, & Crespo, 2006; Hogue, JohnsonLeckrone, & Lisddle, 1999; Spoth & Redmond, 1992). It is also unsurprising that as well as underestimating children’s alcohol use, they are unaware of where their children drink and where they obtain their alcohol. With regard to the sociodemographic variables, the samples in some countries, such as Spain and the Czech Republic, were more likely to have underestimating parents, though the effect size was low. This difference is difficult to interpret on the basis of sociocultural assumptions, given the different geographical and cultural contexts involved. Another interesting finding was that underestimation was associated with lower emotional warmth in the father, but not in the mother. In this sense, parental control appears to be less important than the affective link with the children, which is consistent with the idea that the relationship with the father is important for information about substance use, since the children are the most relevant source of such information (Keijsers, Branje, VanderValk, & Meeus, 2010; Kerr et al., 2010; Stattin & Kerr, 2000). This result can also be interpreted in the light of the idea that parenting style cannot be understood as a variable independent of the adolescent’s behavior (Kerr, Stattin, & Ozdemir, 2012; Racz & McMahon, 2011). In this regard, poorer knowledge of the children’s substance-use patterns may determine greater parental warmth, rather than the reverse. In addition to the quality of the relationship with the child, age was another relevant variable. Parents, regardless of their country of origin, thought that their children aged under 15 did not use substances, and indeed, the majority believed this. If prevention programs are to be applied prior to this age and parents are to be involved in them, it seems clear that they must obtain more accurate information on their children’s use.
170 / FERNANDEZ-HERMIDA ET AL.
Logistic regression analysis showed that underestimation was predicted by living in the Czech Republic, being male, the quantity of alcohol estimated to be used by the partner of the reporting parent, the quantity of alcohol used by the child in the last 30 days, and parental ignorance of the source of the alcohol. In contrast, none of the other sociodemographic variables examined, such as parental employment status, parental educational level, family structure, or whether or not the parents were immigrants, were related to this error of judgment. Again, this analysis highlights the importance of variables associated with alcohol use in the child, though some sociodemographic characteristics, such as sex and country of origin, also appear to have an influence. One conclusion that can be drawn from this work is that there seems to be a relation between underestimation and the country in which it is measured. At least, of the five countries studied, there was a tendency for underestimation in the Czech Republic. It may be that there are sociocultural conditions that make this error of judgment more likely in parents from that country. Another conclusion is that the variables associated with risk of use, or with estimated use itself, are related to underestimation. This is concordant with the fact that the families most at risk are those least likely to participate in prevention programs (Alhalabí-Diaz et al., 2006). It may be that this lack of participation will give rise to more risk, more substance use, more parental ignorance, and finally, less parental willingness to become involved in prevention work, and this should be taken into account in the field of prevention. The results obtained in this work have some limitations. It cannot be stated with certainty that the sample is representative, given that the sampling of the schools was incidental, rather than random. In any case, the margin of error is quite small, as mentioned in the paragraph on sample description, so that the results can be considered significant. The cross-sectional nature of the study means that causation cannot be assumed. Moreover, care should also be taken when interpreting the results of the logistic regression, given the large number of cases that were excluded for having missing data. In spite of these limitations, though, the data obtained are in line with those from other recent research in this field, and support the universality of parental underestimation and its relation to risk factors for alcohol use in young people. The marked parental tendency for underestimation is a well-known fact, as is the reluctance of parents to participate in prevention programs. What the present work appears to suggest is the need to establish effective information mechanisms for those parents whose children are most at risk of substance use, in whom ignorance of their children’s use can discourage participation in prevention and early intervention initiatives. It remains for future research to confirm that improved parental knowledge can result in better rates of participation in both primary and secondary prevention programs.
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE /
171
REFERENCES Alhalabí-Diaz, S., Secades-Villa, R., Perez, J. M. E., Fernandez-Hermida, J. R., GarciaRodriguez, O., & Crespo, J. L. C. (2006). Family predictors of parent participation in an adolescent drug abuse prevention program. Drug and Alcohol Review, 25(4), 327-331. doi: 10.1080/09595230600741149 Bailey, J. A., Hill, K. G., Oesterle, S., & Hawkins, J. D. (2009). Parenting practices and problem behavior across three generations: Monitoring, harsh discipline, and drug use in the intergenerational transmission of externalizing behavior. Developmental Psychology, 45(5), 1214-1226. doi: 2009-12605-003 [pii] 10.1037/a0016129 DiClemente, R. J., Wingood, G. M., Crosby, R., Sionean, C., Cobb, B. K., Harrington, K., et al. (2001). Parental monitoring: Association with adolescents’ risk behaviors. Pediatrics, 107(6), 1363-1368. Elliott, G., Morleo, M., Harkins, C., Cook, P. A., & Phillips-Howard, P. A. (2011). Parents’ perceptions of their children’s alcohol consumption Retrieved from http:// www.cph.org.uk/showPublication.aspx?pubid=720 Fernandez-Hermida, J. R., Secades-Villa, R., Vallejo Seco, G., & Errasti Perez, J. M. (2003). Evaluation of what parents know about their children’s drug use and how they perceive the most common family risk factors. Journal of Drug Education, 33(3), 337-353. Fisher, S. L., Bucholz, K. K., Reich, W., Fox, L., Kuperman, S., Kramer, J., et al. (2006). Teenagers are right—Parents do not know much: An analysis of adolescent-parent agreement on reports of adolescent substance use, abuse, and dependence. Alcoholism: Clinical and Experimental Research, 30(10), 1699-1710. doi: 10.1111/j.1530-0277. 2006.00205.x García, F., & Gracia, E. (2010). ¿Qué estilo de socialización parental es el idóneo en España? Un estudio con niños y adolescentes de 10 a 14 años [What is the appropriate parenting style in Spain? A study with children and adolescents aged 10-14]. Infancia y Aprendizaje, 33, 365-384. Green, A. E., Bekman, N. M., Miller, E. A., Perrott, J. A., Brown, S. A., & Aarons, G. A. (2011). Parental awareness of substance use among youths in public service sectors. Journal of Studies on Alcohol and Drugs, 72(1), 44-52. Henry, G. T. (1990). Practical sampling. Newbury Park, CA: Sage. Hogue, A., Johnson-Leckrone, J., & Lisddle, A. (1999). Recruiting high risk families into family-based prevention and prevention research. Journal of Mental Health Counseling, 4, 337-352. Keijsers, L., Branje, S. J. T., VanderValk, I. E., & Meeus, W. (2010). Reciprocal effects between parental solicitation, parental control, adolescent disclosure, and adolescent delinquency. Journal of Research on Adolescence, 20, 88-113. Kerr, M., Stattin, H., & Burk, W. J. (2010). A reinterpretation of parental monitoring in longitudinal perspective. Journal of Research on Adolescence, 20, 39-64. Kerr, M., Stattin, H., & Ozdemir, M. (2012). Perceived parenting style and adolescent adjustment: Revisiting directions of effects and the role of parental knowledge. Developmental Psychology, 48(6), 1540-1553. doi: 10.1037/a0027720 Laird, R. D., Criss, M. M., Pettit, G. S., Dodge, K. A., & Bates, J. E. (2008). Parents’ monitoring knowledge attenuates the link between antisocial friends and adolescent delinquent behavior. Journal of Abnormal Child Psychology, 36(3), 299-310. doi: 10.1007/s10802-007-9178-4
172 / FERNANDEZ-HERMIDA ET AL.
Laird, R. D., & Marrero, M. D. (2011). Mother’s knowledge of early adolescent’s activities following the middle school transition and pubertal maturation. Journal of Early Adolescence, 31, 209-233. Morleo, M., Cook, P. A., Elliott, G., & Phillips-Howard, P. A. (2013). Parental knowledge of alcohol consumption: A cross sectional survey of 11-17 year old schoolchildren and their parents. BMC Public Health, 13(1), 412. doi: 10.1186/1471-2458-13-412 O’Donnell, L., Stueve, A., Duran, R., Myint, U. A., Agronick, G., San Doval, A., et al. (2008). Parenting practices, parents’ underestimation of daughters’ risks, and alcohol and sexual behaviors of urban girls. Journal of Adolescent Health, 42(5), 496-502. doi: 10.1016/j.jadohealth.2007.10.008 Racz, S. J., & McMahon, R. J. (2011). The relationship between parental knowledge and monitoring and child and adolescent conduct problems: A 10-year update. Clinical Child and Family Psychology Review, 14(4), 377-398. doi: 10.1007/s10567011-0099-y Rohner, R. P. (1990). Handbook for the study of parental acceptance and rejection (3rd ed.). Storrs, CT: Rohner Research Publications. Smith, T. M. F. (2001). Biometrika centenary: Sample surveys. Biometrika, 88(1), 167-243. doi: 10.1093/biomet/88.1.167 Spoth, R., & Redmond, C. (1992). Study of participation barriers in family-focused prevention: Research issues and preliminary results. International Quarterly of Community Health Education, 4, 365-388. Stanton, B. F., Li, X., Galbraith, J., Cornick, G., Feigelman, S., Kaljee, L., et al. (2000). Parental underestimates of adolescent risk behavior: A randomized, controlled trial of a parental monitoring intervention. Journal of Adolescent Health, 26(1), 18-26. doi: S1054-139X(99)00022-1 [pii] Stattin, H., & Kerr, M. (2000). Parental monitoring: A reinterpretation. Child Development, 71(4), 1072-1085. Williams, R. J., McDermitt, D. R., Bertrand, L. D., & Davis, R. M. (2003). Parental awareness of adolescent substance use. Addictive Behaviors, 28(4), 803-809. doi: S0306460301002751 [pii] Yang, H., Stanton, B., Cottrel, L., Kaljee, L., Galbraith, J., Li, X., et al. (2006). Parental awareness of adolescent risk involvement: Implications of overestimates and underestimates. Journal of Adolescent Health, 39(3), 353-361. doi: S1054-139X(05) 00549-5 [pii] 10.1016/j.jadohealth.2005.12.008
Direct reprint requests to: Jose-Ramon Fernandez-Hermida, Ph.D. Department of Psychology University of Oviedo Plaza Feijoo s/n 33003 – Oviedo – Spain e-mail: [email protected] [email protected]
Copyright of Journal of Drug Education is the property of Baywood Publishing Company, Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
CROSS-NATIONAL STUDY ON FACTORS THAT INFLUENCE PARENTS’ KNOWLEDGE ABOUT THEIR CHILDREN’S ALCOHOL USE*
JOSE-RAMON FERNANDEZ-HERMIDA, PH.D. University of Oviedo, Spain AMADOR CALAFAT, M.D. Irefrea – European Institute of Studies on Prevention, Spain ELISARDO BECOÑA, PH.D. University of Santiago de Compostela, Spain ROBERTO SECADES-VILLA, PH.D. University of Oviedo, Spain MONTSE JUAN, PH.D. Irefrea – European Institute of Studies on Prevention, Spain HARRY SUMNALL, PH.D. Liverpool John Moores University, United Kingdom
ABSTRACT
Previous research has shown that parents underestimate their children’s substance use. The aim of the present work was to analyze parental estimation of their children’s use of alcohol in five countries from northern, central, and southern Europe, and to explore the variables that influenced this perceptual
*This article was partially funded by the European Commission, Directorate General for Justice, which supports the project JLS/DPIP/2008-2/112, European Family Empowerment; and also by the Spanish Delegación del Gobierno para el Plan Nacional sobre Drogas (Government Delegation for the National Drug Plan), Order 12 July 2013). 155 Ó 2013, Baywood Publishing Co., Inc. doi: http://dx.doi.org/10.2190/DE.43.2.d http://baywood.com
156 / FERNANDEZ-HERMIDA ET AL.
bias. The sample comprised 1181 parent-children dyads living in Sweden, Slovenia, the Czech Republic, Spain, and Portugal. In accordance with the findings of previous studies, we found high parental underestimation of substance use, which was greater for more frequent alcohol use or the use of illegal drugs. This underestimation appears to be subject to some degree of sociocultural influence, and is also influenced by the severity of the children’s use.
Parental knowledge about their children’s substance use is usually imprecise, with a marked tendency for underestimation (Fernandez Hermida, Secades-Villa, Vallejo Seco, & Errasti Perez, 2003; Stanton, Li, Galbraith, Cornick, Feigelman, Kaljee, et al., 2000; Williams, McDermitt, Bertrand, & Davis, 2003). This is important because this information deficit has been linked to greater likelihood of childhood substance use or delinquent behavior and conduct problems (Bailey, Hill, Oesterle, & Hawkins, 2009; DiClemente, Wingood, Crosby, Sionean, Cobb, Harrington, et al., 2001; Laird, Criss, Pettit, Dodge, & Bates, 2008; Laird & Marrero, 2011; Racz & McMahon, 2011) and to changes in patterns of parental intervention (O’Donnell, Stueve, Duran, Myint, Agronick, San Doval, et al., 2008). There is a large body of research analyzing the factors that potentially influence underestimation. Parents’ perception of control over their children is one of these. In a large-scale study of Spanish parent-children dyads it was found that parents whose children used alcohol or other drugs underestimated use and overestimated the control they had over their children (Fernandez Hermida et al., 2003). Specifically, 41.7% underestimated cigarette smoking and 46.7% alcohol use, while only 9% of parents with children who used cannabis knew that their child was using it. As has been seen in other studies, this relation between overestimation of control and underestimation of use is neither uncommon nor spurious (Kerr, Stattin, & Burk, 2010). Related to perceived control, another variable whose influence has been analyzed is the degree of monitoring and level of parent-child communication perceived by parents. In a study with a sample of 985 Canadian adolescents and parents, it was found that the percentage of parents who underestimated their children’s substance use was 61% in the case of tobacco, 66% in that of alcohol, and 89% in that of illegal drugs (Williams et al., 2003). Interestingly, parental knowledge about their children’s substance use was associated with children’s reports of high levels of family communication and parental reports of low levels. This seemingly paradoxical finding is probably related to how family communication is assessed, with children’s voluntary reporting of their activities being a greater component of disclosure than parental monitoring (Stattin & Kerr, 200). Accordingly, children perceive a high level of family communication, so that it may be they are also more willing to talk about their levels of substance use.
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE /
157
However, as parents may perceive child substance use as a form of failure of internal family communication (Williams et al., 2003), even parents with accurate information on child behavior may feel a subjective sense of failure. If this interpretation is correct, and the flow of information between parents and children were high, the results of the following study are in total accordance. A sample of 754 dyads of African-American parents-adolescents were analyzed, again suggesting high underestimation of risk behaviors, with a rate ranging from 53 to 86% (Yang, Stanton, Cottrel, Kaljee, Galbraith, Li, et al., 2006). Specifically, 72% underestimated marijuana and alcohol use, and 50% cigarette smoking. However, the conclusions drawn from this research were surprising. Indeed, such underestimation appeared to be strongly associated with higher levels of monitoring and open communication, with adolescents with better school results and who participated more in religious services, and with lower likelihood of the adolescent being involved in risk behaviors. This same result that associates high perceived monitoring and greater parental underestimation can be found in another, more recent study (Green, Bekman, Miller, Perrott, Brown, & Aarons, 2011). It emerges as especially paradoxical that greater family communication and perceived control, which should involve better knowledge of the children’s substance use, leads to greater underestimation. It cannot be ruled out that this greater parental underestimation was focused on experimental adolescent behaviors, which are often of relatively low frequency and duration. It would therefore make sense for a higher rate of underestimation to be associated both with protective factors and with lower probability of the children being involved in risk behaviors. Overestimation, in contrast, would be more likely in adolescents who were more at risk or who were in contexts conducive to risk behaviors. In such cases, overestimation might work as a type of self-fulfilling prophecy, which could lead to parents’ disengagement from supportive child rearing strategies, given their poor expectations of success. In other cases, researchers have studied children’s age as an important factor; the result is always that the younger the child, the greater the underestimation. Parents made better estimates of their children’s alcohol or tobacco use where children were older or had better school results in the Canadian study mentioned above (Williams et al., 2003). This is also the principal conclusion of a study with 935 parent-child dyads in England (Morleo, Cook, Elliott, & Phillips-Howard, 2013). In accordance with these results, it might be thought that parents always tend to believe that their children do not use substances, especially the younger the children are. The percentage of parents who consider the possibility that their children use substances increases as the child gets older, so that underestimation starts to decrease. This hypothesis can also be confirmed in one of the studies already referred to (Green et al., 2011), where 985 young people (and their parents) considered “high risk” and receiving professional support through a range of public services (judicial, social, health, school, etc.) in San Diego, California, were interviewed to determine the accuracy of parental estimates of
158 / FERNANDEZ-HERMIDA ET AL.
children’s substance use, as well as to identify possible factors that predict parental knowledge of this risk behavior and of related problems. As with previous research, parents tended to underestimate their children’s substance use. The accuracy of parents’ estimates was higher when their children were abstinent, but the error increased where children reported use of substances. A significant percentage of the parents were unaware of their children’s problems associated with the use of alcohol (30%) and other substances (50%). It also emerges clearly from a study (Elliott, Morleo, Harkins, Cook, & Phillips-Howard, 2011) carried out in the UK with a sample of 964 parent-children dyads that a minority of the parents (9%) mistakenly believed that their children had not tried alcohol. In 53% of cases, the parents were correct in reporting that their children had never tried alcohol, while the reports of 33% correctly judged that their children reported at least some previous use. Furthermore, 17% of parents with children who drank underestimated this behavior in the previous month, while 72% were correct in estimating that their child had not been drunk in the last month. This study yielded low figures for underestimation, as the majority of the children sampled did not use alcohol, or if they did, not in problematic fashion. Once again, it seems that the results for underestimation are linked to the prevalence of use. Type of drug also appears to play a role. Parents tend to believe that their children do not use substances, and agreement figures were higher for cannabis than for sedatives, and lower for problems related to alcohol than for those related to drugs (Green et al., 2011). It would seem once more that young people’s frequency of use is what determines the probability of underestimation. The higher the prevalence of use, the more likely it is that parents who generally believe that their children do not use substances are mistaken. Other factors that may have an influence (Green et al., 2011) are race (better knowledge in Whites than in Hispanics), level of parental depression (the higher the depression level, the lower the knowledge), and the child’s functional impairment as perceived by the parents (the more the perceived impairment, the more the knowledge). In the case of other substances, the predictors were race (the same as for alcohol), sex (better knowledge in the case of males), and functional impairment as perceived by the parents (the greater the perceived impairment, the greater the knowledge). The above-cited studies have two limitations that may reduce the significance of the results obtained. First of all, the research was carried out in just one country, the majority of it in the United States. To the best of our knowledge, there has been no cross-national research on the possible relationship between cultural and sociodemographic factors and parental knowledge of children’s substance use. Second, these studies did not use a uniform concept of underestimation that permits identification of the most significant cases. Most of the cited studies classify as underestimator parents both those who are unaware of the child’s sporadic use (e.g., a single occasion) and those who are ignorant of regular use. With such a criterion, it is no surprise that the rates of underestimation yielded are
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE /
159
high, especially when it is found that parents generally tend to believe their children do not drink. However, such a wide concept of underestimation includes, in the same classification, on the one hand, parents who have a good rapport with their children and knowledge of their drug use, but who are unaware that they have used alcohol sporadically, and on the other, those who are unaware that their children drink more frequently and problematically. Moreover, the present study also examines the relation between certain characteristics of parenting style (warmth and control) and underestimation, with the aim of clarifying the relationship between these variables and cultural factors. We describe an international study including samples with different cultural traditions, and which applies a more precise criterion on defining underestimation. This data would be useful for understanding the mechanisms of underestimation and, hence, for developing strategies to maximize parents’ interest in preventive and early intervention initiatives. METHOD Objective The present study falls within the framework of a broader European research project aimed at exploring and developing preventive options for European families in relation to their children’s substance use. The specific objective of this work was to determine whether sociodemographic factors such as country of origin, age, and sex of the adolescents, persons with whom they live, socioeconomic or educational level of the parents, and so on, are related to accuracy of parents’ knowledge about their children’s use of alcohol, tobacco, or illegal drugs. Furthermore, the research also sought to corroborate the influence of variables such as perceived warmth and control, which affect parenting style, on the accuracy of parental information about frequency of use and access to alcohol. Sample and Procedure A survey was carried out between October 2010 and February 2011 in five European locations (Coimbra in Portugal, Ljubljana in Slovenia, Mallorca in Spain, Prague in the Czech Republic, and Stockholm in Sweden), with samples of school students aged 11 to 19. A total of 69 schools participated, with the aim of including around 1,000 students per region. The type of sampling was incidental. The final sample consisted of 10,652 participants (3,587 adults and 7,065 children), and was stratified by type and size of school and geographical location. With the sample size employed, and given the test variances and confidence level of 95%, the maximum error of the estimations made with the sample of parents is .0007, and in the case of the children, .35 (Henry, 1990; Smith, 2001).
160 / FERNANDEZ-HERMIDA ET AL.
A common survey methodology was used in all the countries. The survey was delivered to the students in their classrooms by specially-trained researchers who followed an established procedure. Data were collected using a self-administered paper-and-pencil questionnaire. The procedure for obtaining consent from participants differed between countries. Participants’ anonymity and confidentiality were guaranteed, and institutional ethical research approval, licenses, and authorizations for undertaking the survey were obtained in each country. Parents received their questionnaires via their children. In general, the parents returned the completed questionnaire directly to the school or by post. In cases in which the parents had more than one child at the school who had completed the survey, they were instructed to refer only to the eldest of them. Reminders were issued to parents in order to improve rates of questionnaire return. Even so, in Slovenia, Sweden, and the Czech Republic, fewer parental questionnaires than expected were collected. A quasi-anonymous code was generated in order to allow matching across dyads. The code included in the child and parent surveys was made up of the first three letters of the mother’s name, child’s birthday date (number), the first three letters of his her name, and the birth month number. In a few cases (about 3%), the code was wrong and matching was not feasible. In total, 10,652 surveys, 3,587 from adults (33.7%) and 7,065 (66.3%) from children, were included in the analysis, with 2,509 (23.55% of the total number of surveys) parent-child pairs providing sufficient information to allow for matching of adult-child dyads. Given that the aim was to determine whether the parents were aware of their children’s use, we excluded from the analyses those dyads in which the children had never used alcohol. Consequently, the sample used in this study is reduced to 1,181 cases of youngsters aged 11 to 19 who have used alcohol on at least one occasion. Measures The information was obtained via ad-hoc questionnaires. For the purposes of this article, the following variables were assessed in the children: Sociodemographic Data
Age, sex, education, parent characteristics (i.e., both, single, step-parents), number of siblings, country of birth, ethnicity, and number of times moved house in the previous 5 years was ascertained. Substance Use (Alcohol, Tobacco and Cannabis) in Parents and Children
Substance use was assessed via questions that enquired about the prevalence and frequency of use of alcohol, tobacco, and illegal drugs (e.g., “How often do you use alcohol?”). Alcohol use frequency was coded as: Never, Less than once
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE /
161
a month, Once a month, Once a week, Two to four times a week, and Daily. Tobacco use was assessed according to current smoking status (never smoked, single lifetime episode, former regular use, infrequent current user, regularly smoke between one and six cigarettes per week, regularly smoke more than six cigarettes per week). Frequency of illicit drug use was assessed through questions on period prevalence (lifetime, last year, and last month use). Illegal substances were cannabis, cocaine, ecstasy, amphetamines, heroin, and mephedrone. Semeron was included as a verification of false reporting of illegal drug use. We also asked about the quantity of alcohol used and the number of (selfdefined) drunken episodes in the last month. Furthermore, there were questions on the preferred place for drinking and where the alcohol was obtained from, as well as about the estimated proportion of friends who used alcohol (coded “none of them” to “all of them”). This last question was also asked with respect to tobacco (smoking) and illegal drugs. Also, in the case of illegal drugs, the questionnaire assessed perceived difficulty of access to each substance. Parents were asked to estimate their children’s alcohol use using the same response categories, but unlike the children’s questionnaire, tobacco and illicit drug use were assessed via a dichotomous scale (uses, does not use). Moreover, parents were required to report their own drinking and smoking, and (if relevant) those of their partner. Finally, they were also asked to state whether they had used any illegal drug in their lifetime, indicating the frequency (i.e., lifetime, last year, last month). Parental Control and Affect
Control and affect were assessed by means of children’s scores on two subscales of the Parental Acceptance-Rejection Questionnaire, PARQ (Rohner, 1990). In Spain, the PARQ© has been applied previously, providing a reliable measure of the extent to which youngsters perceive these aspects in their parents (García & Gracia, 2010). The WAS (Warmth/Affection Scale) is made up of eight items (e.g., “He/She says nice things about me”) and is a reliable measure of the extent to which the adolescent perceives his or her parents as loving, responsive, and involved. The Parental Control Scale (PCS) is made up of 13 items (e.g., “He/She makes sure that I know exactly what I can and can’t do”). The PCS assesses the extent to which the adolescent perceives strict parental control. Cronbach’s alpha for Control Scale mother’s version was .646, and for father’s version, .731. Cronbach’s alpha for the Warmth Scale mother’s version was .899, and for the father’s version, .929. Analyses Descriptive analyses were initially undertaken to explore the discrepancies between substance use reported by the children and parental estimates. Discrepancies in estimation for the three different types of substance (alcohol, tobacco,
162 / FERNANDEZ-HERMIDA ET AL.
and illegal drugs) were categorized as underestimation (parents think their children do not use, or estimate use as less frequent than their child’s report), agreement (frequency of children’s use reported by parents and the children themselves is identical), or overestimation (parents estimate substance use frequency to be greater than the child reports), for each type of substance use. Subsequently, prior to carrying out bivariate and multivariate analyses, the parents were divided into two groups according to their degree of underestimation of their children’s alcohol use. The first group was made up of parents who accurately estimated, or who only slightly underestimated their children’s use, and to whom we refer as “non-underestimators” (representing 72.4% of the sample). It is important to point out that, in this case, we adopted a restricted definition of alcohol underestimation. Where children reported use less frequently than monthly, and parents believed that their child abstained, we did not class these parents as “underestimators” (50.7% of the sample). This was because brief episodic or experimental use of alcohol is likely to be non-problematic, and underestimation of this behavior is unlikely to relate to poor parental monitoring. The second group (27.6%) is made up of parents who significantly underestimate. Once the groups had been constituted, bivariate correlation analysis was carried out on the variables that best predicted the dyad’s group membership, selecting those which emerged as statistically significant. Finally, binary logistic regression was carried out, including those variables identified as significant in the bivariate study as predictors of accuracy of parental estimates of children’s substance use. All statistical analysis was carried out using SPSS v20. RESULTS Substance Use The discrepancies between parental estimates and children’s reported substance use are shown in Table 1. The percentage of discrepancy was calculated by comparing the score given by the parents with that given by the children in each variable. In the case of tobacco and illegal drugs, only those cases in which the children reported use of the substance evaluated are included, and these were compared against parental estimates of alcohol use. As shown in Table 1, there were discrepancies between the children’s reported use of substances and their parents’ estimates. The percentages of parents who correctly estimated their children’s use decreased considerably as the frequency of child alcohol use increased (see ratio A/B in Table 1). Overall, 79.1% of parents underestimated their children’s alcohol use. Similar patterns emerged for parental estimates of drunken episodes in the last month or use of tobacco and illegal drugs. With respect to tobacco and illegal drugs, the data obtained from parents did not reveal whether or not there was overestimation, as the response format was dichotomous (uses/does not use).
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE /
163
Table 1. Parental Estimation of Children’s Use of Alcohol or Other Substances
Variable Alcohol use < 1 time per month
% according to % according to parents who children who acknowledge acknowledge this frequency this frequency or higher (B) or higher (A) 100a
% discrepancy: Parents who underestimate or overestimate use Ratio A/B
38.6
2.59
Monthly alcohol use
43.3
12.8
3.38
Weekly alcohol use
17.1
4.7
3.63
Use 2/4 times per week
3.6
.5
7.2
Daily alcohol use
1.2
.1
At least one drunken episode in the last month
24.0
5.3
UnderOverestimate estimate
79.1
4.1
4.53
19.9
1.9
12
At least one cigarette per week (260 cases, 22% of the total)
100
23.4
4.27
76.6
NA
Lifetime prevalence of illegal drug use (273 cases, 23.1% of the total)
100
17.1
5.85
82.9
NA
aWe excluded from the sample those dyads in which the children reported not having used alcohol.
164 / FERNANDEZ-HERMIDA ET AL.
Source of Alcohol and Location of Use These variables indicate parents’ knowledge about where their children drink alcohol and where they had obtained it. The results can be seen in Tables 2 and 3. Many parents appear not to have a clear idea about either the source of their children’s alcohol, or its location of use. The data indicated that parents most
Table 2. Parents’ Knowledge about Where Their Children Drink Alcohol Percentage (frequency) of adolescents who report drinking in each location
Percentage (frequency) of parental concordance with children’s report
Home
22.6 (267)
17.2 (46)
Public places (parks, street, beach)
28.9 (341)
14.4 (49)
Friends’ houses
40.1 (474)
22.6 (107)
Relatives’ houses
11.7 (138)
23.2 (32)
Bar/pub/club/disco
56.1 (662)
28.4 (188)
Drinking location
Table 3. Parents’ Knowledge about the Source of the Alcohol Their Children Drink
Source of alcohol Parents
Percentage (frequency) of adolescents who report each source
Percentage (frequency) of parental concordance with child’s report
13.5 (160)
12.5 (20)
Siblings
9.5 (112)
5.4 (6)
Friends
39.0 (460)
23.3 (107)
Friends’ parents
8.7 (103)
6.8 (7)
Other adults
9.9 (117)
12.8 (15)
Stolen from home
7.2 (85)
5.9 (5)
Bar/pub/club/disco
44.7 (528)
40.2 (212)
Shop/supermarket
30.4 (359)
19.5 (70)
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE /
165
easily identified bars as the places where their children obtained and drank alcohol. Given that, in general, parents tended to report that their children did not drink, it was not surprising that when they were asked about the source and location of use of the alcohol, the majority were also ignorant of them. Substance Use by Friends A total of 31% of the adolescents report that their friends use some type of illegal drug. In contrast, just 13.3% of the parents correctly reported this, rising to 19.2% if the question referred specifically to classmates. Difficulty of Access to Illegal Drugs On a scale of 1 (very difficult) to 4 (very easy), parents score a mean of 1.92 (SD = .83), and children a mean of 1.74 (SD = .69), indicating that parents perceived it as somewhat easier for children to obtain such substances, though a majority still believed that it was very difficult or quite difficult. Factors that were associated with the accuracy of parents’ knowledge about their children’s substance use are shown in Table 4. Significant variables were then entered into a binary regression model and used to predict estimation category, in relation to the grouping variable of underestimators and non-underestimators. The regression equation correctly classified 76.9% of the 733 cases subjected to analysis. The capacity for correct classification was better in the case of non-underestimators (93.1%) than in that of underestimators (32%). The predictive power of the variables entered, in order from highest to lowest, was: country, for the value corresponding to the Czech Republic (OR: 3.749, p < 0.05); estimation of partner’s alcohol use, for the value of “never” (OR: 3.229, p < 0.01); child’s sex, for the value of “boy” (OR: 1.559, p < 0.05); parental estimate amount of alcohol used by the child in the last 30 days (OR.: 1.116, p < 0.001); and disagreement about the source of the alcohol (OR: .981, p < 0.05). DISCUSSION In this study we defined parental underestimation as the tendency to estimate children’s substance use at lower levels than reported by the child. Our data suggest that the majority of parents underestimate substance use in their children (around 80%). More accurate estimates of children’s substance use were reported by approximately 20% of parents, but even this group tended to overestimate. These results are in accordance with those obtained in other research to date (Fernandez Hermida et al., 2003; Green et al., 2011; Yang et al., 2006). However, this high proportion of “underestimating” parents derives from the fact that parents with children who use substances in an experimental manner (i.e., low frequency) are often unaware of such alcohol or drug use. Such patterns
.000
.000
.000
.009
.008
.000
Test used Xnon-underestimator = 15.38 (s = 1.61), Xunderestimator = 15.82 (s = 1.47), t(628) = –4.487 c2 = 12.511 (with continuity correction) c2 = 25.098
c2 = 6.838 (with continuity correction) c2 = 13.790
Xnon-underestimator = 7.64 (s = 3.74), Xunderestimator = 10.22 (s = 5.15), t = –8.185
Variable
Age of child
Sex of child
Country of origin
Family structure
Parental educational level
Amount of alcohol drunk by the child in the last 30 days
Statistical significance (2-tailed) Comments
Cohen’s The quantity of alcohol used in the last 30 d = .62 days by the children of underestimators is markedly higher.
Cramer’s Parents who underestimate tend to have V = .110 medium educational levels, underestimation being less likely both from those with only basic education and those with university education.
Cramer’s The children of underestimators are more V = .079 likely to live with the mother only.
Cramer’s There is a slight tendency to underestimate in V = .147 Spain and the Czech Republic. The opposite is the case in Portugal, Sweden, and Slovenia.
Cramer’s Children of underestimators are more likely V = .106 to be male.
Cohen’s The children of parents who underestimate d = .28 are older.
Effect size
Table 4. Analysis of Factors with a Statistically Significant Relation (p < .05) to Parental Underestimation
166 / FERNANDEZ-HERMIDA ET AL.
Cramer’s The children of underestimators are more V = .249 likely to report having friends who use alcohol.
Cohen’s Underestimators are more likely to be d = .52 mistaken about the source of the alcohol their children drink.
Cohen’s Underestimators are less likely to know where d = .28 their children normally drink the alcohol.
Cramer’s It is more likely for the children of underV = .260 estimators to have used illegal drugs.
Cohen’s The children of underestimators report easier d = .43 access to illegal drugs.
.000
.000
.000
.000
.000
c2 = 71.346
Xnon-underestimator = 82.08 (s = 12.92), Xunderestimator = 75.19 (s = 14.51), t = 7.848
Xnon-underestimator = 76.13 (s = 21.20), Xunderestimator = 69.86 (s = 25.25), t = 3.948
c2 = 74.688 (with continuity correction)
Xnon-underestimator = 1.65 (s = .65), Xunderestimator = 1.94 (s = .76), t(445) = –5.585
Proportion of children’s friends who use alcohol
Parental concordance with child’s report source of alcohol
Parental concordance with child’s report of location of alcohol use
Use of illegal drugs by the child
Child’s perceived access to illegal drugs
Cohen’s The children of underestimators are more d = .58 likely to report one or more drunken episodes in the last month.
.000
Xnon-underestimator = .17 (s = .38), Xunderestimator = .41 (s = .49), t(469) = –7.766
Number of drunken episodes in last month according to the child
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE / 167
Cramer’s The children of parents who underestimate V = .256 their alcohol use are more likely to be current cigarette smokers. Cohen’s The partners of underestimators drink less. d = .92
Cohen’s Non-underestimator fathers score higher than d = .23 underestimator fathers in emotional warmth.
.000
.022
.001
c2 = 74.131 (with continuity correction)
Xnon-underestimator = 3.48 (s = 1.48), Xunderestimator = 3.19 (s = 1.72), t(932) = 2.288 Xnon-underestimator = 3.14 (s = .73), Xunderestimator = 2.97 (s = .80), t(1064) = 3.299
Partner’s use of alcohol
Warmth/Affection father
Comments
Child’s current use of tobacco (smoking)
Effect size
Test used
Variable
Statistical significance (2-tailed)
Table 4. (Cont’d.)
168 / FERNANDEZ-HERMIDA ET AL.
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE /
169
of use, although they may still warrant concern, are less likely to result in problematic outcomes. Therefore, in this study we adopted a stricter criterion for defining underestimation in order to detect underestimation of more frequent, and hence potentially more problematic, substance use. Using this criterion, the number of underestimating parents fell to 27.6%. The results of the binary analyses suggested that parental underestimation was associated with higher alcohol use and frequency, as well as with greater likelihood of the child’s reporting illegal drug use. Children of underestimators were more likely to be older and male, to have used more alcohol in the last month and to report more drunken episodes in the same period, to perceive greater alcohol use by their friends, to use illegal drugs, and to perceive access to illegal drugs as easier. This finding of an association between parental underestimation and greater use by children is not a novel one (Fisher, Bucholz, Reich, Fox, Kuperman, Kramer, et al., 2006), and suggests that parents whose children may be in more need of prevention activities are those with the poorest knowledge of their actual level of use, and who are probably more difficult to involve in any type of preventive or therapeutic activity (Alhalabí-Diaz, Secades-Villa, Perez, Fernandez-Hermida, García-Rodriguez, & Crespo, 2006; Hogue, JohnsonLeckrone, & Lisddle, 1999; Spoth & Redmond, 1992). It is also unsurprising that as well as underestimating children’s alcohol use, they are unaware of where their children drink and where they obtain their alcohol. With regard to the sociodemographic variables, the samples in some countries, such as Spain and the Czech Republic, were more likely to have underestimating parents, though the effect size was low. This difference is difficult to interpret on the basis of sociocultural assumptions, given the different geographical and cultural contexts involved. Another interesting finding was that underestimation was associated with lower emotional warmth in the father, but not in the mother. In this sense, parental control appears to be less important than the affective link with the children, which is consistent with the idea that the relationship with the father is important for information about substance use, since the children are the most relevant source of such information (Keijsers, Branje, VanderValk, & Meeus, 2010; Kerr et al., 2010; Stattin & Kerr, 2000). This result can also be interpreted in the light of the idea that parenting style cannot be understood as a variable independent of the adolescent’s behavior (Kerr, Stattin, & Ozdemir, 2012; Racz & McMahon, 2011). In this regard, poorer knowledge of the children’s substance-use patterns may determine greater parental warmth, rather than the reverse. In addition to the quality of the relationship with the child, age was another relevant variable. Parents, regardless of their country of origin, thought that their children aged under 15 did not use substances, and indeed, the majority believed this. If prevention programs are to be applied prior to this age and parents are to be involved in them, it seems clear that they must obtain more accurate information on their children’s use.
170 / FERNANDEZ-HERMIDA ET AL.
Logistic regression analysis showed that underestimation was predicted by living in the Czech Republic, being male, the quantity of alcohol estimated to be used by the partner of the reporting parent, the quantity of alcohol used by the child in the last 30 days, and parental ignorance of the source of the alcohol. In contrast, none of the other sociodemographic variables examined, such as parental employment status, parental educational level, family structure, or whether or not the parents were immigrants, were related to this error of judgment. Again, this analysis highlights the importance of variables associated with alcohol use in the child, though some sociodemographic characteristics, such as sex and country of origin, also appear to have an influence. One conclusion that can be drawn from this work is that there seems to be a relation between underestimation and the country in which it is measured. At least, of the five countries studied, there was a tendency for underestimation in the Czech Republic. It may be that there are sociocultural conditions that make this error of judgment more likely in parents from that country. Another conclusion is that the variables associated with risk of use, or with estimated use itself, are related to underestimation. This is concordant with the fact that the families most at risk are those least likely to participate in prevention programs (Alhalabí-Diaz et al., 2006). It may be that this lack of participation will give rise to more risk, more substance use, more parental ignorance, and finally, less parental willingness to become involved in prevention work, and this should be taken into account in the field of prevention. The results obtained in this work have some limitations. It cannot be stated with certainty that the sample is representative, given that the sampling of the schools was incidental, rather than random. In any case, the margin of error is quite small, as mentioned in the paragraph on sample description, so that the results can be considered significant. The cross-sectional nature of the study means that causation cannot be assumed. Moreover, care should also be taken when interpreting the results of the logistic regression, given the large number of cases that were excluded for having missing data. In spite of these limitations, though, the data obtained are in line with those from other recent research in this field, and support the universality of parental underestimation and its relation to risk factors for alcohol use in young people. The marked parental tendency for underestimation is a well-known fact, as is the reluctance of parents to participate in prevention programs. What the present work appears to suggest is the need to establish effective information mechanisms for those parents whose children are most at risk of substance use, in whom ignorance of their children’s use can discourage participation in prevention and early intervention initiatives. It remains for future research to confirm that improved parental knowledge can result in better rates of participation in both primary and secondary prevention programs.
PARENTS’ KNOWLEDGE AND CHILDREN’S ALCOHOL USE /
171
REFERENCES Alhalabí-Diaz, S., Secades-Villa, R., Perez, J. M. E., Fernandez-Hermida, J. R., GarciaRodriguez, O., & Crespo, J. L. C. (2006). Family predictors of parent participation in an adolescent drug abuse prevention program. Drug and Alcohol Review, 25(4), 327-331. doi: 10.1080/09595230600741149 Bailey, J. A., Hill, K. G., Oesterle, S., & Hawkins, J. D. (2009). Parenting practices and problem behavior across three generations: Monitoring, harsh discipline, and drug use in the intergenerational transmission of externalizing behavior. Developmental Psychology, 45(5), 1214-1226. doi: 2009-12605-003 [pii] 10.1037/a0016129 DiClemente, R. J., Wingood, G. M., Crosby, R., Sionean, C., Cobb, B. K., Harrington, K., et al. (2001). Parental monitoring: Association with adolescents’ risk behaviors. Pediatrics, 107(6), 1363-1368. Elliott, G., Morleo, M., Harkins, C., Cook, P. A., & Phillips-Howard, P. A. (2011). Parents’ perceptions of their children’s alcohol consumption Retrieved from http:// www.cph.org.uk/showPublication.aspx?pubid=720 Fernandez-Hermida, J. R., Secades-Villa, R., Vallejo Seco, G., & Errasti Perez, J. M. (2003). Evaluation of what parents know about their children’s drug use and how they perceive the most common family risk factors. Journal of Drug Education, 33(3), 337-353. Fisher, S. L., Bucholz, K. K., Reich, W., Fox, L., Kuperman, S., Kramer, J., et al. (2006). Teenagers are right—Parents do not know much: An analysis of adolescent-parent agreement on reports of adolescent substance use, abuse, and dependence. Alcoholism: Clinical and Experimental Research, 30(10), 1699-1710. doi: 10.1111/j.1530-0277. 2006.00205.x García, F., & Gracia, E. (2010). ¿Qué estilo de socialización parental es el idóneo en España? Un estudio con niños y adolescentes de 10 a 14 años [What is the appropriate parenting style in Spain? A study with children and adolescents aged 10-14]. Infancia y Aprendizaje, 33, 365-384. Green, A. E., Bekman, N. M., Miller, E. A., Perrott, J. A., Brown, S. A., & Aarons, G. A. (2011). Parental awareness of substance use among youths in public service sectors. Journal of Studies on Alcohol and Drugs, 72(1), 44-52. Henry, G. T. (1990). Practical sampling. Newbury Park, CA: Sage. Hogue, A., Johnson-Leckrone, J., & Lisddle, A. (1999). Recruiting high risk families into family-based prevention and prevention research. Journal of Mental Health Counseling, 4, 337-352. Keijsers, L., Branje, S. J. T., VanderValk, I. E., & Meeus, W. (2010). Reciprocal effects between parental solicitation, parental control, adolescent disclosure, and adolescent delinquency. Journal of Research on Adolescence, 20, 88-113. Kerr, M., Stattin, H., & Burk, W. J. (2010). A reinterpretation of parental monitoring in longitudinal perspective. Journal of Research on Adolescence, 20, 39-64. Kerr, M., Stattin, H., & Ozdemir, M. (2012). Perceived parenting style and adolescent adjustment: Revisiting directions of effects and the role of parental knowledge. Developmental Psychology, 48(6), 1540-1553. doi: 10.1037/a0027720 Laird, R. D., Criss, M. M., Pettit, G. S., Dodge, K. A., & Bates, J. E. (2008). Parents’ monitoring knowledge attenuates the link between antisocial friends and adolescent delinquent behavior. Journal of Abnormal Child Psychology, 36(3), 299-310. doi: 10.1007/s10802-007-9178-4
172 / FERNANDEZ-HERMIDA ET AL.
Laird, R. D., & Marrero, M. D. (2011). Mother’s knowledge of early adolescent’s activities following the middle school transition and pubertal maturation. Journal of Early Adolescence, 31, 209-233. Morleo, M., Cook, P. A., Elliott, G., & Phillips-Howard, P. A. (2013). Parental knowledge of alcohol consumption: A cross sectional survey of 11-17 year old schoolchildren and their parents. BMC Public Health, 13(1), 412. doi: 10.1186/1471-2458-13-412 O’Donnell, L., Stueve, A., Duran, R., Myint, U. A., Agronick, G., San Doval, A., et al. (2008). Parenting practices, parents’ underestimation of daughters’ risks, and alcohol and sexual behaviors of urban girls. Journal of Adolescent Health, 42(5), 496-502. doi: 10.1016/j.jadohealth.2007.10.008 Racz, S. J., & McMahon, R. J. (2011). The relationship between parental knowledge and monitoring and child and adolescent conduct problems: A 10-year update. Clinical Child and Family Psychology Review, 14(4), 377-398. doi: 10.1007/s10567011-0099-y Rohner, R. P. (1990). Handbook for the study of parental acceptance and rejection (3rd ed.). Storrs, CT: Rohner Research Publications. Smith, T. M. F. (2001). Biometrika centenary: Sample surveys. Biometrika, 88(1), 167-243. doi: 10.1093/biomet/88.1.167 Spoth, R., & Redmond, C. (1992). Study of participation barriers in family-focused prevention: Research issues and preliminary results. International Quarterly of Community Health Education, 4, 365-388. Stanton, B. F., Li, X., Galbraith, J., Cornick, G., Feigelman, S., Kaljee, L., et al. (2000). Parental underestimates of adolescent risk behavior: A randomized, controlled trial of a parental monitoring intervention. Journal of Adolescent Health, 26(1), 18-26. doi: S1054-139X(99)00022-1 [pii] Stattin, H., & Kerr, M. (2000). Parental monitoring: A reinterpretation. Child Development, 71(4), 1072-1085. Williams, R. J., McDermitt, D. R., Bertrand, L. D., & Davis, R. M. (2003). Parental awareness of adolescent substance use. Addictive Behaviors, 28(4), 803-809. doi: S0306460301002751 [pii] Yang, H., Stanton, B., Cottrel, L., Kaljee, L., Galbraith, J., Li, X., et al. (2006). Parental awareness of adolescent risk involvement: Implications of overestimates and underestimates. Journal of Adolescent Health, 39(3), 353-361. doi: S1054-139X(05) 00549-5 [pii] 10.1016/j.jadohealth.2005.12.008
Direct reprint requests to: Jose-Ramon Fernandez-Hermida, Ph.D. Department of Psychology University of Oviedo Plaza Feijoo s/n 33003 – Oviedo – Spain e-mail: [email protected] [email protected]
Copyright of Journal of Drug Education is the property of Baywood Publishing Company, Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
