Addictive Behaviors 39 (2014) 729–732
Contents lists available at ScienceDirect
Addictive Behaviors
Short Communication
Cannabis use motives and personality risk factors Karen Hecimovic, Sean P. Barrett ⁎, Christine Darredeau, Sherry H. Stewart Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
H I G H L I G H T S • • • • •
Study findings suggest that motives for cannabis use vary according to personality risk factors. Anxiety sensitivity was associated with cannabis use for conformity motives. Introversion/Hopelessness was associated with cannabis use for coping motives. Sensation seeking was associated with cannabis use for expansion motives. IMP was associated with using cannabis because it was readily available.
a r t i c l e Keywords: Cannabis Motives Personality
i n f o
a b s t r a c t According to the model of substance abuse of Conrod, Pihl, Stewart, and Dongier (2000), four personality factors (i.e., anxiety sensitivity [AS], introversion/hopelessness [I/H], sensation seeking [SS], and impulsivity [IMP]) are associated with elevated risk for substance use/misuse, with each personality factor being related to preference for particular drugs of abuse (e.g., AS with anxiolytics). However, cannabis use has not been consistently linked to any one of these personality factors. This may be due to the heterogeneity in cannabis use motives. The present study explored the association between these four personality risk factors and different cannabis use motives. Cannabis users completed an interview about their motives for cannabis use as well as the self-report Substance Use Risk Profile Scale (SURPS; Woicik, Conrod, Stewart, & Pihl, 2009), which measures the four personality risk factors. Results showed that AS was associated with conformity motives and I/H was associated with coping motives for cannabis use. SS was positively associated with expansion motives and IMP was associated with drug availability motives. Thus, personality risk factors in the model of Conrod et al. (2000) are associated with distinct cannabis use motives in a pattern consistent with theory. © 2013 Elsevier Ltd. All rights reserved.
Cannabis is the most widely used illicit substance in Canada, with 39.4% of those aged 15 years or older reporting lifetime use (Health Canada, 2011). Despite this prevalence, relatively little is known about cannabis use risk factors. Recently, research has linked different forms of drug use to different personality characteristics (e.g., Adams et al., 2003; Sher, Bartholow, & Wood, 2000). One example is the model of Conrod, Pihl, Stewart, and Dongier (2000), which attributes substance use/misuse to four distinct personality risk profiles: anxiety sensitivity (AS), introversion/hopelessness (I/H), sensation seeking (SS), and impulsivity (IMP). Each of these traits has been linked with preference for a specific type of drug of abuse and with distinct substance use motivations using both cross-sectional (e.g., Woicik, Stewart, Pihl, & Conrod, 2009) and longitudinal research designs (e.g., Krank et al., 2011). These associations have been observed in both adult (e.g., Conrod et al., 2000; ⁎ Corresponding author at: Department of Psychology and Neuroscience, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada. Tel.: +1 902 494 2956; fax: +1 902 494 6585. E-mail address: [email protected] (S.P. Barrett). 0306-4603/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.addbeh.2013.11.025
Woicik et al., 2009) and adolescent (e.g., Krank et al., 2011; Woicik et al., 2009) samples. Two of these personality traits, AS and I/H, have been associated with substance use as a way of dealing with negative affect (Woicik et al., 2009). For example, elevations in AS have been linked with anxiolytics use to manage anxiety, while elevations in I/H have been associated with the use of analgesics to escape depressed affect (Conrod et al., 2000). Moreover, in both adolescent and adult populations, high levels of AS and I/H have been linked to alcohol use as a means of coping (Comeau, Stewart, & Loba, 2001; Conrod et al., 2000; Woicik et al., 2009). A third personality dimension, SS, has been linked with higher rates of alcohol use to increase positive emotions and experiences (Conrod et al., 2000; Woicik et al., 2009). Finally, IMP is characterized by disinhibited behavior when presented with positive reinforcement. Field, Christiansen, Cole, and Goudie (2007) found that adolescents who are heavy drinkers exhibit impulsive behaviors, and Woicik et al. (2009) reported similar findings in an adult population, with high IMP being associated with a non-specific pattern of motives for heavy alcohol use. Moreover, IMP has been linked with the use of cocaine and other psychostimulants —drugs that deliver immediate reward (Conrod et al., 2000; Woicik et al., 2009).
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K. Hecimovic et al. / Addictive Behaviors 39 (2014) 729–732
To date, cannabis use has not been consistently linked to any specific personality dimension in the model of Conrod et al. (2000). For example, findings on the association between SS and cannabis use have been mixed. Arnett (1994) found cannabis use to be positively correlated with SS. Similarly, Woicik et al. (2009) found SS to be positively correlated with the use of drugs related to stimulating, mood-enhancing effects, including cannabis and other hallucinogens. In contrast, Comeau et al. (2001) found no correlation between SS and cannabis use in an adolescent sample. While some studies have shown no relation between anxious or depressive personalities and cannabis use (Chabrol, Ducongé, Casas, Roura, & Carey, 2005), others have found AS to be negatively correlated with cannabis use (Stewart, Karp, Pihl, & Peterson, 1997; Woicik et al., 2009). Finally, Conrod et al. (2000) reported that the risk for cannabis abuse was equal across the four personality types in a sample of adult female substance abusers. One possible explanation for the lack of consistent findings is the considerable heterogeneity in cannabis use motives (Simons, Correia, Carey, & Borsari, 1998). In fact, distinct personality risk factors may be associated with different cannabis use motives. Thus, the purpose of the present study was to begin to explore whether I/H, AS, SS, and IMP are associated with different motives for using cannabis. 1. Method 1.1. Participants One hundred seventy seven (105 male) adult cannabis users were recruited from the Halifax, Nova Scotia community, through internet advertisements as part of a larger study (Olthuis, Darredeau, & Barrett, 2013). The only inclusion criterion was a history of cannabis use. Participants ranged in age from 18 to 59 years (mean = 27.4 years; SD = 9.5 years). 1.2. Procedure After giving consent, participants were interviewed privately by a trained research assistant. They were asked to report their age of first cannabis use, use in the past 30 days, total number of days used, and whether they had ever co-administered cannabis with another substance. One portion of the interview investigated participants' motives for cannabis use. Participants received a motives card that listed 29 potential reasons for cannabis use. These reasons were author-compiled based on a review of the literature as well as pilot interviews with several cannabis users. Participants were asked to recall all instances of cannabis use in their lifetime and to indicate whether they had ever used cannabis for each of the 29 motives in turn. Participants followed along using the motives card and responded either “yes” or “no” to each motive. A list of the motives along with rates of endorsement in the sample is presented in Table 1. At the end of the interview, participants completed the Substance Use Risk Profile Scale (SURPS; Woicik et al., 2009), a 23-item scale that measures the four distinct personality risk factors in the model of substance use risk of Conrod et al. (2000): I/H, AS, SS, and IMP. The SURPS has been shown to possess excellent psychometric properties (Krank et al., 2011; Woicik et al., 2009). The alphas for the SURPS scales ranged from acceptable (.70 for AS) to very good (.88 for I/H) in the present sample. 2. Results As shown in Table 2, there was a high degree of variability in the number of lifetime uses of cannabis reported by participants. The mean age participants began using cannabis was 15.2 (SD = 3.6) years, and 176 (99.4%) participants reported using other drugs or alcohol while under the influence of cannabis at least once in their lifetime. In order to identify the core cannabis use motive dimensions, we conducted a principal components analysis with Varimax rotation on
Table 1 Motives for cannabis use and number of participants who responded ‘yes’ to having used cannabis for each motive in order from most to least commonly endorsed. Item number/Item content
n/177
%
2. To get high/stoned/drunk/buzzed 24. To have fun 25. To relax 1. Out of curiosity 19. To celebrate 15. To enjoy the feeling 10. To help with sleep 22. To see things differently/expand awareness 11. To reduce anxiety 20. To be more creative 18. To help with feeling down 16. To heighten senses 12. To reduce pain 23. To forget about problems/as an escape 28. Because it was safer than other drugs 26. To be more open to experiences 4. To increase the effects of another drug 21. To help socialize 6. To study or concentrate 3. To fit in with peers 29. Because it was easier to get than other drugs 27. For sexual reasons 5. To decrease the effects of another drug 13. To avoid withdrawal from cannabis 17. To feel more confident 14. To help with withdrawal from another drug 8. To give you more energy 7. To stay awake 9. To reduce appetite/manage weight
176 172 172 170 170 169 142 131 131 128 126 125 122 117 116 110 107 104 93 93 87 75 70 54 48 45 42 28 18
99 97 97 96 96 95 80 74 74 72 71 71 69 66 66 62 60 59 53 53 49 42 40 31 27 25 24 16 10
the 29 cannabis use motive items. The number of factors to retain was determined using parallel analysis, a more stringent method than the Kaiser's (1961) eigenvalues N 1.00 criterion (O'Connor, 2000). We used orthogonal rotation in order to identify uncorrelated, distinct cannabis use motives. Four components were retained as indicated by both mean and 95th percentile eigenvalues criteria in the parallel analysis; the four components explained 37.6% of the item score variance. Examination of salient factor loadings suggested that the first component pertained to enhancement motives (i.e., strong loadings from “to have fun”, “to enjoy the feeling”), the second to expansion motives (i.e., strong loadings from “to see things differently/expand awareness”, “to be more creative”), the third to conformity motives (i.e., strong loadings from “to fit in with peers”, “to help socialize”), and the fourth to coping motives (i.e., strong loadings from “to help when feeling down”, “to forget about problems/as an escape”). The rotated component matrix is available from the corresponding author upon request. We then correlated factor scores from the principal components analysis with SURPS personality scales. To account for multiple testing, we used a Bonferroni-adjusted alpha level of p = .01 (.05/4 motive factors) for determining statistical significance; correlations at the unadjusted alpha level of p = .05 were interpreted as trends. SS was significantly positively associated with expansion motives (r = .259, p = .001), AS was significantly positively associated with conformity motives (r = .226, p = .003) and significantly negatively associated with expansion motives (r = − .188, p = .01), and I/H was significantly Table 2 Number of days cannabis was used by participants in their lifetime. Number of days
n/177
%
1–5 6–10 11–20 21–50 51–100 101–500 N500
3 6 3 5 12 28 120
1.7 3.4 1.7 2.8 6.8 15.8 67.8
K. Hecimovic et al. / Addictive Behaviors 39 (2014) 729–732
positively associated with coping motives (r = .184, p = .01). There was also a trend for AS to be positively associated with coping motives (r = .173, p = .02). No additional significant associations or trends were observed. Next we conducted further exploratory analyses at the item level to determine whether the SURPS personality factors were associated with particular cannabis use motives. Specifically, independent samples ttests were conducted to compare each of the four SURPS scores between groups of individuals who endorsed versus denied each cannabis use motive item. To account for multiple testing, we used a Bonferroniadjusted alpha level of p = .002 (.05/29 motives items); group differences at p = .01 were interpreted as trends. As shown in Fig. 1a, those endorsing the motives “to see things differently/expand awareness”, t(174) = 3.45, p = .001, and “to be more creative”, t(175) = 3.59, p b .001, had significantly higher SS scores than those denying these motives. As shown in Fig. 1b, those endorsing the motive “to forget about problems/as an escape”, t(170) = 3.75, p b .001, had significantly higher AS scores than those denying this motive. Similar trends for higher AS scores were seen among those endorsing the motives “to help when feeling down”, t(169) = 2.52, p = .01, and “to help socialize”, t(169) = 2.57, p = .01. As seen in Fig. 1c, those endorsing the motive “to help socialize”, t(172) = 3.08, p = .002, had significantly higher I/H scores than those denying this motive. A similar trend for higher I/H scores was seen among those endorsing the motive “to help when feeling down”, t(172) = 2.84, p = .005. As shown in Fig. 1d, those endorsing the motive “because it was easier to get than other drugs”, t(173) = 3.46, p = .001, had significantly higher IMP scores than those denying this motive. A similar trend for higher IMP scores was seen among those endorsing the motive “to help when
**
Mean I/H scores
Yes
Mean AS scores
No
To see things differently/ expand awareness
c)
**
Motives for Cannabis use 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5
d) No
To help when feeling down
The present study found that the four personality risk factors in the personality risk model of Conrod et al. (2000)were associated with different motives for cannabis use. I/H was associated with coping motives and AS also showed a trend for an association with coping motives. These findings are congruent with previous literature linking I/H and AS to the use of substances to help cope with negative emotional states (Conrod et al., 2000; Woicik et al., 2009). Further investigation at the item level revealed AS to be significantly correlated with the motive “to forget about problems/as an escape” while both AS and I/H tended to be associated with “to help socialize” and “to help when feeling down”. The similarities between the motives may be due to individuals with high AS or I/H using substances for negative reinforcement (Conrod et al., 2000; Woicik et al., 2009). However, in the analyses with the cannabis use motive factor scores, only AS and not I/H was associated with conformity motives for cannabis use, which is consistent with evidence that cannabis may be used as a means to reduce social anxiety specifically (Comeau et al., 2001). Elevations in SS were positively associated with the expansion motives factor for cannabis use. At the item level, individuals high in SS reported using cannabis for the motives “to see things differently/expand awareness” and “to be more creative”. Simons et al. (1998) suspected that cannabis use is associated with expansion motives because of its psychedelic properties; however the present study suggests that it
**
To help socialize
Yes No
*
To help when feeling down
Yes
*
3. Discussion
To be more creative
Motives for Cannabis use 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7
feeling down”, t(173) = 2.83, p = .005. No additional significant associations or trends were observed.
b)
Motives for Cannabis use 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6
Mean IMP scores
Mean SS scores
a)
731
*
**
To help socialize
To forget about problems / as an escape
Motives for Cannabis use 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5
Yes No
*
**
To help when feeling down Because it was easier to get than other drugs
Fig. 1. Mean SURPS scores with standard error for those who answered ‘yes’ or ‘no’ to cannabis use motives. ** = significant group difference (p b .002), * = trend toward group difference (p b .01).
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K. Hecimovic et al. / Addictive Behaviors 39 (2014) 729–732
might just be a certain subset of cannabis users who are motivated by such properties. Finally, IMP was not found to be associated with any of the four components of cannabis use motives overall. This was not unexpected given the findings of Woicik et al. (2009) that individuals characterized by this personality trait will use alcohol with a non-specific pattern of motives. However, at the item level, IMP was associated with the use of cannabis because it was easily available, suggesting that impulsive individuals may use cannabis due to temptations related to ready accessibility. Interestingly, a trend also emerged with the motive “to help when feeling down”. This finding suggests that individuals high in IMP are also using cannabis for self-medication. Impulsive individuals are marked by their inability to weigh immediate reward against long term consequences (Conrod et al., 2000; Field et al., 2007) and might use cannabis to relieve negative affect in a quick and easy manner or as a short term solution to problems. The present study involved a large sample of cannabis users varying in demographic features. However, this study is not without limitations, with the strongest being potential recall biases since it is unlikely that participants could recall every time they used cannabis. Second, the motives measure asked whether participants had ever used cannabis for a number of motives. Associations with personality may have proved stronger if motives were rated on a continuum of relative frequency of cannabis use for each motive. In addition, a new motives measure was developed for the present study in order to include potential motives that have not been investigated in previous studies such as availability. Despite this, it is interesting to note that the factor analysis revealed four core motivational components that closely mirrored those found in studies that have used validated cannabis motives questionnaires (Comeau et al., 2001; Simons et al., 1998). Moreover, although the present study assessed personality risk factors, it did not include a direct measure of psychopathology. One might expect clinical samples to demonstrate a stronger association between personality risk factors and motives for cannabis use; however the extent to which the present findings can be extended to those experiencing clinically significant symptoms remains unknown. It would also be interesting for future research to examine whether the observed associations vary by sex. Finally, it is likely that personality risk factors interact with a variety of contextual and environmental factors to motivate cannabis use. While such potential moderating factors were beyond the scope of this study, the present findings may provide a useful starting point for understanding the heterogeneity in cannabis use motives and risk factors. By understanding how individual differences are associated with different cannabis use motives, individualized prevention and treatment plans may be developed (see Conrod, Stewart, Comeau, & Maclean, 2006). For instance, individuals high in AS might be taught less risky ways of dealing with their underlying anxiety and need to fit in, while individuals high in SS might be encouraged to explore other less risky means of enhancing creativity without the use of cannabis. By tailoring prevention and treatment interventions specifically to personality types, individuals may develop more suitable ways of managing their motivational tendencies for drug use.
Role of funding sources Funding for this study was provided a Canadian Institutes of Health Research (CIHR) Catalyst Grant. CIHR had no role in the study design, collection, analysis or interpretation of the data, writing of the manuscript, or the decision to submit the paper for publication. Contributors Karen Hecimovic completed the analyses and wrote the first draft of the manuscript. Sean Barrett, Christine Darredeau and Sherry Stewart designed the study and wrote the protocol. All authors contributed to and have approved the final manuscript. Conflict of interest There are no conflicts of interest.
References Adams, J. B., Heath, A. J., Young, S. E., Hewitt, J. K., Corley, R. P., & Stallings, M. C. (2003). Relationships between personality and preferred substance and motivations for use among adolescent substance abusers. American Journal of Drug and Alcohol Abuse, 29(3), 691–712. http://dx.doi.org/10.1081/ADA-120023465. Arnett, J. (1994). Sensation seeking: A new conceptualization and a new scale. Personality and Individual Differences, 16, 289–296. Health Canada (2011). Canadian Alcohol and Drug Use Monitoring Survey. Retrieved from Health Canada website: http://www.hc-sc.gc.ca/hc-ps/drugs-drogues/stat/ _2011/summary-sommaire-eng.php#a3 Chabrol, H., Ducongé, E., Casas, C., Roura, C., & Carey, K. B. (2005). Relations between cannabis use and dependence, motives for cannabis use and anxious, depressive and borderline symptomatology. Addictive Behaviors, 30(4), 829–840. http://dx.doi.org/ 10.1016/j.addbeh.2004.08.027. Comeau, M. N., Stewart, S. H., & Loba, P. (2001). The relations of trait anxiety, anxiety sensitivity, and sensation seeking to adolescents' motivations for alcohol, cigarette and marijuana use. Addictive Behaviors, 26(6), 803–825. Conrod, P. J., Pihl, R. O., Stewart, S. H., & Dongier, M. (2000). Validation of a system of classifying female substance abusers on the basis of personality and motivational risk factors for substance abuse. Psychology of Addictive Behaviors, 14(3), 243 − 256. Conrod, P. J., Stewart, S. H., Comeau, N., & Maclean, A. (2006). Efficacy of cognitive– behavioral interventions targeting personality risk factors for youth alcohol misuse. Journal of Clinical Child & Adolescent Psychology, 35(4), 550–563. http://dx.doi.org/ 10.1207/s15374424jccp3504_6. Field, M., Christiansen, P., Cole, J., & Goudie, A. (2007). Delay discounting and the alcohol Stroop in heavy drinking adolescents. Addiction, 102(4), 579–586. http://dx.doi.org/ 10.1111/j.1360-0443.2007.01743.x. Kaiser, H. F. (1961). A note on Guttman's lower bound for the number of common factors. Multivariate Behavioral Research, 1, 249–276. Krank, M., Stewart, S. H., O'Connor, R., Woicik, P. B., Wall, A., & Conrod, P. J. (2011). Structural, concurrent, and predictive validity of the Substance Use Risk Profile Scale in early adolescence. Addictive Behaviors, 36(1-2), 37–46. http://dx.doi.org/ 10.1016/j.addbeh.2010.08.010. O'Connor, B. P. (2000). SPSS and SAS programs for determining the number of components using parallel analysis and Velicer's MAP test. Behavior Research Methods, Instrumentation, and Computers, 32, 396–402. Olthuis, J. V., Darredeau, C., & Barrett, S. P. (2013). Substance use initiation: The role of simultaneous polysubstance use. Drug and Alcohol Review, 32(1), 67–71. http://dx.doi.org/10.1111/j.1465-3362.2012.00470.x. Sher, K. J., Bartholow, B.D., & Wood, M.D. (2000). Personality and substance use disorders: A prospective study. Journal of Consulting and Clinical Psychology, 68(5), 818–829. http://dx.doi.org/10.1037/0022-006X.68.5.818. Simons, J., Correia, C. J., Carey, K. B., & Borsari, B. E. (1998). Validating a five-factor marijuana motives measure: Relations with use, problems, and alcohol motives. Journal of Counseling Psychology, 45, 265–273. Stewart, S. H., Karp, J., Pihl, R. O., & Peterson, R. A. (1997). Anxiety sensitivity and self-reported reasons for drug use. Journal of Substance Abuse, 9, 223–240. http://dx.doi.org/ 10.1016/S0899-3289(97)90018-3. Woicik, P. B., Stewart, S. H., Pihl, P. O., & Conrod, P. J. (2009). The Substance Use Risk Profile Scale: A scale measuring traits linked to reinforcement-specific substance use profiles. Addictive Behaviors, 34(12), 1042–1055.
Contents lists available at ScienceDirect
Addictive Behaviors
Short Communication
Cannabis use motives and personality risk factors Karen Hecimovic, Sean P. Barrett ⁎, Christine Darredeau, Sherry H. Stewart Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
H I G H L I G H T S • • • • •
Study findings suggest that motives for cannabis use vary according to personality risk factors. Anxiety sensitivity was associated with cannabis use for conformity motives. Introversion/Hopelessness was associated with cannabis use for coping motives. Sensation seeking was associated with cannabis use for expansion motives. IMP was associated with using cannabis because it was readily available.
a r t i c l e Keywords: Cannabis Motives Personality
i n f o
a b s t r a c t According to the model of substance abuse of Conrod, Pihl, Stewart, and Dongier (2000), four personality factors (i.e., anxiety sensitivity [AS], introversion/hopelessness [I/H], sensation seeking [SS], and impulsivity [IMP]) are associated with elevated risk for substance use/misuse, with each personality factor being related to preference for particular drugs of abuse (e.g., AS with anxiolytics). However, cannabis use has not been consistently linked to any one of these personality factors. This may be due to the heterogeneity in cannabis use motives. The present study explored the association between these four personality risk factors and different cannabis use motives. Cannabis users completed an interview about their motives for cannabis use as well as the self-report Substance Use Risk Profile Scale (SURPS; Woicik, Conrod, Stewart, & Pihl, 2009), which measures the four personality risk factors. Results showed that AS was associated with conformity motives and I/H was associated with coping motives for cannabis use. SS was positively associated with expansion motives and IMP was associated with drug availability motives. Thus, personality risk factors in the model of Conrod et al. (2000) are associated with distinct cannabis use motives in a pattern consistent with theory. © 2013 Elsevier Ltd. All rights reserved.
Cannabis is the most widely used illicit substance in Canada, with 39.4% of those aged 15 years or older reporting lifetime use (Health Canada, 2011). Despite this prevalence, relatively little is known about cannabis use risk factors. Recently, research has linked different forms of drug use to different personality characteristics (e.g., Adams et al., 2003; Sher, Bartholow, & Wood, 2000). One example is the model of Conrod, Pihl, Stewart, and Dongier (2000), which attributes substance use/misuse to four distinct personality risk profiles: anxiety sensitivity (AS), introversion/hopelessness (I/H), sensation seeking (SS), and impulsivity (IMP). Each of these traits has been linked with preference for a specific type of drug of abuse and with distinct substance use motivations using both cross-sectional (e.g., Woicik, Stewart, Pihl, & Conrod, 2009) and longitudinal research designs (e.g., Krank et al., 2011). These associations have been observed in both adult (e.g., Conrod et al., 2000; ⁎ Corresponding author at: Department of Psychology and Neuroscience, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada. Tel.: +1 902 494 2956; fax: +1 902 494 6585. E-mail address: [email protected] (S.P. Barrett). 0306-4603/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.addbeh.2013.11.025
Woicik et al., 2009) and adolescent (e.g., Krank et al., 2011; Woicik et al., 2009) samples. Two of these personality traits, AS and I/H, have been associated with substance use as a way of dealing with negative affect (Woicik et al., 2009). For example, elevations in AS have been linked with anxiolytics use to manage anxiety, while elevations in I/H have been associated with the use of analgesics to escape depressed affect (Conrod et al., 2000). Moreover, in both adolescent and adult populations, high levels of AS and I/H have been linked to alcohol use as a means of coping (Comeau, Stewart, & Loba, 2001; Conrod et al., 2000; Woicik et al., 2009). A third personality dimension, SS, has been linked with higher rates of alcohol use to increase positive emotions and experiences (Conrod et al., 2000; Woicik et al., 2009). Finally, IMP is characterized by disinhibited behavior when presented with positive reinforcement. Field, Christiansen, Cole, and Goudie (2007) found that adolescents who are heavy drinkers exhibit impulsive behaviors, and Woicik et al. (2009) reported similar findings in an adult population, with high IMP being associated with a non-specific pattern of motives for heavy alcohol use. Moreover, IMP has been linked with the use of cocaine and other psychostimulants —drugs that deliver immediate reward (Conrod et al., 2000; Woicik et al., 2009).
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K. Hecimovic et al. / Addictive Behaviors 39 (2014) 729–732
To date, cannabis use has not been consistently linked to any specific personality dimension in the model of Conrod et al. (2000). For example, findings on the association between SS and cannabis use have been mixed. Arnett (1994) found cannabis use to be positively correlated with SS. Similarly, Woicik et al. (2009) found SS to be positively correlated with the use of drugs related to stimulating, mood-enhancing effects, including cannabis and other hallucinogens. In contrast, Comeau et al. (2001) found no correlation between SS and cannabis use in an adolescent sample. While some studies have shown no relation between anxious or depressive personalities and cannabis use (Chabrol, Ducongé, Casas, Roura, & Carey, 2005), others have found AS to be negatively correlated with cannabis use (Stewart, Karp, Pihl, & Peterson, 1997; Woicik et al., 2009). Finally, Conrod et al. (2000) reported that the risk for cannabis abuse was equal across the four personality types in a sample of adult female substance abusers. One possible explanation for the lack of consistent findings is the considerable heterogeneity in cannabis use motives (Simons, Correia, Carey, & Borsari, 1998). In fact, distinct personality risk factors may be associated with different cannabis use motives. Thus, the purpose of the present study was to begin to explore whether I/H, AS, SS, and IMP are associated with different motives for using cannabis. 1. Method 1.1. Participants One hundred seventy seven (105 male) adult cannabis users were recruited from the Halifax, Nova Scotia community, through internet advertisements as part of a larger study (Olthuis, Darredeau, & Barrett, 2013). The only inclusion criterion was a history of cannabis use. Participants ranged in age from 18 to 59 years (mean = 27.4 years; SD = 9.5 years). 1.2. Procedure After giving consent, participants were interviewed privately by a trained research assistant. They were asked to report their age of first cannabis use, use in the past 30 days, total number of days used, and whether they had ever co-administered cannabis with another substance. One portion of the interview investigated participants' motives for cannabis use. Participants received a motives card that listed 29 potential reasons for cannabis use. These reasons were author-compiled based on a review of the literature as well as pilot interviews with several cannabis users. Participants were asked to recall all instances of cannabis use in their lifetime and to indicate whether they had ever used cannabis for each of the 29 motives in turn. Participants followed along using the motives card and responded either “yes” or “no” to each motive. A list of the motives along with rates of endorsement in the sample is presented in Table 1. At the end of the interview, participants completed the Substance Use Risk Profile Scale (SURPS; Woicik et al., 2009), a 23-item scale that measures the four distinct personality risk factors in the model of substance use risk of Conrod et al. (2000): I/H, AS, SS, and IMP. The SURPS has been shown to possess excellent psychometric properties (Krank et al., 2011; Woicik et al., 2009). The alphas for the SURPS scales ranged from acceptable (.70 for AS) to very good (.88 for I/H) in the present sample. 2. Results As shown in Table 2, there was a high degree of variability in the number of lifetime uses of cannabis reported by participants. The mean age participants began using cannabis was 15.2 (SD = 3.6) years, and 176 (99.4%) participants reported using other drugs or alcohol while under the influence of cannabis at least once in their lifetime. In order to identify the core cannabis use motive dimensions, we conducted a principal components analysis with Varimax rotation on
Table 1 Motives for cannabis use and number of participants who responded ‘yes’ to having used cannabis for each motive in order from most to least commonly endorsed. Item number/Item content
n/177
%
2. To get high/stoned/drunk/buzzed 24. To have fun 25. To relax 1. Out of curiosity 19. To celebrate 15. To enjoy the feeling 10. To help with sleep 22. To see things differently/expand awareness 11. To reduce anxiety 20. To be more creative 18. To help with feeling down 16. To heighten senses 12. To reduce pain 23. To forget about problems/as an escape 28. Because it was safer than other drugs 26. To be more open to experiences 4. To increase the effects of another drug 21. To help socialize 6. To study or concentrate 3. To fit in with peers 29. Because it was easier to get than other drugs 27. For sexual reasons 5. To decrease the effects of another drug 13. To avoid withdrawal from cannabis 17. To feel more confident 14. To help with withdrawal from another drug 8. To give you more energy 7. To stay awake 9. To reduce appetite/manage weight
176 172 172 170 170 169 142 131 131 128 126 125 122 117 116 110 107 104 93 93 87 75 70 54 48 45 42 28 18
99 97 97 96 96 95 80 74 74 72 71 71 69 66 66 62 60 59 53 53 49 42 40 31 27 25 24 16 10
the 29 cannabis use motive items. The number of factors to retain was determined using parallel analysis, a more stringent method than the Kaiser's (1961) eigenvalues N 1.00 criterion (O'Connor, 2000). We used orthogonal rotation in order to identify uncorrelated, distinct cannabis use motives. Four components were retained as indicated by both mean and 95th percentile eigenvalues criteria in the parallel analysis; the four components explained 37.6% of the item score variance. Examination of salient factor loadings suggested that the first component pertained to enhancement motives (i.e., strong loadings from “to have fun”, “to enjoy the feeling”), the second to expansion motives (i.e., strong loadings from “to see things differently/expand awareness”, “to be more creative”), the third to conformity motives (i.e., strong loadings from “to fit in with peers”, “to help socialize”), and the fourth to coping motives (i.e., strong loadings from “to help when feeling down”, “to forget about problems/as an escape”). The rotated component matrix is available from the corresponding author upon request. We then correlated factor scores from the principal components analysis with SURPS personality scales. To account for multiple testing, we used a Bonferroni-adjusted alpha level of p = .01 (.05/4 motive factors) for determining statistical significance; correlations at the unadjusted alpha level of p = .05 were interpreted as trends. SS was significantly positively associated with expansion motives (r = .259, p = .001), AS was significantly positively associated with conformity motives (r = .226, p = .003) and significantly negatively associated with expansion motives (r = − .188, p = .01), and I/H was significantly Table 2 Number of days cannabis was used by participants in their lifetime. Number of days
n/177
%
1–5 6–10 11–20 21–50 51–100 101–500 N500
3 6 3 5 12 28 120
1.7 3.4 1.7 2.8 6.8 15.8 67.8
K. Hecimovic et al. / Addictive Behaviors 39 (2014) 729–732
positively associated with coping motives (r = .184, p = .01). There was also a trend for AS to be positively associated with coping motives (r = .173, p = .02). No additional significant associations or trends were observed. Next we conducted further exploratory analyses at the item level to determine whether the SURPS personality factors were associated with particular cannabis use motives. Specifically, independent samples ttests were conducted to compare each of the four SURPS scores between groups of individuals who endorsed versus denied each cannabis use motive item. To account for multiple testing, we used a Bonferroniadjusted alpha level of p = .002 (.05/29 motives items); group differences at p = .01 were interpreted as trends. As shown in Fig. 1a, those endorsing the motives “to see things differently/expand awareness”, t(174) = 3.45, p = .001, and “to be more creative”, t(175) = 3.59, p b .001, had significantly higher SS scores than those denying these motives. As shown in Fig. 1b, those endorsing the motive “to forget about problems/as an escape”, t(170) = 3.75, p b .001, had significantly higher AS scores than those denying this motive. Similar trends for higher AS scores were seen among those endorsing the motives “to help when feeling down”, t(169) = 2.52, p = .01, and “to help socialize”, t(169) = 2.57, p = .01. As seen in Fig. 1c, those endorsing the motive “to help socialize”, t(172) = 3.08, p = .002, had significantly higher I/H scores than those denying this motive. A similar trend for higher I/H scores was seen among those endorsing the motive “to help when feeling down”, t(172) = 2.84, p = .005. As shown in Fig. 1d, those endorsing the motive “because it was easier to get than other drugs”, t(173) = 3.46, p = .001, had significantly higher IMP scores than those denying this motive. A similar trend for higher IMP scores was seen among those endorsing the motive “to help when
**
Mean I/H scores
Yes
Mean AS scores
No
To see things differently/ expand awareness
c)
**
Motives for Cannabis use 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5
d) No
To help when feeling down
The present study found that the four personality risk factors in the personality risk model of Conrod et al. (2000)were associated with different motives for cannabis use. I/H was associated with coping motives and AS also showed a trend for an association with coping motives. These findings are congruent with previous literature linking I/H and AS to the use of substances to help cope with negative emotional states (Conrod et al., 2000; Woicik et al., 2009). Further investigation at the item level revealed AS to be significantly correlated with the motive “to forget about problems/as an escape” while both AS and I/H tended to be associated with “to help socialize” and “to help when feeling down”. The similarities between the motives may be due to individuals with high AS or I/H using substances for negative reinforcement (Conrod et al., 2000; Woicik et al., 2009). However, in the analyses with the cannabis use motive factor scores, only AS and not I/H was associated with conformity motives for cannabis use, which is consistent with evidence that cannabis may be used as a means to reduce social anxiety specifically (Comeau et al., 2001). Elevations in SS were positively associated with the expansion motives factor for cannabis use. At the item level, individuals high in SS reported using cannabis for the motives “to see things differently/expand awareness” and “to be more creative”. Simons et al. (1998) suspected that cannabis use is associated with expansion motives because of its psychedelic properties; however the present study suggests that it
**
To help socialize
Yes No
*
To help when feeling down
Yes
*
3. Discussion
To be more creative
Motives for Cannabis use 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7
feeling down”, t(173) = 2.83, p = .005. No additional significant associations or trends were observed.
b)
Motives for Cannabis use 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6
Mean IMP scores
Mean SS scores
a)
731
*
**
To help socialize
To forget about problems / as an escape
Motives for Cannabis use 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5
Yes No
*
**
To help when feeling down Because it was easier to get than other drugs
Fig. 1. Mean SURPS scores with standard error for those who answered ‘yes’ or ‘no’ to cannabis use motives. ** = significant group difference (p b .002), * = trend toward group difference (p b .01).
732
K. Hecimovic et al. / Addictive Behaviors 39 (2014) 729–732
might just be a certain subset of cannabis users who are motivated by such properties. Finally, IMP was not found to be associated with any of the four components of cannabis use motives overall. This was not unexpected given the findings of Woicik et al. (2009) that individuals characterized by this personality trait will use alcohol with a non-specific pattern of motives. However, at the item level, IMP was associated with the use of cannabis because it was easily available, suggesting that impulsive individuals may use cannabis due to temptations related to ready accessibility. Interestingly, a trend also emerged with the motive “to help when feeling down”. This finding suggests that individuals high in IMP are also using cannabis for self-medication. Impulsive individuals are marked by their inability to weigh immediate reward against long term consequences (Conrod et al., 2000; Field et al., 2007) and might use cannabis to relieve negative affect in a quick and easy manner or as a short term solution to problems. The present study involved a large sample of cannabis users varying in demographic features. However, this study is not without limitations, with the strongest being potential recall biases since it is unlikely that participants could recall every time they used cannabis. Second, the motives measure asked whether participants had ever used cannabis for a number of motives. Associations with personality may have proved stronger if motives were rated on a continuum of relative frequency of cannabis use for each motive. In addition, a new motives measure was developed for the present study in order to include potential motives that have not been investigated in previous studies such as availability. Despite this, it is interesting to note that the factor analysis revealed four core motivational components that closely mirrored those found in studies that have used validated cannabis motives questionnaires (Comeau et al., 2001; Simons et al., 1998). Moreover, although the present study assessed personality risk factors, it did not include a direct measure of psychopathology. One might expect clinical samples to demonstrate a stronger association between personality risk factors and motives for cannabis use; however the extent to which the present findings can be extended to those experiencing clinically significant symptoms remains unknown. It would also be interesting for future research to examine whether the observed associations vary by sex. Finally, it is likely that personality risk factors interact with a variety of contextual and environmental factors to motivate cannabis use. While such potential moderating factors were beyond the scope of this study, the present findings may provide a useful starting point for understanding the heterogeneity in cannabis use motives and risk factors. By understanding how individual differences are associated with different cannabis use motives, individualized prevention and treatment plans may be developed (see Conrod, Stewart, Comeau, & Maclean, 2006). For instance, individuals high in AS might be taught less risky ways of dealing with their underlying anxiety and need to fit in, while individuals high in SS might be encouraged to explore other less risky means of enhancing creativity without the use of cannabis. By tailoring prevention and treatment interventions specifically to personality types, individuals may develop more suitable ways of managing their motivational tendencies for drug use.
Role of funding sources Funding for this study was provided a Canadian Institutes of Health Research (CIHR) Catalyst Grant. CIHR had no role in the study design, collection, analysis or interpretation of the data, writing of the manuscript, or the decision to submit the paper for publication. Contributors Karen Hecimovic completed the analyses and wrote the first draft of the manuscript. Sean Barrett, Christine Darredeau and Sherry Stewart designed the study and wrote the protocol. All authors contributed to and have approved the final manuscript. Conflict of interest There are no conflicts of interest.
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