Personal and Social Characteristics Differentiating Adoptive Relatives of Schizophrenics and Nonschizophrenics: A Preliminary Report Based on Interviews John
Rimmer, Sandy David Rosenthal,
Cole, Bjorn Jacobson, Seymour S. Kety, Fini Schulsinger, and Paul Wender
M
ANY INVESTIGATORS have reported a variety of traits. personal characteristics, and communications styles to occur more frequently in the families of schizophrenics than in other populations. Among these are the report that 6057 of mothers of schizophrenics show overprotection or rejection ’ and the report of more anxiety and aggressive traits in schizophrenics’ parents.’ One investigator has reported that all families that have reared a schizophrenic are seriously disturbed” and that in 48% of all families rearing a schizophrenic. one severely unstable parent is present. d Others have reported schizophrenic mothers as less critical” and more often quiet and with good affect than control mothers.” Hirsch and Leff, in a review of the literature regarding the abnormalities in the parents of schizophrenics. find fault with many of these studies of schizophrenic families due to poor controls and the possible contamination of results by genetic relationships.’ As part of a larger study, in Denmark, of genetic.
social, and other traits involved in the etiology of schizophrenia, extensive interview data were collected on the adoptive and biologic relatives-mothers. fathers, and siblingsof a sample of schizophrenics and of a control group of nonschizophrenics.“,!’ Use of information about the adoptees families’ relatives, obtained in the Danish study, provides the opportunity for an examination of personal and social traits using a carefully drawn control free of genetic contamination. Previous papers have reported a significant increase in schizophrenia in the biologic relatives of schizophrenics contrasted to biologic controls and no significant difference in the rate of schizophrenia between index and control adoptive relatives. Continuing the examination of factors that might be related
Comprehensive
Psychiatry,
Vol.
20, No. 2 (March/April).
1979
151
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ET AL.
to schizophrenia, the following paper will report the results obtained in the preliminary examination of those social and environmental variables that were found to differentiate between those who reared a schizophrenic and those who didn’t, and those reared with a schizophrenic and those not, in all cases lacking a biologic relationship to a schizophrenic. MATERIALS
AND METHODS
A sample of 33 schizophrenic adoptees. diagnosed consensually by four raters on the basis of hospital transcripts, was selected from all Danish adoptees in the greater Copenhagen area in Denmark during 1924-1947. A matched control group of adoptees was also drawn from this pool. The method utilized in sample selection and diagnostic criterion for schizophrenia has been described in previous reports .R,YSuffice it to say the controls were matched with schizophrenics by sex. age at transfer to adoptive parents, and age and socioeconomic status of the adoptive family using a Danish scale that combined income. fortune. occupation, and address. Following the selection of the adoptees, adoptive relatives were identified using the Folkeregister. The Folkeregister is a population address register maintained by law in Denmark. If possible, all relatives located were personally interviewed using an extensive interview. Sufficient information was collected in 94% of these relatives to permit a judgment regarding a diagnosis of psychiatric illness. There was no difference in the proportion of the two groups interviewed. In addition to an extensive interview, which included psychiatric history and symptoms, information about any treatment for psychiatric problems also was obtained. As mentioned in prior reportss.rO this resulted, in some cases, in the diagnosis of some adoptee relatives as schizophrenic, leading to reassignment of categories for the analysis of this paper. In the analysis that follows, the adoptee relatives were separated into the following groups to keep separate the effect of rearing or being reared with a schizophrenic. with no possibility of a genetic influence. (I) Mothers and fathers of schizophrenic adoptees were mothers and fathers who had reared a child who was diagnosed as a schizophrenic to whom they were not biologically related. (2) Mothers and fathers of control adoptees were mothers and fathers who reared a child who was not diagnosed as schizophrenic to whom they were not biologically related. (3) Adoptees schizophrenics’ siblings were those not biologically related to a schizophrenic, reared with a child who received a diagnosis of schizophrenia to whom they were not biologically related. (4) Control adoptees siblings were those not biologically related to a schizophrenic. reared with a child who did not receive a diagnosis of schizophrenia, to whom they were not biologically related. Fathers of schizophrenics as a group have been relatively unexamined, as contrasted to the research on schizophrenic mothers, although recent research suggests that fathers could play a pivotal role.’ Siblings of a schizophrenic also represent a group about which there is relatively little research. The siblings represent a population which should reflect the pathology of parents, as well as providing a source of information regarding parents’ relationships to each other. to the schizophrenic. and to the sibling himself. Following the categorization of the adoptees relatives, the variables from the original interview were subjected to analysis to find those for which there was a significant difference t.05. using Fisher’s exact p) between index and control. The variable categories and number of variables in each category examined are given in Table I. The variables selected in each group comparison were then subjected to further analysis using the discriminants analysis subroutine of the Statistical Package for the Social Sciences (SPSS).” Discriminant analysis is an analytic technique. highly analagous to multiple regression that seeks to select from a large set of variables a smaller set that will provide maximum discrimination between groups, in this case index and control relatives. It first selects new variables after controlling for the effects of variables already in the equation, including rejecting a variable once selected. The level of significance employed in this study for selection and/or rejection was .50 or lower. In addition to selection of those variables that provide the best discrimination of group membership, other information is provided. The first is the standardized discriminant coefficient for each variable selected. This provides information on the relative contribution of the variable to discriminations given the other variables in the equation.
CHARACTERISTICS
OF RELATIVES
Second is the classification analysis.
the classification
the discriminant accuracy check
function
of individuals
into groups using the discriminant
was the comparison obtained
from
of the variables
of known
categories
the same individuals.
in this case than if classification
on the accuracy
153
OF SCHIZOPHRENICS
is applied
selected.
coefficients.
For this
against those obtained
One expects
to a new group.
a higher
using
degree
of
but this does supply a rough
The chance accuracy
of prediction
expected
for
two groups is WY.
RESULTS
The first results to be presented are those obtained for adoptive mothers. Table 2 presents variables that differentiated between adoptive mothers who reared a schizophrenic and those who did not. In addition to giving the exact p value, the table indicates the percent of each group positive for the given characteristic. Only four variables differentiated the two groups of mothers. When these variables were subjected to discriminant analysis, two variables were selected as providing discrimination (Table 3). The results in Table 3 indicate that denial Table
1. Categories
and Number of Variables for Analysis
Categories
Number
of Variables
General demographic characteristics of subject and spouse, i.e., education, income, housing, marital history
32
Parents-general demography, Current health Childhood health
60 31 16 14
attitudes, pathology
General childhood, i.e., impression of parents, character of home Character-age O-7 age 7-l 5 Psychopathic traits-age O-7 age 7-15
20 20 27 27 27 30 3 7 9 8 14 12 8 5 41 9 32 4 11 467
Kind of person now Mental health Body image Decisiveness Anal traits Oral traits Aggressive behavior Intellectual functioning Confidence in others Sensitivity to others Sparetime activity Impression by interviewer Impression Interviewer Interviewer Total
of subject’s home
by interview of subject evaluation of thought structure evaluation of ego function
Table 2. Adoptive
Self report as meticulous Adequate voice modulation Denial used as a defense Interviewed alone
Mothers:
Differentiating
Variables
Index
Control
(n = 171
(n = 12)
0% 76% 41% 71%
33% 33% 92% 25%
Exact p One-Talled
.021 ,026 ,007 ,020
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RIMMER
ET AL.
was almost as powerful separating the groups as and that percent of cases were assigned to right group these two The next examined was of adoptive Table 4 the results the first Three variables between those who reared schizophrenic and who did none of variables had selected for When the variables were to discrianalysis, the presented in 5 were The classification of 87% almost identical that obiained mothers. It noteworthy that with aggression,” the most discriminator, according the preliminary of Table is the strong when of the two variables controlled. The analysis was of the siblings of The results in the analysis are in Table It may noted that Table 3. Results of Discriminant Variables Selected
Analysis for Adoptive Weight -.780t -.396
Used denial as a defense Self-report as meticulous
Mothers ACCW3C~"
90%’
*Percent correct and number of misses. tDashes indicate direction.
Table 4. Adoptive
Father: Differentiating
Lived in rented property Dislike responsibility Preoccupied with aggressive thoughts
Table 5. Results of Discriminant:
Variables Control
Index (n = 11)
(n = 14)
Exact p One-Tailed
65% 36% 9%
21% 0% 57%
,041 ,026 ,017
Analysis of Adoptive Fathers
Variables Selected
Weight
ACCWXy'
Likes responsibility Lives in rented property Preoccupied with aggressive thoughts
-.7146t .5676
87%”
--.2751
*Percent correct and number of misses. tDashes indicate direction.
Table 6. Adoptive
Siblings: Differentiating Index In = 10)
Shifting levels of school performance Difference in parents’ attitude between sibling and subject “Normal” attachment to mother Great interest in food Guilt after expression of anger A fast thinker Difficulty establishing confidence in others
Variables Control in = 16)
Exact/~
One-Tailed
60% 30%
19% 0%
,042 ,046
70% 0% 40% 20% 10%
100% 38% 0% 75% 50%
.046 ,035 ,014 ,032 ,045
CHARACTERISTICS
OF RELATIVES
155
OF SCHIZOPHRENICS
one variable from the two preceding analyses is selected, that of difficulty establishing confidence in others. It is surprising that although a significant difference is found for difference in parents’ attitude to subject and siblings (index siblings being schizophrenic). in only 30% of index cases was such a difference reported. The results obtained from the discriminant analysis of these variables is given in Table 7. Three variables were selected with “differences in parents’ attitude” and ‘*guilt after anger” almost twice as strong as “fast thinker.” DISCUSSION The preceding results were obtained in the analysis of variables to identify those that discriminated between those who reared a schizophrenic and those who did not, using a carefully selected control and both groups lacking biologic relation to a schizophrenic. Following identification of those variables for which a statistically significant difference between index and control populations was found, discriminant analysis was employed to select those variables that had the greatest unique contribution to the difference between the index group and the control group. The analysis was nontheoretical and straightforward to find relationships between social, rearing and environmental variables, and schizophrenia. Combinations, interactions, and other theoretical transformations of variables were not undertaken. Therefore. the results do not invalidate any theoretical position, but suggest that it may prove difficult to evaluate a theoretical position from this data since so few significant relations were found. Despite selection of few variables, vet-y high predictive accuracy was obtained for the four groups, ranging from 90% accuracy. using two variables for adoptive mothers, to 87%. with three variables for adoptive fathers. However. using results from a given sample for prediction is biased toward higher accuracy. Unfortunately, the sample was too small for splitting of groups and prediction of membership from one group to the other. Generally, the results did not support any theoretical point of view, and fewer significant associations were obtained than expected on the basis of chance. Although the use of a matched. control population selected for comparison and both populations free of biologic relation to schizophrenia provides a reasonable explanation for the few significant associations. there are other possible explanations for the results. First. retrospective bias in regard to the rearing relatives of the schizophrenic has not been removed. However. the results indicate that rearing a schizophrenic produces parents who do not deny, who are anxious. and who don’t talk Table 7. Results of Discriminant: Variables
Analysis of Adoptive Siblings
Selected
Difference in parents’ attitude between siblings and subject Guilt after expression of anger A fast thinker ‘Percent correct and number of misses. tDash indicates direction.
Weight
.6588 .6133 -.3205t
Accuracy’
88%
’
156
RIMMER
ET AL,
too much. This might be the result of greater contact with psychiatrists or forced evaluation of themselves due to pathology in their offspring. In other studies of adoptive parents’* it has been reported that parents of normal adoptees were found to be guarded, withholding, and evasive in reporting subjective experiences and pathology, while the adoptive parents of schizophrenics were markedly outspoken and free in these areas. However, this openness should result in reports of greater pathology, not less. Second, the fact that the study dealt with adoptees and their families places possible constraints on both the family history of those being adopted as well as on the social background of those who qualify for adoption.‘” This could eliminate the influence of variables strongly associated with schizophrenia in other child-rearing environments. Third, it has been stated that the parental behavior and attitudes involved in the production of schizophrenia may be individually unique and so subtle and complex as to require indepth, extensive interviewing over many months to uncover.3,4 Such traits would be missed by the type of interview used in our study. Such indepth interviewing would be impossible given the limits of this adoption study and would eliminate any blindness regarding who did or did not rear a schizophrenic. Finally, another possible criticism is that important narrative and clinical information has been lost by the use of single variables. In an attempt to evaluate clinically the information collected during the interview, the interviews were read by Dr. Rimmer and individuals were assigned to the index or control category. Edited interviews were used with all references to parents. siblings, or children removed. Although no systematic criteria were used, the subject was assigned to the control category if the following were noted: (1) inconsistent responses, (2) contradictory behavior or responses, (3) evidence of inappropriate or flat affect, (4) striking or unusual living conditions, (5) an unusual or striking observation by the interviewer (BJ), and (6) any indication in narrative portions of interview of some unusual peculiar or bizarre aspect of the subject’s life. Using this method, 84% of parents (p = .0002) were correctly assigned, but only 54% of siblings. The figure for siblings is not surprising, since the best discriminator, according to computer analysis, was removed for edited interviews. The 84% figure for parents is strikingly similar to the 81% accuracy obtained in the computer analysis. Both computer and clinician classification achieved similar levels of accuracy for parents of schizophrenics, and neither supported the stereotype of the schizophrenic parent as frequently reported. CONCLUSION
Previous paper+’ have reported a significant association between schizophrenia in biologic relatives of schizophrenics. This paper examined the role of social environment variables in schizophrenics. To summarize the results: (1) Mothers who reared a schizophrenic in this sample could be characterized as not using denial as a defense and as not reporting themselves as meticulous. These results are in contrast to the much more striking pictures of the schizophrenic mother frequently found in the
157
CHARACTERlSTlCS OF RELATIVES OF SCHIZOPHRENICS
literature. (2) The fathers more closely conform to what might be expected on the basis of a literature review. They may be characterized as disliking responsibility. living in rented property, and not preoccupied with aggression. The last, however, is contrary to some reports of increased aggression in families of schizophrenics. (3) The final group of individuals examined were adoptee siblings. It was hoped that this comparison would yield information on the rearing practices and attitudes of parents that might have been undiscovered in interviews with parents, as well as pathology in those reared by parents who had reared a schizophrenic. The results obtained for the siblings were that they reported a difference between parents’ attitude toward siblings and the subject; they had guilt after expression of anger and were not fast thinkers. None of the parental separation or conflict variables were found to discriminate between the two groups. In addition, the best discriminator, difference in parents’ attitude, was reported by only 3 out of IO siblings. Overall, the results obtained were somewhat surprising. First. at the preliminary level of analysis, many fewer variables were found to differentiate each group than the 46 expected on the basis of change alone, given the number ot variables and the level of significance employed. Second. the variables selected appeared neither consistent nor reflected any theoretical point of view, i.e., no one variable was selected for mothers. fathers. parents. and siblings, and conflicting variables were frequently selected. The failure to find many strong and/or consistent associations between social environmental variables does not indicate that social environmental variables do not have influence, but clearly points to the complexity of entangling them. It may be, as has been suggested by others. that what is pathologic in those who rear schizophrenics is not unusual, but becomes significant etiologically when these traits interact with a vulnerable individual.lJ REFERENCES I.
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