Effect of Sibling Perception of Differential Parental Treatment in Sibling Dyads With One Disabled Child

Effect of Sibling Perception of Differential Parental ‘Ireatment in Sibling Dyads With One Disabled Child LUCILLE WOLF, M.Sc., SANDRA FISMAN, M.B., DEBORAH ELLISON, M.A., AND TOM FREEMAN, M.D.

ABSTRACT Objective: To examine sibling perception of parental differential treatment in families of children with pervasive devel-

opmental disorder (PDD), Down syndrome (DS), and nondisabled controls. Method: Sibling self-conceptand social support were studied in the context of sibling perceptions of parental differential treatment and caretaker plus teacher evaluations of sibling behavioral adjustment. Measures were completed at time 1 and time 2.The effect of parental stress and the difficulty of the disabled child, as well as the sibling relationship, were considered. Results: For siblings of PDD children, internalizing and externalizing behavior problems identified by caretakers were evident at time 1 and more accentuated at time 2, at which time teachers also identifiedthese difficulties.DS siblings were reported by caretakers and teachers to have only internalizingproblems and only at time 2. These difficulties relatedto the perceptionfor PDD siblings that they were preferred over their disabled sibling and for the DS sibling that their disabled sibling was preferred. Feelings of low competence predicted internalizingdifficulties. Social support, especially over time, had a positive effect for all siblings, includingthe controls. Conclusion: The elucidation of specific mechanisms contributingto adjustment problems in the siblings of disabled children will allow for the development of specific preventive interventions. J. Am. Acad. Child Adolesc. Psychiatry, 1998,37(12):1317-1325. Key Words: parental differentialtreatment, sibling self-concept, social support, sibling adjustment.

It would be unrealistic, given the importance of the sibling relationship, to presume that having a disabled sibling would not exert a profound effect on the psychological well-being of other siblings in the family. The effects of a sibling relationship cannot be adequately explained solely on the basis of demographics of the family (gender and birth order) and the characteristics of the disability; rather a transactional, family systems perspective, which takes into consideration both the direct and indirect effects on the sibling relationship over time, is required Acceptedjuly 9, 1998. From the Division of Child and Adolescent Pychiatry, Children?Hospital of Western Ontario, Child and Parent Resource Institute (CPN), and Departments of Pycholoa and Pychiatry, University of Western Ontario (UWO), London, Ontario, Canada. Dr. Fisman is Chair of the Child Division and Profissoc UWO. Ms. Wolfis a research epidemiologist at CPN. Ms. Ellison is with the Department ofPycholoa, UWO. Dr. Freeman is afamily practitioner at Byron Family Medical Centre and Associate Profissor, UWO. Supported by a research grant from the Department of Pychiany Research Fund, UWO, and the McConachie Foundation for Down Syndrome Research. Reprint requests to Dr. Fisman, Division of Child and Adolescent Pychiatry, Room 6118, 6South, Phase I, W C Children?Hospital ofwestern Ontario, 800 Commissioners Road East, London, Ontario, Canah N6C 2V5. 0890-8567/98/3712-1317/$03.00/001998 by the American Academy of Child and Adolescent Psychiatry.

to yield a greater understanding of the impact of siblings on development (Lobato et al., 1988). The effects of differential parental treatment of siblings on their behavior and their relationship is an area of fairly recent empirical study. The majority of the research concerns nondisabled dyads (Brody et al., 1992; Dunn et al., 1991). The home environment may differ for siblings of children with and without a disability. The nondisabled sibling may encounter less parental attention (McKeever, 1983), increased care and chore responsibilities (McHale and Gamble, 1989), risk for poor peer relations (Cadman et al., 1988), lower level of participation in outside activities (Dyson, 1989), and loss of companionship (Siemon, 1984). Sibling dyads comprise one of the subsystems of the family, and there are both direct and indirect factors and processes within the larger system that influence this relationship. The emotional atmosphere in the family and the perception of parental differential treatment are associated with the quality of sibling relationships (Brody and Stoneman, 1987). Differential treatment may affect children’s behavioral and emotional adjustment, as well as the quality of sibling relationships (Dunn and Stocker, 1989). While par-

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ents strive to provide equal treatment for their children, they may not achieve this goal or acknowledge differential treatment (Furman and Adler, 1986). Greater levels of differential treatment have been described in families with disabled children (McHale and Pawletko, 1992). Children are sensitive and perceptive to differential treatment, and their reactions vary at different stages of development. In families without a disabled child, consistent and positive maternal rearing practices have been demonstrated to beneficially affect siblings’ relationships and behavior, to reduce hostility, and to increase prosocial behavior, whereas maternal negative treatment is associated with negative and conflictual sibling relationships and child adjustment (Brody et al., 1987; McHale and Gamble, 1989; Stocker et al., 1989). The picture with a disabled child may be more complex, with different effects on the siblings adjustment and on the sibling relationship (McHale and Pawletko, 1992). In families without a disabled child, positive selfconcept has been correlated with favorable sibling relationships (Dunn and Plomin, 1990). In addition, the receipt of social support is reported to enhance resilience in children (Garmezy, 1984; Werner, 1989). There is strong evidence for an inverse relationship between social support and levels of psychological symptomatology in children (Barrera, 1981; Compas et al., 1986). However, in families with a disabled child, there may be different factors that are operative; for example, the lack of parental favoritism and the absence of feelings of hyperresponsibility on the part of the sibling to make up for the disabled child are correlated with favorable sibling relationships (Seligman, 1987). Bischof and Tingstrom (1991) noted that although siblings perceive their mother to be partial to the child with the disability, there are no significant differences on measures of self-concept or behavior; however, there are no studies that examine both self-concept and social support in the context of differential treatment and behavioral adjustment. This study assessed the effects, at two points in time, of parental differential treatment of siblings on the behavioral adjustment of the nondisabled sibling. The factors of interest were the nondisabled siblings’ perceptions of differential treatment; their self-competence and the social support they perceived from parents, teachers, and peers; and the warmth and closeness of their sibling relationship. Both the primary caregiver and the teacher provided data on the externalizing and

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internalizing behavior of the nondisabled sibling. Collection of data from the nondisabled sibling, the primary caregiver, and teacher assisted in the collection of unbiased data. We hypothesized that siblings who experienced low self-competence and perceived differential treatment in favor of the disabled child would exhibit increased externalizing and internalizing behavior, as reported by the parent and teacher. In addition, we hypothesized that siblings who perceived low social support and parental differential treatment in favor of the child with the disability would exhibit increased externalizing and internalizing behavior as reported by the parent and the teacher. Finally, siblings who perceived differential parental treatment in favor of the disabled child would report low warmth in the sibling relationship. METHOD Participants One hundred thirty-seven families participated at time 1. Participants included 46 siblings of children with pervasive developmental disorder (PDD) according to DSM-IZZ-R criteria (American Psychiatric Association, 1987), 45 siblings of children with Down syndrome (DS), and their primary caregivers and teachers. Both groups were receiving or had received diagnostic assessment and services from two regional centers in southwestern Ontario. All families meeting the eligibility criteria (below) were invited to participate. Forty-six siblings of typically developing children were recruited from a family medical practice in southwestern Ontario and served as controls. Participation rates for the families contacted were 92% PDD, 85% DS, 60% controls, and 98% for their teachers. The significantly lower participation rate for controls may have selected out a more willing group of volunteers. Siblings were between the ages of 8 and 16 years at the time of the first testing; the target children were between 4 and 18 years of age. Siblings were matched on race, gender, and ordinal position. If two siblings in the family fit the criteria, the one closest in age to the target child was selected. Three years later at time 2, children in 126 families were restudied: 41 PDD, 42 DS, and 43 controls. Criteria for inclusion in the study consisted of the following: the sibling and target child were natural siblings and were living at home with at least one natural parent; they were no more than 4 years apart in age; they were not twins; there were no other significant disabilities in the family; and parents could read, write, and speak English. Table 1 includes demographic characteristics of the study population. Significant differences were observed only with regard to income, with the controls having higher income, and the expected higher number of males in the PDD sample.

Measures

Behavior and Social-Emotional Functioning of the Designated Sibling. The Survey Diagnostic Instrument (Cadman et al., 1988) adapted from the Child Behavior Checklist (Achenbach and Edelbrock, 1983) for use in the Ontario Child Health Study (OCHS

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scales) (Boyle et al., 1987) was completed by the primary caregiver to record behavioral problems and competencies of the designated sibling. This instrument is designed for children from age 4 upward. Teachers completed a teacher version of the instrument. A total behavior score was obtained, as well as scores for internalizing and externalizing behavior problems. The OC HS scales have demonstrated good internal consistency (all estimates > 0.74) and testretest reliability (all estimates > 0.65 reliability) (Boyle et al., 1993). Self-Perception. Siblings completed the Self-Perception Profile for Children (Harter, 1985). This measure of self-competence calculates five specific domains-scholastic competence, social acceptance, athletic competence, physical appearance, and behavioral conduct-in addition to a global self-worth score. Internal consistency reliabilities for all subscales range from 0.71 to 0.86. Harter (personal communication) suggested that the original scale be used throughout the study rather than changing to the adolescent version. Social Support. The Social Support Scale for Children (Harter, 1986) was used to measure siblings perceived support. Four sources of support are measured: parents, teachers, classmates, and close friends. Validity data show a significant correlation between perceived support by Classmates and parents, and the child’s self-concept. Internal subscale reliabilities range from 0.72 to 0.88 (Harter, 1986). Parent Psychosocial Measure. The Parenting Stress Index-Short Form (PSIISF) (Abidin, 1990), a direct derivative of the full-length PSI (Abidin, 1986), focuses on three factors-parent distress, parent-child dysfunctional interaction, and difficult child-in addition to a total parenting stress score. Internal reliability coefficients for the

Procedure Families were sent letters describing the study and inviting their participation. Primary caregivers and siblings provided signed consents. Confidentiality and the right to terminate association with the project at any time were assured. Packets of questionnaires were sent to the primary caregiver (128 mothers and 9 fathers), the designated sibling, and hidher current teacher. Stamped, self-addressed envelopes were provided for each participant, specifically to ensure confidentiality for the siblings.

Data Analysis

TABLE 1 Demographic Data

Primary caregiver‘s education Elementary Secondary Some college College Marital status Married Separated Divorced Common-law Remarried Widowed Income <$50,000 >$50,000 Gender of sibling Male Female Gender of disabled child Male Female No. of children in family Two Three Four or more

domains range from 0.80 to 0.87 and 0.91 for the total score. Testretest reliability ranges from 0.68 to 0.85 and 0.84 for the total score. Validity is shared with the PSI long form. SiSling Relationships. Siblings completed the Sibling Relationship Questionnaire-Brief version (Furman and Buhrmeister, 1985), which measures 16 dimensions of sibling relationship. The internal consistency coefficients exceed 0.70. Reported test-retest reliability is 0.71. Four factors are obtained using this measure: Warmth/Closeness, Relative Power/Status, Conflict, and Rivalry. No significant correlation has been found with social desirability ( r = 0.14) (Furman and Buhrmeister, 1985). This study used two factors, Warmth/Closeness and Rivalry, as measures of the siblings perception of the relationships with the target child and the siblings perception of parental differential treatment. Demographic Data. A questionnaire was created to obtain pertinent demographic data.

PDD ( n = 46)

DS ( n = 45)

Control ( n = 46)

0 16 22 8

1 15 19 10

0 13 20 13

40 1 0 2 2 1

42 1 1 1 0

43 1 1 0 1 0

Previous analyses (Fisman et al., 1996) indicated group differences in both levels of the dependent variables (PDD siblings evidenced more behavior problems than the other two groups) and the factors affecting the severity of behavior problems. Thus, in testing the hypotheses, it was decided to analyze each group separately. In addition, because the relations among the variables and their relative influence on the dependent measures was of interest at both time points, it was decided to analyze the time 1 and time 2 data separately. Regression analysis was used to test the first two hypotheses, and correlation analysis was used to test the third hypothesis. Two sets of additional analyses were undertaken for explanatory purposes. The first assessed whether the parents’ view of the difficulty in dealing with the disabled child would influence the siblings’ perceptions of parental differential treatment, and the second assessed differences among the groups of siblings in how social support from different sources related to the four dependent variables.

24 22

22 23

11 35

RESULTS

18 28

17 28

18 28

38 8

21 24

24 17

16 19 10

5

0

26 14

6

Note: PDD = pervasive developmental disorder; DS = Down syndrome.

Hypothesis 1: Siblings who experience low self-competence and perceive that the parent shows preferencefor the handicapped sibling will have adjwtment problems. Separate regressions were completed for each group; the Harter self-competence score and the Parental Preference score were regressed on each of the dependent variables (parent and teacher reports of externalizing behavior problems and parent and teacher reports of internalizing problems) for time 1 and time 2 (Table 2).

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TABLE 2 Regressions With Perceived Competence and Parental Preference Time 1

p Wt. Comp.

p wt.

%

p wt.

YO

Variance

Time 2

p wt.

Pref.

Comp.

Pref.

Variance

p < .05 p < .05

-.3895* -.3685*

-.0168 -.2651*

NS NS

15.7 13.5 NS NS

p < .001 p < .05 p < .05 p < .05

-.2701* -.3768* -.2968 -.4353*

-.4437* .1841 -.1955 -.0934

31.8 20.6 15.0 21.6

NS NS NS NS

NS NS NS NS

-.2416*

.3210*

-.3233*

.2 126

Variable

PDD PEXT PINT TEACHEXT TEACHINT DS PEXT PINT TEACHEXT TEACHINT Control PEXT PINT TEACH EXT TEACHINT

p

< .05

-.3535*

.1441

16.5 NS NS NS

NS NS NS

NS

p

< .01

NS

p < .05 NS NS NS NS

NS 28.8 NS 16.5 NS NS NS NS

Note: PDD = pervasive developmental disorder; DS = Down syndrome; p Wt. Comp. = f3 weight competence; p Wt. Pref. = report of externalizing problems: PINT = parent report of internalizing problems; TEACHEXT = teacher report of externalizing problems; TEACHINT = teacher report of internalizing problems; NS = not significant. * Significant predictor in the regression equation.

p weight preference: PEXT = parent

Siblings of PDD Children

Time 1. The regressions were significant for both parent reports of externalizing behavior and parent reports of internalizing problems, indicating greater adjustment problems associated with lower feelings of competence and feelings of the sibling that he/she is preferred over the handicapped child. Both perceived competence and perceived parental preference were significant predictors for parent reports of internalizing behavior problems. The only significant predictor for parent reports of externalizing behavior problems was the siblings’ level of perceived competence. Time 2. All four regressions were significant. For parent reports of externalizing behavior problems, both predictors were significant, indicating that greater externalizing behavior problems are associated with lower feelings of competence and feelings on the part of the sibling that he/she is preferred over the handicapped child. For parent and teacher reports of internalizing behavior problems, only perceived competence was a significant predictor. For this group of children, feeling that they were not competent was associated with reports by both parents and teachers of internalizing problems. For teacher reports of externalizing behavior problems, neither of the predictors was significant on its own. Thus, for siblings of PDD children, feeling that they were less 1320

competent and that they were preferred by the parent correlated with adjustment problems that were more pronounced at time 2. Siblings of Down Syndrome Children

Time 1. None of the four regressions were significant. Time 2. Regressions were significant for both parent and teacher reports of internalizing problems. For parent reports of internalizing problems, both siblings’ level of perceived competence and parental preference were significant predictors. For teacher reports of internalizing problems, only perceived competence was a significant predictor. Thus, for siblings of DS children, feelings of low competence and believing that their disabled sibling is preferred by the parents are related to increases in internalizing problems that evidence themselves later, offering partial support for hypothesis 1. Siblings of Control Children

Time 1. The only significant regression was for parent reports of externalizing behavior. Only perceived competence was a significant predictor in the regression equation, indicating that low levels of perceived competence are related to greater externalizing behavior problems. Time 2. None of the regressions were significant. Thus for siblings of control children, hypothesis 1 was not supported.

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Hypothesis 2: Siblings who receive low socialsupportand view their parents as showing preferencef o r the handicapped child will evidence greater adjustmentproblems. Separate regressions again were used for each group by regressing Harter social support scores and Parental Preference scores on each of the dependent variables for time 1 and time 2 (Table 3). Siblings of PDD Children

Time 1. None of the regressions were significant. Time 2. Regressions for both parent reports of externalizing and internalizing problems were significant. For parent reports of externalizing behavior problems, both perceived levels of social support and parental preference were significant predictors, indicating that children who felt low levels of social support and that they were preferred over their disabled siblings exhibited higher levels of externalizing behavior problems. For parent reports of internalizing problems, only level of social support was a significant predictor, indicating that low levels of social support are associated with greater internalizing problems. Thus, for siblings of PDD children, hypothesis 2 was partially supported. Siblings of Down Syndrome Children

Time 1. None of the regressions were significant.

Time 2. Regressions were significant for parent reports of internalizing problems, teacher reports of externalizing behavior, and teacher reports of internalizing problems. For parent reports of internalizing problems, both social support and parental differential treatment were significant predictors. Greater internalizing problems were associated with low levels of social support and believing that the disabled sibling was preferred by the parents. For teacher reports of externalizing and internalizing problems, only social support was a significant predictor, indicating low levels of social support associated with higher levels of both internalizing and externalizing problems as reported by teachers. Thus, for siblings of children with DS, hypothesis 2 was partially supported. Siblings of Control Children

Time 1. The only significant regression was parent reports of externalizing behavior problems. Only the level of social support was a significant predictor in this regression equation, with low levels of social support associated with greater externalizing behavior problems. Time 2. The only significant regression was teacher reports of internalizing problems. The only significant predictor in this regression was social support, indicating low levels of social support associated with higher levels of internalizing problems as reported by teachers. Thus,

TABLE 3 Regressions With Perceived Social Support and Parental Preference Variable

YO Variance

Time

p wt.

p wt.

2

SUPP.

Pref.

% Variance

NS NS NS NS

NS NS NS NS

p < .001 p < .05

-.2820* -.2962*

-. 1903

-.4267*

32.3

NS NS NS NS

NS NS NS NS

p p p

16.3 NS NS NS

NS NS NS p < .05

Time 1

p Wt.

p wt.

SUPP.

Pref.

PDD

PEXT PINT TEACHEXT TEACHINT

NS NS

15.2

NS NS

DS

PEXT PINT TEACHEXT TEACHINT

NS < .01 < .05 < .01

-.3420* -.3856* -.4955*

.4544* ,1922 .19 13

NS 26.8 20.3 30.4

,1448

NS NS NS 20.2

Control

PEXT PINT TEACHEXT TEACHINT

p < .05 NS NS NS

-.3543*

.1154

-.4233*

Note: P D D = pervasive developmental disorder; DS = Down syndrome; p Wt. Supp. = p weight support; p Wt. Pref. = p weight preference; PEXT = parent report of externalizing problems; PINT = parent report of internalizing problems; TEACHEXT = teacher report of externalizing problems; TEACHINT = teacher report of internalizing problems; NS = not significant. * Significant predictor in the regression equation.

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for siblings of control children there was limited support for hypothesis 2.

Hypothesis 3: Siblings who perceive differential treatment will report low warmth in the sibling relationship. Correlation analysis was used to test this hypothesis, correlating differential treatment scores with siblings' reports of the warmth of their relationship with the disabled child. None of the correlations were significant, and thus hypothesis 3 was not supported. DifferentialTreatment as a Function of Child Difficulty

Time I . The Difficult Child subscale of the PSI/SF was divided into high and low difficulty scores using the cutoff suggested by Abidin (1990) representing the 90th percentile in child difficulty. This scale was used to measure the difficulty of the disabled or target child, in the case of a control family, as rated by the parent. Analysis of variance was performed on the Parental Preference score by child difficulty as reported by parents (high or low) and group membership. A significant interaction was obtained. For siblings of PDD and control children, when child difficulty was reported by the parents as high, the siblings preference scores rose, indicating they were more likely to believe that they were preferred by their parents over the disabled sibling or target child. For siblings of DS children, the opposite was true. When parents reported that the disabled child was difficult, the sibling's preference scores fell, indicating they were more likely to believe that the disabled child was preferred by the parents. The interaction was no longer significant at time 2. Sources of Social Support

The Social Support Scale for Children was divided into its four subscales (Support From Parents, Support From Teachers, Support From Classmates, and Support From Close Friends). These subscales were correlated with each of the four dependent measures (parent reports of externalizing and internalizing behavior problems and teacher reports of externalizing and internalizing behavior problems). Time 1 Social Support

Siblings of PDD Children. Social support received from teachers and close friends was negatively correlated with both parent and teacher reports of externalizing behavior problems (Table 4). For this group of children, receiving social support from teachers and close friends 1322

TABLE 4 Correlations Between Sources of Social Support and Dependent Measures for Time 1

PDD ( n = 46) PEXT PINT TEACHEXT TEACHINT DS ( n = 45) PEXT PINT TEACHEXT TEACHINT Control ( n = 46) PEXT PINT TEACHEXT TEACHINT

Parent

Teacher

Classmate

Friend

-.1580 .0874 -.0898 ,1963

-.4095** .lo60 -.3499* .1221

-.1778 -.0538 -.2789 .2550

-.3374* -.2364 -.305 1 * .lo23

-. 1655 -.2059 -.lo76 .lo39

-.2847 .0720 -.2542 .0308

.0358 -.0753 -.1103 .0824

-.2183 -.0718 -.2478 .1492

-.2431 -.0765 -.2529 -.2380

-.2553 -.0840 -.1852 -.2994

-. 1423 -. 1482

-.2825

-.3717* .0586 -.2974 -. 1288

-.0994

Note: PDD = pervasive developmental disorder; DS = Down syndrome; PEXT = parent report of externalizing problems; PINT = parent report of internalizing problems; TEACHEXT = teacher report of externalizing problems; TEACHINT = teacher report of internalizing problems. " p < .05; * * p < .01.

led to fewer externalizing behavior problems, while support from parents and classmates was unrelated to the degree of behavior problems exhibited. Siblings of Down Syndrome Children. Social support from any source was unrelated to behavioral adjustment problems (Table 4). Siblings of Control Children. Social support from close friends was negatively correlated with parent reports of externalizing problems. Social support from close friends was related to fewer externalizing behavior problems as reported by parents (Table 4). Time 2 Social Support

Siblings of PDD Children. At time 2, social support from teachers continued to be negatively correlated with parent reports of externalizing behavior problems. As well, social support from parents was negatively correlated with teacher reports of internalizing and externalizing behavior problems. For this group of children at time 2, social support from teachers was related to fewer externalizing behavior problems as seen by parents, while social support from parents was related to fewer externalizing and internalizing behavior problems as seen by teachers (Table 5). Siblings of Down Syndrome Children.At time 2, social support from parents was negatively correlated with par-

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TABLE 5 Correlations Between Sources of Social Support and Dependent Measures for Time 2

PDD ( n = 46) PEXT PINT TEACHEXT TEACHINT DS ( n = 45) PEXT PINT TEACHEXT TEACHINT Control ( n = 46) PEXT PINT TEACHEXT TEACHINT

Parent

Teacher

Classmate

Friend

-.0888 -.1441 -.3678* -.4005*

-.498 1 * -.2706 -.2979* -.2685

-.1850 -.2834 -.0726 -.0003

-.2726 -.2241 -. 1847 -.2927

-.3600* -.2521 -.4095* -.2667

-. 1927 -.2245 -.3665* -.5388**

-. 1393

.0615

-.2062 -.3231*

.0307 .0329 -.2983 -.3663*

.1414 .0184 .1886 -.0451

-.0833 ,0295 -.0572 -.2902

-.0034 -. 1190 -.0742 -.5837**

-.0060 -.0619586 -. 1745 -. 1684

Note: PDD = pervasive developmental disorder; DS = Down syndrome; PEXT = parent report of externalizing problems; PINT = parent report of internalizing problems; TEACHEXT = teacher report of externalizing problems; TEACHINT = teacher report of internalizing problems. * p < .05; * * p < .01.

ent and teacher reports of externalizing behavior problems. Social support from teachers was negatively correlated with teacher reports of externalizing and internalizing problems. Social support from classmates and close friends was also negatively correlated with teacher reports of internalizing behavior problems. For this group of children at time 2, social support became an important factor in ameliorating behavioral adjustment problems (Table 5). Siblings of Control Children. At time 2, social support from classmates was negatively correlated with teacher reports of internalizing problems. So for this group of children, there was a change in both the source of social support and its ameliorating effects (Table 5). DISCUSSION

The results of this study confirm the complexity of sibling perceived parental differential treatment in families with a disabled child, as well as the importance of examining sibling relationships over time rather than relying on a single cross-sectional observation. For both the PDD and DS siblings, adjustment problems related to perceived parental differential treatment became more evident over the 3-year period. In addition, as we have demonstrated previously (Fisman et al., 1996), living

with a DS sibling is an entirely different experience than living with a PDD sibling. Of particular interest is the effect of the direction of perceived sibling parental preferential treatment in the siblings of PDD children compared with those of DS children. For the siblings of PDD children, it is the perception that they are preferred over their handicapped sibling that is predictive of adjustment difficulties. In contrast, for the DS siblings, it is the perception that their handicapped sibling is preferred, particularly over time, that is associated with internalizing adjustment difficulties. This latter finding is more logically predictable and congruent with findings in nondisabled family contexts that indicate that receiving more favorable treatment is correlated with sibling well-being (Dunn et al., 1991). Analysis of the interaction effect of parental perception of the degree of difficulty of the handicapped child and healthy sibling perception of parental differential treatment is interesting. The difference in direction of perceived differential treatment in the PDD versus the DS siblings is consistent; the PDD siblings perceived themselves as preferred in the presence of parental descriptions of a high level of difficulty in the handicapped child, with the DS sibling perceiving the handicapped sibling to be preferred under the same circumstances. The finding was more evident at initial sampling than 3 years later, suggesting some degree of sibling accommodation to the difficulty of the handicapped sibling with time and increasing maturation. In addition to positive self-competence, the receipt of social support has been reported to enhance resilience in children (Garmezy, 1984; Werner, 1989). There is also strong evidence for an inverse relationship between social support and levels of psychological symptomatology demonstrated by children (Barrera, 1981; Compas et al., 1986). Barrera noted that in considering social support it is important to consider both the provider and the subjective appraisal of the support. This was done in our study within the context of perceived parental differential treatment. For the siblings of the handicapped groups (PDD and DS), social support became a more significant factor over time. The difference in direction of perceived parental preferential treatment remains consistent in the context of social support, with lower levels of social support associated with parent and teacher reports of adjustment difficulties. At both time samplings, social support received from teachers in the case of PDD siblings was important in mitigating against adjustment

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problems. The protective effect of a significant adult ouside of the family system who maintains a supportive relationship with a child at risk (in this case the sibling of a PDD child) has been well described (Rae-Grant et al. 1989; Werner, 1989). While maternal differential treatment has been associated with the quality of sibling relationships (Brody et al., 1987) in families of normally developing school-age children, this was not the case in our study. Sibling perception of differential treatment, whether toward themselves or their handicapped sibling, was not associated with low warmth in the sibling relationship. While a warm sibling relationship and low sibling conflict are of themselves protective against externalizing behavior problems for DS and normally developing children (Fisman et al., 1996), these factors do not seem to be related to perceived parental differential treatment. It may be that differential treatment as perceived by the sibling, when associated with feelings of low self-competence and low social support, is associated with sibling adjustment rather than sibling relationship problems. The main drawback to this study is the absence of observational measures of caretaker differential treatment. This is offset by the use of three different respondents: the healthy siblings, their teacher, and their caretaker.This allows us to evaluate preferential treatment from the sibling's perspective and adjustment from the parent and teacher viewpoint. Research with a disabled child has not routinely included the perceptions of the sibling, but only that of the mother, which may be biased (Thompson et al., 1994). Families with a disabled sibling represent a potentially interesting context in which to explore the effects of differential treatment. Given the extreme levels of differential treatment in the context of the handicapped child's family, this provides a unique opportunity to study differential treatment and its effects even where siblings are close in age (Powell and Ogle, 1985) regardless of the gender and ordinal makeup. In addition, the use of two cross-sectional data sets on the same children at 3-year intervals has revealed more associations for differential behavior than would a single cross-sectional analysis. It is likely that, over time, direct parental behavior may become less important than differential behavior in predicting sibling adjustment. Clinical Implications

It seems that within the family with a disabled child who generates extremely high levels of caretaker distress, 1324

as with the PDD child (Fisman et al., 1996; Wolf et al., 1989), the perception by the nonhandicapped child that he/she is receiving differentially positive treatment from a caretaker parent may give rise to a complex variety of emotional reactions. Feelings of anxiety, guilt, and anger may be expressed by internalizing and/or externalizing the distress. In spite of the perception of being preferred, over time, associated feelings of low self-competence become increasingly predictive of adjustment problems. This suggests that there is a significant impact on the child's evolving internal working model of himselWherself and impairment of hidher development of self-esteem. In families with a DS child, in which the levels of parental stress are lower (Fisman et al., 1996) and the DS child more acceptable (Noh et al., 1989), the self-competence of the healthy sibling may be impacted in a different fashion. Where siblings perceive that their handicapped DS sibling is preferred over them and they report lower selfcompetence, they are described by their parent and teacher as having more internalizing symptoms. This becomes more evident over time. A different mechanism from that in the PDD families is probably operational. With more time and attention devoted to the handicapped child, the nondisabled sibling may feel neglected and ignored (McHale and Pawletko, 1992).This is also reflective of the tendency to externalize distress at a younger age while developing more internalizing symptoms with the transition into puberty. Finally, securing a supportive relationship for the healthy sibling outside of the stressed family system may be an important component of intervention for the at-risk PDD sibling and serve as a beneficial factor in determining the child's adjustment. These findings are important in planning effective preventive interventions for the siblings of disabled children. REFERENCES Abidin RR (1986). Parenting Stress Index. Charlottesville, VA: Pediatric Psychology Press Abidin RR (1990), Parenting Stress Index-Short Form. Charlottesville, VA: Pediatric Psychology Press Achenbach T, Edelbrock C (1983), Manual for the Child Behavior Checklist and Revised Child Behavior Profile. Burlington: University of Vermont Department of Psychiatry American Psychiatric Association (1987), Diagnostic and Statistical Manual of Mental Disorders, 3rd edition-revised (DSM-Ill-R). Washington, DC: American Psychiatric Association Barrera M (1981), Social support in the adjustment of pregnant adolescents: assessment issues. In: Social Networks and Social Support, Goctlieb BH, ed. Beverly Hills, CA: Sage, pp 69-96 Bischof LG, Tingstrom D H (1991), Siblings of children with chronic disabilities: psychological and behavioral characteristics. Counsel Psycho1 Q 4311-321 (special issue: Disability in the Family: Research, Theory and Practice)

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