The sibling relationship is unique in that it lasts the longest of all human relationships. Closeness in the sibling relationship, however, changes over time. In the general population, siblings show decreased satisfaction with their sibling relationship in adolescence, particularly as peer relationships become more important, which is followed by decreased contact in early adulthood as siblings establish their independent lives. During the middle and later adult years, siblings share increased satisfaction and contact (Cicirelli, 1994).
We know relatively little about the trajectory of sibling relationships when one sibling has an autism spectrum disorder (ASD). Studies of siblings of individuals with an ASD have focused on the sibling relationship during childhood (e.g., McHale, Sloan, & Simeonsson, 1986; Rivers & Stoneman, 2003; Roeyers & Mycke, 1995) or have included siblings in varied life stages (e.g., childhood through young adulthood; Bägenholm & Gillberg, 1991). Thus, we have limited knowledge about the sibling relationship at specific points during the life course and how the sibling relationship changes over time in this population. Understanding developmental differences in the sibling relationship in adolescence and adulthood in this population is important because siblings are often responsible for the well-being of their brother or sister with an ASD when their parents are no longer able to provide or oversee care.
Past research on the childhood sibling relationship when one sibling has an ASD has yielded inconsistent findings. In some studies, siblings who have a brother or sister with an ASD reported admiration of their brother or sister and were satisfied with their relationship (Kaminsky & Dewey, 2001; Rivers & Stoneman, 2003; Roeyers & Mycke, 1995). In other studies, siblings experienced less closeness, had a decreased number of interactions, and viewed the brother or sister with an ASD as a burden (Bägenholm & Gillberg, 1991; Knott, Lewis, & Williams, 1995). Siblings of children with an ASD have reported limited family interactions (Opperman & Alant, 2003) and feeling more isolated and lonely than siblings of children with other disabilities (Bägenholm & Gillberg, 1991).
Some of the inconsistent findings across studies may be due to different sample characteristics and methods of data collection. Many studies use a wide age range of siblings (e.g., ages 5−20; e.g., Bägenholm & Gillberg, 1991) which may obscure some age-related changes in the sibling relationship and sibling well-being. Moreover, the variability in findings suggests that there may be unmeasured factors that are associated with the sibling relationship and well-being. The current study extends previous research by examining siblings in two specific age groups (adolescence and adulthood) and by examining factors that may explain variability in the sibling relationship at each life stage.
In addition, recent research shows that the symptoms of ASDs change over time (Seltzer et al., 2003; Shattuck et al., 2007). As a result, the effects on the sibling relationship may differ according to the life stage of both the sibling and the brother or sister with an ASD. The ASD impairments of social interaction, communication, and behavior tend to become less severe over time, although they remain problematic for most individuals with an ASD across the life course (Seltzer et al., 2003; Shattuck et al., 2007). Thus, although such impairments may continue to impact the sibling relationship throughout adolescence and adulthood, the lessening of severity may lead to improved sibling relationships over time.
In this paper, we investigated how the sibling relationship and sibling well-being is different during adolescence versus adulthood when one sibling has an ASD, and asked whether there are different predictors of these sibling outcomes for the two age groups. To our knowledge, there has been no published research prior to our ongoing study on the sibling relationship during adulthood when one sibling has an ASD. Therefore, we looked to the research literature on siblings of adolescents and adults with developmental disabilities other than autism, to inform our predictions regarding sibling relationships over the life course when one sibling has an ASD.
Wilson, McGillivray, and Zetlin (1992) compared adolescent and adult siblings of individuals with developmental disabilities, and found that adolescent siblings experienced more embarrassment, were more concerned about social stigma, and were more worried about being isolated by their peers than were adult siblings. Similarly, Begun (1989) reported that during adolescence, siblings who had a brother or sister with a developmental disability expressed more conflict and less satisfaction with their sibling relationships than in adulthood. These researchers also found that the acceptance of brothers or sisters with disabilities was greater during adulthood.
In this study we also examined differences in sibling psychological well-being, coping skills, and social support. In the general population, adolescents report higher levels of depressive symptoms than adults (Radloff, 1991). Coping skills refer to the person's active or passive strategies and behaviors to deal with stressful events (Carver, Scheier, & Weintraub, 1989). Problem-focused coping strategies actively aim to solve problems and reduce the effects of stressful events, whereas emotion-focused coping strategies aim to regulate or eliminate undesirable emotions that are associated with stressful events (Carver et al., 1989). In our previous research, using a subset of the participants used in the current analyses, adult siblings who used more problem-focused coping strategies reported a closer sibling relationship with their brother or sister with an ASD (Orsmond & Seltzer, 2007). With respect to social support, adolescents, in general, report that the greatest sources of support come from friends and parents (Lempers & Lempers-Clark, 1992; Smetena, Campione-Barr, & Metzger, 2006). During later adolescence and throughout adulthood, support gained from committed romantic relationships tends to replace the support previously provided through parents and friends (Doherty & Feeney, 2004).
Based on the research reviewed above, we posed four research questions: (1) Do adolescent siblings of individuals with an ASD differ from adult siblings with respect to engagement in shared activities and reported positive affect in the sibling relationship?; (2) Do adolescent siblings of individuals with an ASD differ from adult siblings in psychological well-being, coping, and social support?; (3) How does gender influence the relationship and well-being of adolescent and adult siblings?; and (4) How do the characteristics of the brother or sister with an ASD (e.g., age, behavior problems), family characteristics (e.g., family size), and sibling resources (e.g., coping, support, and psychological well-being) predict engagement in shared activities and positive affect in the sibling relationship?
We predicted that, similar to typically developing sibling dyads and siblings of adults with other types of developmental disabilities, adult siblings would have more positive relationships than adolescent siblings with their brother or sister with an ASD (Begun, 1989; Cicirelli, 1994; Wilson et al., 1992). Also similar to the general population, we expected sibling engagement in shared activities to be greater in adolescent siblings because they are more likely to live together with the brother or sister with an ASD than adult siblings.
We also expected that adult siblings of an individual with an ASD would report more favorable psychological well-being than adolescent siblings, in part not only because this is the pattern seen in the general population, but also because we anticipated that the stress associated with living with a brother or sister with an ASD would likely lessen when siblings are no longer living together in adulthood. We expected that adult siblings would use more problem-focused coping strategies and fewer emotion-focused coping strategies than adolescent siblings, and that adult siblings would rely less on social support from their parents and friends than would adolescent siblings. These predictions were informed by the developmental shifts observed in the general population (Skinner & Zimmer-Gember, 2007)
We hypothesized that engagement in shared activities and positive affect in the sibling relationship would differ according to the gender composition of the sibling dyad for both age groups. In prior research, we found that adult brothers with a sister with a developmental disability were the least involved and reported the lowest levels of positive affect in the sibling relationship, but that the gender of the sibling with the developmental disability did not condition the relationship for sisters (Greenberg, Seltzer, Orsmond, & Krauss, 1999; Orsmond & Seltzer, 2000). We predicted a similar pattern in the current sample, that is, that sisters would have an equally close relationship with their brother or sister with an ASD, but that the sibling relationship would be conditioned by the gender of the sibling with an ASD for brothers.
Finally, we predicted that behavior problems in the brother or sister with ASD would negatively impact sibling relationships (Greenberg et al., 1999; Seltzer, Greenberg, Krauss, Gordon, & Judge, 1997; Seltzer et al., 2003), but that siblings from larger families would have more positive relationships (Howlin, 1988; McHale, Sloan, & Simeonsson, 1986). With respect to sibling resources, we hypothesized that for both adolescent and adult siblings, sibling engagement in shared activities and positive affect in the sibling relationship would be higher when the sibling had more favorable psychological well-being, used more problem-focused coping skills, and reported greater social support (Kaminsky & Dewey, 2002; McHale et al., 1986; Orsmond & Seltzer, 2007; Seltzer et al., 1997). We also explored whether sibling resources (psychological well-being, coping skills, and social support) buffered the negative impact of behavior problems in the brother or sister with an ASD on the sibling relationship. By posing these questions, we hoped this study would provide important information regarding the level of sibling engagement at a time in life when siblings may need to take a more active role in the relationship as parents begin to relinquish their active caregiving role.