Self-reported stress among adolescent siblings of individuals with autism spectrum disorder and Down syndrome

Abstract

Despite the prevalence of studies showing increased stress among mothers of individuals with autism spectrum disorders, few studies have examined general stress among typically developing siblings. This study used an online survey to compare the levels of self-reported stress between adolescent siblings of individuals with autism spectrum disorder and Down syndrome. Sibling of individuals with autism reported significantly more overall stress than did siblings of individuals with Down syndrome, as well as more stress specifically attributed to the brother/sister with autism. The two groups did not differ on perceived social support from family and friends. In linear regression models, the disability group (autism vs Down syndrome) was significantly related to sibling stress above and beyond target child behavior problems, perceived social support, and demographic factors. These results help shed light on the daily experiences of adolescent siblings of individuals with autism and call for more research into potential interventions to address increased stress levels.

Keywords

adolescents autism spectrum disorders Down syndrome siblings stress

Over the past few decades, research on siblings of individuals with intellectual and developmental disabilities has emerged as a growing field. Clinicians, families, and scientists increasingly understand the importance of the sibling relationship (Hodapp et al., 2005), as it is typically the longest relationship individuals will have in their lifetime (Cicirelli, 1995). As individuals with disabilities live longer, the experience of typically developing siblings becomes increasingly important, as many of these siblings may take on caregiving responsibilities when aging parents are no longer able to fulfill such responsibilities (Hodapp et al., 2005). Therefore, it is necessary to understand the sibling experience developmentally, particularly underlying factors that may contribute to suboptimal outcomes for siblings across the lifespan.

Stress

Researchers who study siblings of individuals with intellectual and developmental disabilities (IDD) across the lifespan often focus on behavioral outcomes, such as problem behaviors, adjustment, and psychopathological symptoms (Lovell and Wetherell, 2016; Petalas et al., 2009a; Tomeny et al., 2014). However, findings in these studies are decidedly mixed, with some researchers reporting no increased risk for negative outcomes in their sample of children and adolescents (e.g. Kaminsky and Dewey, 2002; Neely-Barnes and Graff, 2011; Rodgers et al., 2016), while others found that siblings of individuals with IDD had worse outcomes than siblings in comparison groups (e.g. Gau et al., 2010; Goudie et al., 2013; Verté et al., 2003). Although many studies have examined potential individual differences in factors that may predict such sibling outcomes, the field has yet to develop a full understanding of the processes that drive such outcomes. We hypothesize that stress may play an important role in driving various sibling emotional and behavioral outcomes and aim to study individual differences in sibling stress. Şenel and Akkök (1996) found that siblings of children with intellectual disabilities reported significantly more stress than siblings of children without disabilities, but since then, stress has not been further examined as an outcome in and of itself among siblings.

Stress among parents of individuals with IDD

Although few studies have measured self-reported stress among adolescent siblings of individuals with IDD, the literature on stress among parents and caregivers is quite robust. Parents of children with IDD tend to report high levels of general and parenting stress (e.g. Baxter et al., 2000; Robinson and Neece, 2015), with parents of children with autism spectrum disorder (ASD) reporting even more stress than parents of children with other disabilities (see Hayes and Watson, 2013 for a review). As siblings of individuals with IDD, particularly those living with the target child (the child with IDD), are likely exposed to many of the same environmental factors as parents, it is likely that siblings will also experience elevated levels of stress.

Stress in adolescence

The literature has long recognized adolescence as an especially salient developmental period for stress, with the “storm and stress” pattern more likely to appear in adolescence than in any other age (see Rew et al., 2014 for review). However, it is also recognized that there are vast individual differences among adolescents that impact teens’ ability to manage stress and stressful life events (e.g. Arnett, 1999). Therefore, it is important to examine not only stress during adolescence among siblings of individuals with IDD but also the individual factors that may impact siblings’ experience of stress. Among the factors that may relate to sibling stress is gender; studies show that adolescent females tend to report higher levels of overall stress than males (e.g. Leadbeater et al., 1995; Martin et al., 1995)

Predictors of sibling outcomes

Throughout the sibling literature, several factors have been identified that impact various sibling outcomes. Although stress has not been frequently examined as an outcome among siblings of individuals with disabilities, it is likely that many of the variables that relate to other sibling experiences, such as anxiety, coping, and overall adjustment, may also play a role in sibling stress.

Behavior problems

One of the most consistently identified factors in sibling research is the presence and severity of behavior problems in the brother/sister with disabilities. Increased behavior problems in the target child have been found to relate to numerous sibling outcomes, including behavior problems in the sibling, anxiety, feelings about the target child, and positive affect in the sibling relationship (Hastings, 2003; Neece et al., 2010; Shivers et al., 2013; Shivers and Dykens, 2017). Among parents of children with IDD, behavior problems are highly correlated with parenting stress (e.g. Estes et al., 2009; Lovell and Wetherell, 2015; Robinson and Neece, 2015). Due to the consistently found relation between target child behavior problems and both sibling negative outcomes and parenting stress, it is likely that such behavior problems are also an important factor in sibling stress.

Social support

Perceived social support is an important factor to the mental and emotional health of adolescents. In particular, perceived social support was found to be positively correlated with increased resilience, and perceived support from family members was negatively correlated with perceived stress among adolescents and young adults (Bruwer et al., 2008). Additionally, among mothers of children with ASD, informal supports, such as social support from friends and extended family, tends to be a better buffer against the effects of stress than formal supports, such as professional services (see Boyd, 2002 for a review). Among siblings of individuals with IDD, the results are not as clear, with some studies finding no significant relation between social support and reported outcomes, such as sibling challenges, as measured by the Strengths and Difficulties Questionnaire (e.g. Giallo and Gavidia-Payne, 2006), or social support serves as a moderating factor between target child behavior problems and sibling difficulties, rather than a direct correlate (Hastings, 2003). However, these studies relied on parent report for sibling outcomes. Thus, it is possible that sibling self-report of social support may be more strongly related to sibling stress.

Sibling relationship

The relationship between the sibling and the target child is an important part of the sibling experience. Like many other aspects of sibling life, studies show mixed results, with some researchers reporting no differences in relationships between siblings of individuals with and without IDD (e.g. Cuskelly and Gunn, 2003; Stoneman, 2005), while Kaminsky and Dewey (2001) found that siblings of individuals with Down syndrome (DS) reported closer sibling relationships than did sibling of individuals with ASD. More behavior problems in the target child have been found to be related to less close sibling relationships (Hastings and Petalas, 2014; Orsmond et al., 2009), and more positive sibling relationships were related to lower levels of sibling anxiety (Pollard et al., 2013). It is therefore possible that the quality of the sibling relationship is also related to stress among adolescent siblings of individuals with IDD.

DS/ASD

Throughout the literature, family members of individuals with DS have been frequently shown to have different experiences than family members of individuals with ASD. Among families in general, the “Down syndrome advantage” refers to the overall pattern of less stress and more rewards related to the target child (see Hodapp et al., 2001 for a review). In the sibling literature, studies have shown that adult siblings of individuals with DS report more warmth in the sibling relationship, more positive affect toward their brother/sister, and lower levels of depressive symptoms than do siblings of individuals with ASD (Hodapp and Urbano, 2007; Orsmond and Seltzer, 2007). Additionally, adolescent siblings of individuals with ASD report lower overall relationship quality than do siblings of individuals with DS (Pollard et al., 2013). In an observational study of sibling dyads, child siblings of individuals with DS spent more time and initiated more interactions with their brother/sister than did siblings of individuals with ASD (Knott et al., 1995). This consistent pattern of differences suggests that siblings of individuals with ASD are also likely to report different levels of stress than siblings of individuals with DS.

The current study

This study aims to examine self-reported stress among adolescent siblings of individuals with ASD and DS in relation to the following research questions:

Do siblings of individuals with ASD (ASD-Sibs) report more overall stress than siblings of individuals with DS (DS-Sibs)?

Do ASD-Sibs report different amounts of perceived social support, sibling warmth, conflict, and hostility, or target child behavior problems than DS-Sibs?

How do personal factors (e.g. perceived social support, gender), family factors (e.g. target child behavior problems, target child gender), and the sibling relationship relate to overall sibling stress?

How does group membership (ASD vs DS) relate to sibling stress when controlling for personal, family, and sibling relationship factors?

Method

Participants

The sample included 215 typically developing adolescent siblings of individuals with ASD (n = 116) or DS (n = 99). For the combined sample, the mean age of the siblings was 14.94 (standard deviation (SD) = 1.75) years, and the mean age of the target child (the brother or sister with ASD or DS) was 13.41 (SD = 4.75) years. The gender split of the siblings was fairly even (53.5% female, n = 115), though nearly three-quarters of the target children were male (73.0%, n = 157). The majority of the respondents’ parents were married (83.7%, n = 180), and families averaged 3.27 children in the household. The two groups—ASD and DS—differed significantly on number of children in the family and age and gender of the target child, the latter of which is to be expected, given the preponderance of males diagnosed with ASD, compared to females (Centers for Disease Control and Prevention, 2016), and the former of which is consistent with previous research on families of individuals with DS (e.g. Burke et al., 2011). Full demographics of the two groups can be found in Table 1.

Table 1.

Demographic characteristics by group.

	ASD-Sibs (N = 116)		DS-Sibs (N = 99)		χ²/t value
	Mean (SD)	Sample (N, %)	Mean (SD)	Sample (N, %)	χ²/t value
Sibling gender
Female		55.2 (64)		51.5 (51)	0.29
Male		44.8 (52)		48.5 (48)
Sibling age (years)	15.00 (1.76)		14.87 (1.74)		0.59
Parents’ marital status
Married		81.0 (94)		86.9 (86)	1.33
Not married		19.0 (22)		13.1 (13)
Number of siblings	2.97 (1.45)		3.62 (1.51)		3.21**
Location
Urban		13.8 (16)		16.3 (16)	23.97***
Suburban		27.6 (32)		57.1 (56)
Rural		58.6 (68)		26.5 (26)
Target child age	14.78 (4.16)		11.82 (4.92)		−4.78***
Target child gender
Female		12.2 (14)		43.4 (43)	26.61***
Male		87.8 (101)		56.6 (56)

p < 0.01, ***p < 0.001.

Procedure

Recruitment

Siblings of individuals with ASD were recruited with the assistance of the Interactive Autism Network (IAN) Research Database at the Kennedy Krieger Institute in Baltimore, a research registry for individuals with ASD and their families. Siblings of individuals with DS were recruited with the assistance of various state and local DS organizations, identified through the Global Down Syndrome Foundation. Organizations were sent an e-mail with the eligibility information and link to the survey, which they could then choose to pass on to the families they serve. Institutional Review Board (IRB) approval information from the primary investigator was available upon request. Siblings were eligible to complete the survey if they were between the ages of 12 and 18 years, had no intellectual or developmental disabilities, and were living at home with the target child.

Survey completion

Because the majority of the participants were minors, the survey link was provided to parents, who first read the survey information and provided consent for their child to complete the survey. If the parent provided consent, then the sibling could access an information and assent page. Once consent from the parent and assent from the sibling were attained, the sibling could complete the questionnaire, which took 10–15 min. Upon completion, siblings were directed to a separate website, where they could provide their contact information and receive a US$20 electronic gift card as compensation. Compensation information was not linked to survey responses, keeping sibling answers anonymous.

In order to ensure adequate sample size, the survey was available online for 8 months. Both parents and siblings completed the survey using REDCap, a secure, online platform for surveys and databases (Harris et al., 2009). The survey was only available online. The entire survey was piloted with five local adolescents as young as 12 years to determine readability and approximate timing before it was disseminated to the intended research population.

Due to the online platform and wide distribution, the survey included a large number of spam and incomplete responses. Spam responses were determined by inconsistent responses (e.g. ages that did not match the older/younger distinction provided and monotype responses to a given instrument), instructional questions not part of the measures (e.g. “Please click ‘Never’”), and repetitive or illegible responses to open-ended questions (e.g. 25 respondents in a row all entering the same text-box answer). More than 90% of the responses (n = 2213) were deemed unusable and not included in the analyses.

Measures

Perceived Stress Scale

The 10-item version of the Perceived Stress Scale (PSS-10; Cohen and Williamson, 1988) was used to determine the siblings’ perceptions of overall stress in their lives. The PSS was chosen because of its brevity and general focus; that is, the questions address overall stress, not individual stressors that apply to certain subpopulations. Respondents rate 10 items on a 5-point Likert-type scale (0 = never to 4 = very often) in regard to how frequently they felt a certain way in the past month (e.g. “In the last month, how often have you felt you were unable to control the important things in your life?”). Four of the items were worded positively (e.g. “In the last month, how often have you felt that things were going your way?”) and were reverse-scored. Total scores ranged from 0 to 40. Chronbach’s α for the current sample was 0.82. The PSS has previously been used with children as young as 11 years (Nguyen-Rodriguez et al., 2008; α = 0.89).

Individual stressors

In addition to overall stress, siblings rated their individual stress due to specific factors in response to the question “How much stress do/does ______________ cause you?” Individual stressors provided were academics/school, extracurricular activities, friends/peers, girlfriend/boyfriend, family, sibling (e.g. the target child), physical environment, physical and mental health, and other. Examples were given for each topic to ensure understanding. Students rated the stress of each factor on a sliding scale of 0 (no stress) to 100 (the most stress).

The list of individual stressors was created for this survey to determine relative sources of overall self-reported stress. The list was piloted with the aforementioned local sample of adolescents, which led to the addition of examples for each topic. Individual stressors were only compared by group; they were not included in correlations or regression, as the current measure is not yet validated in a larger sample.

Demographics

In order to maximize sibling ability to respond to all questions without parental help, demographic information was kept at a minimum. Siblings provided their own age and gender, the age and gender of the target child, how many total siblings were in the family, their parents’ marital status, each parents work status (working or not working), and geographic classification (rural, urban, or suburban).

Multidimensional Scale of Perceived Social Support

Sibling perception of support received from family, friends, and significant other was assessed with the Multidimensional Scale of Perceived Social Support (MSPSS; Zimet et al., 1988). The MSPSS consists of 12 items ranked on a 7-point Likert-type scale (1 = very strongly disagree to 7 = very strongly agree) for a total score ranging from 7 to 84. The siblings responded to statements about perceived support from family (e.g. “My family really tries to help me”), friends (e.g. “I can count on my friends when things go wrong”), and significant others (e.g. “There is a special person who is around when I am in need”). Chronbach’s α for the total scale was 0.92. The MSPSS has been validated in children as young as 11 years (Bruwer et al., 2008; α = 0.88).

Sibling Relationship Inventory

The sibling’s perception of his or her relationship with the target child was measured with the Sibling Relationship Inventory (SRI; Stocker and McHale, 1992), which was developed for children and adolescents. The SRI consists of 17 items rated on a 5-point Likert-type scale describing how often the given events and feelings occur. These items are divided into three subscales: warmth (8 items; “How much do you admire your brother/sister or think he or she is pretty special or neat?” α = 0.78), rivalry (4 items; “How often do you feel that your mother treats your brother/sister better than she treats you?” α = 0.85), and hostility (5 items; “How often would you say you do things to your brother/sister like tease, bug, or call him or her names?” α = 0.76). The SRI has been previously used with children as young as 10 years (Padilla-Walker et al. (2010), α = 0.81).

Developmental Behavior Checklist

Level of behavior problems in the target child was measured with the 24-item Short Form of Developmental Behavior Checklist (DBC-P24; Taffe et al., 2007). The DBC-P24 was developed from the 96-item DBC (Einfeld and Tonge, 1995) to provide researchers with a brief measure and a single Total Behavior Problems score. Siblings rated the target child based on how often he or she exhibits problems behaviors (e.g. becomes overexcited, laughs or giggles for no obvious reason, tells lies), using a 3-point scale (0 = not at all, 1 = somewhat or sometimes true, and 2 = very true or often true). Due to concerns from the IRB, item 8 (inappropriate sexual activity with another) was removed, leaving 23 items for a total score of 0–46. Chronbach’s α for the current sample was 0.80. Although the DBC is typically completed by parents, the measure has a fifth-grade reading level, making it appropriate for the adolescents completing the current survey.

Data analysis

For research questions 1 and 2—group differences in stress, social support, sibling relationship, and brother/sister behavior problems—variables were compared between groups using t-tests. Effect sizes were calculated by dividing the mean difference by the pooled SD to determine Cohen’s d. For research question 3—how individual and family factors relate to self-reported stress (per the total score of the PSS)—relations were determined using bivariate correlations, t-tests (to compare stress by dichotomous variables), and two-way analyses of variance (ANOVAs) to test any interactions between variables as they relate to stress. Finally, for research question 4—how group membership relates to stress (as measured by the PSS) when accounting for individual and family factors—hierarchical linear regression was used. Model 1 included factors that have been previously found to be related to sibling outcomes in the literature: target child behavior problems and perceived social support. Model 2 added sibling relationship factors. Finally, Model 3 added group membership to determine whether or not ASD versus DS was related to sibling stress above and beyond other factors. Because the group membership factor was significant, Model 4 added the interaction term of target child behavior problems and group membership.

Because multiple scales from the same measure were included in some regression models, collinearity diagnostics were run. All variables included in the model had variance inflation factors (VIF, a measure of how much variance is inflated due to collinearity) of <2, which is well below the value of 10 that is generally accepted as indicative of collinearity (Mela and Kopalle, 2002). All regression models controlled for target child age and gender, residential setting, and total number of children in the family.

No single variable had more than two missing responses (<1%); therefore, mean imputation was used, following the recommendation of Harrell (2001). The sample sizes and distribution of the dependent variable met the assumptions for the conducted analyses (Anscombe, 1973; Sawilowsky and Blair, 1992).

Results

Research question 1

ASD-Sibs reported significantly greater overall stress than did DS-Sibs (t(213) = –4.62, p < 0.001), which is indicative of a moderate effect size (d = 0.64). The mean overall stress level for ASD-Sibs was 20.23 on a 40-point scale, which is approximately equivalent to siblings indicating that they “sometimes” feel generally stressed. In comparison, the mean reported stress level for DS-Sibs was 16.58 (SD = 6.26), which is nearly 10% lower than ASD-Sibs on the 40-point scale. In regard to specific stressors and independent variables, DS-Sibs reported significantly more stress due to extracurricular activities (t(213) = 3.01, p < 0.01), and ASD-Sibs reported more stress due to the brother/sister (t(213) = –3.23, p < 0.01).

Research question 2

ASD-Sibs reported significantly more brother/sister behavior problems than DS-Sibs (t(213) = –2.85, p<0.01) and significantly less warmth in the sibling relationship (t(213) = 3.01, p < 0.01). There were no group differences in hostility or conflict in the sibling relationship or in any type of perceived social support. Group means and t values for all included variables can be found in Table 2.

Table 2.

Variable means (SD) by group.

	ASD-Sib	DS-Sib	t value	Cohen’s d
Total stress	20.23 (5.18)	16.58 (6.26)	−4.62***	0.64
Family support	18.12 (5.40)	18.10 (4.97)	−0.03	0.00
Friends’ support	17.42 (6.08)	17.17 (5.84)	−0.31	0.04
Significant other support	18.55 (5.17)	17.69 (5.40)	−1.20	0.16
Sibling warmth	17.07 (6.14)	19.23 (4.36)	3.01**	0.41
Sibling hostility	6.45 (3.29)	6.12 (3.61)	−0.66	0.10
Sibling conflict	5.90 (3.72)	5.52 (4.44)	−0.68	0.09
Target child behavior problems	19.53 (7.46)	16.76 (6.71)	−2.85**	0.39
Specific stressors
Academics	65.17 (23.19)	63.75 (23.81)	−0.44	0.06
Extracurricular activities*	33.41 (25.90)	44.30 (25.74)	3.00**	0.42
Social life	41.79 (30.51)	42.33 (27.07)	0.13	0.02
Romantic life/significant other	23.63 (29.64)	23.47 (29.79)	−0.04	0.01
Family	55.05 (27.46)	49.84 (29.63)	−1.32	0.18
Target child	48.25 (27.90)	36.41 (24.60)	−3.23**	0.45
General environment	31.68 (27.44)	25.71 (27.11)	−1.59	0.22
Personal health	42.66 (32.78)	41.05 (31.05)	−0.36	0.05

p < 0.01, ***p < 0.001.

Research question 3

Sibling stress was significantly positively correlated with target child behavior problems and negatively correlated with all perceived social support. Stress was not correlated with any aspect of the sibling relationship, although both conflict and hostility were positively correlated with target child behavior problems. The full correlation matrix can be found in Table 3.

Table 3.

Bivariate correlation matrix.

	1	2	3	4	5	6	7
1. Total stress
2. Target child behavior problems	0.39
3. Family support	−0.43	−0.27
4. Friend support	−0.25	−0.10	0.59
5. Significant other support	−0.26	−0.15	0.48	0.55
6. Sibling warmth	−0.04	0.03	0.10	0.19	0.18
7. Sibling hostility	0.06	0.20	−0.93	−0.09	−0.09	−0.25
8. Sibling conflict	0.10	0.24	−0.15	−0.07	−0.04	−0.08	0.50

The values in italics: p < 0.05; values in boldface: p < 0.01.

Overall stress levels were also compared by sibling and target child gender. Female siblings (M = 19.26, SD = 5.79) reported marginally more stress than male siblings (M = 17.73, SD = 6.11; t(213) = –1.89, p = 0.06), and siblings of brothers (i.e. target child was male) reported significantly more stress (M = 19.40, SD = 5.77) than siblings of sisters (M = 16.11, SD = 5.91; t(213) = 3.67, p < 0.001). However, two-way ANOVA yielded a non-significant interaction term for group membership by target child gender, (F(1, 211) = 0.07, p = 0.79), which indicates that the stress difference by target child gender is likely driven by the preponderance of male target children in the ASD group.

Research question 4

Regression model 1 included target child behavior problems and perceived social support. Behavior problems and family support were significantly related to sibling stress; support from friends and significant others were not. Model 2 added sibling warmth, hostility, and conflict, none of which independently related to sibling stress nor significantly improved the model fit. Model 3 added group membership (ASD vs DS), which was independently related to sibling stress and significantly improved the variance explained by the model. Finally, because of the group difference in target child behavior problems, the interaction term of group and behavior problems was added, which independently related to sibling stress and improved the variance explained by the model. Cohen’s f² for the final model was 0.61, indicating a moderate effect size. Regression coefficients and R² values can be found in Table 4.

Table 4.

Regression coefficients for hierarchical linear models of sibling stress.

	B	Standard error	β	R²	ΔR²
Model 1
Target child behavior problems	0.22	0.05	0.27***
Family support	−0.37	0.09	−0.32***
Friend support	−0.07	0.07	−0.07
Significant other support	0.01	0.09	0.01	0.30
Model 2
Target child behavior problems	0.22	0.06	0.26***
Family support	−0.37	0.09	−0.32***
Friend support	−0.08	0.07	−0.08
Significant other support	0.01	0.09	0.01
Sibling warmth	0.03	0.07	0.03
Sibling hostility	0.01	0.12	0.01
Sibling conflict	0.01	0.11	0.01	0.30	0.00
Model 3
Target child behavior problems	0.19	0.05	0.22**
Family support	−0.37	0.09	−0.32***
Friend support	−0.08	0.07	−0.08
Significant other support	−0.03	0.09	−0.03
Sibling warmth	0.07	0.07	0.06
Sibling hostility	0.03	0.12	0.02
Sibling conflict	0.00	0.11	0.00
Group (ASD vs DS)	3.04	0.81	0.25***	0.35	0.05***
Model 4
Target child behavior problems	0.20	0.05	0.25***
Family support	−0.36	0.09	−0.31***
Friend support	−0.11	0.07	−0.11
Significant other support	0.00	0.09	0.00
Sibling warmth	0.09	0.07	0.09
Sibling hostility	0.06	0.12	0.04
Sibling conflict	0.03	0.11	0.02
Group (ASD vs DS)	8.53	1.96	0.71***
Group × behavior problems	−0.31	0.10	−0.50**	0.38	0.03**

p < 0.01, ***p < 0.001.

Figure 1 illustrates that stress reported by ASD-Sibs did not differ by level of brother/sister behavior problems, but DS-Sibs who reported lower levels of brother/sister behavior problems reported less overall stress than both ASD-Sibs and DS-Sibs who reported high levels of brother/sister behavior problems.

Figure 1.

Interaction between group membership and brother/sister behavior problems on sibling stress.

Discussion

This study sought to examine self-reported stress among adolescent siblings of individuals with ASD or DS and how such stress related to individual and family factors. Results indicate that siblings of individuals with ASD report significantly higher levels of overall stress than do siblings of individuals with DS, despite roughly equal reports of support from family members, friends, and significant others. Additionally, group membership was significantly related to overall stress, even when controlling for demographics, social support, and behavior problems among the target child.

The higher levels of stress reported by siblings of individuals with ASD are novel among the current population, though it is in line with previous findings of increased stress in mothers of children with ASD (e.g. Hayes and Watson, 2013). As all of the participating siblings still live at home with the target child, it is likely that the sibling is exposed to many of the same environmental and behavioral factors that cause stress in mothers. It is important to note that although ASD-Sibs did report greater stress related to their brother/sister, the PSS is designed to measure overall stress and does not include questions specific to family experiences or siblings. Therefore, though the target child may be a contributing factor, the increased stress experienced by ASD-Sibs is general.

In addition to significant differences in stress, target children in the ASD group had significantly higher levels of behavior problems than target children in the DS group, which fits with findings from previous studies (e.g. Griffith et al., 2010). However, though behavior problems were significantly related to sibling stress, group membership was as well suggesting that increased behavior problems among children with ASD were not the sole contributor to increased sibling stress. These findings support existing research that the experiences of siblings of individuals with ASD are measurably different than those of siblings of individuals with other IDD.

Despite differences in overall stress, ASD-Sibs did not report any less social support from family, friends, or significant others than did DS-Sibs. This result is particularly salient, both in regard to the significant relation between family support and overall stress and in response to the possibility of different amounts of attention paid to the target child and the sibling by the parents (e.g. Petalas et al., 2009b). Although the target children in the ASD group had significantly more behavior problems, such additional family stressors did not seem to negatively impact siblings’ perception of support they received from their family members.

Collectively, these findings represent an important addition to the current knowledge on siblings of individuals with IDD. By measuring self-reported sibling stress, the researchers were able to gain new insight into sibling perceptions of their own experiences, as well as potential mediating factors in broader sibling outcomes. These results represent an important next step in understanding the processes that drive varying sibling outcomes. Among parents of children with IDD, including ASD, particularly mothers, findings of increased stress that relate to poorer mental and emotional well-being have led to the development of stress-management interventions for parents, many of which have resulted in significant reductions in stress and increases in positive outcomes.

Implications

The current results have several implications for research. The finding of increased stress among ASD-Sibs opens the door to future studies of stress among siblings and factors that contribute to or buffer the results of such stress. More research is needed to determine what aspects of having a brother or sister with ASD, in addition to behavior problems, cause stress among siblings, potentially including severity of intellectual disability and/or autistic symptoms. Future studies would also benefit from using varying measures of stress, beyond brief questionnaires. Additional surveys, as well as biological measures, can help researchers better understand when siblings experience significant increases in stress. Studies of diurnal cortisol in parents of children with ASD have revealed altered daily patterns of stress hormone, particularly in parents of children with increased behavior problems (Dykens and Lambert, 2013). Because siblings living at home are likely exposed to many of the same behavioral problems, it is possible that such siblings may also experience altered hormonal patterns in biological responses to increased stress. Such chemical differences can have long-term impacts on sibling development (e.g. Shirtcliff and Essex, 2008); thus, biological measures of stress are an important consideration for future researchers.

Theoretically, sibling researchers can continue to draw on findings from literature of children in families of individuals without disabilities. In particular, the emotional security hypothesis (Davies and Cummings, 1994) can potentially be applied to the experiences of siblings of individuals with IDD. Davies and Cummings describe how marital conflict can affect children’s outcomes; in families of individuals with IDD, behavior problems could also serve as destabilizing events in children’s lives, impacting siblings’ emotional security and causing siblings stress. The application of the emotional security hypothesis can help better understand the family processes and environmental factors that contribute to individual differences in sibling outcomes.

Limitations and strengths

This study has several limitations that should be considered by researchers and clinicians. First, due to a desire to keep the survey short and accessible to adolescents as young as 12 years, limited demographics were collected. Thus, the racial, geographic, and socioeconomic makeup of the sample is unknown, so full generalizability cannot be determined. Although IAN is a national database and DS organizations from across the country were contacted, the survey did not ask participants to indicate their state of residence. Thus, it is unknown how many states were represented in the final sample. Because the survey was only available online, it is possible that the sample skews toward families of higher socioeconomic status. The lack of information on geographic and socioeconomic information also relates to the fact that the full response rate for the sample is unknown. Therefore, it is possible that the current sample comprised individuals who, for various reasons, do not represent the full population of ASD and DS siblings. Additionally, the short nature of the survey also meant that several potentially contributory variables were left out, including the siblings’ personal resilience traits and recent stressful life events. Finally, the use of entirely sibling report may have provided an incomplete picture of target child behavior problems; future research may benefit from multiple reporters.

Perhaps most importantly, as with all online surveys, it was not possible to fully assess the veracity of all participants’ claims to group membership. Although the parent consent form specified that all participating siblings be free from IDD, it is possible that siblings, particularly ASD-Sibs, could have sub-threshold levels of autistic symptoms. Given recent findings of the gender differences in the heritability of ASD (e.g. Zhao et al., 2007) and the gender differences in stress found in this study and others, understanding the interplay of genetic and environmental factors is especially important for studying siblings. Additionally, due to potential comorbidity of ASD and DS, it is possible that target children in the DS group also had autistic symptoms. Although behavior problems are often the most salient aspect of symptom severity for siblings (e.g. Hastings, 2003; Shivers et al., 2013), future studies would benefit from assessing more factors of the target child’s disability.

These limitations are offset by a number of strengths. First, the sample size is larger than that of many sibling studies, allowing for the inclusion of more variables in the final regression model, including control variables to account for group differences in demographics. This model then showed that group membership (e.g. ASD vs DS) significantly predicted sibling stress above and beyond behavior problems, perceived social support, and age and gender of the sibling and target child, highlighting the robustness of the finding. Additionally, the use of self-report is an important aspect of sibling research, as studies have shown that parent and sibling report of the sibling experience frequently differs (e.g. Guite et al., 2004; Senner and Fish, 2010). Finally, the use of comparison groups allowed researchers to examine how reports of stress compare based on the nature of the target child’s disability, as well as what individual factors correlate with stress.

Conclusion

The present findings are, to our knowledge, the first to illustrate significant differences in self-reported stress between ASD-Sibs and DS-Sibs. These results provide an important step in describing how siblings may experience emotional and mental health outcomes that have been found in caregivers of individuals with ASD and provide a foundation for future research into sibling stress, including the eventual development of interventions to address high levels of stress.

Supplemental Material

AUT722432_Lay_Abstract – Supplemental material for Self-reported stress among adolescent siblings of individuals with autism spectrum disorder and Down syndrome

Supplemental material, AUT722432_Lay_Abstract for Self-reported stress among adolescent siblings of individuals with autism spectrum disorder and Down syndrome by Carolyn M Shivers, Casey McGregor and Ashlea Hough in Autism

Footnotes

Acknowledgements

Data from this article have never been presented at a regional, national, or international conference, either in oral or poster form. The authors would like to thank the families of participants for their contributions. The authors would like to thank the Virginia Tech Center for Autism Research and Dr Angela Scarpa-Friedman for their support in instrument development and recruitment.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

References

Anscombe

(1973) Graphs in statistical analysis. The American Statistician 27: 17–21.

Arnett

(1999) Adolescent storm and stress, reconsidered. The American Psychologist 54: 317–326.

Baxter

Cummins

Yiolitis

(2000) Parental stress attributed to family members with and without disability: a longitudinal study. Journal of Intellectual & Developmental Disability 25: 105–118.

Boyd

(2002) Examining the relationship between stress and lack of social support in mothers of children with autism. Focus on Autism and Other Developmental Disabilities 17: 208–215.

Bruwer

Emsley

Kid

et al . (2008) Psychometric properties of the Multidimensional Scale of Perceived Social Support in youth. Comprehensive Psychiatry 49: 195–201.

Burke

Urbano

Hodapp

(2011) Subsequent births in families of children with disabilities: using demographic data to examine parents’ reproductive patterns. American Journal on Intellectual and Developmental Disabilities 116(3): 233–245.

Centers for Disease Control and Prevention (2016) Autism spectrum disorder (ASD): identified prevalence of autism spectrum disorder. Available at: http://www.cdc.gov/ncbddd/autism/data.html (accessed 14 January 2017).

Cicirelli

(1995) Sibling Relationships across the Life Span. New York: Plenum Press.

Cohen

Williamson

(1988) Perceived stress in a probability sample of the US. In: Spacapam

Oskamp

(eds) The Social Psychology of Health: The Claremont Symposium on Applied Social Psychology. Newbury Park, CA: SAGE, pp.31–67.

10.

Cuskelly

Gunn

(2003) Sibling relationships of children with Down syndrome: perspectives of mothers, fathers, and siblings. American Journal on Mental Retardation 108: 234–244.

11.

Davies

Cummings

(1994) Marital conflict and child adjustment: an emotional security hypothesis. Psychological Bulletin 116: 387–411.

12.

Dykens

Lambert

(2013) Trajectories of diurnal cortisol in mothers of children with autism and other developmental disabilities: relations to health and mental health. Journal of Autism and Developmental Disorders 43: 2426–2434.

13.

Einfeld

Tonge

(1995) The developmental behavior checklist: the development and validation of an instrument to assess behavioral and emotional disturbance in children and adolescents with mental retardation. Journal of Autism and Developmental Disorders 25: 81–104.

14.

Estes

Munson

Dawson

et al . (2009) Parenting stress and psychological functioning among mothers of preschool children with autism and developmental delay. Autism 13: 375–387.

15.

Gau

Chou

Lee

et al . (2010) Behavioral problems and parenting style among Taiwanese children with autism and their siblings. Psychiatry and Clinical Neurosciences 64: 70–78.

16.

Giallo

Gavidia-Payne

(2006) Child, parent and family factors as predictors of adjustment for siblings of children with a disability. Journal of Intellectual Disability Research 50: 937–948.

17.

Goudie

Havercamp

Jamieson

et al . (2013) Assessing functional impairment in siblings living with children with disability. Pediatrics 132: e476–e483.

18.

Griffith

Hastings

Nash

et al . (2010) Using matched groups to explore child behavior problems and maternal well-being in children with Down syndrome and autism. Journal of Autism and Developmental Disorders 40: 610–619.

19.

Guite

Lobato

Kao

et al . (2004) Discordance between sibling and parent reports of the impact of chronic illness and disability on siblings. Children’s Health Care 33: 77–92.

20.

Harrell

(2001) Regression Modeling Strategies. New York: Springer.

21.

Harris

Taylor

Thielke

et al . (2009) Research electronic data capture (REDCap) – a metadata-driven methodology and workflow process for providing translational research informatics support. Journal of Biomedical Informatics 42(2): 377–381.

22.

Hastings

(2003) Behavioral adjustment of siblings of children with autism engaged in applied behavior analysis early intervention programs: the moderating role of social support. Journal of Autism and Developmental Disorders 33: 141–150.

23.

Hastings

Petalas

(2014) Self-reported behaviour problems and sibling relationship quality by siblings of children with autism spectrum disorder. Child: Care, Health and Development 40: 833–839.

24.

Hayes

Watson

(2013) The impact of parenting stress: a meta-analysis of studies comparing the experience of parenting stress in parents of children with and without autism spectrum disorder. Journal of Autism and Developmental Disorders 43: 629–642.

25.

Hodapp

Urbano

(2007) Adult siblings of individuals with Down syndrome versus with autism: findings from a large-scale US survey. Journal of Intellectual Disability Research 51: 1018–1029.

26.

Hodapp

Glidden

Kaiser

(2005) Siblings of persons with disabilities: toward a research agenda. Mental Retardation 43: 334–338.

27.

Hodapp

Fidler

et al . (2001) Less stress, more rewarding: parenting children with Down syndrome. Parenting 1: 317–337.

28.

Kaminsky

Dewey

(2002) Psychosocial adjustment in siblings of children with autism. Journal of Child Psychology and Psychiatry 43: 225–232.

29.

Knott

Lewis

Williams

(1995) Sibling interaction of children with learning disabilities: a comparison of autism and Down’s syndrome. Journal of Child Psychology and Psychiatry and Allied Disciplines 36: 965–976.

30.

Leadbeater

Blatt

Quinlan

(1995) Gender-linked vulnerabilities to depressive symptoms, stress, and problem behaviors in adolescents. Journal of Research on Adolescence 5: 1–29.

31.

Lovell

Wetherell

(2015) Child behaviour problems mediate the association between coping and perceived stress in caregivers of children with autism. Research in Autism Spectrum Disorders 20: 17–23.

32.

Lovell

Wetherell

(2016) The psychophysiological impact of childhood autism spectrum disorder on siblings. Research in Developmental Disabilities 49: 226–234.

33.

Martin

Kazarian

Breiter

(1995) Perceived stress, life events, dysfunctional attitudes, and depression in adolescent psychiatric inpatients. Journal of Psychopathology and Behavioral Assessment 17: 81–95.

34.

Mela

Kopalle

(2002) The impact of collinearity on regression analysis: the asymmetric effect of negative and positive correlations. Applied Economics 34: 667–677.

35.

Neece

Blacher

Baker

(2010) Impact on siblings of children with intellectual disability: the role of child behavior problems. American Journal on Intellectual and Developmental Disabilities 115: 291–306.

36.

Neely Barnes

Graff

(2011) Are there adverse consequences to being a sibling of a person with a disability? A propensity score analysis. Family Relations 60: 331–341.

37.

Nguyen-Rodriguez

Chou

Unger

et al . (2008) BMI as a moderator of perceived stress and emotional eating in adolescents. Eating Behaviors 9(2): 238–246.

38.

Orsmond

Seltzer

(2007) Siblings of individuals with autism or Down syndrome: effects on adult lives. Journal of Intellectual Disability Research 51: 682–696.

39.

Orsmond

Kuo

Seltzer

(2009) Siblings of individuals with an autism spectrum disorder: sibling relationships and wellbeing in adolescence and adulthood. Autism 13: 59–80.

40.

Padilla-Walker

Harper

Jensen

(2010) Self-regulation as a mediator between sibling relationship quality and early adolescents’ positive and negative outcomes. Journal of Family Psychology 24(4): 419.

41.

Petalas

Hastings

Nash

et al . (2009a) Emotional and behavioural adjustment in siblings of children with intellectual disability with and without autism. Autism 13: 471–483.

42.

Petalas

Hastings

Nash

et al . (2009b) “I like that he always shows who he is”: the perceptions and experiences of siblings with a brother with autism spectrum disorder. International Journal of Disability, Development and Education 56: 381–399.

43.

Pollard

Barry

Freedman

et al . (2013) Relationship quality as a moderator of anxiety in siblings of children diagnosed with autism spectrum disorders or down syndrome. Journal of Child and Family Studies 22: 647–657.

44.

Rew

Johnson

Young

(2014) A systematic review of interventions to reduce stress in adolescence. Issues in Mental Health Nursing 35: 851–863.

45.

Robinson

Neece

(2015) Marital satisfaction, parental stress, and child behavior problems among parents of young children with developmental delays. Journal of Mental Health Research in Intellectual Disabilities 8: 23–46.

46.

Rodgers

Warhol

Fox

et al . (2016) Minimal risk of internalizing problems in typically-developing siblings of children with high-functioning autism spectrum disorder. Journal of Child and Family Studies 25: 2554–2561.

47.

Sawilowsky

Blair

(1992) A more realistic look at the robustness and Type II error properties of the t-test to departures from population normality. Psychological Bulletin 111: 352–360.

48.

Şenel

Akkök

(1996) Stress levels and attitudes of normal siblings of children with disabilities. International Journal for the Advancement of Counseling 18: 61–68.

49.

Senner

Fish

(2010) Comparison of child self-report and parent report on the sibling need and involvement profile. Remedial and Special Education 33: 103–109.

50.

Shirtcliff

Essex

(2008) Concurrent and longitudinal associations of basal and diurnal cortisol with mental health symptoms in early adolescence. Developmental Psychobiology 50: 690–703.

51.

Shivers

Dykens

(2017) Adolescent siblings of individuals with and without intellectual and developmental disabilities: self-reported empathy and feelings about their brothers and sisters. American Journal on Intellectual and Developmental Disabilities 122: 62–77.

52.

Shivers

Deisenroth

Taylor

(2013) Patterns and predictors of anxiety among siblings of children with autism spectrum disorders. Journal of Autism and Developmental Disorders 43: 1136–1346.

53.

Stocker

McHale

(1992) The nature and family correlates of preadolescents’ perceptions of their sibling relationships. Journal of Social and Personal Relationships 9: 179–195.

54.

Stoneman

(2005) Siblings of children with disabilities: research themes. Mental Retardation 43: 339–350.

55.

Taffe

Gray

Einfeld

et al . (2007) Short form of the developmental behaviour checklist. American Journal of Mental Retardation 112: 31–39.

56.

Tomeny

Barry

Bader

(2014) Birth order rank as a moderator of the relation between behavior problems among children with an autism spectrum disorder and their siblings. Autism 18: 199–202.

57.

Verté

Roeyers

Buysse

(2003) Behavioural problems, social competence and self-concept in siblings of children with autism. Child: Care, Health and Development 29: 193–205.

58.

Zhao

Leotta

Kustanovich

V, et al.

et al (2007) A unified genetic theory for sporadic and inherited autism. Proceedings of the National Academy of Sciences of the United States of America 104: 12831–12836.

59.

Zimet

Dahlem

Zimet

et al . (1988) The Multidimensional Scale of Perceived Social Support. Journal of Personality Assessment 52: 30–41.

Supplementary Material

Please find the following supplemental material available below.

For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.

For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.

0.00 MB

0.11 MB