Predictors of Clinically Significant Anxiety in Non-autistic Siblings of Children With Autism.

OBJECTIVE: As the prevalence of autism rises, attention to the well-being of siblings of autistic individuals is increasingly important. The present study aimed to identify predictors of clinically significant anxiety in non-autistic siblings of youth with autism. METHOD: Data were derived from the Simons Simplex Collection. Participants included 53 siblings with clinically significant anxiety (anxious group) and 53 siblings without elevated anxiety (comparison group), who were matched to the anxious group on various demographic characteristics. Logistic regression was used to assess factors associated with group status. A nonparametric supervised machine learning model was used to confirm predictor strength. RESULTS: Maternal anxiety emerged as a robust predictor of siblings being in the anxious group (b = 2.75, odds ratio [OR] = 15.56, p < 0.01). Stereotyped (b = 0.16, OR = 1.17, p = 0.04) and ritualistic behaviors (b = 0.28, OR = 1.32, p = 0.04) in probands, alongside poorer adaptive behavior in non-autistic siblings (b = -0.05, OR = 0.95, p = 0.01), were also significantly associated, albeit less strongly, with anxious group classification. CONCLUSION: Maternal anxiety may be a salient predictor of clinically significant anxiety in non-autistic siblings of youth with autism. The present findings offer novel insights for possible intervention considerations for autistic youth and their families.