Symptoms of autism spectrum disorder and anxiety: shared familial transmission and cross-assortative mating

Background: In order to shed more light on the frequent co-occurrence of Autism Spectrum Disorder (ASD) and anxiety in children, the aims of the study were (a) to examine whether ASD and anxiety share familial transmission indicated by cross-symptom associations between parental and children's symptoms (e.g., parental anxiety predicting children's ASD) in addition to associations for similar symptoms; (b) to investigate the possibility that cross-assortative mating (i.e., whether ASD symptoms in one parent are positively associated with anxiety symptoms in the other parent) increases the risk for both ASD and anxiety in children. Method: In 231 families of clinically referred children, parents rated both their own and the other parent's ASD and anxiety symptoms and one parent those of the index child and siblings (n = 447, aged 2.5-18 years). ASD symptoms were assessed using the Social Responsiveness Scale (SRS-2) and anxiety symptoms using the Achenbach System of Empirically Based Assessment (ASEBA) instruments. Results: Parental ASD and anxiety symptoms predicted similar symptoms in children, dependent on the informant type. Additionally, parental anxiety symptoms across both self-report and informant-report predicted children's ASD symptoms and maternal self-reported ASD symptoms predicted children's anxiety symptoms. ASD and anxiety symptoms were correlated within parents, but we found only one cross-symptom association between parents. Conclusions: Cross-symptom associations between parental and children's ASD and anxiety symptoms suggest shared familial transmission of ASD and anxiety, but further research is needed to clarify the underlying mechanisms. Cross-assortative mating does not seem a likely explanation for the co-occurrence of ASD and anxiety in children.