Subclinical autism spectrum symptoms in pediatric obsessive–compulsive disorder

Trine Wigh Arildskov, David R. M. A. Højgaard, Gudmundur Skarphedinsson, Per Hove Thomsen, Tord Ivarsson, Bernhard Weidle, Karin Holmgren Melin, Katja A. Hybel

The literature on subclinical autism spectrum (ASD) symptoms in pediatric obsessive-compulsive disorder (OCD) is scarce, and it remains unclear whether ASD symptoms are related to OCD severity. The aims of the present study were to assess the prevalence of ASD symptoms and age and sex differences in children and adolescents with OCD, and to explore the relation between ASD symptoms and OCD severity. This is the largest study of ASD symptoms in an OCD population to date, and the first directly aimed at elucidating sex and age differences in this matter. The study used baseline data from the Nordic Long-term OCD Treatment Study in which parents of 257 children and adolescents with OCD aged 7-17 completed the Autism Spectrum Screening Questionnaire. OCD severity was assessed with the Children's Yale-Brown Obsessive Compulsive Scale. Pediatric OCD patients were found to exhibit elevated rates of ASD symptoms compared to a norm group of school-age children. ASD symptoms were concentrated in a subgroup with a prevalence of 10-17 %. This subgroup was characterized by a male preponderance with a sex ratio of approximately 2.6:1, while children versus adolescents with OCD exhibited similar rates. Autism-specific social and communication difficulties were not related to OCD severity, while restricted repetitive behavior was positively related to OCD severity. The results indicate that clinicians need to be aware of ASD symptoms in children and adolescents with OCD since one out of ten exhibits such symptoms at a clinical sub-threshold.