Autistic traits and obsessive-compulsive symptom severity: a retrospective six-month follow-up study.

Autistic traits have been increasingly associated with obsessive-compulsive disorder (OCD), yet their influence on longitudinal symptom severity and treatment-related change remains poorly understood. This retrospective longitudinal study included 38 adults with DSM-5 OCD who completed six months of guideline-based pharmacological treatment. Obsessive-compulsive symptom severity was assessed using the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) at baseline, one month, and six months. Autistic traits were evaluated at the six-month follow-up using the Autism Spectrum Quotient (AQ). Linear mixed-effects models served as the primary analyses, while repeated-measures analyses of covariance were performed as sensitivity analyses. Exploratory analyses examined the contribution of individual AQ subscales. Higher autistic trait levels were independently associated with persistently greater OCD symptom severity across the six-month follow-up, whereas the rate of treatment-related improvement did not differ according to autistic trait levels. This association was primarily driven by compulsive rather than obsessive symptoms. Exploratory analyses further identified social skills and attention switching as the AQ dimensions most strongly associated with overall OCD severity and compulsive symptom burden, whereas attention to detail was not significantly associated with symptom severity. These findings suggest that autistic traits represent stable markers of greater clinical burden in OCD without necessarily conferring poorer pharmacological treatment responsiveness. The results further support a dimensional conceptualization of autistic traits and highlight social functioning as a potentially important contributor to OCD symptom burden.