Autism spectrum disorders in adult outpatients with obsessive compulsive disorder in the UK

Objectives: Patients with obsessive compulsive disorder (OCD) frequently show traits of autism spectrum disorders (ASD). This is one of the first studies to explore the clinical impact of the overlap between OCD and ASD as a categorical diagnosis. Methods: A cross-sectional survey in 73 adult outpatients with DSM-IV OCD. Autistic traits were measured using the Autism-Spectrum Quotient (AQ). A clinical estimate ASD diagnosis was made by interview using DSM-IV-TR criteria. OCD patients with and without autistic traits or ASD were compared on demographic and clinical parameters and level of OCD treatment-resistance based on treatment history. Results: Thirty-four (47%) patients scored above the clinical threshold on the AQ (≥26) and 21 (27.8%) met diagnostic criteria for ASD. These diagnoses had not been made before. Patients with autistic traits showed a borderline significant increase in OCD symptom-severity (Yale-Brown Obsessive Compulsive Scale (Y-BOCS); p =.054) and significantly increased impairment of insight (Brown Assessment of Beliefs Scale; p =.01). There was a positive correlation between AQ and Y-BOCS scores (p =.04), but not with OCD treatment resistance. Conclusion: There is a high prevalence of previously undiagnosed ASD in patients with OCD. ASD traits are associated with greater OCD symptom-severity and poor insight.