Childhood, adolescent and adult age at onset and related clinical correlates in obsessive–compulsive disorder: a report from the International College of Obsessive–Compulsive Spectrum Disorders (ICOCS)

Objective: Many studies suggest that age at onset (AAO) is an important factor for clinically differentiating patients with juvenile and adult onset of obsessive–compulsive disorder (OCD). The present international study aimed to assess the prevalence of different AAO groups and compare related socio-demographic and clinical features in a large sample of OCD patients. Methods: A total of 431 OCD outpatients, participating in the ICOCS network, were first categorised in groups with childhood (≤12 years), adolescent (13–17 years) and adult-onset (≥18 years), then in pre-adult and adult onset (≥18 years) and their socio-demographic and clinical features compared. Results: Twenty-one percent (n = 92) of the sample reported childhood onset, 36% (n = 155) adolescent onset, and 43% (n = 184) adult onset. Patients with adult onset showed a significantly higher proportion of females compared with the other subgroups (χ2=10.9, p< 0.05). Childhood- and adolescent-onset patients had been more frequently treated with cognitive behavioural therapy (CBT), compared to adult-onset patients (χ2=11.5; p < 0.05). The pre-adult- versus adult-onset analysis did not show any additional significant difference. Conclusions: The present international multicentre study confirms that OCD onset occurs more frequently before adult age, with approximately one out of five patients showing childhood onset. Pre-adult onset was associated with higher rate of CBT, while adult onset was more prevalent in females.