Age of onset in obsessive-compulsive disorder: Admixture analysis with a large sample

Background Research into age of onset in obsessive-compulsive disorder (OCD) has indicated significant differences between patients with early and late onset of the disorder. However, multiple criteria have been used arbitrarily for differentiating between early-and late-onset OCD, rendering inconsistent results that are difficult to interpret. Method In the current study, admixture analysis was conducted in a sample of 377 OC patients to determine the number of underlying populations of age of onset and associated demographic and clinical characteristics. Various measures of anxiety, depression, co-morbidity, autism, OCD, tics and attention deficit hyperactivity disorder (ADHD) symptoms were administered. Results A bimodal age of onset was established and the best-fitting cut-off score between early and late age of onset was 20 years (early age of onset â