Incidence of obsessive-compulsive disorder in adults.

This study addressed the incidence of obsessive-compulsive disorder (OCD) in adults in the general population. The Baltimore cohort of 3481 subjects, originally sampled during the 1981 multisite Epidemiologic Catchment Area Study, was traced. From 1993 to 1996, 1920 people were reinterviewed using the Diagnostic Interview Schedule. The incidence of DSM-III-R obsessive-compulsive disorder in adults was estimated at .55 per 1000 person-years. There was a relatively high rate of new cases in elderly women. It appeared that there were two peaks of onset of OCD over the life span, both of which occur later in female subjects. Subjects with adult incidence OCD often presented for psychiatric treatment, though they did not specify obsessive-compulsive symptoms as the reason. The difference in diagnostic criteria between DSM-III and DSM-III-R substantially influenced the threshold for new case identification.