Obsessive-compulsive Disorder and the Risk of Subsequent Mental Disorders: A Community Study of Adolescents and Young Adults

Background: Comorbidity of obsessive-compulsive disorder (OCD) with other mental disorders has been demonstrated repeatedly. Few longitudinal studies, however, have evaluated the temporal association of prior OCD and subsequent mental disorders across the age period of highest risk for first onset of mental disorders. We examined associations between prior OCD and a broad range of subsequent mental disorders and simulated proportions of new onsets of mental disorders that could potentially be attributed to prior OCD, assuming a causal relationship.

Methods: Data from 3,021 14- to 24-year-old community subjects were prospectively collected for up to 10 years. DSM-IV OCD and other DSM-IV mental disorders were assessed with the Munich-Composite International Diagnostic Interview. We used adjusted time-dependent proportional hazard models to estimate the temporal associations of prior OCD with subsequent mental disorders.

Results: Prior OCD was associated with an increased risk of bipolar disorders (BIP; [hazard ratio, HR = 6.9, 95% confidence interval, CI, (2.8,17.3)], bulimia nervosa [HR = 6.8 (1.3,36.6)], dysthymia [HR = 4.4 (2.1,9.0)], generalized anxiety disorder (GAD; [HR = 3.4 (1.1,10.9)], and social phobia [HR = 2.9 (1.1,7.7)]). Of these outcome disorders, between 65 and 85% could be attributed to OCD in the exposed group, whereas between 1.5 and 7.7% could be attributed to OCD in the total sample.

Conclusions: This study provides strong evidence that prior OCD is associated with an increased risk of subsequent onset of BIP, bulimia nervosa, dysthymia, GAD, and social phobia among adolescents and young adults. Future studies should evaluate if early treatment of OCD can prevent the onset of these subsequent mental disorders.