Comorbidity of obsessive-compulsive and psychotic symptoms: a review.

Co-occurrence of psychotic and obsessive-compulsive symptoms was first reported nearly 70 years ago. This paper reviews published reports from two perspectives: psychotic disorders with obsessive-compulsive symptoms and obsessive-compulsive disorder (OCD) with psychotic symptoms. Older investigations reported a low rate of comorbidity between these two disorders, but more-recent studies, in which systematic diagnostic criteria have been used, have suggested that the rate of co-occurrence of symptoms is higher than was previously thought. The difficulty in diagnosing patients with obsessive-compulsive and psychotic symptoms is reviewed, and the importance of this distinction for treatment and prognosis is discussed. Although the comorbid diagnosis of schizophrenia and OCD, or of OCD and psychotic features, seems to portend a worse prognosis than for either illness alone, the available data suggest that some patients with schizophrenia and OC symptoms may improve with traditional antiobsessional treatment.