The prevalence of clinically recognized obsessive-compulsive disorder in a large health maintenance organization

Little is known about the prevalence of obsessive-compulsive disorder (OCD) as recognized in clinical settings. The authors report data on the prevalence of clinically recognized OCD in a large, integrated, group practice health maintenance organization (HMO).

The authors examined the database of outpatient diagnoses for the 1.7 million people (age >or=6) in the San Francisco Bay Area and Sacramento who were continuously enrolled in Kaiser Permanente from May 1995 through April 1996. OCD diagnoses were confirmed by chart review.

The 1-year prevalence of clinically recognized OCD was 84/100,000 (95% confidence interval: 80-89/100,000), or 0.084%. It varied among the 19 clinics within the HMO but was nowhere higher than 150/100,000. Prevalence was higher among women than among men but was higher among boys than among girls. Above age 65, OCD prevalence decreased markedly in both genders. Period prevalence rates increased by 60% as the length of the study period doubled from 1 to 2 years, more than would be expected for a chronic disease requiring regular care. About three-quarters of both children and adults with OCD had comorbid psychiatric diagnoses; major depression was common in both groups.

Although previously reported prevalences of 1%-3% from community studies may have included many transient or misclassified cases of OCD not requiring treatment, the very low prevalence of clinically recognized OCD in this population suggests that many individuals suffering from OCD are not receiving the benefits of effective treatment.