Psychiatric disorders in the families of patients with obsessive-compulsive disorder.

The rate of comorbid diagnoses in a group of 92 patients with obsessive-compulsive disorder (OCD) was examined, with particular attention being paid to mood disorders. The family history method was used to study the frequency of psychiatric disorders in the patients' families and to analyze the characteristics of the familial loading for OCD and mood disorders. A comorbid diagnosis of mood disorder occurred in 35.9% of the patients. The morbidity risk for OCD in the patients' families accounted for 3.4%; when 21 patients with an age of onset under 14 were examined, the morbidity risk in first degree relatives reached 8.8%. This tendency did not appear to be true for mood disorders.