Late-onset obsessive-compulsive disorder: a case series.

Obsessive-compulsive disorder (OCD) is a common and potentially disabling illness with onset usually in the second or third decade of life. Onset after age 50 is relatively rare and may be more likely to have an organic etiology. Out of an OCD patient population of over 1,000, the authors found 5 cases in which symptoms of OCD first developed late in life. Four of the 5 patients had intracerebral lesions in the frontal lobes and caudate nuclei, findings consistent with current theories about the pathogenesis of "idiopathic" OCD.