The dexamethasone suppression test in patients with primary obsessive-compulsive disorder.

The dexamethasone suppression test (DST) was administered to 16 obsessive-compulsive disorder (OCD) patients. Six of these patients (37.5%) had an abnormal DST response. There was a trend for patients with the DST abnormality to have higher depression rating scale scores and a higher incidence of family history of affective illness compared to DST suppressors. Although 7 of the 16 OCD patients met DSM-III criteria for major depressive disorder, in every case the affective symptoms were secondary to the primary obsessional illness. The relationship of the DST to the specificity of psychiatric diagnoses is discussed.