Prolactin response to d-fenfluramine in obsessive-compulsive patients, and outcome of fluvoxamine treatment.

BACKGROUND Although several studies have directly explored serotonin (5-HT) transmission in patients with obsessive-compulsive disorder (OCD), their results have been inconsistent and their clinical relevance is doubtful. METHOD According to a double-blind placebo-controlled design, plasma prolactin (PRL) response to a specific serotonergic probe, d-fenfluramine, was measured in 20 drug-free obsessive-compulsive patients and in 20 matched healthy controls. After the neuroendocrine test, 15 patients completed a 10-week treatment with fluvoxamine. Psychopathological assessment was performed before and after therapy. RESULTS PRL response in OCD patients was blunted under the drug-free condition; correlated inversely with pretreatment ratings of obsessive-compulsive and depressive symptomatology; and correlated inversely with the improvement in obsessive-compulsive score observed after fluvoxamine treatment. CONCLUSIONS These results support the idea of a dysfunction of 5-HT transmission in OCD, and suggest that the greater this impairment, the better the response to drugs which selectively block the reuptake of 5-HT.