Plasma prolactin response to d-fenfluramine in obsessive—compulsive patients before and after fluvoxamine treatment

The prolactin (PRL) responses to oral d-fenfluramine (30 mg) and placebo were assessed in 13 patients with obsessive—compulsive disorder (OCD) and in matched healthy subjects. After the neuroendocrine test, all patients were treated with fluvoxamine maleate (150–300 mg/day). At the end of the 10th week of treatment, 10 patients underwent again the neuroendocrine assessment. In drug-free patients, the PRL response to d-fenfluramine was significantly lower than in the comparison group. After 10-week fluvoxamine treatment, the PRL response to the serotonergic agent normalized. These findings suggest that, at least at the neuroendocrine level, central serotonergic responsivity is reduced in drug-free OCD patients, and that long-term fluvoxamine administration is associated with its normalization.