ABNORMAL SEROTONERGIC CONTROL OF PROLACTIN AND CORTISOL SECRETION IN PATIENTS WITH SEASONAL AFFECTIVE-DISORDER

The effects of the serotonergic agent d,l-fenfluramine (60 mg PO) or a placebo on serum prolactin (PRL) and cortisol levels were evaluated i n seven patients (five men and two women) with seasonal affective diso rders (SAD) and in eight normal controls (eight men and two women). Bo th groups were tested in fall/winter when patients with SAD suffered d epressive symptoms and in spring/summer, when patients were euthymic. Spring/summer and fall/winter tests gave similar results. PRL and cort isol patterns were similar in all subjects after placebo, whereas both hormonal responses to d,l-fenfluramine were significantly lower in pa tients with SAD than in normal controls. Correlation studies between t he two hormonal responses revealed that on both periods the amplitudes of PRL and cortisol increments were significantly and positively corr elated in patients with SAD. These data show diminished serotonergic r esponsiveness in SAD regardless of the actual depressive status of the patients. They are consistent with a decrease of central serotonergic activity in SAD.