EFFECT OF FLUOXETINE ON MELATONIN IN PATIENTS WITH SEASONAL AFFECTIVE-DISORDER AND MATCHED CONTROLS

Background. The aim was to investigate the secretion profile of melato nin and seasonal affective disorder before and after treatment with fl uoxetine. Method. A six-week case-controlled study with repeated overn ight blood sampling was conducted. Ten patients fulfilling the criteri a for major depressive disorder, seasonal type, with a 29-item Hamilto n Depression Rating Scale (HDRS) score of at least 20 were compared wi th ten age- and sex-matched healthy controls in a clinical laboratory. The effects of fluoxetine (20 mg/day) on the HDRS and melatonin conce ntration were measured. Results. Fluoxetine significantly reduced mela tonin levels in both groups. There was no significant difference in me latonin secretion between the groups. Conclusions. The effect of fluox etine differs from tricyclics and fluvoxamine, both of which increase melatonin.