Plasma prolactin (PRL) response to fenfluramine (FF) (60 mg orally) and placebo challenge was examined in eight remitted depressed patients who were withdrawn for 14 days from maintenance pharmacotherapy with clomipramine (CMI) plus lithium carbonate (Li) (n = 6) or Li alone (n = 2), 6 months after recovering from their major depressive episode. The patients had undergone identical FF challenge tests while drug free prior to commencing treatment with electroconvulsive therapy (ECT) (n = 4) or CMI supplemented with Li (n = 4) and after completing the above treatments. PRL response to FF in the remitted, drug-free state was significantly enhanced compared to the response prior to treatment (while depressed and drug-free) and not significantly different from the response following treatment with ECT (n = 4) or CMI plus Li (n = 4) 6 months before. Other work of a similar nature supports the view that enhanced serotonergically mediated hormone release in drug-withdrawn, remitted depressives, represents a long-standing change in central serotonergic responsiveness and not a continued effect of antidepressant treatment or a manifestation of medication withdrawal.