Hormonal responses to fenfluramine in depressive subtypes.

In order to study putative differences in central neurotransmitter function in depressive subtypes, serum cortisol and prolactin responses to the putative serotonin agonist fenfluramine were examined in 30 subjects with major depression. Patients with endogenous depression (melancholia) as defined by each of ICD-9, DSM-III, RDC and Newcastle scale demonstrated a reduced prolactin response to 60 mg oral fenfluramine when compared with non-endogenous subjects. This was independent of either prolactin or cortisol baseline levels, and indicates that there are differences in brain neurotransmitter function in the endogenous and non-endogenous subtypes of depression. Basal prolactin levels were reduced in bipolar compared with unipolar subjects, and delusional compared with non-delusional patients, although there were no differences in the prolactin responses to fenfluramine between these subgroups. Basal cortisol levels and cortisol response to fenfluramine did not distinguish between any of the subtypes.