BLUNTED SEROTONERGIC RESPONSIVITY IN DEPRESSED INPATIENTS

We found a 38% lower maximal prolactin response to an oral challenge d ose of 60 mg of dl-fenfluramine relative to placebo in younger (<30 ye ars) depressed inpatients compared with the response in age-matched he althy controls (p < .03). Severity of depression did not correlate wit h prolactin response. Prolactin responses in older depressed patients (greater than or equal to 30 years) did not differ from older controls . Younger depressed patients differed from older depressed patients in terms of earlier age of onset of first lifetime episode of major depr ession, greater degree of suicidal intent during a recent suicide atte mpt, double the level of hopelessness on admission to hospital, and a higher rate of comorbid borderline personality disorder. A blunted pro lactin response to fenfluramine may be interpreted as evidence for red uced serotonergic function in younger depressed patients and may under lie their observed greater suicidality and hopelessness.