Blunted prolactin responses to d-fenfluramine in sociopathy. Evidence for subsensitivity of central serotonergic function.

Using a neuroendocrine probe we studied nine male offenders in a forensic hospital, convicted of murder, with a diagnosis of antisocial personality disorder, who had been behaviourally 'quiescent' for varying periods and who had not recently been abusing drugs. Nine healthy age-matched men also participated. All subjects received 30 mg d-fenfluramine (d-FEN), a 5-HT releasing agent, orally, after an overnight fast, and serial samples for prolactin estimation were taken hourly for five hours. Responses were significantly impaired in the patients, suggesting a subsensitivity of certain 5-HT systems in antisocial personality disorder, regardless of recent or ongoing behavioural disturbance.