BEHAVIORAL AND NEUROENDOCRINE RESPONSES TO M-CHLOROPHENYLPIPERAZINE IN SUBTYPES OF ALCOHOLICS AND IN HEALTHY COMPARISON SUBJECTS

Objective: The purpose of this study was to explore central serotonerg ic functions in subgroups of alcoholics and in health comparison subje cts. Method: The mixed serotonin (5-HT) agonist/antagonist m-chlorophe nylpiperazine (m-CPP) was administered to male alcoholic patients who were classified according to the criteria of von Knorring et al. as ty pe I alcoholics (late onset) (N=16) or type II alcoholics (early onset with antisocial traits) (N=24) and to 22 healthy comparison subjects. Psychological, physiological, and neuroendocrine measures were obtain ed before and after the m-CPP infusion. Results: m-CPP elicited subtyp e-related differential effects among the alcoholics; the type I alcoho lics reported more anger and anxiety, and the type II alcoholics repor ted increased euphoria and a greater likelihood of drinking. The healt hy comparison subjects exhibited a greater increase in plasma ACTH res ponse to the m-CPP infusion than the alcoholics regardless of subtype. Conclusions: Differences in certain 5-HT receptor functions may expla in some of the clinical characteristics that differentiate the type II and type I subgroups of alcoholic patients. Furthermore, alcoholics m ay have reduced sensitivity of 5-HT2C receptors in comparison with hea lthy subjects.