Tryptophan Depletion and Behavioral Disinhibition in Men at Risk for Alcoholism and Antisocial Behavior

Abstract

The present studies tested the hypothesis that experimentally altering central nervous system serotonin (5-HT) synthesis through tryptophan depletion (T-) would increase behavioral disinhibition in susceptible individuals. The oral administration of a mixture of amino acids devoid of tryptophan (trp), the amino acid precursor of 5-HT, is a safe and effective method of lowering brain 5-HT synthesis, and presumably 5-HT function. Previous clinical studies have reported a negative relationship between brain serotonergic functioning and impulsivity. Impulsive fire-setters, particularly those with a family history of alcoholism, as well as impulsive violent offenders, have lower levels of cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA), a metabolite of 5-HT, compared to nonimpulsive violent offenders and healthy controls (Linnoila, De Jong & Virkkunen, 1989; Virkkunen et al., 1994). Two groups, selected on the basis of an increased risk for alcoholism or antisocial behavior, respectively, were tested: young men with multigenerational family histories of alcoholism, and adolescent males with past histories of aggressive, disruptive behavior.