ACUTE EFFECT OF ALTERED TRYPTOPHAN LEVELS AND ALCOHOL ON AGGRESSION IN NORMAL HUMAN MALES

Normal males received amino acid mixtures designed to raise-or lower t ryptophan availability, and thus to raise or lower brain serotonin syn thesis. They also received alcoholic or non-alcoholic drinks. The subj ects were tested in the Taylor Competitive Reaction Time Task in which they competed against a (non-existent) partner in a reaction time tas k. The magnitude of electric shocks that the subjects were willing to give to their bogus partner was used as a measure of aggression. Lower ed tryptophan levels and ingestion of alcohol were associated with inc reased aggression. Our data support the idea that low serotonin levels may be involved in the etiology of aggression. They suggest that subj ects with low brain serotonin levels may be particularly susceptible t o alcohol-induced violence.