Influence of trait hostility on tryptophan depletion-induced laboratory aggression

Previous research has indicated that laboratory aggression in men increases after temporarily reducing the synthesis and neurotransmission of serotoni n (5-HT) in the brain using the plasma L-tryptophan (Trp) depletion techniq ue. Further research indicates that male subjects selected for high trait h ostility are particularly prone to increased aggression following plasma Tr p depletion. In a recent study of laboratory aggression in male control sub jects, we demonstrated that laboratory aggression increased following inges tion of a Trp-depleting beverage, but not after ingestion of a Trp-containi ng beverage nor under food-restricted conditions. We report here that the i ncreases in aggression under Trp-depleted conditions were specific to men w ho scored the highest on the Buss-Perry Aggression Questionnaire. These pre liminary data support earlier findings that compared to non-hostile men, ho stile men may be more prone to behavior change induced by the perturbation of the 5-HT neurotransmitter system. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.