Student Prize Award Abstract
1996 Poster Paper Award

THE TREATMENT OF SELF-INJURIOUS BEHAVIOR IN RHESUS MONKEYS USING A SEROTONIN ENHANCING AGENT

K.P. Weld, J.A. Mench, and R.A. Woodward
National Institute of Alcohol Abuse and Alcoholism, Laboratory of Comparative Ethology, Poolesville, MD 20837, U.S.A.

The purpose of this study was to investigate the potential of tryptophan as a pharmacological treatment for spontaneous, self-directed aggression. Tryptophan in primates is converted centrally to serotonin (5-HT), which is implicated in the mediation of many behaviors including aggression. The subjects were three rhesus monkeys (Macaca mulatta) located at the National Institutes of Health Animal Center in Poolesville, Maryland. Subjects had a recent history of self-inflicting wounds that required clinical attention. Following primary wound treatment, subjects were placed on a dietary supplement of L-tryptophan (TRP). Behavioral data and cerebrospinal fluid (CSF) were collected at scheduled intervals during one week of placebo pretest, two treatment periods each lasting three weeks (period one = 50 mg TRP/kg dose and period two = 100 mg TRP/kg dose) and a two week placebo posttest. Self-aggressive behaviors decreased (p<.05) and CSF concentrations of the serotonin metabolite, 5-hydroxyindolacetic acid, increased as a result of tryptophan administration (p<.05). Self-aggression did increase during the posttest placebo period but not to the level or intensity of the pretest placebo period. TRP is a potential treatment for self-aggressive behavior in rhesus monkeys.