Social impulsivity inversely associated with CSF5-HIAA and fluoxetine exposure in vervet monkeys

Animal and humnn research suggests that the central serotonin system is inv olved in the inhibition of impulsive behavior. Two studies were designed to assess this relationship in male vervet monkeys (Cercopithecus aethiops sa baeus) rising a standardized test of impulsivity in a social context: the I ntruder Challenge. In the first study an inner of impulsivity in response t o an unfamiliar adult male intruder (including latency to approach and aggr essive and assertive interactions) was inversely correlated With levels of the serotonin metabolite, 5-hydroxyindoleacetic acid (5-HIAA) in cisternal cerebrospinal fluid (r = -0.33, p < .01, n = 138). The approach, but not ag gressive, component of the Impulsivity Index runs the primary contributor t o this relationship (partial r = -0.27, p < .01). The second experiment com pared responses to the Intruder Challenger after 9 weeks of daily treatment with fluoxetine (2 mg/kg, i.m.) or vehicle. Fluoxetine-treated subjects (n = 6) had significantly lower Impulsivity Index scores than controls (n = 1 2). The results from these two investigations provide evidence for serotone rgic influences on social impulsivity. (C) 2001 American College of Neurops ychopharmocology. Published by Elsevier Science Inc.