Serotonin function and antiaggressive response to fluoxetine: a pilot study

The reported inverse relationship between indices of central serotonin (5-HT) function and indices of impulsive aggression in human subjects suggests the possibility that enhancement of 5-HT activity will reduce impulsive aggressive behavior. Although evidence for this hypothesis is emerging, the relationship between baseline central 5-HT system function and antiaggressive responses to treatment with 5-HT agents has not yet been examined in human subjects.

In this pilot study, we examined the relationship between: a) pretreatment prolactin responses to d-fenfluramine (PRL[d-FEN]) challenge; and b) antiaggressive responses to 12 weeks of treatment with either fluoxetine or placebo in 15 impulsively aggressive personality disordered subjects as observed in a 12-week, double-blind, placebo-controlled trial.

Among all subjects there were positive correlations between the pretreatment PRL[d-FEN] response and the percent improvement in Overt Aggression Scale-Modified scores for "Aggression" and "Irritability." These correlations were present in the fluoxetine (n = 10), but not in the placebo (n = 5), treated subjects.

These data suggest the possibility that the antiaggressive response to fluoxetine is directly, rather than inversely, dependent on the responsiveness of central 5-HT synapses in the brain of impulsive aggressive personality disordered subjects.