Individual differences in aggressive responding to intravenous flumazenil administration in adult male parolees.

Nonhuman and human studies have shown that benzodiazepine (BZD) receptor agonists can modify aggressive behaviour. However, it is unknown whether flumazenil, a BZD receptor antagonist, enhances or inhibits aggressive behaviour. The present study was designed to investigate the effects of acute administrations of flumazenil on aggressive responding in adult humans. Six adult males with histories of childhood conduct disorder (DSM IV R) participated in experimental sessions. Aggression was measured using the Point Subtraction Aggression Paradigm (PSAP; Cherek 1992), which provided subjects with aggressive and monetary-reinforced response options. Acute doses of flumazenil (2 and 3mg) did not produce statistically significant changes in either monetary-reinforced responding or aggressive responding. The analysis of individual subjects data revealed that aggressive responses varied across subjects. The results are discussed in terms of individual differences based on the previous history of BZD abuse. Additional laboratory research is needed to better clarify the behavioural mechanisms by which BZD receptor antagonists modify human aggressive responding.