Mechanisms underlying aggressive and hostile behavior in amphetamine users

Purpose of review To review current evidence linking amphetamine use with aggression and to consider possible factors that might underlie this association. Recent findings Although evidence that amphetamine use is related to increased levels of aggression continues to grow, the underlying processes or mechanisms remain somewhat elusive. In this review, three possible underlying factors are considered. Neurotoxic, pharmacological effects of amphetamine on the dopaminergic and serotonergic systems are related to aggressive, hostile behavior in both animal and human studies. Of particular interest is the converging evidence that amphetamine use is related to impairment in executive functions (including self-control) that are regulated by the prefrontal cortex. Taken together, these findings suggest that amphetamine users may have an impaired capacity to control or inhibit aggressive impulses. Furthermore, high levels of impulsivity related to amphetamine use may also play a role. Finally, amphetamine use is associated with increased positive symptoms of psychosis, particularly paranoia, that contribute to a perception of the environment as a hostile, threatening place. Summary Taken separately, each of these factors may lead to an increase in aggression with increased use of amphetamine, but their interactive or synergistic effects may be particularly problematic.