Biological correlates of aggression and violence in humans

This paper reviews the main genetic, neurochemical, hormonal and psychophysiological findings in relation to aggression and violence in humans. Although socioenvironmental variables are undoubtedly involved, a number of twin acid adoption investigations also support the influence of genetic factors in the etiology of aggressive behaviour. The neurochemical substrate of aggression is markedly complex. Although serotonine appears to be the main neurotransmitter implicated, other neurotransmitter systems (dopamine, opiates, nitric oxide...) also participate in the control and/or modulation of these behaviours. Many animal and human studies have established an association between androgen levels and aggression. In this context, we describe investigations examining the activational and organizational effects of androgens and the actions of antiandrogens. Finally, several recent psychophysiological studies carried out in violent subjects are analyzed.