Neurobiology of Violence

The behavioural manifestations of violence are heterogeneous and result from the complex interplay of neurobiological, social, individual, economic and environmental causes. In this chapter, we have summarised the neurobiological mechanisms of violence, including neurochemical and metabolomic imbalances as well as neuroimaging and genetic/epigenetics underpinnings. Current knowledge suggests that different forms of violent behaviour (e.g. reactive versus proactive) depend on the activation of different brain circuits and neurotransmitter systems. Among them, the more solid evidence points toward the serotonin (5-HT) system in terms of changes in 5-HT levels and 5-HT receptor function, but also genetic and epigenetic modifications at the level of the enzymes involved in the synthesis, degradation and/or reuptake of 5-HT. However, no predictive biomarkers of violent behaviour have yet been identified. For this reason, future studies in large and controlled clinical and community populations examining genetic and epigenetic markers as well as behavioural-cognitive, brain imaging and metabolomics signatures of violence are warranted.