Introduction

Inappropriate aggression and violence is a pervasive feature of contemporary society. In humans, it affects all ages; violent behaviour in children (e.g. conduct disorder) is relatively common. Understanding, prevention and treatment of these conditions is frequently incomplete and unsatisfactory. At a research level, there is often little integration between sociological, psychological and neurobiological approaches, even though the three address the same topic. An additional problem with aggression is that it is a compendium of different behaviours.

The great advances in our knowledge of brain function have helped our understanding of the neural mechanisms underlying behaviour. This chapter focuses on what we know of these as they apply to aggression. It draws evidence both from studies on experimental animals, and investigations of normal humans or those with a variety of illnesses. Experimental and clinical studies give very different information, but must be integrated if rational therapy for unwanted or excessive aggression is to be developed.

First, we define aggression and its relation to other social behaviours. Next, we discuss the structure of the brain as it relates to aggression, with particular emphasis on the limbic system. This anatomical view of the brain is complemented by its neurochemical architecture, and we discuss this in relation to aggressive behaviour.