There has been an apparent shift in majority opinion within psychiatry over the last 20 years on the nature of the relationship between mental illness and violence. Where once there was perhaps widespread scepticism, research, while sometimes producing conflicting results, appears ultimately to have led to the emergence of an almost universal consensus that there is a link. This paper will review the nature of the evidence for such a link between mental illness and violence and explore some of the newer suggestions about why mental illness may sometimes be related to violence.