The media, the general public, and politicians often emphasize that mental illness is a precursor and a cause of violence, particularly emphasizing an assumed relationship between mental illness, including psychopathy and psychosis, and the use of guns to commit violence. We report which individuals with serious mental health problems have an increased risk to commit violence (including gun violence). Second, we answer the question to what extent serious mental health problems explain most violence and especially gun-related violence. And what is the opinion of experts on these questions? Third, we review which effective screening instrument can help to identify individuals with mental health problems who are at risk to carry a gun and commit violence. For policy makers and legislators, this article points out that most psychiatric disorders are not related to violence, with some exceptions such as schizophrenia and bipolar disorder, and often only in conjunction with substance use. We show that the attributable risk of mental illness to explain violence in general is low. We also emphasize that conduct disorder in late childhood or adolescence is a better predictor of violence than is mental illness at a later age. Empirically based screening methods to identify individuals with mental health problems who are prone to violence appear to have limited utility. Implications are discussed for clinicians and practitioners working in the justice system, researchers, and policy makers.
Keywords: criminology; homicide; mental health and violence; violent offenders.