Mental disorders and violence risk : epidemiological and clinical cohort studies

Abstract

Introduction: Violence morbidity and mortality has been increasingly recognized to be of importance for public health. The relationship between mental illness and violent crime is complex because of the involvement of several confounding risk factors.

Aim: The aim of this thesis was to study the risk of interpersonal violence and violent crime in common mental disorders with a focus on the effect of early risk factors, the relationship between interpersonal violence and the serotonin system, as well as the risk of death.

Methods: A birth cohort of 49,000 Swedish men was followed longitudinally in registers for 35 years after conscription and two clinical cohorts of 42 and 161 suicide attempters, respectively, were studied using cross-sectional study designs. Interpersonal violence was studied among individuals with a mental disorder using group comparisons, correlation analyses, and relative risks measured by means of odds ratios and confidence intervals from bivariate and multivariate logistic regression. Mortality was studied among violent offenders using Cox proportional hazard regression analyses.

Results: Mental disorders led to a general increase in the risk for interpersonal violence and violent recidivists had a higher mortality. Mental Retardation, Substance-Related Disorders and early behavioural problems, including violent behaviour in childhood, were important predictors of expressed interpersonal violence in adults. Personality Disorders were a predictor of expressed interpersonal violence in men. Affective-Anxiety Disorders were weak predictors of adult interpersonal violence. No association was found between Psychosis and violent offending. Childhood maltreatment was shown to be a weak predictor of adult interpersonal violence, with aggression dyscontrol only in a subgroup of traumatized individuals with low levels of a serotonin metabolite in the cerebrospinal fluid. Violent recidivists had a significantly higher risk of dying from an Alcohol- or Drug-Related Disorder and by suicide.

Conclusions: Violence risk assessments should include a thorough psychiatric and psychological evaluation, including cognitive tests and information about early behavioural problems and childhood maltreatment. Mental Retardation should be included in the violence risk assessment instruments. Risk assessments for violence also provide tools to identify violent offenders who are at high risk of mortality.