There has been concern about violent acts and other criminal behaviour by people with a possible history of mental health problems. We therefore assessed the effects of community treatment orders (CTOs) on self-, third-party-, and agency-reported criminal behaviour when compared to voluntary treatment.

A systematic search of PubMed/Medline, Embase, PsycINFO and criminal justice bibliographic databases for observational or randomised controlled trials (RCTs) comparing CTO cases with controls receiving voluntary psychiatric treatment. Relevant outcomes were reports of violence and aggression or contacts with the criminal justice system such as arrests and court appearances.

Thirteen papers from 11 studies met inclusion criteria. Nine papers came from the United States and four from Australia. Two papers were of RCTs. Results for all outcomes were non-significant, the effect size declining as study design improved from non-randomised data on self-reported criminal behaviour, through third party criminal justice records and finally to RCTs. Similarly, there was no significant finding in the subgroup analysis of serious criminal behaviour.

On the limited available evidence, CTOs may not address aggression or criminal behaviour in people with mental illness. This is possibly because the risk of violence is increased by comorbid or nonclinical variables, which are beyond the scope of CTOs. These include substance use, a history of victimisation or maltreatment, and the wider environment. The management of risk should therefore focus on the whole person and their community through social and public health interventions, not solely legislative control.