VANCOUVER, Sept. 5 (Xinhua) -- Offenders with mental disorders are not as strongly associated with repeating crime as may be commonly thought, but offenders with substance use do have higher odds of recidivism, according to a new Canadian study.
The study, published earlier this week in the American Psychological Association's Journal Psychology, Public Policy and Law, was based on a two-year research of more than 31,000 offenders in the Canadian province of British Columbia.
According to researchers, abundant research confirms a high prevalence of substance use and mental disorders in correctional samples as the causes that lead to recidivism. However, it is still unclear how these two reasons contribute to the risk of repeat offending.
In the study, the researchers found offenders with non-substance-related mental disorders were at no greater risk of recidivism than those with no diagnosis. In contrast, nearly 50 percent of repeat offenders had a physician-diagnosed substance use disorder in the 5 years prior to their offense.
It's the first study of its kind to use such a large and diverse sample, said Julian Somers, a Simon Fraser University health sciences professor on the research team. "This study highlights the fact that substance use problems are associated with reoffending," he said.
"These individuals are already being identified by the healthcare system. If they received better and more effective treatment then perhaps they would offend less often. This shows that healthcare does have an impact on public safety," Somers said.
The researchers suggested that better treatment for substance use problems, a greater focus on specific types of mental disorders, and a debunking of the stigma regarding people experiencing mental illness are needed.