Cannabis abuse and vulnerability to psychosis: targeting preventive services.

Cannabis is the most widely used illicit substance in the world and due to the high levels of use observed among young people with psychosis, most research has focused on the causal relationship between cannabis use and mental health problems. Despite a large interest in developing intervention models to target this group, there are as yet no established and effective methods of prevention and intervention focusing on cannabis use. In this paper we present the available evidence for the effectiveness of substance use treatments in patients with co-morbid severe mental illness, as well as exploring the prevention and early intervention initiatives for substance use in the general population.