Coexisting severe mental illness (psychosis) and substance misuse: assessment and management in healthcare settings
This guideline covers assessing and managing people aged 14 years and over with coexisting severe mental illness (psychosis) and substance misuse. It aims to help healthcare professionals guide people with psychosis with coexisting substance misuse to stabilise, reduce or stop their substance misuse, to improve treatment adherence and outcomes, and to enhance their lives.
The term psychosis is used to describe a group of severe mental health disorders characterised by the presence of delusions and hallucinations that disrupt a person's perception, thoughts, emotions and behaviour. The main forms of psychosis are schizophrenia (including schizoaffective disorder, schizophreniform disorder and delusional disorder), bipolar disorder or other affective psychosis.
Substance misuse is a broad term encompassing, in this guideline, the harmful use of any psychotropic substance, including alcohol and either legal or illicit drugs. Such use is usually, but not always, regarded as a problem if there is evidence of dependence, characterised by psychological reinforcement of repeated substance-taking behaviour and, in some cases, a withdrawal syndrome. However, substance misuse can be harmful without dependence, especially among people with a coexisting psychosis.