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Home > Psychosis with coexisting substance misuse overview (Dual diagnosis).

National Institute for Health and Care Excellence. (2015) Psychosis with coexisting substance misuse overview (Dual diagnosis). NICE Pathways.

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This pathway covers assessment and management of psychosis with coexisting substance misuse in adults and young people.


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, bipolar disorder or other affective psychosis.


Substance misuse is a broad term encompassing, in this pathway, 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. However, substance misuse can be harmful without dependence, especially among people with coexisting psychosis.


Approximately 40% of people with psychosis misuse substances at some point in their lifetime, at least double the rate seen in the general population. Substance misuse among individuals with psychiatric disorders is associated with significantly poorer outcomes than for individuals with a single disorder

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