Severe Mental Illness and Substance Misuse (Dual Diagnosis)
Severe mental illness and substance misuse (dual diagnosis): community health and social care services.
Dual diagnosis refers to people with a severe mental illness (including schizophrenia, schizotypal and delusional disorders, bipolar affective disorder and severe depressive episodes with or without psychotic episodes) combined with misuse of substances (the use of legal or illicit drugs, including alcohol and medicine, in a way that causes mental or physical damage).
Recent studies have estimated prevalence rates of 20-37% in secondary mental health services and 6-15% in substance misuse settings (Carrà & Johnson, 2009). However, methodological challenges including differing definitions of dual diagnosis, varying timescales for assessing comorbidity, difficulties with diagnosis including diagnostic overshadowing, and the lack of a good theoretical model of the association between severe mental illness and substance misuse, mean that it is still unclear how many people in the UK have a severe mental illness and comorbid substance misuse problems.There is a growing awareness that individuals with dual diagnosis experience some of the worst health, wellbeing and social outcomes, and are among the most vulnerable in society. A clear understanding of the scale of the problem, the current service (including variations), and the mechanisms of change, are vital in order to interpret differences in outcomes and costs for alternative current models of service delivery, new models of service delivery and/or aspirational models of service delivery. The National Collaborating Centre for Mental Health (NCCMH) was commissioned by NICE Centre for Public Health (now the Public Health and Social Care Centre) to conduct evidence reviews to help inform the development of a guideline aimed at optimising service organisation and delivery of community health and social care services for adults and young people with coexisting severe mental illness and substance misuse. This systematic review of the epidemiology and current practice for individuals with dual diagnosis living in the community in the UK.