A review of comorbidity: major mental illness and problematic substance use.

OBJECTIVE: The aim of this paper is to critically review the literature on major mental illness and problematic substance use in order to provide clinicians and policy-makers with evidence to support proposed directions for management of the above.
METHOD: The available literature was accessed using computerised databases and manual searching.
RESULTS: The predominantly North American-based literature is largely descriptive. Those studies which attempt empirical evaluation are limited by methodological weaknesses which include small sample sizes, short follow-up periods, inadequate measurement of substance use, lack of experimental design, and treatment drift over time. However, there is consensus among most studies regarding prevalence rates and treatment.
CONCLUSIONS: Problematic substance use is the most common comorbid condition among people with a major mental illness and is associated with poorer patient outcomes. There is evidence to suggest that the integration of mental health and drug and alcohol services will result in improved detection, assessment and management of comorbidity. Integration refers to the provision of comprehensive services by a single service with staff who are competent in both mental health and drug and alcohol skills. A tolerant, non-confrontational approach to substance use is most appropriate for people with a major mental illness. Treatment programs need to recognise the longitudinal nature of substance abuse and dependence. More research needs to be conducted in this field in order to establish guidelines for effective management.