Objective: To examine the prevalence and profile of people with co-occurring mental and substance use disorders in relation to numerous demographic, diagnostic, and needs-related variables across a comprehensive system of mental health services using a standard methodology.
Method: Data were collected on cases (n = 9839) sampled from specialty tertiary inpatient, specialty outpatient, and community-based mental health programs. Status with respect to co-occurring disorders was based on recorded diagnosis of substance use disorder and the substance abuse measure within the Colorado Client Assessment Record. The demographic and needs profile was compared across groups with or without co-occurring disorders within each level of care.
Results: Overall, the prevalence of co-occurring disorders was 18.5%, and highest among clients receiving specialty tertiary inpatient care (28%), and within selected subpopulations such as younger adults (55%) and those with personality disorders (34%). There were few differences between groups based on co-occurring disorders in the specialty inpatient programs. For outpatient and community settings, the clients with co-occurring disorders were distinguished by a more impaired and complex needs profile and more likely to be young, single, male, and of low education. Across all levels of care, having a co-occurring disorder was strongly associated with antisocial and challenging behaviour, legal involvement, and risk of suicide or self-harm.
Conclusion: The prevalence estimate of co-occurring disorders is likely representative of a multilevel system of care that serves a large, mixed urban and rural population. Results highlight the need to focus on specific subpopulations and sectors in pursuit of more integrated treatment and support for their mental health and addictions problems.
Can J Psychiatry 2008;53(12):810-821
* Clinicians can use sociodemographic characteristics, such as male sex, younger age, and being unemployed, and clinical indicators, such as overall mental health severity and behavioural challenges, to help identify and support people with substance use disorders.
* Treatment and support models for co-occurring mental and substance use disorders must include risk management strategies, given the higher prevalence of challenging behaviours within this population.
* There is a need for system-wide planning regarding co-occurring mental and substance use disorders.
* Although findings were based on a comprehensive mental health system, the results may not be applicable to every jurisdiction.
* Study findings should not necessarily be generalized to acute care, consumer, or peer support programs because they were not included in our study.
* Clinical diagnostic interviews were not feasible to validate study criteria for defining co-occurring disorders.
Key Words: co-occurring disorders, prevalence, comorbidity, mental health, addictions, mental health system research, Colorado Client Assessment Record
Research in clinical populations with co-occurring mental and substance use disorders is consistent in showing the negative impact of the latter on the treatment trajectory and course of illness.1 Although casual mechanisms are far from clear, negative outcomes such as relapse and rehospitalization are associated primarily with impaired adaptive functioning, higher psychiatric severity, poorer medication compliance, unstable housing, and diminished social capital, such as relationships and employment required for good quality of life.2-6 Most, but not all studies, show an association between substance use disorders and suicide among clients of mental health services.2'7 Behavioural challenges, such as aggressiveness, anger management, disruptive behaviour, impulsivity, and problems with affective regulation, are clearly the norm rather than exception, as is criminal justice system involvement. …