In health care, the term "co-occurring disorder" has imprecise meaning. Diabetes and hypertension commonly co-occur, complicate the treatment of one another, and, if both are present, lead to less favorable outcomes. The medical care system recognizes the common nature of this co-morbidity, so treating both in an integrated way is standard care.
In the field of substance abuse, "co-occurring disorder" has come to mean co-occurring substance use and psychiatric disorders (McGovern and McLellan, 2008). The detection, diagnosis, and treatment for substance use disorders and psychiatric disorders have become increasingly sophisticated within the parallel and separate mental health and addiction treatment systems that currently exist in the United States. However, when the two disorders co-occur in the same individual, these systems of care do not intersect as well as they do for other medical diseases like hypertension and diabetes.
Epidemiological and clinical studies have revealed that co-occurring psychiatric problems in the context of a substance use disorder are (1) prevalent; (2) associated with negative treatment and life outcomes; and (3) not typically treated using an integrated approach, despite the evidence that integrated treatments are most effective. The most recent estimates from SAMHSA are that 5.4 million adults in the United States have a co-occurring disorder. Most (53.5%) do not receive treatment, and of those who do, only about 10% receive care for both at the same time. Even fewer receive services that are integrated, i.e., delivered by the same person or program (SAMHSA, 2008).
While the need for integrated care is clearly emerging, there is still separation at policy, practice, and workforce levels between the substance use and psychiatric communities. At the federal level, within the National Institutes of Health there are the National Institute on Mental Health (NIMH), National Institute on Drug Abuse (NIDA), and the National Institute on Alcohol Abuse and Alcoholism (NIAAA). The Department of Health and Human Services includes the Substance Abuse and Mental Health Services Administration (SAMHSA), which offers the promise of integration. But SAMHSA is divided at the next tier into the Center for Mental Health Services (CMHS) and the Center for Substance Abuse Treatment (CSAT). Single state agencies, the primary regulators and funders of mental health and addiction treatment services, are also typically divided along these lines. Providers are licensed, certified, or funded to provide one or the other service, and practitioners receive education, training, and apprenticeships to focus on either substance use or psychiatric disorders.
In the present decade, however, we have witnessed a significant national effort to mobilize improvements in access and integration of mental health and addiction services for people with co-occurring substance use and psychiatric disorders. There has been a national "call to action" in policy documents such as the United States Department of Health and Human Services Substance Abuse and Mental Health Services Administration (SAMHSA) Report to Congress (2002), the Presidents New Freedom Commission on Mental Health (2003), and the Institute of Medicine Quality Chasm series (2005). As a result of increased awareness and motivation, systems and providers now seek more practical guidance about policy, practice, and workforce benchmarks, in order to plan and chart programmatic change, as well as to measure the progress of quality improvement ventures (McGovern and McLellan, 2008; Watkins et al, 2005).
Recently, a measure of program dual diagnosis capability has emerged. The measure, the Dual Diagnosis Capability in Addiction Treatment (DDCAT) index, has translated categories developed by the American Society of Addiction Medicine (ASAM) into practical and operationally defined services. The categories are: Addiction Only Services (AOS), Dual Diagnosis Capable (DDC), and Dual Diagnosis Enhanced (DDE) services (McGovern et al, 2007).
State systems and programs using the DDCAT have effectively initiated policy, practice, and workforce development changes at their levels of operation. Informed consumers, increasingly knowledgeable about the range of possible services for co-occurring disorders, can now make better decisions about where to seek treatment for themselves or a family member. Federal agencies such as the NIH and SAMHSA must continue to support efforts to foster systemic and treatment integration, as well as consider financial and evaluation strategies to sustain the gains made in short term initiatives through the SAMHSA-funded Co-Occurring State Incentive Grant (COSIG) mechanism (five-year infrastructure projects awarded to 19 states).
Finally, the education and training of physicians, nurses, social workers, psychologists, counselors, and other allied health care professionals must offer at least basic generic skills in evidence-based practices for screening, brief intervention, and triage. More highly specialized skills in evidence-based treatments for those professionals invested in this population should also be more readily available with emerging research findings. Substance use and mental health disorders are common, not only in their respective specialty settings, but across all general health care settings and the community. Recognizing and effectively treating these disorders will go far to improving the public health of the millions of Americans and their families who suffer these disorders.