SAMHSA logo Report to Congress








Substance Abuse and Mental Health Services Administration
U.S. Department of Health and Human Services

Chapter 4 - Evidence-Based practices for Co-Occurring Disorders - The Evolution of Treatment for Co-Occurring Disorders


Back to Previous PageGo to Report Table of ContentsGo to Next Page



The Evolution of Treatment for Co-Occurring Disorders

The very fact of co-occurring substance abuse disorders and mental disorders began to emerge as a public health concern in the early 1980s when it became evident that a number of people with serious mental illnesses also had substance abuse problems (Drake and Wallach, 2000; Drake, McLaughlin et al., 1991; Bachrach, 1982; Pepper et al., 1981). Observers note that these were, by and large, young adults with serious mental illnesses who grew up in the post-deinstitutionalization era. They received most of their care in the community, where they had ready access to alcohol and other drugs (Bachrach, 1987; Drake, McLaughlin et al., 1991; Osher and Drake, 1996).

The ADAMHA Reports

In the mid-1980s, the Alcohol, Drug Abuse and Mental Health Administration (ADAMHA), the predecessor of SAMHSA, commissioned a review that examined both research and services issues related to people with co-occurring serious mental illnesses and substance abuse disorders (Ridgely et al., 1986; Ridgely et al., 1987). The reports that followed the review delineated the research evidence on co-occurring disorders available at the time, created a research agenda for the Federal institutes (National Institute of Mental Health, National Institute on Alcoholism and Alcohol Abuse, and National Institute on Drug Abuse), and for the first time, outlined principles of care for people with both serious mental illnesses and substance abuse disorders (Ridgely et al., 1987).

These reports emphasized that most mental health and substance abuse treatment systems were not addressing the problem of co-occurring disorders effectively; that many clinical programs did not take into account the complex needs of their clients with serious mental illnesses; and that individuals with severe mental disorders frequently were excluded from both the mental health and substance abuse treatment systems because of their co-occurring disorders (Galanter et al., 1988). Equally important in the reports was the delineation of significant organizational and financial barriers to the provision of effective services.

Investigators in the substance abuse field were beginning to identify co-occurring mental disorders as a serious concern for the substance abuse treatment field. Much of this research was being conducted in Veterans Administration facilities. In one very important stream of research, McLellan and his colleagues isolated the severity of the mental disorder as a key factor in predicting poor response to substance abuse treatment among people with co-occurring substance abuse disorders and mental disorders (McLellan et al., 1983). However, in response to the ADAMHA reports, the bulk of the treatment research in the late 1980s and through the 1990s continued to emphasize issues related to people with the most severe mental illnesses, resulting in a large gap in the research base on populations other than those with severe mental illness (Ridgely, 1998).

Community Support Program

The Community Support Program (CSP) has been administered for more than ten years under SAMHSA by its Center for Mental Health Services. It began in 1987 in response to the ADAMHA reports when the National Institute of Mental Health (NIMH) Community Support Program initiated 13 demonstration projects to serve young adults (ages 18 to 45) with co-occurring serious mental illnesses and substance abuse disorders. These projects serving high-risk groups, including inner-city residents, minorities, women with children, and migrant farm workers were exploratory studies of clinical needs, integrated services, and treatment responses that might precede clinical services trials (Mueser et al., 1997; Mercer-McFadden et al., 1997). Though limited in the duration of follow-up and by design issues related to control groups, the studies produced several significant results. The CSP demonstration projects showed that individuals with co-occurring substance abuse disorders and mental disorders can be engaged into community-based treatment and that such treatment may reduce the severity of their substance abuse disorder as a result (Mercer-McFadden et al., 1997). They also determined that treatment for co-occurring disorders is a long-term process.

The CSP projects also found that many individuals with co-occurring disorders are not ready for abstinence-based programs. One of the most significant contributions of the program was the discovery that individuals with serious mental illnesses require stage-wise substance abuse interventions that engage clients in treatment first and then provide them with the motivation needed to change (Mercer-McFadden et al., 1997).

Integrated Treatment

Integrated treatment is broadly defined as "any mechanism by which treatment interventions for co-occurring disorders are combined within the context of a primary treatment relationship or service setting" (CSAT, in press). Depending on the needs of the client and the constraints and resources of particular systems, appropriate degrees and means of integration will differ. These range from cross-referral and linkage, through cooperation, consultation, and collaboration, to integration in a single setting or treatment model (Konrad, 1996). Integrated treatment is provided through three levels of service provision:

Integrated Treatment - the interaction between the mental health and/or substance abuse clinician(s) and the individual, which addresses the substance abuse and mental health needs of the individual.

Integrated Program(s) - the organizational structure for providing integrated treatment, the mental health and/or substance abuse program is responsible for ensuring an array of staff or linkages with other programs to address all of the needs of its clients. The program is responsible for ensuring that services are provided in an appropriate and easily accessible setting, services are culturally competent, age, sexuality and gender appropriate.

Integrated System - the organizational structure for supporting an array of programs for people with different needs, including individuals with co-occurring substance abuse disorders and mental disorders. The system is responsible for ensuring appropriate funding mechanisms to support the continuum of services needs, addressing credentialing/licensing issues, establishing data collection/reporting systems, needs assessment, planning and other related functions.

The critical components of an integrated program have been outlined (Minkoff, 1991; Drake et al, 2001) and include the evidence-based practice components described in other sections of this report. The critical components for integrated treatment include staged interventions; assertive outreach; motivational interventions; simultaneous interventions; risk reduction; tailored mental health treatment; tailored substance abuse treatment; counseling; social support interventions; comprehensiveness; addressing "real life" issues in addition to treatment; a longitudinal view of remission and recovery; and cultural sensitivity and competence.

Integrated treatment may involve other service systems. Because individuals with co-occurring disorders have a wide range of other health and social service needs, treatment integration may take the form of systems integration. For example, a mental health center, a local housing authority, a foundation, a county government alcohol and drug agency, and a neighborhood association may join together to establish a treatment center for women with co-occurring disorders and their children (CSAT, in press).

There is no need to create a separate system of care for people who have co-occurring substance abuse disorders and mental disorders. Ideally, integrated treatment builds on existing systems and programs wherever possible (The National Council and SAAS, 2002; AACP, 2000; Osher, 1996; Ridgely et al., 1987). At the same time, as Osher (1996) notes, we must preserve the strengths of the existing mental health and substance abuse treatment systems to serve individuals with "only" a mental or addictive disorder.

However, whether operating at the level of the individual or at the level of systems infrastructures, integrated treatment must be person-centered. Regardless of how it is configured, in its most successful form integrated treatment appears seamless to the individual receiving care, with a consistent approach, philosophy, and set of recommendations (Drake, Essock et al., 2001).

Studies of Comprehensive, Integrated Treatment Programs

Clinical research focused on the issue of co-occurring substance abuse disorders and mental disorders has yielded some promising modalities for treatment. However, the findings are suggestive rather than conclusive since few of the studies were randomized controlled trials and many of the studies suffered from significant methodological limitations (Ley et al., 2000).

Drake and colleagues (1998) reviewed 36 research studies on the effectiveness of integrated treatment in mental health settings for people with co-occurring substance abuse and serious mental illness disorders. These included programs identified as "comprehensive" since they included many of the services believed effective in treating co-occurring disorders - such as assertive outreach, stage-wise treatment, motivational interventions, intensive case management, and family interventions.

Six open clinical trial studies reviewed found excellent engagement in services and substantial reductions in substance abuse (Drake, Mercer-McFadden et al., 1998). Three longer-term clinical trial studies among this group demonstrated substantial rates of stable remission of substance abuse.

Of four studies with research controls included in the Drake review, two compared integrated treatment with non-integrated treatment. One of these (Drake et al., 1997) used a quasi-experimental design to study integrated mental health, substance abuse, and housing services for 217 individuals with co-occurring disorders who were homeless. The integrated treatment group made greater progress toward recovery in substance abuse treatment and showed greater improvement in alcohol abuse. They also spent significantly less time in institutions and more time in stable housing (Drake, Mercer-McFadden et al., 1998). Individuals in both the integrated treatment and treatment-as-usual groups showed similar improvements in psychiatric symptoms and quality of life.

Based on his review of these studies, Drake concludes that "...integrated treatment, especially when delivered for 18 months or longer, resulted in significant reductions of substance abuse and, in some cases, in substantial rates of remission, as well as in reductions in hospital use and/or improvements in other outcomes" (Drake, Mercer-McFadden et al., 1998).

Other studies focusing on people with serious mental illness examined different forms of treatment for co-occurring disorders, including: assertive community treatment (Drake et al., 1998, Jerrell & Ridgely 1995), modified therapeutic communities (Carroll & McGinley 1998, French et al., 1999), behavioral skills training (Jerrell & Ridgely 1995), and cognitive behavioral therapy (Barrowclough et al., 2001). Findings from these studies generally support the proposition that assertive community treatment, therapeutic communities, behavioral skills training and cognitive behavioral therapy may have a positive effect on individuals with co-occurring disorders across a number of different types of outcome measures of substance abuse, psychopathology and general functioning. However, statistically significant effects are found on only some measures (Greenberg 2002). Of the two studies that have endeavored to examine cost-effectiveness, the results are mixed. Clark et al. (1988) found no cost effectiveness differences between ACT and standard case management, while Jerrell, Hu & Ridgely (1994) found cost effectiveness differences for behavioral skills intervention as compared to a modified 12-step recovery program. French and his colleagues (1999) found similar cost but superior outcomes for therapeutic communities as compared to usual care.

In the only evidence-based review of the literature on treatment for people with co-occurring severe mental illness and substance abuse, commissioned by the United Kingdom's Cochrane Collaboration, the investigators concluded that more research is necessary to establish an evidence base for integrated treatment (Ley et al., 2000). Some believe the current research base suggests a reason for "cautious optimism" (Mueser, 1997). In light of the high prevalence and negative consequences of co-occurring substance abuse disorders and mental disorders, Ridgely and Johnson (2001) observe that "the evidence suggests that routine screening and assessment of substance abuse is clearly warranted; that offering and attempting to engage people with dual diagnoses in some kind of treatment that focuses on reducing use and abuse of substances is appropriate; and that, without presuming the superiority of one particular model of treatment over another, there are program features that these models share that may be associated with effectiveness..." More methodologically sound research is needed to confirm current optimism.

Dr. Rosenthal and colleagues at the New York State Psychiatric Institute have developed an integrated treatment approach for schizophrenia and substance abuse in Beth Israel Medical Center's Combined Psychiatric and Addictive Disorders Program. Preliminary findings suggest that these individuals benefit from an integrated treatment approach. They have emphasized the importance of comprehensive assessment of these patients, and the importance of initial engagement to improve compliance with and retention in ongoing treatment (Rosenthal, 2001).

Costs/Cost-Effectiveness. While the Kraft (1997) and Weisner (2001) studies cited above found that integrating mental health services into substance abuse treatment to be cost-effective (CSAT, in press), on balance, the limited data on costs and cost-effectiveness of various types of co-occurring disorders treatment yield mixed findings (Greenberg, 2002).

Nonetheless, some facts do become clear from the research. Foremost, it is far more intensive, extensive, and expensive to treat a person with co-occurring substance abuse disorders and mental disorders than to treat an individual with either disorder alone (RachBeisel et al., 1999). In large part, people with co-occurring disorders are difficult to stabilize in outpatient services and make frequent use of acute care or inpatient services (Jerrell et al., 1994). For example, researchers found that veterans with co-occurring disorders had 10 percent to 30 percent greater costs than veterans without co-occurring disorders (Hoff and Rosenheck, 1998, 1999). Untreated co-occurring disorders also exact cost on other service systems, including the criminal justice, child welfare, and homeless service systems. For example, people who experience chronic homelessness, many of whom have co-occurring disorders, account for only 10 percent of people who are homeless but use nearly half of all homeless emergency assistance resources (Kuhn and Culhane, 1998).

One frequently cited study examined the cost effectiveness of three interventions for people with co-occurring substance abuse disorders and mental disorders: 12-step recovery, case management, and behavioral skills training (Jerrell et al., 1994). All three approaches were found to be effective in reducing acute and subacute service use and increasing involvement with outpatient and case management treatments. Overall, the direct and indirect costs for these individuals were reduced by 43 percent without increasing the burden on clients' families or on the criminal justice system.

A more recent study (Finkelstein et al., 2002b) found that among people with co-occurring substance abuse disorders and mental disorders, the costs of substance abuse treatment were lower if the individual's mental disorder was also treated. The magnitude of the cost-saving varied by the type of mental disorder requiring treatment. Thus, the cost of substance abuse treatment for an individual with a substance abuse disorder and schizophrenia was lowered by an average of $1,991 when the schizophrenia was also treated. Similarly, the cost of substance abuse treatment dropped $1,310 when co-occurring psychosis was treated; and was lowered by $291 when major depression was treated. However, Jerrell and others (e.g., Drake, Essock et al., 2001) caution that the results of the limited number of studies undertaken to date are not definitive. More research is needed to determine both the cost effectiveness of specific co-occurring disorders interventions and the cost-offsets to be realized in other service systems.

Some observers have criticized the research on integrated treatment for its lack of randomized control groups, small numbers of participants, and other methodological flaws (Greenberg, 2002; Ley et al., 2000). Indeed, Drake and his colleagues (Drake, Mercer-McFadden et al., 1998) note a dearth of research on cost and cost-effectiveness, the needs of special populations (e.g., women, people who are homeless), and the effectiveness of specific interventions (such as group therapy) for people with co-occurring substance abuse disorders and mental disorders. Others cite the relative lack of evidence to support the effectiveness of treatment for co-occurring substance abuse disorders and mental disorders for individuals who are not experiencing a serious mental illness, such as schizophrenia or severe depressive illness (Greenberg, 2002; NASMHPD/NASADAD, 1999).

However, for others in research and clinical care, as well as for many consumers, the current research base suggests a reason for "cautious optimism" about the potential effectiveness of integrated treatment for co-occurring disorders (Mueser et al., 1997). Perhaps this is as much a matter of pragmatism as evidence.


Back to Previous PageGo to Report Table of ContentsGo to Next Page


Go to SAMHSA Home Page
This page was last updated on  22 October, 2002
SAMHSA is An Agency of the U.S. Department of Health & Human Services

Email Questions to

  Click for Non-frames / text version of site

Privacy Statement  |  Site Disclaimer  |   Accessibility