Introduction

Lisa Simon Onken, Jack D. Blaine, Sander Genser, and Arthur MacNeill Horton, Jr. Drug use disorders are frequently associated with mental disorders. Data from the Epidemiologic Catchment Area (ECA) study (Regier et al. 1990) showed that over half (53 percent) of individuals who have a lifetime diagnosis of a drug use disorder also have a lifetime diagnosis of a mental disorder. Approximately two-thirds of individuals with a cocaine or opiate use disorder have, at some point in their lives, had a mental disorder. For those with a lifetime diagnosis, 15 percent have had a drug use disorder. Twenty-eight percent of schizophrenics and 42 percent of those diagnosed with antisocial personality disorder have had a drug use disorder. Despite the common co-occurrence of drug use disorders and mental disorders, persons who have both of these problems tend to fall between the cracks of service delivery systems. Individuals with mental disorders who seek treatment in the community may receive it within the mental health services system, and drug-addicted individuals may receive treatment within the drug abuse treatment system. Those requiring treatment for both mental and drug use disorders may not be able to receive comprehensive treatment in one treatment program. In the worst case scenario, the clinicians responsible for the treatment of the mental disorder may not have any idea about what is going on with the addictive disorder (e.g., treatment or severity) and the clinicians responsible for the addiction treatment may not be aware of what is happening with the mental disorder. Unfortunately, those persons who have concurrent mental and addictive disorders are not easily accommodated by the current treatment delivery system. Having separate service delivery systems and separate Federal institutes funding research on mental and addictive disorders has generally fostered the separation of mental health and addictive disorder research. Typically, research on the treatment of mental disorders is addressed within the research programs of the National Institute of Mental Health, while research on the treatment of drug addiction is addressed within the research programs of the National Institute on Drug Abuse. Research on both drug use and mental disorders may, at times, be viewed with skepticism by reviewers who value the "homogeneous" samples needed to decrease "error variance." It is entirely plausible, however, that there are circumstances in which