Challenges in Assessing Substance

Use Patterns in Persons With Comorbid Mental and Addictive Disorders Kate B. Carey Assessment of substance use patterns can be distinguished from two related assessment goals. These consist of screening (i.e., identifying persons with addiction problems) and diagnosis (i.e., determining whether abuse or dependence criteria are met). All three goals are important and relevant to persons with comorbid disorders. Nonetheless, this chapter focuses on substance use assessment for three reasons. One, it is the least studied assessment goal in the comorbidity literature; very few published studies address this topic. Two, substance use assessment is applicable to all persons in treatment for mental disorders. Use of illicit drugs or alcohol is more common than abuse, and information about use patterns may be desired to determine risk for medication-drug interactions and other health concerns. Finally, substance use assessment should play a central role in the treatment of comorbid disorders. It serves as the basis for treatment planning and as a point of departure for outcome assessment. It also constitutes the first step in conducting a functional analysis of drinking and/or drug use for an individual (Sobell et al. 1988). Quantifying patterns of substance use allows for determination of increased versus decreased use, an outcome measure consistent with harm reduction approaches to treatment of substance misuse in the context of major mental disorders (Carey, in press). In the addictions literature, a rich tradition of research exists on topics related to assessing alcohol and drug use patterns. Ample sets of instruments and guidelines for their use have been developed and standardized in substance abuse treatment settings. However, importing such tools for use with persons with major mental disorders raises questions about their psychometric properties and other potential limitations. This chapter briefly summarizes current approaches to, and problems with, substance use assessment. Because self-report measures continue to be widely used, emphasis is placed on factors generally considered to affect the accuracy of self-reported substance use. Next, concerns about the reliability and validity of self-reported substance use in persons with major mental disorders are discussed. Finally, recommendations for enhancing the reliability and validity of assessment instruments are presented, highlighting areas in need of empirical research.