Challenges in assessing substance use patterns in persons with comorbid mental and addictive disorders.

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).