This study examined subject-collateral reports of alcohol use among a sample of 167 dually diagnosed individuals seeking outpatient treatment at a community mental health clinic. All subjects met Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994) criteria for a schizophrenia-spectrum or bipolar disorder and for alcohol abuse or dependence. Subjects were recruited within 2 weeks of treatment entry and completed measures of cognitive functioning, alcohol dependence severity, psychiatric symptoms, and quantity and frequency of substance use over the previous 60 days using the Timeline Follow-Back interview (L. C. Sobell & M. B. Sobell, 1996). They also provided a urine sample, which was screened for recent drug use. Collateral interviews were conducted by phone and included an assessment of the subject's alcohol and drug use over the same 60-day period. Collaterals also reported their confidence in the accuracy of their reports. Overall, the results indicated generally poor subjectcollateral agreement. However, subject-collateral agreement appeared better for those individuals (n = 97) with negative urine drug screens. The most consistent predictor of subject-collateral discrepancy scores was subjects' recent drug use. Recommendations for enhancing the validity of self-reports of substance use in a severely mentally ill population are discussed.
Keywordsalcohol; bipolar; collaterals; self-report; schizophrenia Verbal self-report continues to be the primary method by which clinicians and researchers obtain measurements of a person's past substance use (Connors & Maisto, 2003). Collateral reports are viewed as an important second measure of an individual's drinking and drug use behavior. In a recent review of the subject-collateral (S-C) literature, Connors and Maisto (2003) concluded that "recent research supports the assertion that subjects provide accurate
NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript reports about their drinking and associated consequences" (p. 21). This conclusion was drawn from research examining S-C agreement among various clinical (e.g., outpatient alcoholics) and non-clinical (e.g., general population) subject populations.Although information obtained from alcohol-dependent men and women tends to be reliable and valid, there can be considerable variability in accuracy depending on many factors (Babor & Del Boca, 1992). In an effort to provide a framework for understanding the optimal conditions for obtaining self-report information, Babor, Brown, and Del Boca (1990;Babor & Del Boca, 1992;Babor, Stephens, & Marlatt, 1987) proposed a conceptual model that specifies the major sources of unreliability and invalidity in the questionanswering process. In brief, within the social context of the interview, the respondent's selfreport is said to be influenced directly by a combination of task variables, respondent characteristics, motivation, and cognitive processes. A key benefit of this model is that it sugges...