Subject-collateral reports of drinking in inpatient alcoholics with comorbid cocaine dependence

Greater substance abuse severity has been associated with less reliable self-reports of drinking in individuals with only an alcohol use disorder. In addition, individuals with multiple substance use disorders often report greater substance abuse severity. Therefore, it is important to be confident in the self-reports of substance use in individuals with multiple substance use disorders. Although there is considerable confidence in the use of collateral reports as a measure of drinking in individuals with only a diagnosis of alcohol abuse or dependence, information about subject-collateral agreement for individuals who meet the criteria for more than one substance use disorder is lacking. In this study, we examined subject-collateral reports of substance abuse in individuals presenting for alcohol treatment who met DSM-III-R criteria for alcohol and cocaine use disorder (n = 85). We then compared subject-collateral reports of those individuals to subject-collateral reports for individuals with only a diagnosis of alcohol abuse or dependence (n = 99). Overall, the results demonstrate that self-reports of individuals with alcohol and cocaine use disorders are generally valid. The results revealed no significant differences between groups on measures of subject-collateral consistency for several alcohol use variables. However, a significant difference was found for the number of days of drug use, with subject-collateral agreement being greater for individuals with an alcohol and cocaine use disorder. Additional analyses revealed that subject-collateral discrepancy scores were positively related to the participants' severity of alcohol and drug dependence. Recommendations for enhancing the accuracy of self-reports of drinking and drug use in alcoholics with comorbid cocaine use disorders are discussed.