The ability of single screening questions for unhealthy alcohol and other drug use to identify substance dependence in primary care.

OBJECTIVE: Single screening questions (SSQs) are recommended for the evaluation of unhealthy alcohol use and other drug use (risky use through dependence). In addition, SSQs could provide information on severity that is necessary for brief intervention, information thought to be available only from longer questionnaires. We assessed SSQ accuracy for identifying dependence.

METHOD: In a cross-sectional study, 286 primary care patients were administered SSQs for alcohol and for other drugs (each asks how many times they were used in the past year), the Alcohol Use Disorders Identification Test-Consumption (AUDIT-C), the Drug Abuse Screening Test (DAST), and a diagnostic interview reference standard for dependence. For each test, we calculated area under the receiver operating characteristic (ROC) curve and the ability to discriminate dependence at an optimal cutoff.

RESULTS: The prevalence of alcohol and other drug dependence was 9% and 12%, respectively. Optimal cut points were eight or more times for the alcohol SSQ, a score of three or more for AUDIT-C, three or more times for the other drug SSQ, and a score of four or more for the DAST. The areas under the ROC curve ranged from 0.87 to 0.96. Sensitivity, specificity, and positive and negative likelihood ratios at optimal cut points for the alcohol SSQ were 88%, 84%, 5.6, and 0.1, respectively; for the other drug SSQ were 97%, 79%, 4.6, 0.04, respectively; for the AUDIT-C were 92%, 71%, 3.2, 0.1, respectively; and for the DAST were 100%, 84%, 6.3, 0, respectively. Alcohol SSQ and AUDIT-C positive likelihood ratio 95% confidence intervals did not overlap.

CONCLUSIONS: SSQs can identify substance dependence as well as and sometimes better than longer screening tools. SSQs may be useful for both screening and preliminary assessment, thus overcoming a barrier (seen with lengthy questionnaires) to dissemination of screening and brief intervention in primary care settings.