Abstract
This study compares a number of self-reported measures of drug use with the results of urine testing in a group of patients receiving methadone maintenance treatment. One hundred and twenty-nine subjects were interviewed and 4–5 months later, a second interview was obtained from 87 of these. At each interview subjects were asked about drug use on each of the preceding 7 days and also about the number of days of drug use in the previous month. It was found that most patients were continuing to use heroin, usually fairly infrequently. Direct comparisons of urine test results and self-reported drug use indicate substantial positive correlations. However, there was a tendency for self-report to underestimate drug use in this patient sample. It appears that urine testing is the single most useful measure of drug use. This supports the notion that it is a valid tool in evaluation research. However, the combination of self-report and urine tests provides more information about drug use than any single measure.