Validity of drug use reporting in a high-risk community sample: A comparison of cocaine and heroin survey reports with hair tests

Hair specimens were collected from 322 subjects and analyzed as part of an experimental study administering household surveys during 1997 to a high-ri sk community sample of adults from Chicago, Illinois. Toxicologic results w ere compared with survey responses about recent and lifetime drug use. Abou t 35% of the sample tested positive for cocaine, and 4% tested positive for heroin. Sample prevalence estimates of cocaine use based on toxicologic re sults were nearly five times the survey-based estimates of past month use a nd nearly four times the survey-based estimates of past year use. With the hair test results as the standard, cocaine and heroin use were considerably underreported in the survey. Underreporting was more of a problem for coca ine than for heroin. Among those who tested positive, survey disclosure of cocaine use was associated with higher levels of cocaine detected in hair. In general, when recent drug use was reported, it was usually detected in h air. When a drug was detected in hair, use was usually not reported in the survey. When heroin was detected in hair, cocaine was almost always detecte d as well.