Just say "I don't": lack of concordance between teen report and biological measures of drug use.

Background: Prevalence estimates of illicit drug use by teens are typically generated from confidential or anonymous self-report. While data comparing teen self-report with biological measures are limited, adult studies identify varying degrees of under-reporting.

Methods: Hair analyses for cocaine, opiates and marijuana were compared to confidential teen self- and parent-reported teen drug use in a longitudinal cohort of >400 high-risk urban teens and parents.

Results: Both teens and parents substantially underreported recent teen cocaine and opiate use. However, compared with parents, teens were more likely to deny biomarker-verified cocaine use. Teen specimens (hair) were 52 times more likely to identify cocaine use compared with self-report. Parent hair analyses for cocaine and opiate use were 6.5 times and 5.5 times, respectively, more likely to indicate drug use than were parental self-report. The lack of concordance between self-report and bioassay occurred despite participant's knowledge that a "certificate of confidentiality" protected both teen and adult participants, and that the biological specimens would be tested for drugs.

Conclusions: These findings confirm prior reports of adult under-reporting of their own drug use while extending our understanding of teen's self-admitted drug use. The lack of concordance between teen self- or parent-reported teen drug use and biomarkers confirm our concerns that both teen- and parent-reported teen drug use is limited, at least for youth in high-risk urban settings. Methods of ascertainment other than self- or parent-report must be considered when health care providers, researchers and public health agencies attempt to estimate teen drug-use prevalence.