Validity of adolescent self-report of substance use

The validity of self-report of substance use was examined in 367 adolescents referred for a substance use assessment between 1996 and 2000. Referrals came from a wide variety of sources, including pediatricians, the courts, and social services, as well as their parents. Average age of the sample was 15, 52% were male, and 82% were Caucasian. Adolescents were first asked about the details of their substance use by a clinician using a structured interview with established reliability and validity (Adolescent Drug and Alcohol Diagnosis). They were subsequently asked to provide a urine sample, a requirement they were unaware of when being interviewed about their substance use. If the urine sample was deemed valid by the laboratory technician, it was analyzed by means of fluorescence polarization immunoassay and paper chromatography. If positive screens were obtained for any substance, the sample was subjected to gas chromatography/mass spectrometry for confirmation and quantification. Biochemical test results were compared to self-report. Overall, 28% (961338) of the self-reports were not corroborated by urinalysis. In adolescents who reported nonuse of a substance, 26% (561219) had a positive urinalysis. More surprisingly, 34% (401119) of adolescents reporting substance use in the urinalysis detection window had a negative urinalysis. The present study found self-report of substance use in adolescents to only have fair validity. It is recommended that biochemical corroboration be routinely used for this population.