Description:
Past studies have found that underreporting of marijuana use is particularly high. The present study extends previous research that examined the temporal validity of self-reported marijuana use among juvenile arrestees. Furthermore, the present study explores whether the passage of medical marijuana laws in some states have affected the validity of self-reported marijuana use among juvenile arrestees. Using existing juvenile offender interview and urinalysis data from the Arrestee Drug Abuse Monitoring Program (ADAM) for the years 1998 to 2002, we find that the validity of self-reported marijuana use was low, but quite stable, over time even after the threshold for a positive test was changed. However, study sites in states that had passed medical marijuana laws had significantly higher validity levels than states that had not, suggesting that the passage of medical marijuana laws may affect validity of self-reported marijuana use.