Nonmedical drug use among adolescent students: highlights from the 1999 Ontario Student Drug Use Survey

Background: During the 1990s, rates of nonmedical drug use among adolescent s escalated. We assessed data from 5 cycles of the Ontario Student Drug Use Survey for overall trends in the proportion of students reporting illegal drug use between 1991 and 1999. Methods: The survey is a repeated, cross-sectional, 2-stage cluster-design survey of students enrolled in grades 7, 9, 11 and 13. Outcome measures wer e prevalence of use of 17 drugs, including alcohol and tobacco, over the 12 months preceding the survey. Results: The rates of drug use increased between 1993 and 1999. The 95% con fidence intervals (Cls) for the differences in proportions between 1997 and 1999 indicated significant increases in the overall use of 6 drugs: alcoho l (95% CIdiff 6.1, 1.9-10.3), cannabis (95% CIdiff 46.3, 0.2-8.4), glue (95 % CIdiff 2.3, 1.3-3.3), other solvents (95% CIdiff 5.0, 3.1-5.3), barbitura tes (95% CIdiff 1.9, 0.4-3.4) and hallucinogens such as mescaline and psilo cybin (95% CIdiff 3.5, 0.8-6.9). Fewer grade 7 students in 1999 than in ear lier cohorts reported using alcohol or cigarettes by age 9. Interpretation: The public health implications of the findings are mixed. O n the positive side, there is no evidence of increases in early onset of dr ug use. On the negative side, the overall proportion of students reporting illegal drug use has continued to rise.