1. Substance Abuse and Mental Health Services Administration. National Household Survey on Drug Abuse: Main Findings 1997. Rockville, MD: US Department of Health and Human Services, 1999.
2. Blaze-Temple D, Lo SK. Stages of drug use: a community survey of Perth teenagers. Br J Addict1992;87:215–25.
3. Farrell M, Howes S, Taylor C et al. Substance misuse and psychiatric comorbidity: an overview of the OPCS National Psychiatric Morbidity Survey. Addict Behav1998;23:909–18.
4. Jiang Z, Guo H, Zhu Z, Li Z, Wu Y. An epidemiological survey on use and abuse of antianxiety drugs among Beijing residents. Chin Med J1996;109:801–06.
5. Leigh BC, Miller P. The relationship of substance use with sex to the use of condoms among young adults in two urban areas of Scotland. AIDS Educ Prev1995;7:278–84.