Substance abuse and HIV infection.

This article reviews what is known about the relationships between recreational psychoactive substance use and HIV infection and sexual behaviors that can transmit HIV. The focus of this article is on nonparenterally used recreational substances and their relationship to HIV transmission behaviors, specifically high-risk sexual behaviors of one of the largest groups of persons at risk for infection--self-identified gay and bisexual men. Published and unpublished studies in this area are reviewed in terms of a hierarchy of epidemiologic evidence that ranges from global associations between substance use and high-risk sexual behaviors to prospective studies of substance use in the context of sexual encounters and incident rates of HIV infection. This article also discusses the secondary community impact of these associations and their intervention implications.