A study by researchers at Johns Hopkins and elsewhere has shown that methamphetamine use can fuel HIV infection risk among young men who have sex with men, a group that includes openly gay and bisexual men as well as those who have sex with men but do not identify themselves as gay or bisexual.

The researchers said that nearly one-third participants who reported recent meth use also reported sex with an HIV-infected person, while half reported sex with an injection-drug user. More than half said they have had unprotected sex.

While previous research has linked risky sexual behaviors to drug use in MSM, the new study is the first multicity analysis to also include teenagers, a group made especially vulnerable by lack of experience, the investigators say.

The team’s findings, published in the journal Archives of Pediatrics & Adolescent Medicine, underscore the need for HIV prevention programs to factor in the role of substance abuse. “Drug use is closely linked to risk-taking behaviors, including sexually risky behaviors, so any HIV prevention efforts must, by definition, include drug use prevention and treatment of those with known drug problems,” says Jonathan Ellen, MD, an adolescent health specialist at Johns Hopkins.

Methamphetamine — a popular and relatively cheap street drug — heightens sexual response and lowers inhibitions, the researchers note. “Add meth and you have a formula that leads to increased sexual risk in a group that already has higher prevalence of HIV,” says study investigator Nancy Willard, MS, also a researcher at Johns Hopkins.

The researchers caution that any drug abuse — not just methamphetamine — can push up the rates of risky behavior. Indeed, participants who reported having used other hard drugs, such as cocaine, crack, heroin, and ecstasy, were more likely than nondrug users to have sex with HIV-infected partners (24% versus11%) and more likely to have sex with injection-drug users (20% versus 10%).