A recent study examining marijuana use and sex habits of lesbian, gay and bisexual youth found that those who used marijuana were significantly more likely to engage in sex with multiple partners. The researchers were interested in this because sex with multiple partners is an important contributing factor for contracting sexually transmitted infections, or STIs. The study included surveys of 694 youth in the National Longitudinal Study of Adolescent to Adult Health (Add Health.) The researchers examined the relationship between marijuana use and sex with multiple partners among adolescents and young adults. Researchers used generalized estimating equations (GEE) logistic regression analyses to look for relationships between reported drug use and sex with multiple partners. They adjusted for other substance use, current depression, the relationship between the young person and his or her mother, and for socioeconomic variables. Marijuana use was both concurrently and prospectively associated with increased odds of sex with multiple partners, both among adolescents and young adults. The researchers concluded that two theories might be at play. First, marijuana use may increase risk for sex with multiple partners by impairing users’ decision-making or judgment. Secondly, marijuana use and sex with multiple partners may both be influenced by shared risk factors, including stress.

Take away: Efforts to reduce marijuana use could impact prevention of transmission of HIV and other sexually-transmitted disease in a higher-risk population of adolescents and young adults. Substance-use prevention specialists might make a special effort to communicate these risks to LGBT students on campus.

Zhang X and Wu L (2017) Marijuana use and sex with multiple partners among lesbian, gay and bisexual youth: results from a national sample, BMC Public Health, 17:19