For Whom Does Chemsex Increase Sexual Risk? Considering Pre-Exposure Prophylaxis (PrEP), Antiretroviral Therapy (ART), and the Dual Control Model

Background: Chemsex, or the use of specific substances (e.g., methamphetamines, GHB/GBL) to enhance sexual experiences, is a well-documented risk factor for sexual risk behavior and subsequent HIV transmission among men who have sex with men (MSM). However, it is unclear why chemsex contributes to sexual risk and how HIV prevention measures, such as pre-exposure prophylaxis (PrEP) and antiretroviral therapy (ART), impact this relationship. The present study sought to confirm the event-level association between chemsex engagement and sexual risk, examine how use of PrEP and ART, as well as sexual excitation and inhibition factors, impact this relationship.Methods: A total of 464 MSM (n = 89 living with HIV; n = 93 reporting recent chemsex engagement) in the United States were recruited from August 2023 to January 2024 as part of a study focused on alcohol use and sexual risk behavior. Participants were recruited through advertisements on dating/hookup applications to complete a survey asking about recent sexual encounters, substance use, and sexual excitation/inhibition factors. Generalized hierarchical linear regressions indicated that event-level chemsex engagement is associated with sexual risk behavior, but only for individuals not currently using PrEP or ART.Results: Chemsex engagement had a small positive association with personality-level sexual sensation seeking and compulsive sexual behavior and was associated with decreased desire to use a condom during sexual encounters.Conclusion: Results suggest chemsex primarily contributes to sexual risk among those not using PrEP and ART (i.e., those at greatest risk for HIV) and shows limited association with sexual excitation/inhibition factors.