Day-level associations between drug use and sexual behavior in male couples: Actor partner interdependence modeling of timeline follow-back data

Background: Both marijuana and other illicit drugs (e.g., cocaine/crack, methamphetamines, ecstasy, gamma-hydroxybuterate, and ketamine) have been linked to the occurrence of condomless anal sex (CAS) with casual partners among sexual minority men (SMM) and these associations largely generalize to partnered SMM. Software advances now permit testing the day-level correspondence between participants' sexual behavior and their own drug use (actor effects) as well as their partners' (partner-effects).

Methods: Participants comprised 50 couples (100 individuals) recruited in the New York City metro area. All were 18 or older and identified as cis male. In each couple, at least one partner was 18-29 years old, HIV-negative, reported recent (past 30 day) drug use and recent (past 30 day) CAS with a casual partner or CAS with a non-monogamous or sero-discordant main partner at screening.

Results: Marijuana was associated with CAS between main partners on days both partners reported its use. A similar pattern was observed for other illicit drugs. Respondents were more likely to report CAS with casual partners on days CAS between main partners occurred. Both marijuana and other illicit drugs were associated with increased likelihood of CAS with casual partners on days a main partner did not use drugs. These associations were attenuated on days where partners reported the use of different drugs.

Conclusions: The co-occurrence of CAS with main and casual partners maximizes shared sexual risk. Results support the continued emphasis on dyadic HIV prevention interventions and the development of theoretically-based interventions that may address drug use by both partners in the relationship.