Drug use, depression and sexual risk behaviour: a syndemic among early pre-exposure prophylaxis (PrEP) adopters in Belgium?

Little is known about how interacting psychosocial problems may influence sexual behaviour among men having sex with men taking Pre-exposure prophylaxis (PrEP). This study assessed (1) the prevalence of depression, recreational drug-use and sexual risk behaviour; (2) changes in these psychosocial conditions over time; and (3) the interaction of drug use and depression with sexual risk behaviour. We analysed data of the Belgian Be-PrEP-ared cohort study ( = 200). We assessed depression using the PHQ-9, recreational drug use and receptive condomless anal intercourse (rCAI) with anonymous partners. Frequencies of psychosocial problems were compared at baseline, 9 and 18 months follow-up (FU). Bivariate associations between depression and drug-use behaviour, and their interaction with rCAI with anonymous sexual partners using was examined using linear regression. Receptive CAI increased from 41% at baseline to 53% at M18 ( = 0.038). At baseline, we found an interaction effect of poly-drug use and depression, potentiating rCAI with anonymous partners. Participants reporting poly-drug use associated with depression were significant more likely to report this type of sexual risk behaviour than those who did not report this association ( = 0.030). The high level of intertwined psychosocial problems call for multi-level interventions for those PrEP users experiencing a syndemic burden.