The effect of psychosocial syndemic production on 4-year HIV incidence and risk behavior in a large cohort of sexually active men who have sex with men.

BACKGROUND: Cross-sectional studies have suggested that co-occurring epidemics or "syndemics" of psychosocial health problems may accelerate HIV transmission among men who have sex with men (MSM) in the United States. We aimed to assess how 5 syndemic conditions (depressive symptoms, heavy alcohol use, stimulant use, polydrug use, and childhood sexual abuse) affected HIV incidence and sexual risk behavior over time.
METHODS: Eligible men in a large prospective cohort of sexually active HIV-uninfected MSM completed HIV testing and behavioral surveys at baseline and every 6 months for 48 months. We examined interrelationships between psychosocial problems and whether these interactions increased the odds of HIV risk behaviors and risk of seroconversion over study follow-up.
RESULTS: Among 4295 men, prevalence of psychosocial conditions was substantial at baseline and was positively associated with each other. We identified a statistically significant positive dose-response relationship between numbers of syndemic conditions and HIV seroconversion for all comparisons (with the greatest hazard among those with 4-5 conditions, adjusted hazard ratio = 8.69; 95% confidence interval: 4.78 to 15.44). The number of syndemic conditions also predicted increased HIV-related risk behaviors over time, which mediated the syndemic-HIV seroconversion association.
CONCLUSIONS: The accumulation of syndemic psychosocial problems predicted HIV-related sexual risk behaviors and seroconversion in a large sample of US MSM. Given the high prevalence of syndemic conditions among MSM and the moderate effect sizes attained by traditional brief behavioral interventions to date, the HIV prevention agenda requires a shift toward improved assessment of psychosocial comorbidities and stronger integration with mental health and substance abuse treatment services.