A Longitudinal Investigation of Syndemic Conditions Among Young Gay, Bisexual, and Other MSM: The P18 Cohort Study.

The persistence of disparities in STI/HIV risk among a new generation of emerging adult gay, bisexual, and other men who have sex with men (YMSM) warrant holistic frameworks and new methodologies for investigating the behaviors related to STI/HIV in this group. In order to better understand the continued existence of these disparities in STI/HIV risk among YMSM, the present study evaluated the presence and persistence of syndemic conditions among YMSM by examining the co-occurrence of alcohol and drug use, unprotected sexual behavior, and mental health burden over time. Four waves of data, collected over the first 18 months of a 7 wave, 36-month prospective cohort study of YMSM (n=600) were used to examine the extent to which measurement models of drug use, unprotected sexual behavior, and mental health burden remained consistent across time using latent class modeling.