Tsai AC, Burns BFO,Syndemics of psychosocial problems and HIV risk: A systematic review of empirical tests of the disease interaction concept, 2015, Social Science & Medicine, Volume 139, Pages 26-35.

This systematic review of empirical research on syndemics, points out that though all studies demonstrated statistically significant associations between co-occurring psychosocial problems and one or more (typically HIV-related) outcomes, fewer than one in three studies used an empirical specification that appropriately assessed the extent to which psychosocial problems interact to magnify HIV risk. The study, thus, conclude that more evidence is needed to assess the extent to which diseases interact, either at the level of populations or individuals, to amplify HIV risk