Polysubstance use among youth experiencing homelessness: The role of trauma, mental health, and social network composition

Background: Substance use is common among youth experiencing homelessness (YEH). However, less is known about the use of multiple substances (polysubstance use), or factors associated with polysubstance use among YEH. The present study sought to identify subgroups of YEH based on their recent polysubstance use behavior, and investigate traumatic experiences, mental health and social network composition as predictors. Methods: YEH (N = 1,032; M-age = 21.3) from three drop-in centers in Los Angeles completed an in-person survey and social network interview between October 2011 and June 2013. Latent class analysis (LCA) was used to identify subgroups of youth based on nine types of substance use in the past 30 days; latent class logistic regression was used to identify variables associated with class membership. Results: Five polysubstance use classes were identified: heavy alcohol and marijuana (33.6 %), illicit drug use (4.9 %), high all polysubstance use (14.9 %), primarily marijuana (18.1 %), and low use (28.5 %). Relative to the low use class, traumatic experiences were associated with membership in every polysubstance use class. Suicide attempts were associated with membership in the high all class (OR = 9.41). Number of substance-using, homeless network members was associated with membership in the heavy alcohol and marijuana use class (OR = 1.35). Number of non-substance-using network members (homeless [OR = 0.29] and housed [OR = 0.73]) was associated with lower odds of membership in the high all class. Conclusions: Distinct groups of YEH can be identified by their recent polysubstance use patterns. Traumatic experiences, suicidality, and social network composition are important correlates of polysubstance use among YEH.