Trajectories of adolescent poly-substance use and their long-term social and economic outcomes for males from low-income backgrounds.

Substance abuse is a significant public health concern that disproportionately burdens males and low-income communities. This study examined (1) longitudinal profiles of male adolescent poly-substance use and (2) their association with social and economic participation across early adulthood. Drawing on a cohort of males (n = 890) from low-income neighborhoods, we used group-based multi-trajectory modeling to identify profiles of poly-substance use (alcohol, tobacco, cannabis, illicit drugs) from age 13-17 years. Regression models were used to link substance use profiles to high school graduation, criminal convictions, personal and household earnings, welfare receipt and partnership from age 19-37 years, obtained from administrative records. Child IQ, family adversity and behavioral problems were adjusted for. Four poly-substance use profiles were identified: abstinent (n = 128, 14.4%), late-onset (n = 412, 46.5%), mid-onset (n = 249, 28.1%), and early-onset (n = 98, 11.1%). Relative to the late-onset (reference) group, participants in the early-onset profile were 3.0 times (95%CI = 1.68-5.53) more likely to have left school without a diploma, 2.7 times (95% CI = 1.56-4.68) more likely to have a criminal conviction by age 24 years, earned 10,185 USD less (95% CI =  - 15,225- - 5144) per year at age 33-37 years and had 15,790 USD lower (95% CI =  - 23,378- - 8218) household income at age 33-37 years, a 1.3 times (95%CI = 1.15-1.57) higher incidence of annual welfare receipt and a 24% (95% CI = 5-40) lower incidence of marriage/cohabitation from age 18-35 years. We show that adolescent-onset poly-substance use by age 13 is associated with poor social and economic outcomes. Delaying the onset of substance use and reducing exposure to additional substance classes has potential for high societal cost savings.