Findings show that substance use in adolescence is a factor in socioeconomic achievement by young adulthood depending on the type of substance used. Substances have different chemical properties, but they also have different social consequences. The negative outcomes associated with marijuana use, as opposed to the positive outcomes associated with alcohol, begs the question of whether the social consequences and acceptability of the different substances might influence the socioeconomic outcomes for the young users. Results support previous research in showing that substance use in adolescence is a factor in socioeconomic outcomes in young adults. This is similar to some prior research. Marijuana use has negative or no effect. Marijuana use in adolescence is associated with lowered educational achievement and receipt of public assistance by young adulthood. The effect of other illegal drugs is generally not significant. Four potential mediator variables were shown to have important effects on socioeconomic outcomes. Violent behavior in adolescents and functional limitation has the most general effects, is mostly negative, and associated with decreasing the likelihood of ever having a job and educational achievement, and increasing the likelihood of public assistance receipt. Also found were that even those arrested were more likely to have held a job at one time or another; basically the data show that young adults have mostly had jobs regardless of any other thing that might have happened in their past. Data were collected from 6,504 respondents between 18 and 29 years of age using a wave of data collected by the National Longitudinal Study of Adolescent Health (ADD Health) in 2001. Tables and references