Research & Resources

This study examined the developmental interrelationships between alcohol and marijuana use trajectories among a sample of North American Indigenous adolescents ages 10 to 18 years old who live in the upper midwestern United States and Canada. Distinct groups of adolescents who co-used alcohol and marijuana were formed to create profiles of young adult outcomes. Four joint trajectory groups were identified: 1) no marijuana and no/low alcohol use (34.4 percent); 2) mid-onset alcohol only (14 percent); 3) mid-onset co-use starting at age 13 (24 percent); and 4) early-onset co-use starting at age 11 (22 percent). Findings showed a high probability that adolescents would use marijuana early if they began drinking alcohol at the youngest ages, and that adolescents would not use marijuana if they drank infrequently or delayed drinking until mid-adolescence. 

This paper, “Conjoint adolescent developmental trajectories of alcohol and marijuana use and early adult outcomes among North American Indigenous people,” was funded by the National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism and published in the journal Addictive Behaviors.