Alcohol, tobacco, and marijuana are the substances American adolescents use the most. A recent study led by researchers at the National Institute on Alcohol Abuse and Alcoholism examined how adolescents’ substance use patterns are associated with substance use disorders in young adulthood. Their findings, published in Drug and Alcohol Dependence in March 2014, show that adolescents who drink alcohol and also smoke cigarettes and marijuana are more likely to suffer from alcohol and other substance use disorders as young adults than adolescents who delay trying these substances.

The researchers used data from Waves I (1994–1995) and IV (2008) of the National Longitudinal Study of Adolescent Health (Add Health), the largest, most comprehensive survey of adolescents in the United States, to estimate the prevalence of various patterns of early adolescent use of alcohol, cigarettes, and marijuana, individually and in combination.  They also examined the differences in these patterns based on age, gender, and race/ethnicity among users of all three substances. Then, they examined the effects of these patterns on subsequent young adult substance use behaviors and DSM-IV substance use disorders.

Researchers found that multiple substance use is highly prevalent among U.S. adolescents, with 34.1% reporting early use of alcohol and marijuana, or alcohol, marijuana and cigarettes. They also found that early use of multiple substances is associated with higher rates of substance use dependence in young adults.  According to their analyses, about one-fourth of young adults ages 24 to 32 who had used alcohol, marijuana, and cigarettes before age 16 met the DSM-IV criteria for a substance use disorder. By contrast, only about 16% of young adults who had used these same substances after age 16 met the criteria for a substance use disorder. 

The researchers also examined the associations between the use of multiple substances in early adolescence with a range of subsequent young adult substance use behaviors. They found that adolescents who used alcohol, cigarettes, and marijuana prior to age 16 were twice as likely to meet the criteria for marijuana dependence and three times as likely to be dependent on other illicit drugs.

The authors conclude that prevention programs should aim to encourage kids to delay use of all three problematic substances – alcohol, cigarettes, and marijuana – rather than targeting each substance separately.