The most widely used illicit drug in the United States continues to be marijuana, and its use among emerging adults continues to increase. Marijuana use can result in a range of negative consequences and has been associated with other drug use in adolescents and emerging adults. This study examined the relationship between marijuana use frequency and the use of six other drug classes (opiates, cocaine, stimulants, hallucinogens, inhalants, and sleep medications) among emerging adults. A cross-sectional interview design was used with a community sample of 1,075 emerging adults in the northeastern United States. Using logistic regression analysis controlling for age, ethnicity, gender, and frequency of binge alcohol, daily marijuana use was found to be associated with a significant increase in the expected odds of opiate, cocaine, stimulant, hallucinogen, inhalant, and tobacco use. The findings identify a subgroup of emerging adult marijuana users-those who use daily-that may be vulnerable to additional negative consequences associated with polysubstance use.
Keywords: Marijuana; cannabis; emerging adults; illicit drug use.