Marijuana use among adults: Initiation, return to use, and continued use versus quitting over a one-year follow-up...

This study examined factors associated with marijuana use initiation among never users, prior-to-past year user who return to use, and users who continue use over a 12-month follow-up period.

Two waves (W1 and W2) of the Population Assessment of Tobacco and Health (PATH) Study provided data (N=26,204 aged 18+). Multivariable logistic regression models were used to examine associations of W1 sociodemographic, health/mental health, and other substance use characteristics with W2 use status. As applicable, marijuana initiation age, use frequency, and use problems were also examined.

At W2, 2.36% and 10.42% of W1 never users and prior-to-past year users, respectively, reported having used marijuana, and 72.54% of W1 past-year users reported continued use. Those in the 18-24 age group were most likely to initiate, resume, or continue use. Among never and prior-to-past year users, those who reported more mental health problems at W1 also had greater odds of use at W2. Marijuana initiation and return to use were significantly associated with movement from nonuse to use of other substances. Continued marijuana use, as opposed to quitting, was also associated with other substance use, initiation of marijuana use prior to age 18, weekly or more frequent use (AOR=2.34, 95% CI=1.87-2.93), and use problems (AOR=1.40, 95% CI=1.05-1.85) reported at W1.

Movement between marijuana nonuse and use was substantial during the 12-month follow-up period. Early intervention to prevent initiation of, return to, and continued marijuana and other substance use, especially among young adults, is needed.