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

Highlights

• 2.36% of W1 never marijuana users and 10.42% of former users reported use at W2.

• 72.54% of W1 past-year users reported continued use at W2.

• Those in the 18–24 age group were most likely to initiate, resume, or continue use.

• Those who reported more mental health problems at W1 had greater odds of use at W2.

• Marijuana use and continued use were associated initiation of other substances.

Abstract

Background

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.

Methods

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.

Results

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.

Conclusions

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.

Introduction

Prevalence of marijuana use, share of frequent (i.e., daily/near daily) users, use disorders, and user expenditures have increased in all demographic groups of adults over the past decade (Compton et al., 2016, Davenport and Caulkins, 2016, Hasin et al., 2015). The increase in marijuana use has been attributed, at least in part, to the liberalization of marijuana policies, especially medical marijuana laws, in many states (Cerdá et al., 2012, Hasin et al., 2015, Wen et al., 2015). With legalization of personal/recreational and/or medical marijuana use in increasing numbers of states, use and related problems are projected to continue increasing.

Marijuana use may be less harmful to self and others than alcohol use, other illicit substance use, and tobacco use (Nutt et al., 2010). Marijuana and cannabinoids have modest, short-term, therapeutic effects in adults with chemotherapy-induced nausea and vomiting, adults with chronic pain, and adults with multiple sclerosis-related spasticity (National Academy of Science, Engineering, and Medicine [NASEM], 2017). However, marijuana use has been associated with higher risks of traffic injuries, developing schizophrenia and other psychosis, social anxiety disorder, and other substance dependence (NASEM, 2017; World Health Organization, 2016). Marijuana use during adolescence is associated with impairments in subsequent academic achievement and education, employment and income, and social relationships and social roles; these negative effects stretch into adulthood (Meier et al., 2012, NASEM, 2017). Compared to those with no marijuana use in adolescence, those who used weekly or more frequently also had two to three times the rates of illicit drug use uptake, and daily users had six times the rate of uptake of cigarette smoking and lower cessation rates for all illicit drugs into young adulthood (Swift et al., 2012).

Previous studies show that most adult problem marijuana users try to quit (with or without formal treatment), and that their desire to quit and quitting are primarily motivated by concerns about marijuana’s negative impacts on physical/psychological/cognitive health, legal status, social image/acceptability, interpersonal problems, self-control, self-image, or guilt after using (Chauchard et al., 2013, Copersino et al., 2006, Ellingstad et al., 2006, Pacek and Vandrey, 2014). One study found that spontaneous marijuana use cessation is often associated with an increase in legal substance use such as alcohol, tobacco, and sleeping aids, but it is not associated with initiating new illicit substance use (Copersino et al., 2006). However, another study found that among daily marijuana users who intended to stop using, alcohol and drug use did not increase, and tobacco use was less common on days abstinent from marijuana (Hughes et al., 2016). Return to marijuana use is common among those who try to quit (Chauchard et al., 2013). Compared to successful quitters, unsuccessful quitters had significantly more symptoms of depression and stress, negative affect, less education, lower exposure to formal treatment, higher day-to-day exposure to other marijuana users (e.g., social situations where others were using), and higher cannabis dependence scores (Buckner et al., 2013, Rooke et al., 2011). Poor sleep quality, cigarette smoking, and increased anxiety while discontinuing regular marijuana use have also been associated with relapse (Bonn-Miller and Moos, 2009, Babson et al., 2013, Haney et al., 2013).

More research on longitudinal patterns of marijuana use/nonuse is needed. Using wave 1 (W1) and wave 2 (W2; 12 months later) of a nationally representative panel dataset of individuals aged 18+ years, the present study examined the association of initiation, resumption, and continued use of marijuana at W2 with W1 sociodemographic characteristics, self-reported physical and mental health, and other substance use problems, and, when applicable, marijuana use frequency and use problems. Based on previous research, the study hypotheses were: (1) among W1 never and prior-to-past year (i.e., former or ex-) users, higher pain levels and more severe mental health problems will be associated with increased odds of marijuana use versus nonuse at W2; (2) initiation, resumption, or continued use of tobacco, alcohol, and other drugs between W1 and W2 will be associated with marijuana use initiation, resumption, or continued use at W2; and (3) among W1 prior-to-past-year and past-year users, early marijuana initiation age (i.e., <18 years) and frequent marijuana use and use problems (when using) will also be associated with increased odds of resuming or continuing marijuana use at W2. Examining those who do and do not initiate marijuana use, return to use, and continue use among past-year users will expand knowledge of marijuana use versus nonuse.