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Marijuana use increases as perceived risk decreases in US adults

Marijuana use increased as perceptions of risk from smoking marijuana decreased among adults in the U.S. starting in approximately 2007, when states began introducing cannabis legalization for medicinal use.

“Understanding patterns of marijuana use and dependence, and how these have changed over time is essential for policy makers who continue to consider whether and how to modify laws related to marijuana and for health care practitioners who care for patients using marijuana. Perceived risk of marijuana use is associated with high frequency of use suggesting the potential value for modifying risk perceptions of marijuana use in adults through effective education and prevention messages,” Wilson M Compton, MD, of the National Institute on Drug Abuse, Bethesda, Maryland, said in a press release.

To assess marijuana use and disorders and perception of harms from marijuana use in the U.S., researchers analyzed data from the National Surveys on Drug Use and Health from 2002 to 2014 for 596,500 adults aged 18 years and older.

Marijuana use increased from 10.4% in 2002 to 13.3% in 2014 (P < .0001).

The prevalence of perceiving great risk of harm from smoking marijuana once or twice a week decreased from 50.4% to 33.3% (P < .0001).

Changes in marijuana use and perception began in 2006 to 2007, according to researchers.

When adjusting for covariates, changes in risk perceptions were associated with changes in prevalence of marijuana use; however, marijuana use disorders remained stable at approximately 1.5% during the study period.

“These changes in the prevalence of cannabis use occurred during a period when many U.S. states legalized cannabis for medicinal use, but before four states went on to legalize recreational cannabis use (after 2014). It is probably too soon to draw conclusions about the effects of these legal changes on rates of cannabis use and cannabis related harms, but it is likely that these policy changes will increase the prevalence and frequency of cannabis use and, potentially, cannabis use disorders in the longer term,” Michael Lynskey, PhD, and Wayne Hall, PhD, of the National Addiction Centre, Kings College London, wrote in an accompanying editorial. “To investigate this possibility, the U.S. needs to continue to monitor cannabis use and disorders in large scale surveys, such as the National Survey on Drug Use and Health and the Monitoring the Future national survey of high school students. Monitoring of cannabis use will need to address one of the major limitations of these surveys for this task, namely, that they were designed to provide nationally representative samples and do not necessarily provide representative samples of individual states. U.S. federal funding agencies should consider funding oversampling of representative population samples within states that have and have not legalized cannabis for recreational and medical use.” – by Amanda Oldt

Disclosure : Compton reports ownership of stock in General Electric, 3M, and Pfizer, outside of the submitted work. Lynskey and Hall report no relevant financial disclosures. Please see the full study for a list of all authors’ relevant financial disclosures.