A study using data from three U.S. national surveys indicates that illicit cannabis use and cannabis use disorders increased at a greater rate in states that passed medical marijuana laws than in other states, according to a new article published online by JAMA Psychiatry.
Laws and attitudes regarding cannabis have changed over the last 20 years. In 1991-1992, no Americans lived in states with medical marijuana laws, while in 2012, more than one-third lived in states with medical marijuana laws, and fewer view cannabis use as risky.
Deborah S. Hasin, Ph.D., of the Columbia University Medical Center, New York, and coauthors used data collected from 118,497 adults from three national surveys: the 1991-1992 National Longitudinal Alcohol Epidemiologic Survey, the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions and the 2012-2013 National Epidemiologic Survey on Alcohol and Related Conditions-III.
Study results indicate that overall, from 1991-1992 to 2012-2013, illicit cannabis use increased significantly more in states that passed medical marijuana laws than in other states (1.4 percentage point more), as did cannabis use disorders (0.7 percentage point more).
The authors suggest that future studies are needed to investigate mechanisms by which increased cannabis use is associated with medical marijuana laws, including increased perceived safety, availability and generally permissive attitudes.
The study notes some limitations.
"Medical marijuana laws may benefit some with medical problems. However, changing state laws (medical or recreational) may also have adverse public health consequences. A prudent interpretation of our results is that professionals and the public should be educated on risks of cannabis use and benefits of treatment and prevention/intervention services for cannabis disorders should be provided," the article concludes.
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(JAMA Psychiatry. Published online April 26, 2017. doi:10.1001/ jamapsychiatry.2017.0724; available pre-embargo at the For The Media website.)
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Journal
JAMA Psychiatry