Member Research and Reports

Member Research and Reports

BU: Risk for Cannabis Use Disorders Climbs in States with Medical Marijuana Laws

Illicit cannabis use and cannabis use disorders increased at a greater rate in U.S. states that passed medical marijuana laws than in other states, according to new research co-authored by a Boston University School of Public Health (BUSPH) professor.

BUSPH Dean Dr. Sandro Galea joined researchers at Columbia University’s Mailman School of Public Health and Columbia University Medical Center in a study in JAMA Psychiatry to analyze the differences in cannabis use and cannabis use disorders before and after states passed medical marijuana laws. The study differentiated between earlier and more recent time periods and additionally examined selected states separately.

Overall, from 1991 to 1992 and 2012 to 2013, illicit cannabis use increased significantly more in states that passed medical marijuana laws than in other states, as did cannabis use disorders. In particular, between 2001 and 2002 and 2012 and 2013, increases in use ranged from 3.5 percentage points in states with no medical marijuana laws, to seven percentage points in Colorado. Rates of increase in the prevalence of cannabis use disorder followed similar patterns.

The authors said that while medical marijuana laws may benefit some people with health problems, changing state laws also may have adverse public health consequences, including cannabis use disorders.

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