Medical Marijuana: A Potential Unintended Effect

Illicit marijuana use, cannabis use disorders were more common in states with medical marijuana laws

two joints and some marijuana buds

Medical marijuana might have therapeutic effects for certain patients, but, in states that have medical marijuana laws, the drug might have some negative effects.

Illicit marijuana use and marijuana use disorders appeared to increase in states that had medical marijuana laws, according to a new study.
Using data from three national surveys, Dr. Deborah S. Hasin, PhD, of the Columbia University Medical Center in New York, and team found that, from 1991-92 to 2012-13, states that passed medical marijuana laws saw a 1.4 percent larger increase on average in illicit cannabis use than states that didn’t have such laws on the books.
These researchers identified a similar effect regarding cannabis use disorders like marijuana dependence. In states that had medical marijuana laws, rates of cannabis use disorders increased by 0.7 percent more on average than in states without the laws.
“Medical marijuana laws may benefit some with medical problems,” Dr. Hasin and team wrote in their study. “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.”
This study did not examine why states with medical marijuana laws might have increased rates of illicit cannabis use and cannabis use disorders. The study authors called for more research on that topic.
marijuana leaf and stethescope: signifying medicinal marijuana
Medical marijuana is used to treat or mitigate the symptoms of health problems like cancer, pain, glaucoma and seizure disorders in 29 U.S. states, the District of Columbia, Puerto Rico and Guam, according to the National Conference of State Legislatures.
Dr. Hasin and colleagues noted that more than a third of Americans lived in states that had medical marijuana laws in 2012 — up from zero in 1991. They also noted that fewer Americans now believe that marijuana poses significant health risks.
This study was published in JAMA PsychiatryInformation on study funding sources and potential conflicts of interest was not available at the time of publication.
Dr. Hasin did not respond to a request for comment prior to publication time.
References: 
JAMA Psychiatry, “Did Illicit Cannabis Use Increase More in States with Medical Marijuana Laws?”
http://jamanetwork.com/journals/jamapsychiatry/fullarticle/10.1001/jamapsychiatry.2017.0724
National Conference of State Legislatures, “State medical marijuana laws”
http://www.ncsl.org/research/health/state-medical-marijuana-laws.aspx
Written by: Alex Lindley | Medically reviewed by: Dr. Robert Carlson, M.D.