Weeding through the Public Health Implications of Marijuana Legalization

While arguments for and against legalization of marijuana extend beyond public health debates, these concerns are critical in the discussion of medical and recreational use of cannabis.
Map of pot legalization in the US

By A. Finn McFarland, MS-HCOM Candidate ‘19

Joints, edibles, pills and even lotions—no matter how it’s packaged, 22.2 million Americans report consuming marijuana in the past month.1  Legalization of marijuana is a hotly debated topic in the United States that dates back to the early 1900s, first with the Harrison Narcotics Tax Act and later with the anti-marijuana film “Reefer Madness.” 2  Fast forward nearly 100 years when Colorado and Washington became the first states to legalize recreational use of the drug in 2012. Today several more states have followed with similar legislation.3  In Massachusetts, November 20th marked the first day of legal sales of recreational marijuana.

Marijuana legalization and use is a highly politicized issue. A recent analysis investigated the most common arguments in a sample of news stories to determine how the public views the issue of legalization. The researchers found that pro-legalization articles heavily referenced the potential for a decrease in criminal justice costs as well as an increase in tax revenue. In contrast, the anti-legalization articles most often discussed the public health concerns of cannabis.4  Despite strengths and weaknesses on both sides of the aisle, it is important to note the public health implications of the drug including those associated with recreational use as well as with medical use.

Canada recently legalized recreational marijuana use nationwide. Margie Skeer, associate professor of public health and community medicine and interim director of the Health Communication program, testified in front of the Senate of Canada on the public health implications of legalizing cannabis. Skeer’s research focuses in part on substance misuse and addiction. In her testimony, Skeer highlighted two key public health areas of concern in the legalization of marijuana: accidental ingestion by children and intentional consumption by adolescents. Accidental ingestion of cannabis by children is a critical public health issue as legalization becomes more widespread. Edibles in particular cause a severe risk for ingestion by children because they look, smell, and taste just like the sweet treats children regularly consume. A study published in JAMA Pediatrics investigated unintentional exposures to marijuana among children in Colorado between 2009 and 2015. The researchers saw a 50% increase in marijuana-related hospital visits from two years before recreational legalization and two years after among children aged 9 and under. Nearly half of the cannabis products involved in the cases were edibles.5

Intentional consumption of cannabis among adolescents also poses public health concerns as nearly 20% of teens in the U.S. report current use.6  Significant evidence suggests that exposure to cannabis during adolescence is associated with problems later in life regarding learning and memory.7  Additionally, a growing body of research is revealing associations between marijuana use among adolescents and the development of mental health disorders and cannabis use disorders.8-9

In contrast to public health concerns regarding recreation marijuana use, evidence suggests medicinal use can be beneficial for some people including those undergoing chemotherapy, those with epilepsy, and those suffering from wasting syndrome as a result of AIDS.10  Currently over half of U.S. states have legalized the use of the cannabis plant for medical purposes although the FDA does not recognize the plant as a medication. However the FDA has approved three medications, dronabinol, nabilone and most recently Epidiolex, containing cannabinoids, chemicals found in the marijuana plant. The cannabinoid THC present in dronabinol and nabilone alleviates nausea for chemotherapy patients as well as increases appetites for AIDS patients suffering from severe weight loss. Epidiolex contains cannabidiol (CBD) to treat two forms of epilepsy. A medication not yet approved by the FDA called nabiximols is approved for use in Canada and some European countries to treat some of the muscular effects of Multiple Sclerosis.11

Some evidence suggests that medical marijuana may also help reduce opioid overdoses because it can be prescribed to treat pain instead of highly addictive opioids. The opioid epidemic is a critical public health crisis in the United States and public health professionals are working nationwide to try to curb the issue. A study published in JAMA Internal Medicine suggests that states that have legalized medical marijuana have significantly lower rates of death from opioid overdoses. The authors note that further research to uncover the mechanisms underlying this association is necessary.12

Massachusetts legalized the sale of recreational marijuana in November, over two years after legalizing its possession and use. The Cannabis Control Commission regulates the marijuana industry in Massachusetts and implements the laws regarding its use and sale across the state. The Commission includes a subcommittee that is working to address public health concerns such as package labeling, advertising, and potency. The committee is also investigating measures to address the public health concerns including accidental ingestion by children and intentional ingestion by adolescents. In a 2017 report, the committee recommended establishing a channel for reporting advertising aimed at children and adolescents and establishing funding for prevention and education programs about risks to children and adolescents.13

While arguments for and against legalization of marijuana extend beyond public health debates, these concerns are critical in the discussion of medical and recreational use of cannabis. Children and adolescents may be at risk for adverse outcomes while patients suffering from disease may benefit from the substance. As the U.S. moves forward with state-by-state legalization of cannabis, further research will shed light on whether such policies indeed prove beneficial for both the economy and for public health.


  1. Results from the 2015 National Survey on Drug Use and Health: Detailed Tables, SAMHSA, CBHSQ.
  2. Milestones in U.S. Marijuana Laws, The New York Times.
  3. Counting the Days Till Marijuana's Legal, The New York Times. 
  4. Emma E. McGinty, Hillary Samples, Sachini N. Bandara, Brendan Saloner, Marcus A. Bachhuber, Colleen L. Barry,
    The emerging public discourse on state legalization of marijuana for recreational use in the US: Analysis of news media coverage, 2010–2014,
    Preventive Medicine, Volume 90, 2016, Pages 114-120,
  5. Wang GS, Le Lait M, Deakyne SJ, Bronstein AC, Bajaj L, Roosevelt G. Unintentional Pediatric Exposures to Marijuana in Colorado, 2009-2015. JAMA Pediatr. 2016;170(9):e160971. doi:10.1001/jamapediatrics.2016.0971
  6. Centers for Disease Control and Prevention (CDC). 1991-2017 High School Youth Risk Behavior Survey Data.
  7. National Institute on Drug Abuse. What are marijuana’s long-term effects on the brain?, 25 Jun. 2018; 
  8. Copeland, J., Rooke, S., & Swift, W. (2013). Changes in cannabis use among young people: impact on mental health. Current opinion in psychiatry, 26(4), 325-329.
  9. Winters, K. C., & Lee, C. Y. (2007). Likelihood of developing an alcohol and cannabis use disorder during youth: association with recent use and age. Drug and alcohol dependence, 92(1-3), 239-47.
  10. National Institute on Drug Abuse. Is marijuana safe and effective as medicine?, 25 Jun. 2018
  11. Marijuana and Cannabinoids, NIH, National Center for Complementary and Integrative Health.
  12. Bachhuber MA, Saloner B, Cunningham CO, Barry CL. Medical Cannabis Laws and Opioid Analgesic Overdose Mortality in the United States, 1999-2010. JAMA Intern Med. 2014;174(10):1668–1673. doi:10.1001/jamainternmed.2014.4005
  13. Recommendations for the Cannabis Advisory Board Marijuana Industry Subcommittee to the Cannabis Control Commission, Cannabis Control Commission,  Commonwealth of Massachusetts.