Does legal marijuana for medical purposes lead to improved health?

Researchers investigate how medical marijuana laws and dispensaries affect self-reported health
November 12, 2019

Over the past two decades, 29 states have enacted laws allowing medical marijuana use. During that span, researchers have investigated the potential health effects—both positive and negative—of medical marijuana laws (MML). Studies have found varying degrees of improvements to self-reported health and other benefits along with little evidence of harm. Additionally, research has documented the importance of legally protected medical marijuana dispensaries in enabling access; however, the specific impacts of dispensaries on self-reported health are somewhat unclear.

To gain a clearer picture of the effects of dispensaries, Elena Andreyeva, PhD, and Benjamin Ukert, PhD, both assistant professors in the Department of Health Policy and Management at the Texas A&M School of Public Health, analyzed data from a nationwide health behaviors survey covering a 20-year period of changing MMLs. Their study, published in the journal Forum for Health Economics & Policy, analyzed the effect of MMLs on self-reported health, separately measured effects for MMLs that provide for dispensaries and those that do not, investigated potential changes to risky behaviors such as smoking and heavy drinking and further broke down the various effects based on characteristics such as race, age and chronic pain status.

Advocates of MMLs have highlighted the potential benefits of medical marijuana to chronic pain patients and people who are experiencing nausea due to cancer treatments. Some research has found that MMLs could reduce deaths from opioid overdoses by substituting prescription opioid medications with medical marijuana. Opponents of MMLs have pointed to cardiovascular and respiratory problems that could arise from smoking marijuana, as well as increases in various risky behaviors. However, strong evidence of increased harm has not been found.

From their analysis, Andreyeva and Ukert found that MMLs that include legally protected dispensaries are associated with better self-reported health among people from non-white ethnicities, those with only a high school education and chronic pain patients. Self-reported health improvements were much stronger in states with protected dispensaries than those without. They also found that medical marijuana use is associated with reduced alcohol consumption, though dispensaries may be associated with increased heavy drinking. People who report having pain that limits daily activities showed major improvements in self-reported health; however, non-Hispanic whites between the ages of 20 and 54 reported only small changes in self-reported health. This demographic is likely to use prescription opioids, so the smaller effects might be due to medical marijuana not being significantly better at managing chronic pain. Additionally, medical marijuana may have provided a treatment option for other demographic groups who are less likely to use opioid medications, thus leading to stronger health effects.

Although this study helps clarify the effects of MMLs and the role of legally protected dispensaries, the authors caution that it has some limitations. First, their study focused on short-term effects of MMLs on self-reported health and long-term effects remain unknown. They note that it may be possible that the long-term effects of substituting opioids with medical marijuana may be more notable over a longer period as medical marijuana carries little risk of overdose deaths. However, over the long term, smoking marijuana could lead to lung damage like tobacco does, reducing overall health benefits. Further research using follow-up studies and investigating long-term effects will help to further clarify the roles MMLs and protected dispensaries play.

— Rae Lynn Mitchell

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