Most patients who use medical marijuana use it for chronic pain, study finds

Marijuana buds in a jar
A new study looked at the reasons patients use medical marijuana. (OpenRangeStock/iStock/Getty Images Plus)

Chronic pain is the top reason patients are using medical marijuana, according to a new study.

The study, published in Health Affairs, looked at the conditions for which patients enroll in state-approved medical marijuana programs. After chronic pain, which was the most common qualifying condition for 64.9% of patients in 2016, people are using medical marijuana to treat spasticity from multiple sclerosis and chemotherapy-related nausea and vomiting, according to the analysis of data from 15 states.

Patients are also commonly using medical marijuana to treat post-traumatic stress disorder and cancer.

The study looked to understand whether patients were using cannabis for evidence-based reasons and found that some of the qualifying conditions allowed by state laws often lack good scientific evidence.

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Of all patient-reported qualifying conditions, however, 85.5% had either substantial or conclusive evidence of therapeutic efficacy, according to the study, led by Kevin F. Boehnke, Ph.D., a research investigator in anesthesiology and the Chronic Pain and Fatigue Research Center at the University of Michigan in Ann Arbor.

“We did this study because we wanted to understand the reasons why people are using cannabis medically, and whether those reasons for use are evidence based,” Boehnke said, in a university announcement about the study.

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As of 2018, 33 states and the District of Columbia have approved the medical use of cannabis, while 10 states have legalized marijuana for recreational use. 

Patients who receive cannabis for medical purposes must possess a license to use it. A doctor must certify that patients have a qualifying condition to obtain that license from the state. However, those qualifying conditions vary by state law.

Researchers said it was not surprising that chronic pain was by far the most prevalent qualifying condition for use of medical marijuana, given that 100 million Americans experience chronic pain. And given the country’s opioid epidemic, patients are looking for alternatives to addictive pain medications.

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The study did highlight one problem: The many inconsistencies in data quality among the states that have legalized marijuana. Less than half of the states had data on patient-reported qualifying conditions and only 20 reported data on the number of registered patients.

The study authors said that as medical cannabis use continues to increase, creating a nationwide patient registry would help understand trends in use and the potential effectiveness of marijuana.

But based on available data, they found the number of patients using medical marijuana rose dramatically. More than 800,000 patients were enrolled in medical marijuana programs in 2017 in 19 states.

The researchers argued that it is time for the federal government to change its classification of marijuana as a Schedule 1 drug under the Controlled Substances Act, which defines it as a drug with no currently accepted medical use and a high potential for abuse.

“Since the majority of states in the U.S. have legalized medical cannabis, we should consider how best to adequately regulate cannabis and safely incorporate cannabis into medical practice,” said Boehnke.