Legalization of medical marijuana has won widespread public support in the United States, driven at least in part by enthusiastic health claims made by its advocates.
“We see a wide variety of patients dealing with all sort of ailments. Anywhere from Crohn’s, diabetes, neuropathy, fibromyalgia and chemo and cancer patients, absolutely,” says a worker at a medical marijuana dispensary in a video that has drawn more than 9 million views on YouTube.
But many physicians are far more cautious about medical marijuana, and a number of Missouri medical associations are opposing all of the legalization measures on the Missouri ballot on Nov. 6.
“There are definitely things that are being left out of the conversation, and a lot of it is the science. This is what happens when you put (marijuana on a) ballot, and you ask people what they want,” says Dr. Jennifer Lowry, director of the division of clinical pharmacology, toxicology and therapeutic innovations at Children’s Mercy Hospital in Kansas City.
Medical societies largely opposed
Earlier this month, the Missouri State Medical Association announced its opposition to the measures. Other medical groups opposed to the measures include the Kansas City Medical Society, the St. Louis Metropolitan Medical Society and the Missouri Pharmacy Association.
Lowry points to research showing that marijuana can damage developing brains and that smoking it carries many of the same respiratory and cardiovascular disease risks as smoking cigarettes.
She says that marijuana’s hazards to health have increased in recent decades due to intensive selective breeding, which has dramatically increased the plant’s concentration of tetrahydrocannabinol, or THC, the ingredient that gets users high.
“The marijuana of the 1960s and ’70s is totally different than the marijuana of today,” Lowry says. “Marijuana today is much more potent than it used to be.”
While it’s not physically addictive in the same way opioids are, cannabis use disorder is a dependence problem that’s been growing in recent years. Lowry says parents who use it put their kids at risk for neglect or abuse.
On balance, Lowry thinks medical legalization isn’t worth it.
“If you look at the harm that’s been done to children in regard to marijuana and the potential of continued harm in children, adolescents and adults, those risks outweigh the benefits, and we really need to take a step back,” she says.
National polls show that a majority of physicians support medical marijuana legalization, although a 2018 poll of Kansas City Medical Society members conducted by students at William Jewell College found that a slim plurality opposed legalization, while the rest supported it or took no stance.
Lack of evidence
Aside from health concerns, many doctors, including Kansas City Medical Society president Dr. Joshua Mammen, are concerned about the lack of evidence on its use.
Marijuana use is still illegal under federal law, and that has severely restricted research in the United States on its medical applications.
While the FDA has approved a small number of drugs that are based on marijuana’s active ingredients, there are no approved uses or guidelines for the drug itself.
“When we usually prescribe a medication, we set dosage, set amount of times per day and a round of administration. None of those are available for marijuana,” Mammen says.
There’s also little evidence showing how marijuana interacts with prescription and over-the-counter medications.
The Kansas City Medical Society, along with other medical groups, including the American Medical Association, is calling for the U.S. Drug Enforcement Administration to reclassify marijuana so that it can be more widely studied.
“If there are benefits for marijuana, which there are suggestions that for certain indications marijuana could be potentially useful, then certainly we would be supportive studying it,” Mammen says.
Even if medical marijuana is legalized in Missouri, federal laws will prevent physicians from actually prescribing it. Instead, they will only be able to recommend that patients get cards they can use to obtain marijuana at dispensaries.
The William Jewell poll suggests that a majority of medical society members would be reluctant to do so.
“I think most physicians would be cautious about making claims that marijuana would provide a benefit for specific indications without clearer study,” Mammen.
Supporters not deterred
But those concerns have done little to dissuade advocates.
Jack Cardetti, a spokesperson for New Approach, the group behind Amendment 2 on the Missouri ballot, says the health risks of legalization would be small because few people would actually get the cards they’d need to buy it.
“We’re taking about a very, very small percentage of the population that will end up having these cards and being able to access medical marijuana,” Cardetti says. “We think that that is really overwhelmingly going to go to people that really need it.”
Amendment 2 would legalize medical marijuana for patients with qualifying conditions and allow users to grow it themselves in registered facilities. It would create a 4 percent sales tax, with revenue going to health and veterans’ programs.
Cardetti says that medical marijuana could actually make treatment for pain safer. Some promising research has shown marijuana could be effective for pain management, and states that have legalized it have seen decreases in the prescribing of some kinds of opioids.
“A lot of the medical treatment options come down to opioids, and we know what kind of devastating effect that has,” Cardetti says. “We believe medical marijuana, as most patients believe, is a much safer alternative.”
Cardetti says that medical marijuana supporters and opponents agree on at least one thing: More research is needed. But unlike the various medical groups, he thinks states should be the ones to take the first steps.
“We believe Washington should move on this issue. We believe there should be more studies and testing,” Cardtti says. “But in the meantime, we’re confident that Missourians are going to support this.”
Despite doctors’ concerns, Missouri voters may be on track to legalize medical marijuana on November 6. Polls show that about 9 in 10 Americans support medical legalization.
Alex Smith is a health reporter for KCUR. You can reach him on Twitter @AlexSmithKCUR.