BY DAVID CASARETT, M.D.

A report published by the San Francisco Chronicle this past Tuesday indicated the NFL had reached out the NFL Players Association (NFLPA) to explore the possibility of collaborating on medical marijuana research.

If you’ve been following the relationship between these two organizations and their tense standoff about medical marijuana, you may need to read that sentence several times before it sinks in. In recent years, they’ve been fundamentally at odds about the appropriateness of marijuana use by NFL players.

On one side of the debate is the NFL, and specifically Commissioner Roger Goodell, who has been steadfast and consistent in expressing concerns about players’ use of an addictive substance. On the other side has been the Players Association, which has taken a more nuanced position. That group has emphasized the relatively modest risks of marijuana use, as well as the very significant risks of opioids and opioid addiction, arguing that for many players, marijuana should not only be tolerated, but needs to be studied to understand its potential medical benefits.

There are at least two reasons why we should be delighted that these two influential groups may be coming together and may even be ready to collaborate.

• The first, and most obvious, is that there is pretty good evidence that marijuana can be useful in the treatment of chronic pain. Specifically, marijuana seems to be very useful in the treatment of so-called neuropathic pain — pain that’s due an injured nerve. Although sometimes that happens as a result of medications or diabetes or autoimmune conditions, it also happens frequently as a result of trauma. That includes the sort of physical trauma that football players’ bodies are subjected to every season. In fact, if I had to identify one condition for which marijuana is probably most effective, it would be neuropathic pain. Cannabis’ efficacy on neuropathy is enough to get excited about a potential research partnership between the NFL and the Players Association. But there’s another reason to get interested in that collaboration, and in research in particular. And that has nothing to do with the use of medical marijuana for pain.
• It’s become increasingly clear over the past decade that NFL players are at very high risk of developing chronic traumatic encephalopathy (CTE). For many people familiar with the research that has been done to date, there’s not much question that this risk is real. That’s why the evidence in a new study published in The Journal of the American Medical Association is at least confirmatory if not conclusive. Now there’s not much doubt that NFL players who spend any time in the game are likely to develop brain damage.

The most significant finding of this most recent study speaks for itself: of 111 NFL players from the sample 110, or 99 percent had evidence of traumatic brain injury. Moreover, those players with a professional football history had worse pathology compared with those who played semi-professional, high school, or college football. That fact is important because it suggests not only that football-related trauma is responsible for brain injury, but also that there may be a dose effect. In other words, more exposure may lead to more and worse injury.
So what does chronic traumatic encephalopathy have to do with medical marijuana?Although the field of medical marijuana research is still very new, and there’s a lot we don’t know, there have been some interesting hints that some of the ingredients of medical marijuana might be useful in protecting the brain against a variety of injuries.One study in rats used synthetic cannabinoids, which are molecules produced in a laboratory but which are similar to those found in marijuana. That study found that those cannabinoids can decrease inflammation in response to injury.Interestingly, that study also found cannabinoid receptors buried in plaques that are associated with Alzheimer’s Disease, suggesting a potential link with dementia. In another study, researchers found that one ingredient of marijuana, cannabidiol (CBD), reduced the size of strokes in mice, using a model in which the middle cerebral artery was blocked. It’s preliminary studies like these that generate a lot of enthusiasm for cannabinoids, raising hopes that they might not merely treat symptoms but could actually treat or prevent brain disease and brain injury.
I’m not saying that medical marijuana is an antidote to all brain injuries. And I’m certainly not saying that regular medical marijuana use would prevent the type of brain injuries that are becoming increasingly obvious in football players. However, we do know that when NFL players step on the field they are facing a substantial risk of brain injury and trauma that will result in chronic pain. We also know that those risks increase significantly over time with every game.Could medical marijuana be useful in treating pain, or preventing CTE? We don’t know, and we need research to find out. So the NFL should support research that examines the protective effects of medical marijuana. Research is one part of the $765 million settlement that the NFL reached with players in 2013. Some of that research funding might be used to ask, for instance, whether marijuana is useful in treating players’ chronic pain, or whether it might help some to reduce their use of opioids. Research might also ask whether players who use marijuana medically or recreationally have a lower risk of traumatic encephalopathy. Given the prevalence in the NFL of these problems, which are becoming increasingly hard to ignore, a partnership between the NFL and NFLPA is an essential first step to make that research happen.

Dr. Casarett is the author of Stoned: A Doctor’s Case for Medical Marijuana, and a physician, researcher, and tenured professor at the University of Pennsylvania’s Perelman School of Medicine.