Could CBD fight CTE? What athletes and experts are saying about cannabis and concussions


With Super Bowl LVII fast approaching, the NFL is wrapping up yet another season with fans, athletes, and medical professionals focused on concussions, and increasingly on cannabis as a tool for treating brain injuries and chronic traumatic encephalopathy, a related neurodegenerative disease known mostly by its acronym CTE.

Players advocating for cannabis use in the NFL is not new. In 2015, Bleacher Report reported that while cannabis was banned from the NFL, it was still widely used by NFL players and “coveted” as an “invaluable painkiller.” 

Then researchers began diagnosing the life-crippling disease CTE in the vast majority of brains donated by deceased American football players. More recently, it was discovered that the “odds of CTE double every 2.6 years of football played.” 

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Consequently, while easing pain has been a primary focus of medical cannabis research, concussion treatment is fast climbing the list of concerns. This season’s watershed moment for another concussion-related rules change came in September when Miami Dolphins quarterback Tua Tagovailoa was stretchered off the field after suffering a concussion.

The logic behind exploring the connection between cannabis and concussions — simply put, though you can read a more thorough exploration in this recent research article — is based on evidence that concussions affect the brains chemistry in ways that lead to inflammation and other chemical imbalances within cells, reduced blood flow, heart rate variations, and a host of other conditions that are not well understood at this time.

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Some of these conditions are also changed by the body’s cell-regulating endocannabinoid system, a series of chemical receptors on cells that is also not fully understood. Some experts believe that cannabinoids derived from cannabis, known as phytocannabinoids, may plug into receptors in this complex system and possibly correct the effects of a concussion. 

Right now we have plenty of anecdotal evidence that cannabis and CBD products can help ease the symptoms of concussion, and there are published reviews of preclinical studies that support the idea (in addition to the link above, here and here are two more). But other than that, there’s not a lot of hard data supporting the idea. The research just hasn’t been done.

In my opinion, its a black mark for the medical profession that we dont have answers to this as we should have seen this coming and we should have been studying this a long time ago,” Dr. Robert Cantu, a leading neurosurgery professor at Boston University School of Medicine and director of Massachusetts’ Cantu Concussion Center, told GreenState. “It’s really a shame (that) we don’t have a better handle on what are the risks and rewards of cannabis use.”

The NFL has responded to player pressure to explore this connection by donating $1 million in research funding to the University of California San Diego and University of Regina, Saskatchewan, to focus on how cannabis may help with pain management and treating the consequences of concussions. The concept, referred to as “neuroprotection,” is that cannabis may be able to defend cells against the onslaught of disruptive chemical changes due to concussion. 

“Our interdisciplinary research team believes that different cannabinoid formulations found in medical cannabis have the potential to benefit athletes suffering from the acute and long-term chronic effects of concussions,” said Dr. Patrick Neary, an exercise physiologist and professor in the Faculty of Kinesiology and Health Studies at the University of Regina, in the NFL’s announcement.

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Neary, already a strong advocate for using CBD to treat concussions, said he hopes this NFL-funded research will result in very definitive statements” about how much CBD or CBD-THC a person should take for protection from and treatment of concussions.

CBD is thought to be anti-inflammatory, Neary explained, and he believes it minimizes or mitigates some of the chemical changes” through stimulating the endocannabinoid system and bringing cells back to a state where they can function properly.

“So, if you had a concussion and you call me up and you say, ‘Neary, what should I do?’ I’d say, ‘Go on high CBD!’ I advocate that,” he said.

THC used with CBD and other cannabinoids is also a candidate for helping reduce damage to the brain, but its psychoactive properties give some researchers in this field pause.

Cantu, who has been working in the field of sports-related head injuries since the 1970s and is a leader in the relatively new field of diagnosing and treating people suffering from suspected CTE, worries that prescribing cannabis can be dangerous for some people who struggle with addiction and other mental health issues. 

“We really don’t have any science that says it (cannabis) is useful in CTE. Yes, people with CTE are often people that have had traumatic injuries to various parts of their body in addition to their head, so they’re suffering from pain. From that standpoint, there might be some benefit. And, yes, a number of people with CTE have had anxiety and depression and it might be beneficial, but to make a long and short of it, it’s not been studied in a way that there’s any science to give you any learned answer.”

Cantu emphasized that CTE is an underlying progressive disease that spreads from cell to cell until a person becomes mentally and emotionally debilitated, and that it cannot be detected in a living person. With today’s technology, the disease can only be diagnosed from brain tissue removed from the dead.

The team of neurologists, psychologists, nurses, and therapists he works with can treat the symptoms resulting from post-concussion syndromes through cognitive behavior therapy, counseling, and medication, Cantu said. He warned, however, that although the symptoms can be treated, the underlying disease process cant.”

Consequently, Cantu’s thought is that athletes who believe they have CTE and become obsessed with the idea are hurting themselves more than helping themselves. This, he believes, is because “you can have varying levels of probability to have CTE based on the number of years you took repetitive head trauma, based on whether or not there’s cognitive impairment, based on whether or not the symptoms are progressively getting worse — especially if you progress to the point of dementia. There is no way in a living individual that you can be 100 percent sure whether somebody has CTE or not.”

Neary, who does not research CTE, agrees with Cantu that there are some risks to using cannabis, especially taking it in a form where you are not certain how much of each cannabinoid you are getting per dose. His team will be using a powdered form of CBD in their research.

Even so, he added that “retired (football) players now are really tired of waiting for solutions, because this affects their lives on a daily basis … especially when they’re taking prescription medications such as opioids.”

In addition to his research and a review of existing studies published in The Canadian Journal of Neurological Sciences, Neary’s own anecdotal experience with concussion patients treated with CBD and CBD-THC combinations gives him hope that cannabis-derived cannabinoids will improve lives.

In a 2021 published study, Neary’s team found that CBD and a CBD-THC combination “positively influenced” the physical symptoms of patients with post-concussion syndrome. And, through a personal experience one researcher had with a patient during the study, they witnessed the suggestion of a more broadly positive outcome for any concussion patient.

One of the patients in the study, he said, received a debilitating concussion after hitting her head on a table when retrieving a pen that had rolled under it. When the patient first came into the clinic, Neary said she was only able to speak in two and three-word sentences. Thats all the information she could string together because she was just grappling for the words.” But after eight weeks of treatment with a combination of cannabinoids, the patient “was able to speak in full sentences.”

So, right now we have a field of study rife with tantalizing testimonies and some research establishing correlations between cannabis, our endocannabinoid system, and conditions related to brain injuries. 

“More quality and thorough research… is urgently needed to determine the safety and potential medical benefit of various forms of cannabis for neurologic disorders, especially those for which anecdotal evidence is available but where strong scientific data is lacking,” the American Academy of Neurology states in its position statement on cannabis. 

Neary hopes to begin discovering that strong scientific data when he gets his NFL-funded study involving university varsity athletes up and running in early spring. His team should have some “interesting data” out by midsummer, he said, with a follow-up study running through the next NFL season. 

Jake Ellison has been an award-winning journalist for 30 years in the Pacific Northwest (primarily at the Seattle Post-Intelligencer) covering science, higher education and cannabis legalization. 

Jake Ellison