Episode 26: Medical Marijuana: Going Green for PD?

Dan Keller 00:09

Welcome to this episode of Substantial Matters: Life and Science of Parkinson's. I'm your host, Dan Keller. At the Parkinson's Foundation, we want all people with Parkinson's and their families to get the care and support they need. Better care starts with better research and leads to better lives. In this podcast series, we highlight the fruits of that research, the treatments and techniques that can help you live a better life now, as well as research that can bring a better tomorrow. Over the past few years, people with a variety of chronic medical conditions, including Parkinson's, have become more interested in exploring the use of medicinal cannabis to treat their symptoms, commonly called marijuana. Cannabis contains lots of chemical compounds called cannabinoids that have various effects on the body. More than half of all states in the US have legalized cannabis for medicinal use, but navigating the landscape of its use can be tricky because federal laws have prevented scientific research on it for many years. There is still a lot to learn about what it may be good for, who may benefit from it, and who should probably avoid it, in general and for Parkinson's disease specifically. Dr. Danny Bega of Northwestern University's Parkinson's Disease and Movement Disorders Center, a Parkinson's Foundation Center of Excellence in Chicago, frequently gets questions about the medical use of cannabis.

Dr. Danny Bega 01:46

Either from patients who are using it and want to obtain a medical cannabis card, or patients who don't know much about it but have read that it's become legal in their state, and they want to know about using it for their Parkinson's symptoms. So often they want to know about using it to treat specific symptoms like tremor or dyskinesias, which are the involuntary movements that you can get from Parkinson's, or mobility issues or stiffness. And usually those are the issues they're looking to treat with it. And so they want to know how to obtain it. They want to know if I think it's a good idea for them. Oftentimes, other people have recommended it to them, either friends or family, or they've seen something on Facebook or on the internet, like a dramatic video of someone before and after using marijuana, and that is often the impetus for them coming to ask about it. And so they want the medical opinion about whether they think it's a good idea or not. Do you have an opinion? I do have an opinion. It's not a simple opinion. It's a complicated opinion. To make it as simple as possible, I think there's good palliative purposes for it—palliative care meaning comfort care, when the focus of care is purely on comfort—where today a lot of what we use is narcotic pain medications or anxiety medications. There's a legitimate use for medical marijuana, medicinal marijuana, in those instances, and I don't think we should be restricting it very much for those patients. A lot of times we're talking about end-of-life care in those situations, and when comfort is the focus, I think that we worry less about potential side effects in those situations. When it comes to symptomatic management, I think it's very individualized in terms of whether it might be appropriate or not for certain people. But I think the biggest factor right now in my hesitancy for recommending it is the lack of evidence and the fact that the availability of it has really bypassed the typical regulations that we use for medications that become approved—the typical rigorous studies that medications have to undergo to understand their efficacy and their side effect profile—and in this case, we sort of bypass that. And so when we're recommending it, we're not doing it with the right evidence. And that's my biggest concern. In terms of recreational use, I think it's a completely separate topic. It's not really a medical discussion, more of a social discussion. And I think from that standpoint, I don't really know of evidence to suggest that it should be used for recreational purposes, and there is certainly a side effect profile to be concerned about that should be discussed further.

Dan Keller 04:11

So it sounds like the evidence you have now is mainly anecdotal from patients.

Dr. Danny Bega 04:17

The history of cannabis and the evidence behind it and the science is really interesting and really worthy of study. It's been used for centuries. Actually, it was used as an analgesic, it was used as an antispasmodic, as a sedative, for many, many, many centuries. It kind of came to the Western world later, in sort of the 1800s or so, and then when it came here to the United States, in like the 1970s, it became a Schedule I substance, and that sort of halted the ability to learn about it and to study it. And actually, the American Medical Association opposed it becoming a Schedule I substance at that time, because they knew that that would impair our ability to really study it and understand it. What we do know about it is a few things. We have cannabinoids that our body makes naturally, and so we have cannabis receptors, or cannabinoid receptors, throughout our nervous system, and they're actually one of the most populated receptors we have in our brains. They exist in the part of the brain called the cerebellum, which is a balance part of the brain. They exist in the basal ganglia, which is the part of the brain most affected in Parkinson's, and they exist in other parts of the brain. And so we know that there is reason to believe that binding to cannabinoid receptors actually impacts other neurotransmitters in our brain. Dopamine is an example of a neurotransmitter and the one that people with Parkinson's are deficient in. There are other neurotransmitters in that part of the brain that go haywire that lead to most of the motor symptoms of Parkinson's, and cannabinoids binding to these receptors manipulate other neurotransmitters in our brain. So there's good reason to think that there would be some effect on motor function, but because the receptors are so widespread, there's also reason to wonder what the potential other effects are that using cannabinoids would have. And we know some of those effects just from anecdotes and from other people who use it recreationally. We know that it can affect cognition. We know, at least in the short term, that it can affect cognition, possibly because there are cannabis receptors in the hippocampus—that's the part of the brain that's affected in Alzheimer's, for instance. And we know it can affect judgment. We know it can affect motivation. And so how that particularly plays into Parkinson's, we don't know, but we know that there are these widespread receptors. We also know, interestingly, that there are receptors on inflammatory cells, so there's actually a potential effect on reducing inflammation in the body and in the brain, which is one of the reasons that cannabis has been considered or studied as a protective medicine—whether it could slow down inflammation in our bodies and in our brains. There is animal model data that suggests that both from reducing inflammation and also in terms of improving symptoms, even in animal models of Parkinson's, there are some benefits that can be seen. It's the human data where we really struggle, and what we have right now is a handful—truly a handful—of studies where patients are given some form of a cannabinoid, whether it's inhaled smoked cannabis or a pill that mimics the effects of cannabis, and the effects are sort of studied before and after. Most of those studies are very small, and the quality of the studies is pretty variable. Some of them are good studies that we would call randomized control studies, and some of them are weaker studies that are purely observational. And the results of those studies are actually mixed, so they're not convincing. The results in a couple of those studies show some benefits for things like tremor or dyskinesias, and in other studies, they don't show benefits. And so because of the quality of the studies, the size of the studies, and the variability of the results, we don't really have good evidence for what the positive and negative effects are in Parkinson's.

Dan Keller 07:51

So when patients come to you discussing the possibility of using either cannabinoids in some form or marijuana, do they ever ask for Marinol? I mean, the prescription kind, or are they all thinking the stuff you grind up or smoke or eat?

Dr. Danny Bega 08:05

So they're usually asking for the street drug that we're familiar with, but in a legal form. So they're not usually asking about something like Marinol. There is a difference between those. Certainly, the difference being the THC—and the THC, which you don't have in something like Marinol, is the psychoactive component of it—and it's possible that that's an important component to see benefits such as relaxation benefits and anti-anxiety benefits. It's also possible that's the component that causes some of the problems, some of the psychiatric problems. But there's certainly a difference between the effects of cannabis that has THC and cannabidiol together versus these synthetic forms that don't have all that. What we know about something like Marinol is there is evidence for it for things like nausea and appetite, and so for someone with Parkinson's who has problems with appetite or nausea, which can happen in advanced states, this might be a reasonable thing to consider. But there isn't evidence for Marinol effects on motor symptoms of Parkinson's, for instance.

Dan Keller 09:07

So our body doesn't just make receptors for the fun of it—that takes energy and it takes information—and what binds to it? What's the endogenous compound that binds to our own receptors?

Dr. Danny Bega 09:18

So the reason we make it is because the endogenous cannabinoids we make are to help us with things like nausea, to help us with our appetite and our weight maintenance. There is some effect on pain, so it's a natural pain chemical that we have to reduce pain. It's present for immune function—at least this is thought—that it has some effects on immune function, those sorts of health benefits from the natural ones that we make, and so that's why we have them.

Dan Keller 09:46

So what do you tell a patient, or how do you counsel a patient, you know, sort of in a nutshell?

Dr. Danny Bega 09:52

If it's a patient who's got cognitive problems, which up to 30% of people with Parkinson's may have cognitive issues or dementia, so if it's someone with cognitive problems, I think the discussion ends there. I would be too concerned about worsening their cognition, triggering a delirium, acute confused state from using it. I have that discussion of that would be my concern. There's a lot of good reason to be concerned about that with a psychoactive substance in someone who already is set up for it by having cognitive impairment. I don't feel like it's safe to try them. If it's someone who is younger—and we do have a large population of people with Parkinson's who do present younger, in their 40s, 50s—who is cognitively doing very well, which a lot of the patients do, and don't have a lot of medical comorbidities, don't have a lot of other issues beyond their motor symptoms of Parkinson's, so they're not dealing with a lot of these non-motor problems like cognitive issues or hallucinations, this is someone where the discussion is more difficult. Oftentimes, I'll start by asking them if they've tried it themselves before, because many have, and what the effects they had noticed were, because sometimes they're asking for it because they've tried it and they know that it has helped them with a certain symptom. And that's a discussion that every individual physician has to be comfortable with on their own. There have been rare occasions where someone like that has come to me, and I've worked with them on obtaining it and monitoring them very closely and seeing what the effects are and having a plan for if they have any problems on it. Even in those circumstances, I do feel somewhat uncomfortable with the fact that I don't know really the strain that they're using, the amount of THC or cannabidiol in it, the frequency of use, or the exact amount of use. But as long as I maintain a close relationship and monitor them carefully, it's something that can be considered. But again, every physician has to make that decision for themselves based on their comfort, since this is something that's not technically approved. My personal belief is, for those patients, if it's between something like cannabis or something that's legal, something that's FDA-approved like a narcotic or a benzodiazepine, which is also FDA-approved, my preference would be towards cannabis over some of these medications that we've been prescribing for years that are also unsafe. But I would say that a small minority of patients that I feel like it would be appropriate with. I am concerned, as I said, about cognition. I'm also concerned about potential for balance problems. So someone with serious balance issues, I would be having that discussion about being concerned about prescribing it, and I would kind of explain to them why I wouldn't want to prescribe it for them. And also I'd have to be worried about motivation. We talk about exercise as one of the most important things in Parkinson's, and we know, after study after study after study shows us that exercise is essential for people with Parkinson's. So if there's any concern that using medical marijuana will lower motivation and make it so that a patient is not exercising regularly, that would be a reason to take it away or to avoid using it as well. But I educate my patient. I just explain to them where this comes from. While it's legal on one end, depending on the state that they're in, there are these concerns about lack of evidence, and they have to accept that with the understanding that we don't know enough about this drug, and so that's an understanding that they have to be educated about.

Dan Keller 12:59

Good. I appreciate it. Thanks.

Dan Keller 13:09

Ultimately, the decision to try medical cannabis lies with you and your doctor, but our website at parkinson.org is a good starting point to become more informed about the issues, pros and cons, and cautions surrounding its use. And as always, the PD Information Specialists on our toll-free helpline are here to answer questions and provide information about this topic or anything else having to do with Parkinson's. You can reach them at 1-800-4PD-INFO. On April 17, the Parkinson's Foundation is hosting a webinar, “Marijuana and PD: What Do We Really Know?” Ask the helpline for information or register online at parkinson.org/expertbriefings. Don't worry if you can't tune in live. All past Parkinson's Foundation webinars are available for viewing at parkinson.org/expertbriefings. And remember to check our social media channels for special activities related to Parkinson's Awareness Month going on now. If you have any questions about the topics discussed today, or if you want to leave feedback on this podcast or any other subject, you can do it at parkinson.org/feedback. At the Parkinson's Foundation, our mission is to help every person diagnosed with Parkinson's live the best possible life today. To that end, we'll be bringing you a new episode in this podcast series every other week. Until then, for more information and resources, visit parkinson.org or call our toll-free helpline at 1-800-4PD-INFO—that's 1-800-473-4636. Thank you for listening.