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Cannabis side effects for senior and older adult patients with Alison Moore, MD, MPH


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AMA Update

Cannabis side effects for senior and older adult patients with Alison Moore, MD, MPH

Jun 1, 2023

Cannabis use among seniors is on the rise, but so are visits to the emergency department as a result. Joining to discuss the risks of cannabis for seniors and what doctors wish their patients knew about it is Alison Moore, MD, MPH, professor and chief of geriatrics, gerontology and palliative care at the University of California San Diego. AMA Chief Experience Officer Todd Unger hosts.


  • Alison Moore, MD, MPH, professor and chief of geriatrics, gerontology and palliative care, University of California San Diego

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Unger: Hello and welcome to the AMA Update video and podcast series. Today we're talking about the growing use of cannabis among seniors and the unique risks for this population. I'm joined today by Dr. Alison Moore, professor and chief of geriatrics, gerontology and palliative care at the University of California, San Diego. I'm Todd Unger, AMA's chief experience officer in Chicago. Dr. Moore, Thanks for joining us.

Dr. Moore: It is my pleasure to be here. Thank you.

Unger: Now, when we talk about cannabis use, much of the chatter lately has been about teens or young adults. However, earlier this year, you and your colleagues published a study on a less talked about area and that's cannabis use among seniors. Why don't you start by telling us a little bit about that study and what you found?

Dr. Moore: Thank you. Yes, well, Todd, cannabis use is rising among older adults, as you said, and that is—just to define older adults, that is those who are age 65 and older. Using data from the National Survey of Drug Use and Health, we know that past year use of marijuana, as it's called in that survey, in the year 2021 was a little more than 7% in this age group.

But in 2012, the amount of past year cannabis use or marijuana use was 1.4% in 2012. So this is a five-fold increase over this time period. This motivated our group to study cannabis further in this age group, and in the study you mentioned, we examined trends in emergency department visits that were associated with cannabis use among older adults in California from the year 2005 to 2019. And we found that these rates increased more than 1800% from almost 21 visits per 100,000—or 21 per 100,000 visits in 2020—2005 to 395 per 100,000 visits in 2019.

Unger: So you're starting off with kind of a low base, but you've got substantial increases there. What do you think is driving from 1.2 to 7 in terms of the percentage of folks that are using cannabis?

Dr. Moore: Well, number 1, it's the legalization of cannabis. So most states now have legalized cannabis in some form, and so that is really part of the reason that the rates are increasing. Another one is that the people who are now in the older age group, the 65 plus are part of the Baby Boomer generation, and we know this generation has more permissive attitudes about substance use. And then third and maybe most important is that older adults are using cannabis to treat symptoms that aren't easily managed by other traditional treatments or conventional treatments, medications. So those are the three big things we think are really driving these increased rates.

Unger: Let's talk a little bit about the last one that you mentioned. In regard to kind of treating symptoms like that, do seniors actively engage their doctors about those issues, either with why they're using cannabis or what might be happening in combination with it? What questions do you hear the most often?

Dr. Moore: Well, So. It's interesting. My patients—the reason I got into this area actually is that my patients were asking me about cannabis use about three or four years ago, and I was like, I know nothing about this. I know nothing about this at all. And so it motivated me to understand more about it. I would say that is a little unusual in that, I think, still most physicians don't have a great understanding of much of what cannabis is, and how it can affect older adults, and how it is even used by older adults. So there's a ton to be learned in this area.

Unger: Dr. Moore, just to kind of put a point on that from your 2020 study, it's just 41% of seniors told their health care provider about their cannabis use. Is that right?

Dr. Moore: Yes. We did we did this study—the one you referred to is a study we did in our geriatrics clinic in 2019, and we surveyed our patients using an anonymous survey. Truly, we did not know who they were. And we found that of those who were using cannabis, which was about 15% of the people who answered the survey, as you stated, 41% had told their doctors they were using it.

We know from others' work and some of our ongoing work that some older adults feel comfortable sharing this with their health care providers and others do not. And I think it's primarily because cannabis is still illegal federally and in six states, and so there's stigma around its use. Not everyone feels that they can talk to their physicians about this. We also know that older adults who are using cannabis or interested in using it want to know about how efficacious it is in treating their concerns and about the safety of using cannabis, particularly in combination with their prescription medications.

Unger: Dr. Moore I should really ask you, in addition to the questions that you're getting asked, really, for starters, what do you think is driving the trend of cannabis use among seniors?

Dr. Moore: Well, it's increasingly clear that older adults are using cannabis primarily to treat the symptoms of pain and insomnia. These are conditions that have been challenging to manage using existing treatments and we also know that some of the treatments that used to be commonly used to treat pain, mostly opioids. And insomnia, a variety of sedatives can be dangerous and are not recommended. So many older adults are really, with these conditions, are suffering and they feel stuck. So older adults are also turning to cannabis to treat mental health concerns, such as anxiety and depression, and for caregivers of those with dementia, to treat some of the negative behavioral complications of dementia, such as agitation.

Unger: And do you think the trend toward legalization, then, has kind of open up the floodgates?

Dr. Moore: Oh yes. Oh yes. Again, it's more normalized to be able to use it, so people feel more comfortable, really experimenting at this point is what it is.

Unger: So we have a situation where we've got an increase in seniors who are turning to cannabis for medical reasons and they're, of course, not always telling their doctors about it. What are some of the potential risks related to cannabis that you'd want senior patients to know about?

Dr. Moore: So one of the things that's important not just for cannabis but for many older adults is that, as people age, they're at higher risk for harm from all types of medications, for example, sedatives, certain pain medications, like opioids and substances, like alcohol and cannabis. So this is because with aging. There are changes in our physiology that affect how we react to particular dose of the medication or substance.

Usually, we're at the result that you need less of that medication to get the intended effect or that the medication is in your system for a longer period of time than when you were younger. So for example, cannabis is a fat-soluble substance and with increasing age, you have more body fat relative to water. Those are the two components we think about with physiology. So that means that cannabis sticks around your system longer than it would when you were younger.

Also as we age, we're more likely to have more comorbidities or conditions that can complicate the use of substances and medications. So for example, you may take multiple medications for multiple conditions, but those medications can interact with each other or have some negative outcome when used with each other. So with cannabis, we still need to learn a lot more about how it interacts with medications, but since it is a substance—but cannabis is a substance that's incredibly complicated.

It's been really difficult to study. I say this because cannabis is composed of more than 100 cannabinoids, including the ones we're most commonly aware of, THC, which is the one that has psychoactive effects, affects your brain and how you think and act, and CBD, which really doesn't have that so much. So further, older adults have other risks, being more vulnerable to the impacts of substance on their brains. So they have higher risk for problems with thinking and coordination. And so given THC's impact on the brain, this can really be a challenge.

Unger: So Dr. Moore, if I'm hearing you right, there are some specific ways that cannabis can affect seniors differently. Any other kinds of things that seniors should know about this?

Dr. Moore: So not just seniors but all people should really know that cannabis has potential negative effects on your lungs, your heart, your brain. It can interact with medications. It can lead to dependence on the cannabis. So for example, for the lungs, smoking or vaping cannabis can cause lung injury. This is true because of the smoke. It has toxic substances in it.

It can also affect your heart. So if you're consuming high amounts of particularly THC, you have an increased risk for elevations in your heart rate and your blood pressure. This can increase your risk for stroke or heart attack, and other vascular diseases. Also THC-containing products directly affect the brain. That can increase risk for anxiety or even paranoia and other types of psychosis.

And we've spoken about the interaction with medications, which is really unknown yet for the most part. And as we mentioned at the beginning of this conversation, our article on ED visits associated with cannabis is real and associated primarily with people having motor vehicle accidents and falls. Finally, cannabis can increase your risk for poisoning, so if you're using cannabis as an edible, like a gummy or a tincture, it takes between 30 minutes to two hours to see the effect of that cannabis, the desired effect you're looking for.

And so people may feel like they should be experiencing that sooner, so they take more and more. And they end up in an overdose situation, which can lead to anxiety, psychosis and loss of consciousness. So it's a lot of risks associated with cannabis, again, depending on the nature of how you're using it, how much you're using it, the type of product.

Unger: Well, let's have a final question here that puts it all together. You've got more seniors that are interacting with cannabis, more than likely not talking to their doctor about it and the potential for serious harm here. How should physicians work to kind of increase transparency, comfort for their patients to talk with them about this?

Dr. Moore: Thank you for that. So it's important to be open to the topic. Like other potentially sensitive topics, like use of other substances, alcohol, other drugs and items like sexual function, it's important to be nonjudgmental and to be comfortable when you're asking. The most important thing to do, number one, is to ask.

We find that if you don't ask, you just don't know, so it's important to regularly ask your patients about their use of all kinds of substances and to ask in a way that normalizes a potentially positive response, that is, they're using it. So instead of asking, do you use cannabis, you might ask, how often do you use cannabis for medical or recreational purposes?

You might even preface that by saying that you're going to be asking in the context of your conversation about use of medications and substances that may affect health and so asking about substances, like alcohol, tobacco, cannabis. If the older adult then says, yes, they're using cannabis, you can follow up by asking if they use it for medical and/or recreational purposes. And then you can ask so for what reasons do they use it.

Do they use it for pain, or sleep, or anxiety or to relieve stress? You can then ask what types of products they use. Are they THC only? Those you can only get at dispensary.

THC and CBD, same thing, only available at a dispensary. Or only CBD, those you can get at the grocery store, the drug store, online. And you can ask how they use it. That is, do they smoke it or vape it? Do they use it as a gummy, or a tincture or a topical, like a cream?

This, of course, presumes that physicians a pretty decent amount about cannabis, which I think is still not the case for most of us. As I mentioned earlier, I only know as much as I do because my patients started asking me about it and I decided to learn more, and in part, because I'd spent most of my career investigating alcohol use in older adults. So looking at cannabis made sense for me to look at it really much further.

Unger: Dr. Moore, this has been so interesting, and I'm sure our audience will find this really helpful. Thank you so much for joining us. We'll be back soon with another AMA Update. In the meantime, you can find all our videos and podcasts at Thanks for joining us today. Please take care.

Disclaimer: The viewpoints expressed in this podcast are those of the participants and/or do not necessarily reflect the views and policies of the AMA.