Dr. David Casarett will always remember the moment in 2013 when a patient asked for his opinion on medical marijuana. “Do you think it could help me,” she asked. He replied with what he knew, that it was illegal federally and also in Pennsylvania, where he lives and practices at Penn Medicine.
He also told her that cannabis has no known medical benefits.
“Then she pulled out a couple printouts from trials that had been done, and she said, ‘I found these online. It sure looks like medical cannabis has some benefits. Maybe you should read these?’ And I was embarrassed my patient knew more about this than I did.”
Casarett listened to his patient, and he read the trial reports. He talked with his colleagues, and he researched some more on his own. And when he found out he was wrong — that marijuana has indeed been scientifically proven to help with some diseases and medical conditions — he knew he had his next book.
And “Stoned: A Doctor’s Case for Medical Marijuana” was published by Penguin Random House in July 2015.
The book knowingly and compassionately begins with the epigraph, “What is a weed? A plant whose virtues have never been discovered. — Ralph Waldo Emerson.”
“Years ago a lot of my physician colleagues thought (medical marijuana) was going to be a fad that would pass or that they could just ignore it,” said Casarett, a physician, researcher and tenured professor at the University of Pennsylvania’s Perelman School of Medicine who has been published in the Journal of the American Medical Association and The New England Journal of Medicine. “But even in Pennsylvania, a lot of my physician colleagues are realizing that this is something they have to know about. They may decide that they won’t recommend it, but we have to know about it.”
Casarett will talk on cannabis’ risks and benefits from 5-7 p.m. March 25 at the Reiman Theater inside the University of Denver’s Margery Reed Hall, 2306 E. Evans Ave. Tickets are $8-$15. The Cannabist had a wide-ranging conversation with the Ivy League professor and doctor on marijuana’s risks, its benefits as well as the most common misinformation out there.
The Cannabist: Did you write “Stoned” specifically for doctors?
David Casarett: I used doctors as an example, just figuring that doctors had a lot to learn about cannabis, but everyone else does, too. This book is for anyone who is using or thinking about using medical cannabis. It’s also for all those people who have come to the industry, dispensary owners or growers or researchers.
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Cannabist: What’s the best feedback you’ve gotten from the book so far?
Casarett: Some people have told me that it’s really useful to have such an unbiased view, and that’s rewarding to me because that’s exactly what I was going for. There are books out there that are very pro-cannabis written by people who strongly believe in its benefits. I wanted to write a book that wouldn’t talk people into using it or talk them out of it. And now when they sit down to have a conversation with a patient, physician or family member, they can talk about what we know, what’s real and what is hypothetical. It’s very factual.
Cannabist: I’m sure you’re familiar with the important medical marijuana analysis published in the Journal of the American Medical Association last year, which found that while cannabis helps with some ailments, its efficacy regarding most conditions is unproven. What did you think about JAMA’s analysis?
Casarett: I was really surprised, honestly, that they didn’t come up with more evidence than they did. For example, they concluded there was moderate evidence that medical cannabis could help those with neuropathic pain. But because one of my patients had neuropathic pain, and those were some of the trials she showed me, and there were others that I found, I would have called that evidence much stronger than that. There have been at least half a dozen controlled trials on that, and looking at that quality of evidence I’d say there’s pretty strong evidence there. But the criteria (JAMA) used to judge quality of evidence is very strict. They discounted the validity of any study that’s small, and their definition of small was less than 200 subjects, I think. So how many medical cannabis studies have more than 200 participants? Not many.
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Cannabist: I really appreciate that “Stoned” — as well as your own quest to know more about medical pot — started with you listening to your patient.
Casarett: For me, that’s always been really important. Of the three nonfiction books I’ve written, all have started from conversations with patients … In general, physicians have a unique opportunity to learn from our patients, if we bother to listen to their questions. To be fair, for a lot of general internists who get five-to-10 minutes per patient, it’s really hard to listen. Sometimes they just can’t. But in palliative care and hospice work, I have the opportunity to spend extra time with my patients.
Cannabist: Why do you think the medical profession is trending away from listening to patients?
Casarett: A couple of possible reasons. One is time — everyone is too busy. Another is information — doctors now have lab results to check and test results, and more requirements for documentation. We’re often too busy to take care of patients.
Cannabist: When do you think this medical marijuana conversation will truly open up between practitioners of traditional medicine and their patients?
Casarett: I think it already is, slowly. But I think we can help by giving physicians, in particular, language to have the discussion. That’s been one of my missions with my colleagues — giving them language that they can use to summarize what we know about risks and benefits.
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Casarett: Rescheduled, definitely. It makes no sense that cannabis is Schedule I but marinol (THC) is Schedule III. We also need to reschedule in order to reduce barriers to research. I’m not sure about descheduling. I’m very sympathetic to those arguments. Why should cannabis be scheduled when tobacco and alcohol aren’t? But I’d want to understand much more about the legal and economic implications of descheduling before I weigh in. Maybe it’s the right move, I just don’t know.
Cannabist: After you first started studying the medical benefits of marijuana, was there a moment where you had to privately address everything you thought you knew about cannabis — especially the Drug War-era misinformation about marijuana, as told to you and others by teachers and politicians and parents?
Casarett: That moment really came when I realized that there were medical benefits. For me, that flipped the debate. Now we were talking about a substance that has benefits and risks, not just risks. And in my mind, that made cannabis seem to be in the same box as many other legal drugs I prescribe. Once I realized that medical cannabis offers benefits, the question became whether, when and how to use it safely, rather than how to ban it.
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Cannabist: Massachusetts Sen. Elizabeth Warren recently asked the Center for Disease Control — and the Substance Abuse and Mental Health Services Administration and the Drug Enforcement Administration — to have another look at medical marijuana as an alternative to opioids for pain treatment. Could cannabis be more effective than opioids for patients looking to manage their pain?
Casarett: The short answer is yes. We do know as much as we can know about cannabis, and it does seem to be effective in treating chronic, neuropathic pain, which is pain due to nerve damage. That can be pain that is difficult to treat. It doesn’t always respond to opioids. Physicians prescribe opioids, but they sometimes don’t work and they cause side effects. For neuropathic pain, medical cannabis is a reasonable treatment option for many people. I’ve talked with a lot of patients who have said they’d rather be on medical cannabis than use opioids, for a lot of those reasons. Opioids can cause sedation, nausea, constipation, it makes people feel tired and goofy and not themselves. You take a pill orally and for the next eight-to-12 hours you’ll feel loopy or not yourself. Medical cannabis, with a vaporizer or smoked cannabis, you can control it yourself. I tell a story in the book of one woman who owns a chain of clothing stores in California. She had a workplace injury that caused neuropathic pain, and she started using opioids — but by the time I met her she was off them entirely and relying only on medical cannabis. There is this population of people with chronic neuropathic pain, many of whom might do better on cannabis than opioids.
Cannabist: What do you think about the theories that those addicted to opioids and other more dangerous drugs could use less-addictive, less-dangerous cannabis to kick some of those habits?
Casarett: It’s a little too speculative to comment on at this point. There are some advantages of replacing opioid addiction with cannabis. Cannabis is also addictive, but without the risk of fatal overdose … Still you have to be careful when talking about the replacement of one drug with another. The opioid epidemic is one example. Many physicians argued 15 years ago that we needed to be doing a better job of treating pain and shouldn’t be concerned about addiction. We saw untreated chronic pain, and we know how that turned out — more opioid prescribing, more availability and when we tightened the reins, patients went from legal Oxycontin to illegal Oxycontin to heroin. If we get a lot of people to switch from opioids to cannabis, maybe there will be other problems down the road.
Cannabist: What do you tell your anti-cannabis colleagues about their work in this space?
Casarett: It’s fine if my physician colleagues don’t want to recommend medical cannabis, but they should have enough knowledge to be able to have a discussion with their patient when they’re asked for advice about it … I tell them, ‘Your patients are using it, thinking about using it, they need your advice, so at least be able to give them the summary of benefits and risks.’ If patients are forced to go online and look for evidence, it’ll be hard for them to find clean, accurate information on cannabis’ risks and benefits. There’s a lot of misinformation out there. It doesn’t take long to learn the basics. You can summarize the risks and benefits in a couple sentences.
Cannabist: In your opinion, what is the most dangerous misinformation out there on both sides of the medical cannabis issue?
Casarett: From pro-cannabis groups, there are two. One is that because cannabis is a flower it’s perfectly safe. Heroin is derived from poppies, which are also flowers. Heroin isn’t so safe. Also the advice to use cannabis to cure cancer. I met a woman in Denver who put all her hope in cannabis oil to treat her curable lymphoma; she died six months ago. From the anti-cannabis groups, I worry about case reports of risks. For instance, there are reports of people who used cannabis right before they had a stroke. That’s correlation, but it doesn’t mean that cannabis caused the stroke. It’s easy to get those sorts of case reports published, so there are a lot of them.