On the Tuesday, April 7, 2026, episode of The Excerpt podcast: Cannabis is widely used for medical purposes, yet doctors still can’t prescribe it. From limited clinical trials to federal restrictions, science and policy haven’t caught up. Dr. Staci Gruber of Harvard and McLean Hospital explains what we know about medical marijuana, CBD, and what it will take to prove they work.
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Dana Taylor:
Cannabis is widely known to be a recreational drug illegal in some states and legal in others, but what do you know about cannabis therapies, often referred to as medical marijuana? For well over a century, compounds extracted from the marijuana plant, and there are over 500 of them, have been used as therapies for a variety of medical applications, from treating anxiety to addressing pain. So where are all the clinical trials? And why are doctors still not able to prescribe medical cannabis?
Hello, and welcome to USA TODAY’s The Excerpt. I’m Dana Taylor. Today is Tuesday, April 7th, 2026.
Joining me to discuss this is Dr. Staci Gruber, director of the Marijuana Investigations for Neuroscientific Discovery at McLean Hospital and an associate professor of psychiatry at Harvard Medical School. Dr. Gruber, thank you so much for being here.
Dr. Staci Gruber:
Thanks for having me.
Dana Taylor:
When people hear the word cannabis today, they usually associate it with its recreational use, which involves THC, the psychoactive compound of marijuana. But cannabinoid therapies have been around for well over a century. Briefly, Dr. Gruber, what happened?
Dr. Staci Gruber:
So it’s a great question, and I think you’re exactly right. When people hear the term cannabis or marijuana, they think one thing. Recreational use. It’s a drug for pleasure and fun. They forget that cannabis has an extremely storied past here in this country. It was legal and actually a prescription medication. For example, it was part of our pharmacopeia in 1850, which meant that you didn’t have an indication for use or a recommendation for use as we do now. You actually had a prescription.
Today, you can’t have a prescription for cannabis because it still sits in Schedule I of the Controlled Substance Act, the most restrictive class. It fell out of favor. It became illegal and was pulled from the pharmacopeia and in 1970 placed in that most restrictive class, where it remains today. In 1996, California re-legalized cannabis for medical purposes. And despite that, we have very little information in terms of long-term impact of cannabis use specifically for medical purposes.
But to your point, cannabis has featured into countless civilizations thousands and thousands of years ago to current day. So clearly, people are interested in utilizing and exploring these compounds for medical purposes.
Dana Taylor:
I’m going to stick with something you just mentioned. Fast-forward to today when cannabis is a proven therapy for all sorts of medical conditions, yet as you’ve said, marijuana is still a Schedule I drug alongside heroin and LSD. Why is that?
Dr. Staci Gruber:
So again, when we think of the definition of Schedule I, by definition, Schedule I substances have no accepted medical value, high liability for abuse, and no accepted safety profile. While I think there’s an awful lot of information and evidence suggesting that cannabis has medical value, we certainly don’t have the universe that we currently should have.
But to your point, we have the very first FDA-approved, whole-plant, single purified compound, or cannabidiol, as Epidiolex, that’s approved for pediatric-onset intractable seizure disorders. That’s an amazing thing in terms of where we are today with regard to having an actual medication. But in terms of actual clinical trials demonstrating clinical superiority, for example, of cannabis or cannabinoids for certain things versus other things, we still fall short. That doesn’t mean that because we have a lack of evidence, it doesn’t work. It means that we have a lot of work to do.
Dana Taylor:
Your team at McLean has been instrumental in changing the cannabis narrative with regards to its medical applications. Tell me about the kinds of treatments your team has been investigating.
Dr. Staci Gruber:
Yeah. Despite the fact that cannabis was re-legalized in ’96 in California, we had very little information in terms of what we could understand in terms of long-term impact of medical cannabis. And so I scoured the literature and couldn’t find much. And I wondered if we would see the same things in our medical patients as we have seen in our recreational consumers. And the answer in short is, no, not necessarily.
So we started a program in 2014 called Marijuana Investigations for Neuroscientific Discovery, or the MIND Program. It’s dedicated to looking at the long-term impact of cannabis and cannabinoids used explicitly and specifically for medical purposes. These are longitudinal observational studies where patients use their own products that we test and understand what’s in their weed in terms of the cannabinoid profiles. And we follow them from before a time when they used cannabis all the way out to three, four, five years post-treatment. And we do cognitive and clinical assessments, neuroimaging assessments. We have clinical trials where I formulate custom products designed to address specific symptoms related to different conditions. And we look at the differences between those products versus, for example, placebo, again, at baseline and over periods of time.
So we really have a number of different initiatives designed to look at the impact of these unbelievably promising compounds for different indications and conditions. We have a women’s health initiative at MIND, the only program like it in the country. Actually, it’s called WIM. I like to say, “It’s not just a WIM.” But the Women’s Health Initiative at MIND is dedicated to looking at conditions or indications that either specifically or disproportionately affect women. So, incredibly helpful.
Dana Taylor:
I want to bring up the case of Charlotte Figi here. I know you didn’t treat her directly, but you know of her story, which was really a game-changer for medical cannabis. Charlotte was diagnosed with a rare and severe form of epilepsy at birth. And after years of relentless seizures, her family turned to CBD, what was then a controversial treatment. What followed not only changed Charlotte’s life, but sparked a national conversation that’s still unfolding today. Tell me about her case.
Dr. Staci Gruber:
So I think of Charlotte Figi as the little girl who changed the world. Really, the revolution started with Charlotte. And again, people had this idea of what medical cannabis was really like, and a lot of people said to me, “This is probably just a legal way for people to get high.” She’s a perfect indication of why that is absolutely untrue.
Dravet syndrome is a pediatric-onset intractable seizure disorder. It’s these unbelievable seizures, over 300 a week. And she was one of twins. And this little girl was unbelievably impaired. And the use of a whole-plant, full-spectrum product, which basically means it’s a product made from a plant containing all the cannabinoids, including small amounts of THC but high amounts of CBD, or cannabidiol, which is non-intoxicating, was remarkably effective in allowing her to have a normal life. She was able to walk and talk, and after years of being debilitated really was a completely changed little girl. And it was really almost a miracle story. It changed the way the nation thought about the ways that we might be able to treat people using some of these products. You don’t have to get high or be altered to be treated.
Dana Taylor:
Although Charlotte’s condition ultimately led to her death, she’s remembered in Colorado on April 7th, which is recognized as Charlotte Figi Day. We recently spoke with her mother, Paige, about her legacy. Let’s give a listen.
Paige Figi:
It worked from the very first dose. She stopped seizing. When I believed it was working, I probably saw about 100 other Charlottes, 100 other children with a similar disorder. I needed to believe that I’m not crazy, what I’m seeing isn’t just a weird phenomenon, that it actually was working. So once we realized that, it was probably six months into it, into the treatment that I’m not crazy, this is actually a valid treatment. She became the face and the representation of people who could benefit from this. And now, it’s professional athletes, it’s seniors, it’s first responders. The largest group of people I work with are veterans. They found a solution in this harmless, non-intoxicating substance. And so her face still represents that initial movement of access to this.
Dana Taylor:
In cases like severe childhood epilepsy, like in Charlotte Figi’s case, what do we understand about how CBD is able to reduce seizures?
Dr. Staci Gruber:
It’s a great question. Again, there seems to be evidence, going back many decades actually, that demonstrates that cannabidiol, or CBD, a primary but not the only non-intoxicating compound of the plant, is a remarkably effective anticonvulsant medication compound. So the ways in which we harness these types of compounds for not only seizure disorders, but other conditions has been incredibly instructive. And what we find is that people who are using these products that are rich in CBD really do have a shift and a change.
There have been some studies, meta-analyses that look at large numbers of studies of individuals using these products versus using other products, either standard anti-epileptic drugs or single-extracted, purified compounds like Epidiolex, which is a purified form of CBD. No other cannabinoids or terpenes or anything, just CBD. And it turns out that it’s very likely you have a better clinical response at lower doses using a whole-plant, full- or broad-spectrum product.
What do I mean by that? A whole-plant, full-spectrum product is a product that contains pretty much everything that’s present in the plants that made the product. A broad-spectrum product would be exactly the same, but no quantifiable amounts of THC, the primary intoxicating constituent of the plant. In some cases, we don’t want that on board, in some cases for legal reasons and some for physical reasons, versus an isolate, single-extracted, purified form. In Charlotte’s case, she was using a whole-plant, full-spectrum product, which seems to be incredibly efficacious at addressing these unbelievably devastating symptoms of Dravet syndrome, which Charlotte had, Lennox-Gastaut, a number of these unbelievably challenging pediatric-onset seizure disorders.
Dana Taylor:
Dr. Gruber, you’re one of the world’s leading experts on the use of medical cannabis. What led you to this line of work?
Dr. Staci Gruber:
So we had been studying the impact of recreational cannabis for decades, using lots of different probes, clinical assessments, and cognitive performance and measures of brain structure and function, emotional processing, all sorts of different things. And what we found was that the earlier the onset of recreational cannabis use and the higher the amount and more frequent the amount, the more likely people might have difficulty later.
And I wondered with the passage of time and as we began to see legalized medical cannabis programs, my own state passed the law in 2012, if we would see the same thing in these medical cannabis patients. And I looked through the literature, I scoured it and could find nothing. Literally nothing, despite the fact that medical cannabis reemerged in California in 1996. So we had to start this program. I was desperate to understand the differences.
And as it turns out, the goal of use, whether you’re using for medical purposes or recreational purposes, and again, no judgment here, dictates the products you choose, and the products you choose dictates the outcome, what to expect. So all of these things make everything a whole lot easier in the aggregate to understanding what to expect and how best to proceed when you’re trying to make the decisions of what to use. It’s been an extraordinary journey. It’s probably the most important work I’ve ever done in my career.
Dana Taylor:
When you look across the country, do you see other hospitals following your lead?
Dr. Staci Gruber:
So I think there’s been a huge amount of interest and investment in looking at the impact of cannabis for medical purposes. We see explosions of research studies and initiatives, which is fantastic. We need more. What we need are empirically sound clinical trials that allow us to determine with absolute certainty the efficacy of certain cannabinoids and combinations of cannabinoids and terpenes, the essential oils from the plant that give it its characteristic scent and flavor profile, but also have behavioral health effects. To determine how effective those things are at different conditions, I think there are a lot of folks doing this kind of work at this point. The numbers of investigators and investigations continues to skyrocket as the nation and the world’s interest in exploring and exploiting these compounds continues to expand and increase.
Dana Taylor:
In the landscape of medical therapies, what excites you the most about the future of cannabis?
Dr. Staci Gruber:
I think there are a few things that are very exciting. Many, many people express increased levels of stress and strain and anxiety. The numbers of people dealing with anxiety has gone through the roof since the pandemic and has not gone down. It’s amazing to me to think that we can harness something that is not intoxicating and allow people to take what is often described as an emotional breath in their day-to-day lives. They don’t ruminate. They’re able to relax and sit down, take a breath, unwind, not have their mind get away from them. It’s amazing to look at the impact of some of these products on chronic pain, on the inability for people to sleep through the night.
In many cases, in my case, we’re looking at the impact of some of these novel compounds in addressing certain things that are part of things like bipolar disorder or patients with glioblastoma. This is a game-changer. There’s every reason to be incredibly hopeful and very excited and invested in the next generation of these types of products and treatments for folks with lots of different indications and conditions. It’s when you have people who are suffering and you have things to offer them that haven’t previously been available and isn’t likely to hurt, but could certainly help, you certainly should give it a shot.
Dana Taylor:
There are obviously a lot of misconceptions about medical cannabis that still cloud the field. What do you think people most need to understand here?
Dr. Staci Gruber:
I think first and foremost, I tell everybody cannabis is not one size fits all or even one size fits most. What works for one person for a headache, one person might love ibuprofen, another person might not be able to take it and only has acetaminophen, for example, the same is true here. We have different genetic profiles. We have different metabolism. We have different tolerance for things. So we have to figure out on an individual or personalized level what works.
So when people say, “I tried cannabis and it was bad for X,” hold on. Was it cannabis or was it a specific compound in the cannabis? Most of the time when we hear about the negative effects of cannabis, what we’re really hearing about is the negative effect of THC, not cannabis. There are lots of cannabinoids that are really quite helpful and effective for things that we haven’t even begun to explore. That’s exciting.
So that’s a common misconception. What works for you may not work for your friend or your mother or your brother, and it’s also not a legal way to get high. Most people I deal with every day tell me, “I don’t want to be high or altered. I just want to sleep through the night. I want to take a walk in the woods. I want to be able to do my workouts again. I want to feel like myself.” They’re not looking to be high or altered. Not that there’s anything wrong with that per se, but that’s a big misconception too. So it isn’t necessarily what people think.
On the other side, we have to be careful and be mindful. There are risks associated with cannabis use, even for medical purposes. There are potential drug-drug interactions that we must be mindful of. So it’s, again, something that people shouldn’t enter into lightly, but certainly should explore with the right information and, again, a clear intention. “Know before you go,” I tell people. What are you looking for before you set out to use a product? Know before you go. And what’s in your weed? Know what the constituent profile is of the product you’re purchasing or getting from someone as opposed to just taking a guess, because that’s going to make all the difference.
Dana Taylor:
Dr. Gruber, thank you so much for sharing your expertise with us here on The Excerpt.
Dr. Staci Gruber:
My pleasure.
Dana Taylor:
Thanks to our senior producer, Kaely Monahan, for her production assistance. Our executive producer is Laura Beatty. Let us know what you think of this episode by sending a note to podcasts@usatoday.com. Thanks for listening. I’m Dana Taylor. I’ll be back tomorrow morning with another episode of USA TODAY’s The Excerpt.