This story was featured in The Must Read, a newsletter in which our editors recommend one can’t-miss story every weekday. Sign up here to get it in your inbox.
Alan thought he was in for a mellow night when he popped a 10-mg edible and stretched out on the couch. He had built up his tolerance slowly, starting with CBD drinks, advancing to 5-mg THC chocolates, and finally settling on this 10-mg dose, which he had taken more than once before. But instead of feeling his tension melt away, the 24-year-old noticed his tongue and throat start to swell. He suddenly had trouble swallowing. His heart began to pound. It was as if a full-body alarm had gone off, and it refused to stop. “I was convinced I was having a stroke or heart attack,” he remembers. His family called 911.
At the emergency room, a doctor told Alan (not his real name) that he wasn’t dying. It was just a bad high, he said. Drink some water. Go home. Sleep it off.
A few months later, Alan experienced another panic attack after taking an edible. Otherwise healthy, he soon began experiencing persistent symptoms even when he was sober. “Palpitations, tinnitus, my throat feeling tight, vertigo, dizziness. I had them all,” he says. He even stopped working out, fearing a heart attack. Desperate for answers, he posted the following message on the r/anxiety subreddit: “I’m really scared that this is my new normal, that I’ll never be able to just sit down and think about anything other than my anxiety. That I won’t ever be able to enter the worst of the worst and successfully fight my way out. That I’ve completely lost control of myself and am just at the mercy of whatever triggers my anxiety.” A year and a half later, he says that some—but not all—of his symptoms have subsided.
Scroll through Reddit, and you’ll find post after post written by people claiming that a single gummy left them in a permanent state of anxiety, with recurring panic attacks, a feeling of dissociation that won’t fade, or unbearable physical symptoms. One night, Lexi, 27, had a similar experience with a 10-mg gummy while watching a movie with her husband. “The room was moving, everything looked huge, and I felt very small,” she says. “My heart rate was 180 and I was uncontrollably shaking.” Since then, she says she has started experiencing derealization, a neurological anxiety symptom. “My surroundings feel fake. Almost like in the movies Inception or The Matrix. It feels like I’m dreaming,” she says. While she had experienced panic attacks prior to the movie night, they’re now more frequent and severe. “It completely altered my life. I wish I could go back and never consume the edible.”
As early as 1997, researchers found that cannabis—specifically THC—can trigger recurring panic attacks and uncover latent panic disorders in vulnerable populations. More recently, studies suggest that cannabis users are more likely to develop or have more severe anxiety than the general public. Ziva Cooper, PhD, director of the UCLA Center for Cannabis and Cannabinoids, says it’s a bit of a chicken-and-egg scenario: “One of the primary reasons why people use cannabis is actually to help anxiety,” she says. In other words, cannabis users may be at higher risk for anxiety disorders because they had anxiety beforehand.
Cannabis is a broad category, and the compounds it contains—such as THC, CBD, CBC, and CBG—interact with the body differently. “The chemical composition is probably the most important aspect” of how it will affect the body, Dr. Cooper explains. CBD, for example, eases anxiety at any dose, but THC functions very differently. “Delta-9 THC is—for all intents and purposes—considered a psychedelic molecule,” says Dave Rabin, MD, board-certified psychiatrist, neuroscientist, and executive director of the Board of Medicine. “So it increases what we call ‘self-reflective thinking’—which isn’t always a bad thing.”
For certain people, THC might reduce anxiety at lower doses. But for those who already live in heightened states of anxiety, it’s easy to tip the scale. “At higher doses, one of the hallmark adverse effects of THC that we know—across the board—is anxiety and paranoia,” Dr. Cooper says.
Staci Gruber, PhD, director of the Marijuana Investigations for Neuroscientific Discovery (MIND) program at McLean Hospital and an associate professor of psychiatry at Harvard Medical School, agrees: “In higher doses, THC is almost always anxiogenic [anxiety-inducing] for many people,” she says. Just where the threshold lies—when THC flips from calming to panic-inducing—is unclear. One 2017 study found that a 7.5-milligram dose reduced negative emotions associated with a stressful task, but at 12.5 milligrams, participants experienced “small but significant increases in anxiety, negative mood, and subjective distress.”
Cannabis has a lot of benefits, and fewer risks than alcohol. Some use it in a therapeutic setting to treat disorders like PTSD, and research has shown promise for cannabis use in the management of chronic pain and to reduce reliance on opioids.
But the widespread legalization of cannabis products in the United States has come with some apparent downsides. Today’s weed is famously a lot more potent than it used to be. According to the National Institute for Drug Abuse, the delta-9 THC content in illegal cannabis products quadrupled between 1995 and 2022. And inhalation, which is still the most common method of consumption, is very different from edibles. “Whether you’re vaping or smoking, the rise time—or time to get an effect—is moments to minutes. You inhale, it’s in your lungs; it’s in your bloodstream; it’s in your brain,” says Dr. Gruber. When you smoke, you take in only a small fraction of the dosage. The rest gets burned off.
Edibles, like gummies, cookies, and sodas, have transformed how people ingest THC and are linked with more “unintended consequences,” as Dr. Gruber puts it. They can take up to two or three hours to fully kick in, so they’re deceptively easy to overconsume. (Hence the “when the edible hits” memes.) The body also processes edibles differently. When you eat THC, “your liver converts delta-9 THC, the primary intoxicating constituent, into something even more intoxicating called 11 hydroxy. It’s the gift that keeps on giving,” says Dr. Gruber. The effects can last up to 12 hours, making a bad high feel like a never-ending trip. “If you’ve ever been in that situation, when your own brain or your body defies you or rebels against you, it is terrifying,” says Dr. Gruber. These users “won’t die; they just might wish they were dead.” That may be why emergency room visits are much more common after edible intake than with smoking.
Plus, the dosage of an edible is much trickier to get right. Some people can take 10 mg and feel nothing (literally); for others, that same dose can send them straight into a horror movie. Even when people think they know what they’re in for based on past experiences, they can be caught off guard. “We don’t always believe everything that’s printed on the label is reflected in the actual product,” says Dr. Gruber. “But more specifically, individual metabolism, genetic predispositions, your current [mental] state, [taking them] with or without alcohol—all of these things matter for your personal experience with cannabis.” Put simply, the amount that gives you a “good” high can change day to day.
Not everyone is equally susceptible to cannabis-induced anxiety. A 2009 study found that women, infrequent users, and those with anxiety disorder are at a higher risk. “For people who have a history of challenges with things like anxiety, depression, or a family history of psychosis, we really want to be mindful of exposing them to high levels of THC because it can be decidedly uncomfortable,” says Dr. Gruber. Some people—like Lexi, who has been diagnosed with depression—may be better off avoiding THC entirely. “I’ve tried a couple times since, but I almost immediately start to panic when the high hits,” she says. Dr. Rabin also warns that anyone diagnosed with personality disorders, psychotic disorders, schizophrenia, or bipolar disorder—and, it should go without saying, children— should avoid THC products.
For those who find themselves stuck in a cycle of anxiety after a bad edible experience, recovery can feel frustratingly slow. Unlike the acute effects of THC, which typically wear off within hours, the lingering psychological impact can last for weeks, months, or even years. “People get into these ruminative thought loops—like self-critical thought loops—and they get stuck there,” says Dr. Rabin. “If you don’t have that reassurance of a knowledgeable care provider, you may not have the support to help you break the cycle of that thought loop.” Remind yourself that your symptoms will fade, and avoid worrying that you’ve done permanent damage—you haven’t.
Your personal support system is also crucial. “When I first made the post in my very helpless state, someone commented, sharing their experience,” says Alan. “Before talking to him, I thought I had ruined my life, and, a couple of times, I was really considering ending it. He was finally the proof I needed that there is a light at the end of the tunnel and that recovery was possible. Looking back, that random Redditor likely saved my life.”
Even with research pointing to the anxiogenic effects of THC at higher doses, stories like Alan’s and Lexi’s can seem like outliers—until they don’t. The unpredictability of edibles, combined with personal factors like stress levels, sleep, or even what you ate that day, means that even seasoned users can be caught off guard. So how can people use cannabis in a way that minimizes the risk?
For many, cannabis can be enjoyable—even therapeutic—when used responsibly. “We always recommend people, especially if you’ve never taken cannabis before or not had a lot of experience with it, to start with CBD. Start with the nonpsychoactive cannabinoids and then trickle delta-9 THC in later at very low doses,” says Dr. Rabin. When you introduce THC, it should be at a one-to-one ratio of THC and CBD, he adds: “You don’t really need that much THC to get the benefits that most people are looking for.” (You can use this framework for cannabis use to slowly introduce yourself to THC.)
Because there’s no federal oversight, you should get your cannabis from a dispensary that adheres to state regulations, says Dr. Cooper. And don’t be afraid to have a conversation with your doctor about which products would be best for you. “They can talk to you about safety, they can talk to you about other medications that you’re taking that might interfere,” says Dr. Cooper. “Physicians are protected to be able to talk to their patients about it.”
Then, when you do take edibles, start slowly. “You can always add. You can never take away,” says Dr. Gruber. “Give yourself a fair amount of time to see how you feel in response to a product.”
Both Alan and Lexi, who never touch THC anymore, say they are doing better. Lexi now takes an SSRI and goes to therapy to manage her symptoms. Alan no longer gets regular panic attacks, but dizziness, lightheadedness, and vertigo come and go. “All in all, it feels like my body has aged significantly through all the physical stress it went through,” says Alan. “But I just held onto the advice that the Redditor gave me: It may take time, but you will eventually be yourself again.”
