The use of psychedelics is growing in the U.S. as states move to legalize the drugs and the federal government increases its support for research into their use in treating mental health conditions. A recent survey found that a majority of Americans support psychedelic use for medical reasons. Psilocybin and MDMA in particular have shown promise in treating post-traumatic stress disorder and treatment-resistant depression.
But psychedelics come with risks. Studies have shown that hallucinogens such as psilocybin can trigger manic episodes and bipolar disorder even in people without a history of such concerns. And their use may lead to rare but long-lasting perceptual disturbances.
Last year Johns Hopkins University in Baltimore, known for its psychedelic research, opened the Clinic for Post-Psychedelic Difficulties, the first clinic in the U.S. to specifically study and treat long-term side effects triggered by psychedelic use. Researchers say it’s an important step in addressing and acknowledging the rare adverse events psychedelics can cause. Another clinic to treat psychedelic-related adverse events is expected to open at Emory University in Atlanta this year, according to university officials.
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Psychiatrist Azin Bekhrad, who co-founded and runs the Johns Hopkins clinic in Baltimore, says the goal is to have a network of providers who communicate and collaborate to address “challenging patients and challenging cases.” She says she co-founded the clinic because these serious outcomes remain poorly studied.
One other outpatient clinic dedicated to postpsychedelic difficulties was founded in Berlin in 2017, according to the center’s director, psychiatrist Tomislav Majić. He says that the center typically sees between 150 and 200 patients a year, including telehealth consultations from around the world. Meanwhile the Clinic for Post-Psychedelic Difficulties saw 10 patients in its first year, with services limited to in-person visits or in-state telehealth, Bekhrad says.
For the most part, the Baltimore clinic’s patients are split into two groups, Bekhrad says. Some become manic or psychotic after having a psychedelic experience, sometimes including other drugs or alcohol, she says. Others are referred by their primary care doctors or an ophthalmologist. That’s because about half of the patients suffer from a rare reaction called hallucinogen persisting perception disorder (HPPD), which often appears as a visual disturbance, Bekhrad says. “[It’s] not just the flashback, not just the traumatic sort of experience, but paired with persistent visual problems: visual snow, halos, maybe geometric shapes, things that are really disturbing to them,” she says.
Although HPPD symptoms typically subside after a year, Majić of the Berlin clinic says he has seen patients who suffered for more than 20 years before they sought help simply because they didn’t know where to go or that treatment even existed. The treatments these clinics offer were developed from case studies published in the late 1990s and have recently been tested in larger trials. They typically consist of a regimen of antidepressants and antiseizure medications, with nearly a third of patients showing full recovery within a year.
Researchers still don’t know exactly how common these long-term issues with psychedelics are. This is in part because these drugs are most often used recreationally, so harms go unreported. One study based on a web survey estimated the overall prevalence of HPPD among psychedelic users to be 4.2 percent. Another 2024 meta-analysis in JAMA Psychiatry found that the 4 percent of people who did have serious problems also had preexisting neuropsychiatric disorders.
These numbers may be an undercount, given stigma among researchers against reporting adverse events, Majić says. Part of this reluctance, he adds, comes from a fear left over from when regulators shut down the burgeoning field of psychedelic research in the late 1960s. The drugs were seen as “very negative and very dangerous,” he says, and he worries that scientists may be concerned that reporting adverse events, particularly serious ones, could shut the door to research again.
“What is lacking, in my view, is a really balanced and nonideological perspective on the substances,” Majić says. “On the one hand, they are not toxic, and they’re not addictive.... On the other hand, they’re not without risks.”
Michael Silver, a neuroscientist and director of the University of California, Berkeley’s Center for the Science of Psychedelics, believes strongly that, for many people, psychedelics result in “incredibly powerfully positive experiences” that help address addictive behaviors or resolve trauma. He says he was surprised to hear that there were centers specifically devoted to psychedelic adverse events and notes that he knew of no other centers devoted to adverse events from specific medications.
Silver says he considers the main risks of psychedelics to be psychological rather than neurological, often arising when people enter into the psychedelic experience unprepared or in a problematic environment. Research into the “set and setting” of psychedelic trips and the drugs’ effect on physical and mental outcomes could improve public education and allow for precise treatments, he says.
Dawn Fallik’s research into psychedelic oversight was supported in part by the Pulitzer Center.