Psilocybin, the active compound in hallucinogenic mushrooms, is edging into mainstream psychiatry in parts of Europe – with Switzerland already treating patients and the Czech Republic opening tightly supervised therapies. But France is holding back, limiting its use to clinical trials while doctors wait for stronger evidence of its efficacy.
When Marie Mallevialle arrived at the Geneva University Hospital in 2023, she feared she was “losing her mind”.
Two years earlier, the Franco-Swiss woman had lost her son to a brain tumour. “I was sleeping maybe an hour a night. I had dissociation, lots of flashbacks and reliving,” she explained.
Doctors diagnosed post-traumatic stress disorder. Eye movement desensitisation and reprocessing therapy helped her work through her traumatic memories, but despite medication, the insomnia continued and the sadness remained overwhelming.
“I was stuck in the past,” Mallevialle said.
While researching her condition, she came across psychedelic-assisted psychotherapy, where patients receive substances such as LSD or psilocybin under strict medical supervision – treatments in which Switzerland is often cited as a pioneer.
“Antidepressants, LSD and psilocybin were all born in Switzerland. And contrary to what people think, research never really stopped,” said Daniele Zullino, head of the addiction medicine department and the psychedelic-assisted psychotherapy programme at Geneva University Hospital.
For around a decade, carefully selected patients have been treated with these substances in highly controlled settings.
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Increasing use
Elsewhere in Europe, the landscape is also beginning to shift. Since January, the Czech Republic has become the first European Union country to allow psilocybin in supervised psychotherapy.
The move follows years of work by institutions including the Czech National Institute of Mental Health, in a country that was a pioneer of psychedelic research in the 1950s and 1960s, before international prohibition halted the field in the 1970s.
As in Switzerland, recreational use remains illegal and psilocybin is still classified as a narcotic. Treatments are strictly regulated.
In Australia, authorised psychiatrists have been able to prescribe psilocybin for treatment-resistant depression since July 2023. In Canada, access exists on an exceptional basis under tight conditions.
In the US state of Oregon, supervised psilocybin services have been available to adults since 2023, outside the traditional medical system. In New Zealand, the medicines authority gave a highly restricted green light in June 2025 for authorised psychiatrists to prescribe psilocybin for resistant depression.
At Geneva University Hospital, some 600 patients have already undergone psychedelic-assisted psychotherapy, and demand remains strong.
“We’ve had up to 800 people on the waiting list,” Zullino said. Each case requires approval from Switzerland’s Federal Office of Public Health. “They require psychotherapeutic support before and after."
Treatment protocol
After a year and a half on the waiting list, Mallevialle received authorisation in April 2025 and has just completed her treatment. “It’s not miraculous. You need a lot of therapeutic work beforehand, but it’s quite promising,” she said.
The standard protocol is three sessions, spaced three months apart, but Mallevialle had four.
On the day, patients arrive early in the morning. The setting is adapted “to soften the hospital feel,” she said. A psychiatrist and nurse check the patient’s state of mind and confirm consent.
The psilocybin – 25 milligrams for the usual dose – is taken in capsule form. The patient lies down, wearing an eye mask and headphones. Music is a core part of the therapy.
“Some choose Bach, others AC/DC,” Zullino said. The session lasts six to eight hours.
“The molecule takes about 30 minutes to act, then you go on your journey," Mallevialle explained. “You’re accompanied all day, but you’re the one doing the work.”
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'It's not a party'
Describing what follows is difficult, Mallevialle said. “It’s like a series of short films. There’s music, colours, symbols, concepts. You move from a film about your childhood to one about illness, then motherhood, death. You receive messages, information,” she said.
She described moments of ecstasy and others that were deeply trying. “I was in a boxing ring against injustice, illness,” she said.
The day after each session, a psychotherapy meeting helps put the experience into words, with another follow-up a month later.
Her account echoes those of other patients.
Bernard, who asked that his full name not be used, is undergoing psychedelic-assisted therapy in a private Swiss practice for anxiety disorders. In his second year of treatment, he attends four or five sessions a year.
“Antidepressants are... a crutch to get through hard times, but they’re a plaster. You don’t heal the wound,” he said. “With psilocybin, you go back and clean the wound deeply."
His sessions take place in a house in the countryside, in small groups. Bernard stressed that the experience has nothing to do with recreational drug use. “It’s not a party. It can be frightening, even terrifying, but for me it’s worth it,” he said.
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France remains cautious
Long associated with counterculture and so-called bad trips, hallucinogenic mushrooms were excluded from medical research for decades. Over the past 15 years, scientific interest has returned, with studies exploring the potential for treatment of depression, addiction, anxiety and post-traumatic stress disorder.
In France, psilocybin remains confined to clinical trials.
In Paris, psychiatrist Lucie Berkovitch is taking part in an international trial on treatment-resistant depression at Sainte-Anne Hospital. “There’s a profound difference in mindset between France and Switzerland,” she said.
“In Switzerland, they didn’t wait for full authorisation to treat individual cases. In France, we wait for results to be confirmed before bringing psychedelics into routine care.”
One attraction of psilocybin, she said, is the speed and durability of its effects. “It’s an unusual timeline in psychiatry,” she said, where antidepressants can take weeks to work.
She explained that psilocybin acts on a serotonin receptor known as 5-HT2A. “The substance binds to this receptor and activates it very strongly, which triggers the psychedelic experience,” she said.
Beyond the experience itself, she said psilocybin also appears to have longer-lasting effects on brain connectivity and neuroplasticity, which are altered in depression and chronic stress.
“Psilocybin seems to restore, at least in part, these lost connections,” she said. “The brain becomes more flexible, more receptive to change.”
Studies published in the United States in 2025 reported striking results. One study involved military veterans with treatment-resistant depression who received a dose of psilocybin. Half of the 10 volunteers were in remission six months later.
Although that figure fell to 30 percent one year after treatment, the results were considered encouraging.
Another study followed 18 patients with severe depression who received two doses of psilocybin as part of their therapy. Five years later, 67 percent were in remission.
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Addiction and end of life
Beyond depression, addiction is one of the most closely studied areas.
A study published in the journal Addiction and conducted at Nîmes Hospital involved patients with both alcohol use disorder and depressive symptoms. After 12 weeks, abstinence rates were higher in the group that received a high dose of psilocybin at 25 milligrams than in the group given a very low dose, at 55 percent compared with 11 percent.
The study involved 30 patients, but the findings support those of a larger US study.
End-of-life care is another area under discussion. At Paris Public Hospitals, physician Benjamin Wyplosz wants to launch a trial on the use of psilocybin to relieve psychological suffering in terminally ill patients, but has encountered strong resistance.
“Studies conducted in the United States show that psilocybin reduces distress and anxiety in 70 to 80 percent of cases in palliative care patients, often after a single dose,” Wyplosz said. “No medication today achieves such an effect so quickly.”
The suffering experienced by people facing incurable illness is not depression in the classical psychiatric sense, but a form of demoralisation recognised by the international classification of diseases, and poorly treated by existing drugs.
“And that responds poorly to antidepressants or anti-anxiety medications,” he said. The rapid action of psilocybin is therefore crucial when “time is limited,” Wyplosz said.
Specialists nevertheless urge caution.
“A substance that massively alters perception of self and the world for several hours is bound to worry people,” explained Berkovitch, of Sainte-Anne Hospital. “But we shouldn’t miss care opportunities because of clichés.”
Zullino also calls for humility in the face of sometimes striking results. “For depression, we see miracles, we have to say,” he said. But outcomes vary. “A third are really well after two months. A third improve. A third could be better.”
For Mallevialle, the changes are already tangible. She sleeps better, no longer takes psychiatric medication, has regained weight and is making plans. “I think it’s changed my life, and the way I’m in the world."
This article has been adapted from the original version in French by Aurore Lartigue.
