Magic mushrooms are one of the psychedelics showing real medical potential
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A single dose of psilocybin – the active ingredient in magic mushrooms – produces rapid reductions in symptoms of obsessive-compulsive disorder (OCD), according to the first placebo-controlled trial to test the psychedelic for the mental health condition. The effects also seem to persist for at least 12 weeks, suggesting that psilocybin could provide lasting relief.
“If we give you a trip, we think we can break the cycles of obsessive thinking and behaviour,” says David Nutt at Imperial College London, who wasn’t involved in the research. “The whole point of OCD therapy is about teaching people to behave differently. So, rather than check the lights 15 times, you check them twice.”
About 1 to 3 per cent of people have OCD, a condition characterised by obsessive thoughts and compulsive habits, which can be overwhelming. Treatments tend to include talking therapies and antidepressants, but between 40 and 60 per cent of people with OCD don’t respond to them.
Psilocybin – and other psychedelics like ketamine – have shown promise for mental health conditions. To get a more robust idea of its potential, Christopher Pittenger at Yale School of Medicine and his colleagues decided to test psilocybin for OCD in the first randomised, placebo-controlled trial.
The team recruited 28 adults who had lived with OCD for two decades, on average, and had unsuccessfully tried at least two different treatments. They all had the severity of their symptoms rated using a standard scale, which gives a score of between 0 and 40. They were then randomly assigned to either receive a single oral dose of psilocybin (0.25 milligrams per kilogram of body weight) or niacin (250 milligrams), also known as vitamin B3, which acted as the placebo.
The psilocybin dose was enough to give the participants a psychedelic trip, which tends to involve big changes in perception, thoughts and emotion. “It’s pretty intense, though it varies from person to person,” says Pittenger.
After 48 hours, the symptom scores of the 14 people who received psilocybin decreased by 9.76 points, on average, while those taking niacin stayed about the same. “The speed and durability of the improvement seen after a single dose of psilocybin are remarkable,” says Alex Kwan at Cornell University in Ithaca, New York.
One week later, about 70 per cent of those who took psilocybin still had a symptom score reduction of about 35 per cent, and the benefits persisted at a 12-week follow-up. “It’s definitely better and faster than other medications for OCD,” says Nutt, who was involved in a recent trial, without a placebo group, that similarly found a small dose of psilocybin reduced OCD symptoms.
Kwan says that seeing such an improvement in people who have already tried multiple standard treatments suggests that psilocybin engages the brain in a fundamentally different way, but it’s exact mechanism for helping with OCD is unclear. “If we can uncover that biology, it could transform how we think about treating many psychiatric disorders, not only OCD,” he says.
One idea is that psilocybin enhances the plasticity of the brain, so thoughts that seemed rigid and dominant can become less powerful. That is profound with all psychedelics, says Nutt, who recently showed that one dose of the psychedelic DMT reduces symptoms of depression. “Previously, depressive thoughts dominated their thinking, but after the psychedelic, their brain is more flexible and they put them to one side instead of agreeing with them,” he says.
Another idea is that psilocybin recalibrates the relationship between the brain’s default mode network, which is involved in rumination and the sense of self, and its other areas, says Pittenger. We also know that a single dose of psilocybin can rewire the brain and it may also boost mental health by dampening inflammation.
But the drug could have safety concerns. During the Yale study, one person who already had persistent thoughts about suicide began to actively plan it. The danger passed after standard monitoring, but Pittenger says this highlights the need for clinical safeguards to be in place when administering psilocybin medically. Larger trials also need to confirm the drug’s efficacy and safety, the best dose and who is most likely to benefit or be at risk, he says.
Another recurring problem with psychedelic research is that the effects of these drugs mean that trial participants can often gauge whether they have received them or a placebo. The team tried to mitigate this by using a dose of niacin that can cause psychedelic-like events, such as flushing and an elevated heart rate. Nevertheless, Pittenger says that most of the participants still had a clear idea of what they had received. “This is a weakness of the study, as it is for most such work in the field,” he says.
Need a listening ear? UK Samaritans: 116123; US 988 Suicide & Crisis Lifeline: 988; hotlines in other countries.
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