The psychedelic compound found in magic mushrooms doesn’t just give people a day trip — it can affect the brain for weeks, researchers have found.
Experts say the study helps explain why taking psilocybin – the active ingredient in the drug – can lead to a distorted sense of space, time and self during a trip, as well as sheds light on the mechanism by which it can help in the treatment of major depression.
Dr Joshua Siegel, a co-author of the work from the Washington University School of Medicine in St Louis, said the research could also have benefits for companies testing new psychedelics and similar, but non-hallucinogenic, drugs.
“This can help determine whether a new drug is hitting the right targets and to decide what the optimal dose is,” he said.
Write in the journal NatureSiegel and a team of colleagues report how they conducted a randomized control trial with seven healthy participants who agreed to take psilocybin in the name of science.
“It was also a requirement that they had taken a psychedelic drug at some point in their life, partly because they had taken a high dose, equivalent to 5g of magic mushrooms, and put them in a big, loud, banging, claustrophobic magnet landed. [while] on psilocybin,” Siegel said, adding that the team needed to be sure that participants would be able to tolerate the situation.
“So we wanted to try to make sure that we knew they would be able to tolerate it.”
The participants were randomly assigned either a 25mg dose of psilocybin, or a 40mg methylphenidate – the generic form of Ritalin – but were kept in the dark about what they were given. One to two weeks later, the participants were given the drug they did not initially receive.
The participants underwent MRI scans before, during, between and after being given each drug, while four of the participants returned after six to 12 months to receive another dose of psilocybin and scans. Participants made an average of 18 MRI visits each.
The results show that taking psilocybin – but not methylphenidate – is associated with a loss of synchrony in what is known as the default mode network. It is an interconnected group of brain regions that are active when the mind wanders and the brain is not working on a specific task. Crucially, says Siegel, this network is involved in creating a sense of self, as well as showing links to the perception of space and time.
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“The interpretation is this [that disruption is] which creates this very extraordinary experience [when taking psilocybin],” Siegel said.
While participants’ brain scans largely returned to normal the day after taking psilocybin, Siegel noticed a reduction in communication between the default mode network and the anterior hippocampus—a part of the brain critical for memory and perceptions of space and time – lasted for three weeks. after the dose.
Siegel said the finding could help explain reports of an increase in flexibility in how people see themselves and their relationship to their environment after taking psilocybin. This plasticity is thought to be supported psychedelic-based interventions for conditions such as treatment-resistant depression by making the brain more open to therapy.
Siegel added that while the research process was demanding, there appear to be many volunteers for studies in psychedelic drugs. “We’ve had no problems finding participants,” he said.
