Key Takeaways
Psilocybin works by scrambling a key brain network
Brain scans show the drug disrupts the default mode network, a collection of regions that synchronize when the brain isn’t engaged in a specific task
Most effects wear off with the drug, but small differences persist for weeks
THURSDAY, July 18, 2024 (HealthDay News) -- “Magic” mushrooms achieve their psychedelic effects by temporarily scrambling a brain network involved in introspective thinking like daydreaming and remembering, a new study reports.
Brain scans of people who took psilocybin -- the psychedelic drug in ‘shrooms -- revealed that the substance causes profound and widespread temporary changes to the brain’s default mode network.
These findings provide an explanation for psilocybin’s mind-bending effects, and could lay the groundwork for better understanding how the drug might be used to treat mental health conditions like depression, researchers said.
“There’s a massive effect initially, and when it’s gone, a pinpoint effect remains,” said co-senior study author Dr. Nico Dosenbach , a professor of neurology with the Washington University School of Medicine in St. Louis. “That’s exactly what you’d want to see for a potential medicine.”
“You wouldn’t want people’s brain networks to be obliterated for days, but you also wouldn’t want everything to snap back to the way it was immediately,” Dosenbach added in a university news release. “You want an effect that lasts long enough to make a difference.”
Psilocybin showed promise as a treatment for depression in the 1950s and 1960s, but research into its potential flagged after the federal government deemed the substance an illegal drug in the late ‘60s, researchers explained in background notes.
However, research efforts have revived in recent years as psilocybin has been decriminalized in states like Oregon and Colorado.
“These days, we know a lot about the psychological effects and the molecular/cellular effects of psilocybin,” said lead researcher Dr. Joshua Siegel , an instructor in psychiatry with the Washington University School of Medicine. “But we don’t know much about what happens at the level that connects the two -- the level of functional brain networks.”
To learn more, researchers recruited a handful of people to take either psilocybin or generic Ritalin -- a stimulant used to treat ADHD -- under controlled circumstances.
The team then used MRI brain scans before, during and after to track the drugs’ effects on the participants' brains.
They found that psilocybin caused the brain’s default mode network to desynchronize. The default mode network is a set of interconnected brain regions that all become active when the brain isn’t working on anything in particular.
The default mode network re-established itself after the immediate effects of the drug wore off, but small differences persisted for weeks, researchers found.
No such changes were observed in those who took Ritalin, researchers said.
“The idea is that you’re taking this system that’s fundamental to the brain’s ability to think about the self in relation to the world, and you’re totally desynchronizing it temporarily,” Siegel said. “In the short term, this creates a psychedelic experience. The longer-term consequence is that it makes the brain more flexible and potentially more able to come into a healthier state.”
Each person’s functional brain network tends to be as distinctive as a fingerprint, but psilocybin distorted those networks so thoroughly that people couldn’t be identified through their scans until the drug wore off, the researchers noted.
“The brains of people on psilocybin look more similar to each other than to their untripping selves,” Dosenbach said. “Their individuality is temporarily wiped out. This verifies, at a neuroscientific level, what people say about losing their sense of self during a trip.”
The magnitude of the changes to the functional brain networks also tracked with the intensity each person reported from their individual psilocybin trips, researchers added.
However, the researchers emphasized that the findings should not be read as a reason to self-medicate with magic mushrooms.
Psilocybin is not approved by the U.S. Food and Drug Administration as a treatment for depression or any other condition, and more research is needed to understand its effects, the team said.
The new study was published July 17 in the journal Nature .
More information
The University of California-Berkeley has more about psilocybin’s potential therapeutic value .
SOURCE: Washington University School of Medicine, St. Louis, news release, July 17, 2024
What This Means For You
People should talk with their doctor or psychiatrist about whether psilocybin could help them with a mood disorder.
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