Amazing: Psilocybin Transforms Brain Networks for Weeks

Rana AdamJuly 17, 2024

3 4 minutes read

Amazing: Psilocybin Transforms Brain Networks for Weeks

Summary: A new study finds that psilocybin, the active compound in magic mushrooms, temporarily disrupts brain networks involved in introspective thinking, such as daydreaming and memory. These changes persist for weeks, potentially making the brain more flexible and improving mental health.

These findings could pave the way for psilocybin-based therapies for depression and post-traumatic stress disorder. The research highlights the importance of using these drugs under medical supervision.

Highlights:

Temporary changes: Psilocybin disrupts brain networks for weeks, but not permanently.
Brain flexibility: The drug increases brain flexibility, thereby contributing to mental health.
Medical supervision : The results highlight the need for trained supervision during use.

Source: WUSTL

People who consume psilocybin-containing mushrooms, also known as magic mushrooms, typically have a surreal experience in which their sense of space, time, and self is distorted.

Proponents of this theory have long argued that, under certain conditions, psychedelic experiences can relieve mental distress, and a few scientific studies suggest they might be right.

Understanding precisely how the drug affects the brain will help scientists and doctors exploit its therapeutic potential.

In a new study, researchers at Washington University School of Medicine in St. Louis report that psilocybin, the active compound in magic mushrooms, temporarily scrambles a critical network of brain areas involved in introspective thinking like daydreaming and memory.

These results provide a neurobiological explanation for the drug’s psychotropic effects and lay the foundation for the development of psilocybin-based therapies for mental illnesses such as depression and post-traumatic stress disorder.

“The initial effect is massive, and once it wears off, it’s just a one-time effect,” said co-senior author Nico UF Dosenbach, MD, PhD, professor of neurology. “That’s exactly what you want to see in a potential drug. You don’t want people’s brain networks to be wiped out for days, but you also don’t want everything to go back to the way it was right away. You want an effect that lasts long enough to make a difference.”

The study, available July 17 in Naturecreates a roadmap that other scientists can follow to assess the effects of psychoactive drugs on brain function, potentially accelerating drug development efforts for a number of psychiatric diseases.

Psilocybin showed promise as a treatment for depression in the 1950s and 1960s, but restrictive federal drug policy halted nearly all further research. In recent years, however, regulations have eased and interest in the field has been revived.

“Today, we know a lot about the psychological effects and the molecular/cellular effects of psilocybin,” said first author Joshua S. Siegel, MD, professor of psychiatry. “But we don’t know much about what’s happening at the level that connects the two, the functional brain networks.”

To fill this gap, Siegel assembled a team that included Dosenbach, a brain imaging expert, and co-senior author Ginger E. Nicol, MD, an associate professor of psychiatry who has experience conducting clinical trials with controlled substances.

Together, they designed a way to visualize psilocybin’s impact on individual participants’ functional brain networks—the neural communication pathways that connect different brain regions—and to correlate changes in these networks with subjective experiences.

The team recruited seven healthy adults to take a high dose of psilocybin or methylphenidate, the generic form of Ritalin, under controlled conditions. Because psychedelic experiences carry a risk for users to have negative or frightening experiences, two trained experts stayed with each participant throughout the experiment.

Experts helped prepare participants for what they were likely to experience, provided guidance and support during each experience, and helped volunteers process what happened afterwards.

Each participant underwent an average of 18 functional MRI scans of the brain in the days or weeks before, during, and up to three weeks after their psilocybin experiences. Four participants returned six months later to repeat the experiment.

Psilocybin caused profound and widespread—but not permanent—changes in the brain’s functional networks. In particular, it desynchronized the default mode network, an interconnected set of brain areas that are normally active simultaneously when the brain is not working on anything in particular.

After losing synchronization, the network recovered as the acute effects of the drug wore off, but small differences from pre-psilocybin analyses persisted for weeks. The default mode network remained stable in people who received methylphenidate.

“The idea is that you take this system that is fundamental to the brain’s ability to think about itself in relation to the world, and you temporarily throw it completely out of sync,” Siegel said.

“In the short term, it creates a psychedelic experience. The long-term consequence is that it makes the brain more flexible and potentially more capable of reaching a healthier state.”

Normally, each individual’s functional brain network is as distinctive as a fingerprint. Psilocybin distorted the brain networks so much that individuals could no longer be identified until the acute effects wore off.

“The brains of people on psilocybin are more similar to each other than to their relaxed selves,” Dosenbach said. “Their individuality is temporarily erased. This confirms, at the neuroscientific level, what people say about losing their sense of self during a trip.”

During the experiment, participants were asked to rate their feelings of transcendence, connection, and wonder using the validated Mystical Experience Questionnaire. The magnitude of changes in functional networks was tracked by the intensity of each participant’s subjective experience.

“We were able to get very precise data on the effects of the drug on each individual,” Nicol said.

“This is a step toward precision clinical trials. In psychiatry, we often don’t know who should be given a particular drug, or at what dose or how often. So we end up prescribing one drug after another, changing the dosage, until we find something that works.

“By using this approach in clinical trials, we can identify the factors that determine who benefits and who does not, and make better use of the drugs we have.”

Nicol, Siegel, and Dosenbach stress that people should not interpret their study as a reason to self-medicate with psilocybin. The drug is not approved by the Food and Drug Administration (FDA) as a treatment for depression or any other illness, and there are risks to taking it without the supervision of qualified mental health experts.