Those magic mushrooms

Dr. Weeks’ Comment: Nature cures and the doctor collects the fee…

Neuroscience study uncovers psilocybin-induced changes in brain connectivity

BY ERIC W. DOLAN Share on Facebook Share on Twitter


New research published in Biological Psychology sheds light on the neurophysiological underpinnings of the psychedelic experience. The study provides new details about how psilocybin — the active component in “magic” mushrooms — changes the communication patterns between regions of the brain.

“Psychedelics are currently being investigated for the treatment of psychiatric disorders. However, it is still unclear how they change brain activity and connectivity to induce their unique effects,” explained study author Katrin Preller of the University of Zurich and Yale University.

“We therefore conducted a study to investigate the time-dependent effects of psilocybin on brain connectivity and the association between changes in brain connectivity and receptor pharmacology.”

In the study, 23 healthy human participants underwent MRI brain scanning 20 minutes, 40 minutes, and 70 minutes after receiving either psilocybin or a placebo. The researchers observed reduced connectivity between brain areas involved in planning and decision-making but increased connectivity between areas involved in sensation and movement while the participants were under the influence of the psychedelic drug.

Preller and her colleagues conducted a similar study on LSD, and obtained “virtually identical” results.

“Psilocybin – similar to LSD – induced a pattern of brain connectivity that is characterized by increased synchronization of sensory brain regions and decreased connectivity of associative networks,” she told PsyPost.

“Increased sensory processing but altered integration of this sensory information may therefore underlie the psychedelic state and explain the symptoms induced by psilocybin. Furthermore, this pattern of changes in connectivity was closely associated with spatial expression of the serotonin 2A and 1A receptors – pinpointing these receptors as critical for the effects of psilocybin.”

Another drug called ketanserin, a serotonin 2A antagonist, prevented the effects of both psilocybin and LSD, suggesting that changes in brain connectivity caused by these psychedelic drugs are linked to stimulation of the serotonin 2A receptor.

“In this study we investigated different time points from administration to subjective peak effects. Future studies need to investigate how psilocybin impacts brain connectivity during a later phase and post-acutely,” Preller noted.

The study, “Psilocybin induces time-dependent changes in global functional connectivity“, was authored by Katrin H. Preller, Patricia Duerler, Joshua B. Burt, Jie Lisa Ji, Brendan Adkinson, Philipp Stämpfli, Erich Seifritz, Grega Repovs, John H. Krystal, John D. Murray, Alan Anticevic, and Franz X. Vollenweider.


New psychedelic research sheds light on why psilocybin-containing mushrooms have been consumed for centuries

BY ERIC W. DOLAN Share on Facebook Share on Twitter


A new study from the Center for Psychedelic and Consciousness Research at Johns Hopkins University School of Medicine provides insight into the psychoactive effects that distinguish psilocybin from other hallucinogenic substances. The findings suggest that feelings of spiritual and/or psychological insight play an important role in the drug’s popularity.

The new study has been published in the journal Psychopharmacology.

“Recently there has been a renewal of interest in research with psychedelic drugs,” explained Roland R. Griffiths, a professor of psychiatry and behavioral sciences who is the corresponding author of the new study.

“Studies from the Johns Hopkins Center for Psychedelic and Consciousness Research and elsewhere suggest that psilocybin, a classic psychedelic drug, has significant potential for treating various psychiatric conditions such as depression and drug dependence disorders. This study sought to address a simple but somewhat perplexing question: Why do people use psilocybin?”

“Psilocybin, in the form of hallucinogenic mushrooms, has been used for centuries for the psychoactive effects. Recent US survey studies show that lifetime psilocybin use is relatively modest and quite stable over a period of decades,” Griffiths explained.

“However, the National Institute on Drug Abuse does not consider psilocybin to be addictive because it does not cause uncontrollable drug seeking behavior, does not produce classic euphoria, does not produce a withdrawal syndrome, and does not activate brain mechanisms associated with classic drugs of abuse.”

In the double-blind study, 20 healthy participants with histories of hallucinogen use received doses of psilocybin, dextromethorphan (DXM), and a placebo during five experiment sessions.

“Dextromethorphan was chosen as a comparator to psilocybin because, although it is a hallucinogen with some effects similar to psilocybin, it has a substantially lower rate of non-medical use despite its widespread availability as an over-the-counter cough medicine,” Griffiths told PsyPost.

Each experimental session was separated by about two to seven days. The sessions took place in a living room–like environment, and the participants were instructed to lie down on a couch and listen to music.

The participants completed various assessments during the experimental sessions and wrote a brief description of their experiences afterward. In addition, the participants completed a follow-up questionnaire one week and one month after their last session.

The researchers found that most of the participants reported wanting to take psilocybin again. But only 1 in 4 reported wanting to take DXM again.

“The study showed that several subjective features of the drug experience predicted participants’ desire to take psilocybin again: psychological insight, meaningfulness of the experience, increased awareness of beauty, positive social effects (e.g. empathy), positive mood (e.g. inner peace), amazement, and mystical-type effects,” Griffiths explained.

Nearly half of the participants rated their experience following the highest psilocybin dose to be among the top most meaningful and psychologically insightful of their lives.

“The study provides an answer to the puzzle for why psilocybin has been used by people for hundreds of years, yet it does not share any of the features used to define classic drugs of abuse. The answer seems to reside in the ability of psilocybin to produce unique changes in the human conscious experience that give rise to meaning, insight, the experience of beauty and mystical-type effects,” Griffiths said.

“Future research should determine whether there are other subjective domains of subjective experience or other effects of psilocybin that motivate people to use psilocybin.”

The study, “Subjective features of the psilocybin experience that may account for its self-administration by humans: a double-blind comparison of psilocybin and dextromethorphan“, was authored by Theresa M. Carbonaro, Matthew W. Johnson, Roland R. Griffiths.

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