Recently I was chatting with a friend who is casually interested in psychedelic science. He told me he hadn’t read as much coverage of psychedelics in popular magazines and other mainstream outlets lately, and asked whether research has slowed. My response? Not at all.

According to Pubmed, the online repository of the National Library of Medicine, last year saw far more papers published on psychedelics than ever before — about 33% more than in 2021, which itself was a 19% increase over 2020. And this year is well on pace to surpass 2022.

Every day another email arrives in my inbox with word about the latest papers, many of which address the promise of psychedelic-assisted therapy for depression, addiction, PTSD, and other mental health disorders.

But dig deep into the scientific literature and you’ll find plenty of outliers and oddities that have nothing to do with therapy per se, covering fascinating subjects like psychedelics for headaches or color-blindness; “entity” encounters; and the still-mysterious question of what, exactly, these compounds do to the brain.

Mood-Elevating Microdosing

Whether microdosing psychedelics can help people in meaningful ways independent of the placebo effect continues to be a subject of debate. A March 2023 paper in the journal Biological Psychiatry1 adds to the discourse by reporting that in a placebo-controlled study of 40 healthy male volunteers, microdosing LSD improved self-reported ratings of creativity, connectedness, energy, happiness, irritability, and wellness on dose days relative to non-dose days. However, microdosing was not sufficient to promote enduring changes to overall mood or cognition. Nor was it entirely harmless. Seven of the 40 participants reported treatment-related anxiety, and four dropped out as a result.

Psychedelics for Vegetative Patients

On the other end of the psychedelic spectrum are high doses that completely alter one’s perception of self and reality. If the psychedelic state represents a truly different, “higher” level of consciousness — as implied by the entropic brain theory first posited by Robin Carhart-Harris, David Nutt, and others in an influential 2014 paper2 — could psychedelics then be used to treat disorders of consciousness? More specifically, could they be administered as medicine to a minimally conscious or vegetative patient? And if so, what ethical challenges would be involved in such a treatment? These are some of the thought-provoking questions raised in an April 2023 article in Neuroscience of Consciousness.3

Methods of Action

Two other recent papers further investigate the neurobiology (the biological mechanisms through which nervous systems mediate behavior) and pharmacokinetics (the movement of drugs within the body) of various psychedelics.

On the former front, an article in the journal NeuroImage4 explores how three very different compounds eliciting psychedelic and psychedelic-like effects — nitrous oxide, ketamine, and LSD — induce common brain network changes. Although they act on different receptors (nitrous oxide and ketamine on the NMDA glutamate receptor; LSD on the 5-HT2A serotonin receptor), all three compounds produce consistent changes in specific brain regions involved in sensory integration and consciousness. They also similarly reduce within-network connectivity and increase between-network connectivity in the brain, the authors report.

DMT user survey: “Profound and highly intense experiences occurred.”

Another new paper, published in the European Journal of Drug Metabolism and Pharmacokinetics,5 refines our understanding of the body’s metabolism of N,N-dimethyltryptamine (DMT), a powerful psychedelic being explored as a potential treatment for depression. When DMT is taken alone, its effects are extremely short-lived, typically lasting no longer than about 15 minutes. When ingested as part of the psychedelic brew ayahuasca, which also includes compounds that impede the breakdown of DMT, its effects persist for many hours.

The new study relies on a series of experiments in healthy adults receiving intravenous DMT. According to the authors it is the first to determine, in detail, the full pharmacokinetic profile of DMT following a slow IV infusion in humans. “These findings provide evidence which supports the development of novel DMT infusion regimens for the treatment of major depressive disorder,” they conclude.

Real-World Trip Reports

Two additional studies published in March 2023 survey psychedelic drug users about their experiences with DMT, LSD, and psilocybin.

In Frontiers in Psychology6 comes a thematic and content analysis of the DMT experience developed from in-depth, semi-structured interviews with 36 “screened, healthy, and experienced” DMT users immediately following the trip. The study authors’ insights into how the compound alters “one’s personal and self-referential experiences of the body, senses, psychology, and emotions” are too complex to summarize here. Put it this way: “invariably, profound and highly intense experiences occurred.” The paper also covers convergences with alien-abduction, shamanic, and near-death experiences.

Finally, in the Journal of Psychopharmacology,7 we find survey results from thousands of users of LSD (n=1,996) and psilocybin mushrooms (n=1,368) compiled through the UK-based Global Drug Survey between November 2019 and February 2020. Positive changes were reported across all 17 outcomes evaluated (especially relative to insight and mood), the authors report. Variables most strongly associated with positive outcomes include psilocybin use (versus LSD), seeking advice before use, and seeking to treat post-traumatic stress disorder.

Negative effects were reported by nearly a quarter of respondents. They were most closely associated with LSD use (versus psilocybin) and younger age. Meanwhile, more intense psychedelic experiences were associated with both more positive and more negative outcomes, suggesting that higher doses can be riskier as well as more rewarding.

Nate Seltenrich, Project CBD contributing writer, is the author of the column Bridging the Gap. He is an independent science journalist based in the San Francisco Bay Area, covering a wide range of subjects, including environmental health, neuroscience, and pharmacology. © Copyright, Project CBD. May not be reprinted without permission.

Footnotes

Murphy, Robin J et al. “Acute mood-elevating properties of microdosed LSD in healthy volunteers: a home-administered randomised controlled trial.” Biological psychiatry, S0006-3223(23)01164-2. 28 Mar. 2023, doi:10.1016/j.biopsych.2023.03.013 Carhart-Harris, Robin L et al. “The entropic brain: a theory of conscious states informed by neuroimaging research with psychedelic drugs.” Frontiers in human neuroscience vol. 8 20. 3 Feb. 2014, doi:10.3389/fnhum.2014.00020 Rankaduwa, Sidath, and Adrian M Owen. “Psychedelics, entropic brain theory, and the taxonomy of conscious states: a summary of debates and perspectives.” Neuroscience of consciousness vol. 2023,1 niad001. 4 Apr. 2023, doi:10.1093/nc/niad001 Dai, Rui et al. “Classical and non-classical psychedelic drugs induce common network changes in human cortex.” NeuroImage vol. 273 (2023): 120097. doi:10.1016/j.neuroimage.2023.120097 Good, Meghan et al. “Pharmacokinetics of N,N-dimethyltryptamine in Humans.” European journal of drug metabolism and pharmacokinetics, 1–17. 22 Apr. 2023, doi:10.1007/s13318-023-00822-y Michael, Pascal et al. “An encounter with the self: A thematic and content analysis of the DMT experience from a naturalistic field study.” Frontiers in psychology vol. 14 1083356. 27 Mar. 2023, doi:10.3389/fpsyg.2023.1083356 Kopra, Emma I et al. “Investigation of self-treatment with lysergic acid diethylamide and psilocybin mushrooms: Findings from the Global Drug Survey 2020.” Journal of psychopharmacology (Oxford, England), 2698811231158245. 6 Mar. 2023, doi:10.1177/02698811231158245

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