Psychedelics Research Recap May 2021

Published May 31, 2021

Psychedelic research in May took another critical step forward. The publication of a large part of the phase III trial data from MAPS showed MDMA-assisted psychotherapy to be effective in the treatment of PTSD.

Other research showed us the best picture of our brain under the influence of psychedelics, the genetic markers that predict the intensity of a trip, and how psychedelics may help someone stay sane during Covid.

You can find all the papers that weren’t added in our May Link Overview.

Psychedelics 1, PTSD 0

The headline study this month was the publication of the phase III data from MAPS. The double-blind placebo-controlled study with 90 participants showed that 67% of participants in the MDMA-assisted therapy group no longer qualified for PTSD.

If we can translate this form of therapy from the lab to practice or from the trials to large-scale implementation is the next question on everyone’s mind. A commentary paper dives deep into this question and shows what the differences between both environments are.

Studies usually try and find patients that fit within (only) one mental health disorder. This is done to prevent complications with analyzing the data and with other issues (e.g., alcoholism) flaring up whilst you’re treating something else (e.g., PTSD).

The good thing about the current trial is that it included patients who had comorbidities (multiple disorders). And they improved just as much as the other patients.

Next to the MDMA trial, another trial with ketamine also showed positive results in the treatment of depression, showing the best response for those with childhood physical abuse.

Our collective trauma, Covid and psychedelics

The last year and a half have been different for just about everyone. If you haven’t been affected by Covid, you are sure to know someone who has had it or even lost someone because of it. Can psychedelics help us through these times, is what two studies asked.

A survey study of more than 5500 people found that those who used psychedelics (32% of the sample) had increased positive affect and more resilient personality traits (e.g., plasticity) during Covid.

Another survey of nearly 3000 people found a similar relationship. Those who used psychedelics more had less psychological distress and more social support.

As always, a survey isn’t able to establish causal theories, these are merely correlations. Still, a theory-building paper proposes that psychedelics can lead to healthy behavior changes. They propose that future studies look into the use of psychedelics and improvements in diet, exercise, and other behaviors that lead to more well-being.

Set and settings, psychedelic centers

Places where psychedelics are already leading to positive outcomes are the variety of psychedelic centers out there. Next to the aforementioned clinical trials, data from these centers is just as valuable for researchers.

An observational review investigates the Santo Daimo church (ayahuasca religion) and outlines complex layers of intentions, expectations, visual, auditory, and symbolic environments, social and cultural systems that form a rich tapestry of contextual factors that foster unique experiences.

Another observational study followed participants in the Shipibo healing program and saw that over the course of a year their well-being significantly improved.

A third study dives deeper into a specific protocol used with ayahuasca for the treatment of addiction. The Takiwasi center protocol describes the traditional use of ayahuasca and how outcomes are evaluated.

How do psychedelics work?

How psychedelics work can be asked from many perspectives, and this month was no exception to the many different answers that we can get to this question.

A pre-print reconceptualizes mental health disorders as an emergent property of psychological, biological, and societal symptom networks which reinforce self-sustained patterns of psychopathology. It is hypothesized that psychedelic-assisted psychotherapy can make people more resilient against depression by weakening the network connections between symptoms and disrupting negative feedback of maladaptive patterns.

Another way of putting this is done in a hypothesis paper that proposes that psychedelics (and sleep deprivation) can lead one to fall further on a continuum of increasing flexibility of prior expectations. And so there is less influence of top-down hierarchical (negative) biases/predictions.

If we answer the question at the level of brain organization, then we can look at the best picture we have of our brain on psychedelics (LSD) up to this moment. Here again, we see that psychedelics lead to a flatter hierarchy and thus more distributed processing. A review dives even deeper into the cellular neurobiology of psychedelics.

A pre-print analysis of the data from last month’s big study (psilocybin vs SSRI) shows that brain modularity under psilocybin is decreased. That means that brain connectivity becomes less segregated, so less boxed into different areas. This correlated with the observed antidepressant effects.

Investigating the investigators

By studying psychedelics, we’re learning a lot about the brain, our perception of the world, and what goes wrong (and why, and how to fix it hopefully). But it doesn’t tell us everything, so a group of researchers warns about throwing around terms like consciousness without being very precise. Psychedelics, at this time, don’t tell us anything about the hard problem of consciousness.

The ‘Mystical Type Experience Questionnaire’ (MEQ) is a staple of psychedelic research. A commentary examines the role of mystical frameworks within psychedelic research and identifies the problem of putting subjective experiences into a black box by labeling them as ‘ineffable’ and inaccessible to scientific inquiry.

A final look at research itself comes from a paper that argues that publicly funded research is needed. The author advocates for public funding of independent evaluations of the efficacy of psychedelic drugs, given that current research efforts spurred by private philanthropic interests may propel a widespread use of psychedelics and demands to implement them as a first-line treatment, ahead of the evidence on their safety, efficacy, and long-term effects.

The rest of the psychedelic studies

We now know better how someone will react to psychedelics based on their genes. The CYP2D6 gene (which produces an enzyme that processes psychedelics, amongst other things) or actually the lack of an active version correlates with someone having a longer and more intense trip. This has been found for LSD for the first time. Earlier studies with MDMA have also found similar results.

Tabernanthalog, a non-hallucinogenic ibogaine-analog, keeps producing positive results. The current study finds it restores neural circuits that were disrupted by unpredictable stress. Of course, these studies are (for now) still in mice.

And finally, philosophers who use psychedelics had more non-realist/subjective views of moral and aesthetic value judgments.

Papers Published in May 2021

36 studies from the Blossom database published this month.

Psychedelics and hypnosis: Commonalities and therapeutic implications

Journal of Psychopharmacology· May 31, 2021· Lemercier, C. E., Terhune, D. B.

This literature review (2021) examines the neurophenomenological overlaps between psychedelic states and hypnosis. It proposes that harnessing the power of hypnotic suggestion during the preparation, acute, and integration phases could modulate responses to psychedelics and enhance therapeutic outcomes.

Psychedelics and health behaviour change

Journal of Psychopharmacology· May 29, 2021· Teixeira, P. J., Johnson, M. W., Timmermann, C. et al.

This theory-building paper (2021) argues for the positive impact that psychedelic use can have on health behaviors. Current trials are using psychedelics for mental health disorders, but future studies could look further to improvements in diet, exercise, nature exposure and other behaviours that promote physical and psychological well-being.

Registered clinical studies investigating psychedelic drugs for psychiatric disorders

Journal of Psychiatric Research· May 28, 2021· Siegel, A. N., Lipsitz, O., Gill, H. et al.

This review (2021) summarizes the study characteristics of all ongoing registered clinical trials investigating psychedelic drugs for psychiatric disorders and identifies that their majority focuses on investigating MDMA and psilocybin for treating depression or PTSD, while only 30% of their results are published.

An analog of psychedelics restores functional neural circuits disrupted by unpredictable stress

Molecular Psychiatry· May 25, 2021· Lu, J., Tjia, M., Mullen, B. et al.

In mice subjected to unpredictable mild stress, a single dose of the psychedelic analogue tabernanthalog (TBG) reduced anxiety and rescued deficits in sensory processing and cognitive flexibility. TBG achieved this by promoting regrowth of excitatory dendritic spines, lowering baseline neuronal activity and restoring stimulus‑dependent responses in somatosensory cortical circuits.

Genetic influence of CYP2D6 on pharmacokinetics and acute subjective effects of LSD in a pooled analysis

Scientific Reports· May 25, 2021· Vizeli, P., Straumann, I., Holze, F. et al.

In a pooled analysis of 81 healthy volunteers, genetically determined CYP2D6 functionality significantly altered LSD pharmacokinetics and acute subjective effects: CYP2D6 poor metabolisers showed longer LSD half-lives, ~75% higher AUCs for parent drug and the main metabolite (2‑oxo‑3‑hydroxy‑LSD), and greater/longer subjective effects, whereas common variants in other CYPs had no effect. These results indicate CYP2D6 pharmacogenetics may be relevant to LSD dosing and suggest pharmacogenetic testing before LSD‑assisted psychotherapy warrants further investigation.

N,N-Dimethyltryptamine attenuates spreading depolarization and restrains neurodegeneration by sigma-1 receptor activation in the ischemic rat brain

Neuropharmacology· May 21, 2021· Szabó, Í., Varga, V. É., Dvorácskó, S. et al.

This rat study (n=69) examined whether DMT (1mg/kg/h) administration achieves neuroprotection via Sig-1R activation during an experimentally induced forebrain ischemia in rats and found that DMT attenuated the electrophysiological signature neurodegeneration even when 5-HTR binding was inhibited with a serotonergic antagonist, which confirmed the neuroprotective role of Sig-1R activation in their hypothesis.

Decreased brain modularity after psilocybin therapy for depression

Research Square· May 20, 2021· Daws, R. E., Timmermann, C., Giribaldi, B. et al.

In an open‑label TRD trial and a double‑blind RCT in MDD, psilocybin therapy produced rapid and durable reductions in depressive symptoms. These clinical improvements correlated with a post‑treatment decrease in resting‑state brain network modularity, implicating reduced modularity as a candidate antidepressant mechanism.

Opposite alterations of 5­HT2A receptor brain density in subjects with schizophrenia: relevance of radiotracers pharmacological profile

Translational Psychiatry· May 20, 2021· Diez-Alarcia, R., Muguruza, C., Rivero, G. et al.

This post-mortem study (n=22) quantified the binding density of serotonin 5­HT2A receptors in deceased patients with schizophrenia and found that the active configuration of this receptor, as measured by a two-fold higher agonistic binding of LSD radioligand, had the highest density amongst schizophrenic patients who were not being treated with antipsychotic medication.

Central nervous system-related safety and tolerability of add-on ketamine to antidepressant medication in treatment-resistant depression: focus on the unique safety profile of bipolar depression

Therapeutic Advances in Psychopharmacology· May 19, 2021· Cubała, W. J., Szarmach, J., Galuszko-Wegielink, M. et al.

In an observational study of 49 treatment‑resistant inpatients with major depressive disorder and bipolar disorder, add‑on intravenous ketamine was associated with transient psychomimetic and dissociative symptoms—notably more intense in patients taking citalopram or classic mood‑stabilisers (lamotrigine, valproate, lithium)—with no lasting sequelae; the authors conclude ketamine in TRD, particularly bipolar depression, requires close CNS safety and tolerability monitoring.

Future Directions for Clinical Psilocybin Research: The Relaxed Symptom Network

Psyarxiv· May 19, 2021· Lewis-Healey, E., Laukkonen, R., Van Elk, M.

This paper proposes the "Relaxed Symptom Network" hypothesis: psilocybin-assisted psychotherapy (PAP) reduces depression by weakening connections between symptoms within a dynamic symptom network, thereby lowering vulnerability to relapse. It outlines how applying network theory can clarify PAP's mechanisms and gives practical guidance for future clinical trials.

Protocol for Outcome Evaluation of Ayahuasca-Assisted Addiction Treatment: The Case of Takiwasi Center

Frontiers in Pharmacology· May 19, 2021· Rush, B., Marcus, O., García, S. et al.

This paper presents the Ayahuasca Treatment Outcome Project (ATOP) protocol for evaluating an ayahuasca-assisted, integrative addiction rehabilitation programme at the Takiwasi Center, using mixed quantitative and qualitative methods to assess outcomes and therapeutic mechanisms. It emphasises the role of treatment setting and outlines core principles, measures, strengths and limitations to guide future research on long-term residential psychedelic-assisted treatments.

Relational Processes in Ayahuasca Groups of Palestinians and Israelis

Frontiers in Pharmacology· May 19, 2021· Roseman, L., Ron, Y., Saca, A. et al.

Through 31 in-depth interviews and grounded theory analysis of mixed Palestinian–Israeli ayahuasca ceremonies, the study identifies three relational processes—unity-based identity dissolution, recognition/difference-based connection through cultural exchange, and conflict-related revelations. It concludes that such psychedelic group rituals can aid peacebuilding by generating shared spiritual experiences and surfacing politically charged personal insights that link individual psychology to the wider sociopolitical conflict.

The need for publicly funded research on therapeutic use of psychedelic drugs

World Psychiatry· May 18, 2021· Hall, W.

This perspective paper (2021) advocates the need for public funding of independent evaluations of the efficacy of psychedelic drugs, given that current research efforts spurred by private philanthropic interests may propel a widespread use of psychedelics and demands to implement them as a first-line treatment, ahead of the evidence on their safety, efficacy, and long-term effects.

Therapeutic potential of ketamine for alcohol use disorder

Neuroscience and Biobehavioral Reviews· May 17, 2021· Worrell, S. D., Gould, T. J.

This review (2021) investigates the potential of ketamine for alcohol use disorder (AUD). This is partly motivated by the concurrent depression and PTSD that those with AUD suffer from, for which more evidence of ketamine's effectiveness is known.

From hallucinations to synaesthesia: a circular inference account of unimodal and multimodal erroneous percepts in clinical and drug-induced psychosis

Psyarxiv· May 13, 2021· Leptourgos, P., Bouttier, V., Denève, S. et al.

The paper proposes a unifying circular‑inference account whereby amplification of top‑down predictions produces excessive reliance on priors, crossmodal percepts and stronger illusions (synaesthesia, psychedelic effects), whereas amplification of bottom‑up signals yields overinterpretation of noisy inputs and unimodal hallucinations. It links these effects to a canonical layer‑specific microcircuit in which deep‑layer inhibition removes descending loops and supragranular inhibition counterbalances ascending loops, offering a multiscale, transnosographic framework with theoretical and clinical implications.

Psychedelics and Consciousness: Distinctions, Demarcations, and Opportunities

International Journal of Neuropsychopharmacology· May 13, 2021· Yaden, D. B., Johnson, M. W., Griffiths, R. R. et al.

This review (2021) examines the usage and the meaning of the term 'consciousness' within psychedelic research and how theories of consciousness are operationalized to explain the effects of psychedelics in turn. Although psychedelics are unlikely to elucidate the biological basis for phenomenal consciousness (i.e. the hard problem), they are useful tools for investigating claims about the contents of consciousness, and their altered states.

The Potential Role of Psychedelic Drugs in Mental Health Care of the Future

Pharmacopsychiatry· May 12, 2021· Gründer, G., Jungaberle, H., Gründer, G.

This review (2021) summarizes the challenges for creating a new treatment infrastructure for Psychedelic-assisted psychotherapy in the process of re-contextualizing psychopharmacological interventions within a paradigm that lays particular emphasis on preparation, integration, and the development of structured patient communities as crucial components of therapy.

Exploring the relationship between microdosing, personality and emotional insight: A prospective study

Journal of Psychedelic Studies· May 11, 2021· Dressler, H. M., Bright, S. J., Polito, V.

In a prospective study of microdosers, participants followed for 31 days showed increased conscientiousness and decreased neuroticism (n = 24). Baseline neuroticism correlated with alexithymia and with shorter prior microdosing duration, while extraversion correlated with longer microdosing history and greater lifetime doses, suggesting microdosing may alter otherwise stable personality traits.

Symptom specificity of ayahuasca's effect on depressive symptoms

Journal of Psychedelic Studies· May 11, 2021· Gilbert, C. S., Earleywine, M., Mian, M. N. et al.

In a retrospective study of over 120 participants completing the CESD‑10 one month before and after ayahuasca use, the authors report greater reductions in affective symptoms (hope, depressed mood, happiness) than in cognitive, interpersonal or somatic symptoms (sleep, loneliness, concentration). This symptom-specific pattern parallels serotonergic antidepressants and suggests ayahuasca may be especially helpful for rapidly alleviating affective aspects of depression.

The anterior cingulate cortex as a key locus of ketamine’s antidepressant action

Neuroscience and Biobehavioral Reviews· May 11, 2021· Alexander, L., Jelen, L. A., Mehta, M. A. et al.

This review (2021) argues that the changes in the anterior cingulate cortex (AAC) are the key to ketamine's antidepressant effects. The subgenual and dorsal zones of the AAC are identified as most important in the ability to feel pleasure again.

Use of psilocybin (“mushrooms”) among US adults: 2015-2018

Journal of Psychedelic Studies· May 11, 2021· Yockey, R. A., King, K. A.

Pooled 2015–2018 NSDUH data from 168,650 US adults show 9.68% reported lifetime psilocybin use, with higher prevalence among bisexual-identifying individuals and substantial overlap with LSD, methamphetamine and heroin users. These findings can inform harm-reduction efforts and behavioural‑health messaging.

Long-Term Efficacy of Combination Therapy of Transcranial Magnetic Stimulation with Ketamine for Patients with Treatment-Resistant Depression

CNS Spectrums· May 10, 2021· Best, S. R. D., Pavel, D. G., Haustrup, N.

This retrospective review (n=28) investigated the clinical benefits of combining two therapies, repetitive transcranial magnetic stimulation (rTMS) and ketamine infusion (together CTK), for patients with treatment-resistant depression (TRD). The review found that all 28 patients experienced significant and enduring (two years) decreases in their depressive moods post the CTK therapy. The review also called for further research into method optimization and randomised controlled trials.

MDMA-assisted therapy for severe PTSD: a randomized, double-blind, placebo-controlled phase 3 study

Nature Medicine· May 10, 2021· Mitchell, J., Bogenschutz, M. P., Lilienstein, A. et al.

In a randomized, double‑blind, placebo‑controlled phase 3 trial of 90 patients with severe PTSD (including common comorbidities), MDMA‑assisted therapy produced a large, significant reduction in PTSD symptoms versus placebo (mean CAPS‑5 change −24.4 vs −13.9; P<0.0001, d=0.91) and improved functioning (SDS: P=0.0116, d=0.43). Treatment was well tolerated with no signals of abuse potential, increased suicidality or QT prolongation, indicating MDMA‑assisted therapy is a promising intervention warranting expedited evaluation.

The epidemiology of mescaline use: Pattern of use, motivations for consumption, and perceived consequences, benefits, and acute and enduring subjective effects

Journal of Psychopharmacology· May 5, 2021· Uthaug, M. V., Davis, A. K., Davis, D. et al.

A web-based survey of 452 English-speaking adults found mescaline was typically used infrequently for spiritual or nature-related reasons and produced moderate mystical-type acute effects with minimal challenging effects and few reported legal, psychological or medical harms. About half of respondents had a psychiatric condition and most (>67%) reported improvements after their most memorable mescaline experience, with no differences in effect intensity across mescaline sources, suggesting low abuse potential.

The Shipibo Ceremonial Use of Ayahuasca to Promote Well-Being: An Observational Study

Frontiers in Pharmacology· May 5, 2021· González, D., Cantillo, J., Perez, I. et al.

In an observational study of Western participants attending a Shipibo ayahuasca healing programme, scores for psychological well‑being, happiness, spirituality and quality of life increased significantly and remained elevated up to 12 months post‑stay. Improvements were associated with greater decentering (r = 0.57) and subgroup analyses suggest the changes were attributable to the centre stay rather than the mere passage of time.

Challenges in translational research: MDMA in the laboratory versus therapeutic settings

Journal of Psychopharmacology· May 4, 2021· de Wit, H., Bershad, A. K., Grob, C. S.

The paper shows that substantial methodological differences between laboratory and clinical MDMA studies — in expectancies, social and physical context, participant selection, pharmacology and outcome measures — limit the translational validity of experimental findings. It outlines the challenges these differences create and proposes ways to better align laboratory paradigms with therapeutic practice to improve translation.

Moving Past Mysticism in Psychedelic Science

ACS Pharmacology and Translational Science· May 4, 2021· Sanders, J. W.

This commentary (2021) examines the role of mystical frameworks within psychedelic research and identifies the problem of putting subjective experiences into a black box by labeling them as 'ineffable' and inaccessible to scientific inquiry. The authors recommend a theoretic shift away from supernatural or nonempirical belief systems in favor of a secular framework that aims to measure those experiences more objectively.

Set and Setting in the Santo Daime

Frontiers in Pharmacology· May 4, 2021· Hartogsohn, I.

This observational review (2021) describes ayahuasca use within the set and setting in the Santo Daime church and outlines complex layers of intentions, expectations, visual, auditory, and symbolic environments, social and cultural systems that form a rich tapestry of contextual factors that foster unique experiences. While also describing how the Santo Daime setting can also go wrong, it highlights the role of contextual factors to mitigate harms and facilitate social and personal benefits.

A continuum hypothesis of psychotomimetic rapid antidepressants

Brain and Neuroscience Advances· May 3, 2021· Haarsma, J., Harmer, C. J., Tamm, S.

The paper proposes a continuum hypothesis that psychotomimetic rapid antidepressants (ketamine, classical psychedelics and sleep deprivation) produce acute antidepressant effects by increasing the flexibility of prior expectations within a hierarchical predictive coding framework, thereby linking their antidepressant and psychotomimetic actions. It reviews supporting neurobiological and neuromodulatory evidence, contrasts the idea with other antidepressant theories, and proposes experiments to test the hypothesis.

Antisuicidal and antidepressant effects of ketamine and esketamine in patients with baseline suicidality: A systematic review

Journal of Psychiatric Research· May 1, 2021· Siegel, A. N., Di, J. D., Brietzke, E. et al.

This review (2021) evaluates the effect of esketamine and ketamine in patients with suicidal ideation at baseline. The authors find that esketamine trials did not demonstrate antisuicidal effects, while IV ketamine appeared to rapidly decrease the short term severity of suicidal ideation and depressive symptoms in individuals with baseline suicidal ideation.

Association Between Lifetime Classic Psychedelic Use and Hypertension in the Past Year

Hypertension· May 1, 2021· Simonsson, O., Hendricks, P. S., Carhart-Harris, R. et al.

Using nationally representative US survey data (NSDUH 2005–2014), lifetime use of classic psychedelics was associated with lower odds of past‑year hypertension after adjustment (adjusted odds ratio 0.86, 95% CI 0.81–0.91), an effect driven specifically by lifetime tryptamine use (aOR 0.80, 95% CI 0.73–0.89). These cross‑sectional findings suggest a potential protective link but cannot establish causality; randomised controlled trials are needed to probe mechanisms and causal effects on blood pressure.

Clinical and biological predictors of psychedelic response in the treatment of psychiatric and addictive disorders: a systematic review

Journal of Psychiatric Research· May 1, 2021· Romeo, B., Hermand, M., Pétillion, A. et al.

This systematic review (2021) of studies from 1990 to 2020 aimed to determine factors that can predict successful response to psychedelic treatment. In a variety of disorders, the authors found that the intensity of the experience was the best such predictor.

Distinct trajectories of antidepressant response to intravenous ketamine

Journal of Affective Disorders· May 1, 2021· O'Brien, B., Lijffijt, M., Lee, J. et al.

This open-label study (n=328) found that people who were depressed, for those with childhood physical abuse responded best to ketamine (48mg/70kg) treatment. This analysis was done retrospectively and the analysis consisted of breaking the group in three parts (responders, non-responders, responders with lower initial depression scores).

Do NMDA-R Antagonists Re-Create Patterns of Spontaneous Gamma-Band Activity in Schizophrenia? A Systematic Review and Perspective

Neuroscience and Biobehavioral Reviews· May 1, 2021· Bianciardi, B., Uhlhaas, P. J

This systematic review (2021) compared gamma-band oscillations elicited by NMDA-receptor agonists such as ketamine to neural oscillations observed in patients with schizophrenia. Whereas NMDAR agonists consistently upregulate gamma-band power, connectivity parameters of schizophrenia were inconsistent by comparison and thus incongruent with the hypothesis that their pathophysiological signatures are caused by NMDA-R hypofunction.

Effects of Psilocybin-Assisted Therapy on Major Depressive Disorder

JAMA Psychiatry· May 1, 2021· Davis, A. K., Barrett, F. S., May, D. G. et al.

This randomised open-label study (n=24) found that two sessions with psilocybin (20 and 30mg/70kg) significantly improved depression scores for a population with major depressive disorder (MDD) up to 8 weeks later.

Psychedelic-inspired drug discovery using an engineered biosensor

Cell· May 1, 2021· Dong, C., Ly, C., Dunlap, L. E. et al.

This study describes the development and use of an engineered biosensor (PsychLight) that detects relevant serotonin release to predict the hallucinogenic behavioral effects of psychedelics. This tool is used to identify non-hallucinogenic psychedelic compounds that still elicit antidepressant-like effects.