How does psilocybin therapy work? An exploration of experiential avoidance as a putative mechanism of change

Naturalistic psychedelic therapy: The role of relaxation and subjective drug effects in antidepressant response

BACKGROUND

Psychedelic-assisted therapy (PAT) is permitted in Switzerland under its limited medical use program. Data from patients in this program represent a unique opportunity to analyze the real-world practice of PAT.

AIMS

This study compared the subjective effects of lysergic acid diethylamide (LSD) and psilocybin between patients undergoing PAT and healthy volunteers. For the patients, it also investigated the relationship between antidepressant effects and six measures of acute drug effects.

METHODS

We compared data on acute psychedelic drug effects between 28 PAT patients with data from 28 healthy participants who participated in a randomized, double-blind crossover trial. All participants received varying doses of psilocybin and LSD. Subjective effects were assessed on an hourly basis during the acute drug effects, and the Mystical Experience Questionnaire (MEQ) was completed retrospectively. For patients, depressive symptoms were assessed using the Montgomery-Åsberg Depression Rating Scale (MADRS).

RESULTS

Ratings of overall drug effect and mystical experience were similar across groups. Compared with healthy controls, patients reported lower ratings of ego dissolution. Patients showed a significant decrease in MADRS scores, and the greatest predictor of antidepressant outcome was relaxation during the PAT session. We did not observe a relationship between mystical-type experiences and antidepressant effects. Most patients experienced mild adverse effects which resolved within 48 h.

CONCLUSION

PAT reduced depressive symptoms in this heterogeneous patient group. Patients may experience more challenging psychedelic effects and reduced ego dissolution. Hourly assessment of drug effects may predict clinical outcomes better than retrospectively assessed mystical experiences, and the impact of relaxation during PAT should be investigated further.

On the mushrooming reports of "quiet quitting": Employees' lifetime psilocybin use predicts their overtime hours worked

Despite the recent and sharp rise in psychedelic research, few studies have investigated how classic psychedelic use relates to employees' work-related outcomes. This is surprising given that the increased use, decriminalization, and legalization of classic psychedelics in the United States (U.S.) has the potential to impact both employees and their organizations. Addressing this gap, the current study explores how employees' lifetime psilocybin use relates to the amount of overtime they work, thereby offering insight into what current trends in psilocybin use could mean for businesses. Using pooled, cross-sectional data from the National Survey on Drug Use and Health (2002-2014) on 217,963 adults employed in the U.S. full-time, this study tests whether lifetime psilocybin use is associated with employees' number of overtime hours worked in the past week. After adjusting for sociodemographics and other substance use, a significant negative association is found between employees' lifetime psilocybin use and the amount of overtime they reported working. Specifically, the findings suggest that lifetime psilocybin use in the U.S. full-time working population is associated with an estimated 44,348,400 fewer overtime hours worked per year and may help explain recent findings linking employees' lifetime psilocybin use to a reduction in sick leave taken.

Protocols and practices in psilocybin assisted psychotherapy for depression: A systematic review

BACKGROUND

Psilocybin-assisted psychotherapy (PAP) is a promising treatment option for depression, with randomized controlled trials (RCTs) providing preliminary support for its safety and efficacy. However, there is a lack of consistency across existing treatment protocols and psychotherapeutic approaches. The objective of this review is to summarize and compare current psychotherapy methods of PAP in treating depression and distress in life-threatening illnesses. We sought to comprehensively summarize published psychotherapy protocols from clinical trials to provide insights for future practices.

METHODS

A systematic search of four databases (Embase, MEDLINE, PsycINFO, CINAHL) for data relating to psychotherapy protocols was conducted by two independent reviewers.

RESULTS

In total, our search identified 1869 articles; after removing duplicates, we screened 1107 articles. We included 70 articles in the full-text review and determined that 28 were eligible for the final review. All protocols include sessions before (preparatory) and after (integration) the psychedelic dosing session with supportive monitoring. However, there was substantial variability and inconsistencies in all other aspects of therapy protocols (e.g., duration and number of sessions, model of therapy). Additionally, significant limitations were identified in the frequent need for more clarity in the description of therapeutic approaches.

CONCLUSION

In published clinical trials, PAP has consisted of preparation, supportive dosing, and integration sessions. Beyond this basic framework, significant heterogeneity and lack of clarity were identified in reported psychotherapy protocols, meaning a validated and universally agreed upon protocol for PAP currently does not exist. Future studies should more clearly define and report psychotherapeutic components to identify the safest and most efficacious approaches to PAP.

Psilocybin for the treatment of Alzheimer's disease

Alzheimer's disease (AD) stands as a formidable neurodegenerative ailment and a prominent contributor to dementia. The scarcity of available therapies for AD accentuates the exigency for innovative treatment modalities. Psilocybin, a psychoactive alkaloid intrinsic to hallucinogenic mushrooms, has garnered attention within the neuropsychiatric realm due to its established safety and efficacy in treating depression. Nonetheless, its potential as a therapeutic avenue for AD remains largely uncharted. This comprehensive review endeavors to encapsulate the pharmacological effects of psilocybin while elucidating the existing evidence concerning its potential mechanisms contributing to a positive impact on AD. Specifically, the active metabolite of psilocybin, psilocin, elicits its effects through the modulation of the 5-hydroxytryptamine 2A receptor (5-HT2A receptor). This modulation causes heightened neural plasticity, diminished inflammation, and improvements in cognitive functions such as creativity, cognitive flexibility, and emotional facial recognition. Noteworthy is psilocybin's promising role in mitigating anxiety and depression symptoms in AD patients. Acknowledging the attendant adverse reactions, we proffer strategies aimed at tempering or mitigating its hallucinogenic effects. Moreover, we broach the ethical and legal dimensions inherent in psilocybin's exploration for AD treatment. By traversing these avenues, We propose therapeutic potential of psilocybin in the nuanced management of Alzheimer's disease.

Assessing expectancy and suggestibility in a trial of escitalopram v. psilocybin for depression

BACKGROUND

To investigate the association between pre-trial expectancy, suggestibility, and response to treatment in a trial of escitalopram and investigational drug, COMP360, psilocybin, in the treatment of major depressive disorder (ClinicalTrials.gov registration: NCT03429075).

METHODS

We used data (n = 55) from our recent double-blind, parallel-group, randomized head-to-head comparison trial of escitalopram and investigational drug, COMP360, psilocybin. Mixed linear models were used to investigate the association between pre-treatment efficacy-related expectations, as well as baseline trait suggestibility and absorption, and therapeutic response to both escitalopram and COMP360 psilocybin.

RESULTS

Patients had significantly higher expectancy for psilocybin relative to escitalopram; however, expectancy for escitalopram was associated with improved therapeutic outcomes to escitalopram, expectancy for psilocybin was not predictive of response to psilocybin. Separately, we found that pre-treatment trait suggestibility was associated with therapeutic response in the psilocybin arm, but not in the escitalopram arm.

CONCLUSIONS

Overall, our results suggest that psychedelic therapy may be less vulnerable to expectancy biases than previously suspected. The relationship between baseline trait suggestibility and response to psilocybin therapy implies that highly suggestible individuals may be primed for response to this treatment.

Efficacy and safety of psychedelics for the treatment of mental disorders: A systematic review and meta-analysis

We aim to systematically review and meta-analyze the effectiveness and safety of psychedelics [psilocybin, ayahuasca (active component DMT), LSD and MDMA] in treating symptoms of various mental disorders. Web of Science, Embase, EBSCO, and PubMed were searched up to February 2024 and 126 articles were finally included. Results showed that psilocybin has the largest number of articles on treating mood disorders (N = 28), followed by ayahuasca (N = 7) and LSD (N = 6). Overall, psychedelics have therapeutic effects on mental disorders such as depression and anxiety. Specifically, psilocybin (Hedges' g = -1.49, 95% CI [-1.67, -1.30]) showed the strongest therapeutic effect among four psychedelics, followed by ayahuasca (Hedges' g = -1.34, 95% CI [-1.86, -0.82]), MDMA (Hedges' g = -0.83, 95% CI [-1.33, -0.32]), and LSD (Hedges' g = -0.65, 95% CI [-1.03, -0.27]). A small amount of evidence also supports psychedelics improving tobacco addiction, eating disorders, sleep disorders, borderline personality disorder, obsessive-compulsive disorder, and body dysmorphic disorder. The most common adverse event with psychedelics was headache. Nearly a third of the articles reported that no participants reported lasting adverse effects. Our analyses suggest that psychedelics reduce negative mood, and have potential efficacy in other mental disorders, such as substance-use disorders and PTSD.

Psychological flexibility as a mechanism of change in psilocybin-assisted therapy for major depression: results from an exploratory placebo-controlled trial

Several phase II studies have demonstrated that psilocybin-assisted therapy shows therapeutic potential across a spectrum of neuropsychiatric conditions, including major depressive disorder (MDD). However, the mechanisms underlying its often persisting beneficial effects remain unclear. Observational research suggests that improvements in psychological flexibility may mediate therapeutic effects. However, no psychedelic trials to date have substantiated this finding in a clinical sample. In an exploratory placebo-controlled, within-subject, fixed-order study, individuals with moderate to severe MDD were administered placebo (n = 19) followed by psilocybin (0.3 mg/kg) (n = 15) 4 weeks later. Dosing sessions were embedded within a manualized psychotherapy that incorporated principles of Acceptance and Commitment Therapy. Depression severity, psychological flexibility, mindfulness, and values-congruent living were measured over a 16-weeks study period. Psychological flexibility, several facets of mindfulness, and values-congruent living significantly improved following psilocybin and were maintained through week 16. Additionally, improvements in psychological flexibility and experiential acceptance were strongly associated with reductions in depression severity following psilocybin. These findings support the theoretical premise of integrating psilocybin treatment with psychotherapeutic platforms that target psychological flexibility and add to emerging evidence that increasing psychological flexibility may be an important putative mechanism of change in psilocybin-assisted therapy for MDD and potentially, other mental health conditions.

Deep CANALs: a deep learning approach to refining the canalization theory of psychopathology

Psychedelic therapy has seen a resurgence of interest in the last decade, with promising clinical outcomes for the treatment of a variety of psychopathologies. In response to this success, several theoretical models have been proposed to account for the positive therapeutic effects of psychedelics. One of the more prominent models is "RElaxed Beliefs Under pSychedelics," which proposes that psychedelics act therapeutically by relaxing the strength of maladaptive high-level beliefs encoded in the brain. The more recent "CANAL" model of psychopathology builds on the explanatory framework of RElaxed Beliefs Under pSychedelics by proposing that canalization (the development of overly rigid belief landscapes) may be a primary factor in psychopathology. Here, we make use of learning theory in deep neural networks to develop a series of refinements to the original CANAL model. Our primary theoretical contribution is to disambiguate two separate optimization landscapes underlying belief representation in the brain and describe the unique pathologies which can arise from the canalization of each. Along each dimension, we identify pathologies of either too much or too little canalization, implying that the construct of canalization does not have a simple linear correlation with the presentation of psychopathology. In this expanded paradigm, we demonstrate the ability to make novel predictions regarding what aspects of psychopathology may be amenable to psychedelic therapy, as well as what forms of psychedelic therapy may ultimately be most beneficial for a given individual.

The effect of psilocybin on empathy and prosocial behavior: a proposed mechanism for enduring antidepressant effects

Psilocybin is a serotonergic psychedelic shown to have enduring antidepressant effects. Currently, the mechanism for its enduring effects is not well understood. Empathy and prosocial behavior may be important for understanding the therapeutic benefit of psilocybin. In this article we review the effect of psilocybin on empathy and prosocial behavior. Moreover, we propose that psilocybin may induce a positive feedback loop involving empathy and prosocial behavior which helps explain the observed, enduring antidepressant effects.

Preliminary evidence for the importance of therapeutic alliance in MDMA-assisted psychotherapy for posttraumatic stress disorder

Background: MDMA-assisted psychotherapy (MDMA-AP) is a combined psychotherapeutic and pharmacologic intervention that shows promise in the treatment of posttraumatic stress disorder (PTSD). Although therapeutic alliance has been established as a key predictor across psychotherapies and is emphasised within MDMA-AP treatment manuals, research has not yet examined the relationship between therapeutic alliance and MDMA-AP treatment outcomes.Objective: Examine whether therapeutic alliance predicts changes in PTSD symptoms following MDMA-AP.Method: Twenty-three individuals with chronic PTSD participated in a MDMA-AP clinical trial that included a randomised (MDMA vs. placebo) and open-label phase. The present analyses focused on participants who were administered MDMA over the course of the randomised and open-label phases (n = 22). Therapeutic alliance was assessed using the Working Alliance Inventory at sessions baseline (pre-session 3) and sessions 4 and 9. PTSD symptoms were assessed using the Clinician Administered PTSD Scale and the Impact of Events Scale-Revised.Results: Controlling for baseline clinician-assessed PTSD severity, therapeutic alliance at sessions 4 and 9 (but not baseline) significantly predicted post-MDMA-AP clinician-assessed PTSD severity. Controlling for baseline self-reported PTSD severity, therapeutic alliance at baseline (although this did not survive correction for multiple comparisons) and sessions 4 and 9 predicted post-MDMA-AP self-reported PTSD severity.Conclusions: The present results provide the first preliminary evidence for the relationship between the therapeutic alliance and treatment outcomes within MDMA-AP for PTSD. These findings highlight the important role of psychotherapy, and common psychotherapeutic factors, within MDMA-AP. Replication in studies with larger and more diverse clinical samples remain necessary.Trial registration: ClinicalTrials.gov identifier: NCT00090064.

Psilocybin-assisted psychotherapy for treatment-resistant depression: Which psychotherapy?

This perspective paper explores the choice of psychotherapy for psilocybin-assisted psychotherapy for treatment-resistant depression. There is evidence to support the use of some psychotherapies in treating 'treatment-resistant' depression, and emerging evidence for the efficacy of psilocybin. The next step which is the focus of this paper is to identify psychotherapies that are both effective and congruent with the psilocybin experience. The evidence for the efficacy of the psychotherapies is drawn from a Cochrane review and the analysis of their congruence with the psilocybin experience is drawn from a qualitative meta-synthesis of the experience of psilocybin. The paper will examine whether three one-to-one psychotherapies identified as effective in the treatment of treatment-resistant depression are compatible with the psilocybin experience. Each psychotherapy will be examined in relation to its congruence with the qualitative evidence that suggests the choice of psychotherapy needs to give priority to the subjective experience, facilitate emotional processing, support connectedness with others, acceptance of the self as emotional and support change based on the person's insights into their relationships with others and the world in which they live. We conclude that interpersonal psychotherapy and intensive short-term dynamic psychotherapy align with that experience, although others are currently being trialled.

Beyond the 5-HT2A Receptor: Classic and Nonclassic Targets in Psychedelic Drug Action

Serotonergic psychedelics, such as psilocybin and LSD, have garnered significant attention in recent years for their potential therapeutic effects and unique mechanisms of action. These compounds exert their primary effects through activating serotonin 5-HT2A receptors, found predominantly in cortical regions. By interacting with these receptors, serotonergic psychedelics induce alterations in perception, cognition, and emotions, leading to the characteristic psychedelic experience. One of the most crucial aspects of serotonergic psychedelics is their ability to promote neuroplasticity, the formation of new neural connections, and rewire neuronal networks. This neuroplasticity is believed to underlie their therapeutic potential for various mental health conditions, including depression, anxiety, and substance use disorders. In this mini-review, we will discuss how the 5-HT2A receptor activation is just one facet of the complex mechanisms of action of serotonergic psychedelics. They also interact with other serotonin receptor subtypes, such as 5-HT1A and 5-HT2C receptors, and with neurotrophin receptors (e.g., tropomyosin receptor kinase B). These interactions contribute to the complexity of their effects on perception, mood, and cognition. Moreover, as psychedelic research advances, there is an increasing interest in developing nonhallucinogenic derivatives of these drugs to create safer and more targeted medications for psychiatric disorders by removing the hallucinogenic properties while retaining the potential therapeutic benefits. These nonhallucinogenic derivatives would offer patients therapeutic advantages without the intense psychedelic experience, potentially reducing the risks of adverse reactions. Finally, we discuss the potential of psychedelics as substrates for post-translational modification of proteins as part of their mechanism of action.

Co-use of MDMA with psilocybin/LSD may buffer against challenging experiences and enhance positive experiences

Psilocybin and lysergic acid diethylamide (LSD) experiences can range from very positive to highly challenging (e.g., fear, grief, and paranoia). These challenging experiences contribute to hesitancy toward psychedelic-assisted psychotherapy among health care providers and patients. Co-use of 3,4-Methylenedioxy methamphetamine (MDMA) with psilocybin/LSD anecdotally reduces challenging experiences and enhances positive experiences associated with psilocybin/LSD. However, limited research has investigated the acute effects of co-use of MDMA and psilocybin/LSD. In a prospective convenience sample (N = 698) of individuals with plans to use psilocybin/LSD, we examined whether co-use of MDMA with psilocybin/LSD (n = 27) is associated with differences in challenging or positive experiences. Challenging experiences were measured using the Challenging Experiences Questionnaire and positive experiences were measured using the Mystical Experience Questionnaire and single-item measures of self-compassion, compassion, love, and gratitude. Potentially confounding variables were identified and included as covariates. Relative to psilocybin/LSD alone, co-use of psilocybin/LSD with a self-reported low (but not medium-high) dose of MDMA was associated with significantly less intense total challenging experiences, grief, and fear, as well as increased self-compassion, love and gratitude. Co-use of psilocybin/LSD and MDMA was not associated with differences in mystical-type experiences or compassion. Findings suggest co-use of MDMA with psilocybin/LSD may buffer against some aspects of challenging experiences and enhance certain positive experiences. Limitations include use of a convenience sample, small sample size, and non-experimental design. Additional studies (including controlled dose-response studies) that examine the effects and safety of co-administering MDMA with psilocybin/LSD (in healthy controls and clinical samples) are warranted and may assist the development of personalized treatments.