Effects Of Psilocybin Research Articles

Prospective Preference Assessment for the Psilocybin for Enhanced Analgesia in Chronic nEuropathic PAIN (PEACE-PAIN) Trial

ABSTRACT Background Negative perceptions of psilocybin and challenges of participant enrollment may represent barriers to conducting a randomized controlled trial examining psilocybin for chronic neuropathic pain. Aim Prior to trial initiation, we aimed to examine patient attitudes toward the trial via a prospective preference assessment. Methods Twenty-six patients with chronic neuropathic pain participated in a prospective preference assessment comprising quantitative (survey) and qualitative (interview) components. Content analysis was used to inductively and deductively identify factors that would motivate or discourage participation in the proposed trial. Demographics, clinical characteristics, and perceptions of psilocybin were collected to explore differences in characteristics between patients who were willing and unwilling to participate. Results Survey results showed that most participants (76.9%) were willing to participate in the PEACE-PAIN trial. “Willing” participants reported higher prior psychedelic use (75%) as compared to the “maybe willing” (0%) and “not willing” participants (0%). Interviews indicated that the top two factors that motivated participation included the need for new treatment options (31.7%) and benefits to personal pain management (31.7%). The top two discouraging factors included practical difficulties of research participation (16.7%), and adverse events associated with psilocybin (16.7%). Conclusions The PEACE-PAIN trial study design is supported by patient survey responses but may benefit from modifications, namely incorporating thorough discussions of the current evidence for efficacy, safety, tolerability, and approaches to address adverse effects of psilocybin. Additionally, the interest in participation by individuals with prior psychedelic use holds important methodological implications for the inclusion/exclusion criteria of the trial.

Enhanced visual contrast suppression during peak psilocybin effects: Psychophysical results from a pilot randomized controlled trial.

In visual perception, an effect known as surround suppression occurs wherein the apparent contrast of a center stimulus is reduced when it is presented within a higher-contrast surrounding stimulus. Many key aspects of visual perception involve surround suppression, yet the neuromodulatory processes involved remain unclear. Psilocybin is a serotonergic psychedelic compound known for its robust effects on visual perception, particularly texture, color, object, and motion perception. We asked whether surround suppression is altered under peak effects of psilocybin. Using a contrast-matching task with different center-surround stimulus configurations, we measured surround suppression after 25mg of psilocybin compared with placebo (100mg niacin). Data on harms were collected, and no serious adverse events were reported. After taking psilocybin, participants (n = 6) reported stronger surround suppression of perceived contrast compared to placebo. Furthermore, we found that the intensity of subjective psychedelic visuals induced by psilocybin correlated positively with the magnitude of surround suppression. We note the potential relevance of our findings for the field of psychiatry, given that studies have demonstrated weakened visual surround suppression in both major depressive disorder and schizophrenia. Our findings are thus relevant to understanding the visual effects of psilocybin, and the potential mechanisms of visual disruption in mental health disorders.

Examining differences in the effects and contexts of naturalistic psilocybin use for White participants vs. Participants of Color: A longitudinal online survey study

BackgroundPsilocybin (a psychoactive compound found in “magic mushrooms” or “shrooms”) has been gaining increased attention in research and popular culture as a number of clinical and observational studies have demonstrated that it may have potential for improving mental wellbeing. Relatedly, there has been a substantial uptick in naturalistic (e.g., real-world, non-clinical) psilocybin use in the United States. While a number of longitudinal studies have demonstrated that naturalistic psilocybin use is linked to positive mental health outcomes on average, few studies have examined how the effects of psilocybin and contexts for psilocybin use may differ for White populations compared to Populations of Color. ObjectiveTo examine differences in health outcomes, subjective effects, and contexts of naturalistic psilocybin use in White participants compared to Participants of Color. MethodsThis study used data from a large, online longitudinal study of individuals who planned to engage in naturalistic psilocybin use (N = 2833). We used mixed-effects models to assess whether race/ethnicity (White vs. Participant of Color) moderated associations between time (Time 2 [initial assessment point for longitudinal measures], Time 5 [2–4 weeks post-psilocybin experience, and Time 6 [2–3 months post-experience]) and outcomes related to mental health (depression, anxiety, spiritual wellbeing, cognitive flexibility, emotion regulation [expressive suppression + cognitive reappraisal]). We also used exploratory chi-squared tests to examine differences in contexts for psilocybin use as well as differences in subjective effects related to the psilocybin experience. ResultsRace/ethnicity moderated the associations between time for predicting spiritual wellbeing (beta = −1.8; 95 % CI [−3.4, −0.17]; p < 0.05), cognitive flexibility (beta = −1.5 [−2.7, −0.26]; p < 0.05), and emotion regulation – expressive suppression (beta = 0.25 [0.06, 0.44]; p < 0.05) at Time 6 (but not Time 5). Additionally, Participants of Color reported minor differences in subjective effects and context for use compared to White participants (e.g., more likely to have set an intention prior to use, report time speeding up during the experience, etc.). We found reductions in anxiety and depression for both Participants of Color and White participants, and our moderation tests for these outcomes were not significant. ConclusionRace/ethnicity impacts the associations between psilocybin use and various markers of mental wellbeing. Future longitudinal studies and experimental studies with larger samples of color can further elucidate the preliminary findings from this study.

Psilocybin and the glutamatergic pathway: implications for the treatment of neuropsychiatric diseases.

In recent decades, psilocybin has gained attention as a potential drug for several mental disorders. Clinical and preclinical studies have provided evidence that psilocybin can be used as a fast-acting antidepressant. However, the exact mechanisms of action of psilocybin have not been clearly defined. Data show that psilocybin as an agonist of 5-HT2A receptors located in cortical pyramidal cells exerted a significant effect on glutamate (GLU) extracellular levels in both the frontal cortex and hippocampus. Increased GLU release from pyramidal cells in the prefrontal cortex results in increased activity of γ-aminobutyric acid (GABA)ergic interneurons and, consequently, increased release of the GABA neurotransmitter. It seems that this mechanism appears to promote the antidepressant effects of psilocybin. By interacting with the glutamatergic pathway, psilocybin seems to participate also in the process of neuroplasticity. Therefore, the aim of this mini-review is to discuss the available literature data indicating the impact of psilocybin on glutamatergic neurotransmission and its therapeutic effects in the treatment of depression and other diseases of the nervous system.

Neuroprotective effects of psilocybin in a rat model of stroke

BackgroundPsilocybin is a psychedelic 5HT2A receptor agonist found in “magic mushrooms”. Recent studies have indicated that 5HT2A agonists, such as dimethyltryptamine, given before middle cerebral artery occlusion (MCAo), improve staircase behavior, increased BDNF expression, and reduce brain infarction in stroke rats. The objective of this study is to determine the protective effect of psilocybin in cellular and animal models of stroke.MethodsAdult male and timed-pregnant Sprague-Dawley rats were used for this study. The neural protective effects of psilocybin were determined in primary rat cortical neurons and adult rats. Rats were subjected to a 60-min middle cerebral artery occlusion. Brain tissues were collected for histological and qRTPCR analysis.ResultsPsilocybin reduced glutamate-mediated neuronal loss in rat primary cortical neuronal cultures. Psilocybin-mediated protection in culture was antagonized by the BDNF inhibitor ANA12. Pretreatment with psilocybin reduced brain infarction and neurological deficits in stroke rats. Early post-treatment with psilocybin improved locomotor behavior, upregulated the expression of MAP2 and synaptophysin, and down-regulated the expression of IBA1 in the stroke brain. ANA12 significantly attenuated psilocybin-mediated reduction in brain infarction and improvements in locomotor behavior.ConclusionsPsilocybin reduced brain infarction and improved locomotor behavior in stroke rats; the protective mechanisms involve regulating BDNF expression. Our data support a novel therapeutic approach of psilocybin in stroke.

Single-dose psilocybin alters resting state functional networks in patients with body dysmorphic disorder

Body dysmorphic disorder (BDD) is a severe psychiatric condition characterized by preoccupation with perceived flaws in one's appearance, which the individual views as defective or ugly. Psilocybin, a serotonin 2A receptor agonist with psychedelic properties, has emerged as a potential therapeutic agent for depression and other psychiatric disorders. This study aimed to identify subacute neural changes predicting symptomatic response to psilocybin treatment in adults with BDD. Eight adults with moderate-to-severe nondelusional BDD were administered a single oral 25 mg dose of psilocybin, accompanied by psychological support, and underwent resting state functional magnetic resonance imaging assessments 1 day before and 1 day after the dosing. Both a region of interest (ROI)-to-ROI analysis and multivariate pattern analysis (MVPA) were used to identify changes in resting state functional connectivity (rsFC) at day 1 after dosing that predicted treatment response at week 1, measured by change in Yale-Brown Obsessive Compulsive Disorder Scale Modified for BDD (BDD-YBOCS) score. All participants completed the dosing and follow-up assessments over 12 weeks. BDD-YBOCS scores decreased at week 1 and week 12 after dosing (p&lt;0.001 for both). MVPA revealed a significant increase in rsFC within the Executive Control Network (ECN) at day 1. Increased rsFC within the ECN (dlPFC – Superior Parietal Lobule [FPL]), between the ECN and Default Mode Network (dlPFC – Precuneus), and between the ECN and the Salience Network (dlPFC – insula) were predictive of improvement in BDD symptoms at week 1. These findings are the first report of subacute brain effects of psilocybin in patients with BDD. Given the small sample size and uncontrolled design of the study, larger controlled studies are necessary to validate these observations. Clinical Trials Registration: Clinicaltrials.gov ID: NCT04656301

Psilocybin for major depressive disorder: a systematic review of randomized controlled studies.

The purpose of this systematic review of randomized controlled trials (RCTs) was to evaluate the effectiveness, safety, and tolerability of psilocybin in adult patients with major depressive disorder (MDD). A systematic search (up to September 14, 2023) was conducted for RCTs that examined the efficacy, safety, and tolerability of psilocybin in physically healthy adult patients with MDD. Three independent researchers extracted data from publications where the primary outcome was a change in depressive symptoms, and key secondary outcomes were changes in anxiety symptoms and suicidal ideation, discontinuation rates for any reason, and adverse drug reactions (ADRs). Five RCTs with 472 adult patients with MDD on psilocybin (n = 274) and controls (n = 198) were included. Two of the five RCTs (40%) reported mixed results, while the other three (60%) found that psilocybin had a beneficial effect on MDD treatment. Four RCTs (80%) assessing the anxiolytic effects of psilocybin for treating MDD found that psilocybin was significantly more effective than the control group in improving anxiety symptoms. Psilocybin was more effective than the control group in improving suicidal ideation in one out of five RCTs. Discontinuation rates were similar for any reason between the psilocybin group (2-13%) and the control group (4-21%) (P > 0.05). Four RCTs (80%) reported ADRs in detail. The most common ADR in both groups was headache. Psilocybin was effective in improving depressive symptoms in over half of the included studies and reduced anxiety symptoms in patients with MDD. The long-term efficacy and safety of psilocybin for MDD treatment needs to be further investigated in large RCTs.

Evaluating the potential for psilocybin as a treatment for post-traumatic stress disorder.

Post-traumatic stress disorder (PTSD) is a debilitating psychiatric condition that develops following exposure to a traumatic event. Individuals with this condition experience numerous physiological and behavioral alterations, including intrusive memories, avoidance of trauma-related stimuli, heightened anxiety, hypervigilance, impaired cognition, elevated resting heart rate and blood pressure, and altered neuroendocrine function, to name a few. In most patients, currently available pharmacological and psychological treatments are insufficient to alleviate the array of symptoms associated with the disorder. Thus, novel treatment options that can more effectively target the core etiology of PTSD are desperately needed. Recent work demonstrating the psychoplastogenic effects of psychedelics has reinvigorated research to examine their therapeutic potential in psychiatric conditions. Psilocybin, one psychedelic found in the Psilocybe genus of mushrooms, has exhibited promising antidepressant and anxiolytic effects in preclinical and clinical studies. The purpose of this review is to summarize the existing research that has examined the behavioral effects of psilocybin and link it to potential efficacy in treating PTSD-related symptoms. The proposed mechanisms for psilocybin's effects are then explored, as are the benefits and drawbacks for the agent's therapeutic use. Finally, the challenges faced by investigators aiming to study psilocybin as a therapeutic aid in future studies are discussed in order to shed light on this budding area of research. Significance Statement Current pharmacotherapy for PTSD is insufficient. Traditional antidepressants and anxiolytics help reduce symptom severity, but nonresponse rates often reach levels greater than 50%, emphasizing the need for more effective treatment options. The goal of this review is to summarize the existing evidence for and the potential mechanisms of the antidepressant and anxiolytic effects of psilocybin, a psychedelic compound found in the Psilocybe genus of mushrooms. We then relate the observed effects to psilocybin's potential use as a treatment for PTSD.

Effect of psilocybin versus escitalopram on depression symptom severity in patients with moderate-to-severe major depressive disorder: observational 6-month follow-up of a phase 2, double-blind, randomised, controlled trial

Effect of psilocybin versus escitalopram on depression symptom severity in patients with moderate-to-severe major depressive disorder: observational 6-month follow-up of a phase 2, double-blind, randomised, controlled trial

Insights into the efficacy of psilocybin in treating depression and other disorders

This article discusses evidence that offers insights into the effects of psilocybin on the brain and its potential role in alleviating the symptoms of some neuropsychiatric conditions.

Psilocybin Facilitates Fear Extinction: Importance of Dose, Context, and Serotonin Receptors.

A variety of classic psychedelics and MDMA have been shown to enhance fear extinction in rodent models. This has translational significance because a standard treatment for post-traumatic stress disorder (PTSD) is prolonged exposure therapy. However, few studies have investigated psilocybin's potential effect on fear learning paradigms. More specifically, the extents to which dose, timing of administration, and serotonin receptors may influence psilocybin's effect on fear extinction are not understood. In this study, we used a delay fear conditioning paradigm to determine the effects of psilocybin on fear extinction, extinction retention, and fear renewal in male and female mice. Psilocybin robustly enhances fear extinction when given acutely prior to testing for all doses tested. Psilocybin also exerts long-term effects to elevate extinction retention and suppress fear renewal in a novel context, although these changes were sensitive to dose. Analysis of sex differences showed that females may respond to a narrower range of doses than males. Administration of psilocybin prior to fear learning or immediately after extinction yielded no change in behavior, indicating that concurrent extinction experience is necessary for the drug's effects. Cotreatment with a 5-HT2A receptor antagonist blocked psilocybin's effects for extinction, extinction retention, and fear renewal, whereas 5-HT1A receptor antagonism attenuated only the effect on fear renewal. Collectively, these results highlight dose, context, and serotonin receptors as crucial factors in psilocybin's ability to facilitate fear extinction. The study provides preclinical evidence to support investigating psilocybin as a pharmacological adjunct for extinction-based therapy for PTSD.

Psilocybin in the Management of Substance Use Disorders: A Summary of Current Evidence

Background: Following clinical trials on psilocybin for the treatment of pain, anxiety, and depression in patients with cancer, scientific interest emerged in its use for substance use disorders. Methods: In this review of the literature, we summarize available trials looking at the use of psilocybin in addiction Results: One double-blind, randomized clinical trial looked at the effect of psilocybin on heavy drinking in adults diagnosed with alcohol dependence. Several trials are currently ongoing to assess psilocybin’s efficacy in the management of different SUDs. Otherwise, the current evidence is insufficient to derive any conclusions on the possible efficacy of psilocybin in substance use disorders. Conclusions: More well-powered, blinded, randomized controlled trials are needed to investigate the possible therapeutic effects of psilocybin in addiction while identifying the appropriate conditions that promote its safe use.

Investigating the therapeutic efficacy of psilocybin in advanced cancer patients: A comprehensive review and meta-analysis.

Psilocybin, a naturally occurring psychedelic compound found in certain species of mushrooms, is known for its effects on anxiety and depression. It has recently gained increasing interest for its potential therapeutic effects, particularly in patients with advanced cancer. This systematic review and meta-analysis aim to evaluate the effects of psilocybin on adult patients with advanced cancer. To investigate the therapeutic effect of psilocybin in patients with advanced cancer. A comprehensive search of electronic databases was conducted in PubMed, Cochrane Central Register of Controlled Trials, and Google Scholar for articles published up to February 2023. The reference lists of the included studies were also searched to retrieve possible additional studies. A total of 7 studies met the inclusion criteria for the systematic review, comprising 132 participants. The results revealed significant improvements in quality of life, pain control, and anxiety relief following psilocybin-assisted therapy, specifically results on anxiety relief. Pooled effect sizes indicated statistically significant reductions in symptoms of anxiety at both 4 to 4.5 months [35.15 (95%CI: 32.28-38.01)] and 6 to 6.5 months [33.06 (95%CI: 28.73-37.40)]. Post-administration compared to baseline assessments (P < 0.05). Additionally, patients reported sustained improvements in psychological well-being and existential distress following psilocybin therapy. The findings provided compelling evidence for the potential benefits of psilocybin-assisted therapy in improving quality of life, pain control, and anxiety relief in patients with advanced cancer.

M165 - Physiological Effects of Psilocybin, Psilacetin, and DOI in Rats

M165 - Physiological Effects of Psilocybin, Psilacetin, and DOI in Rats

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.

Engaging Mood Brain Circuits with Psilocybin (EMBRACE): a study protocol for a randomized, placebo-controlled and delayed-start, neuroimaging trial in depression

BackgroundMajor depressive disorder (MDD) is a leading cause of disability worldwide across domains of health and cognition, affecting overall quality of life. Approximately one third of individuals with depression do not fully respond to treatments (e.g., conventional antidepressants, psychotherapy) and alternative strategies are needed. Recent early phase trials suggest psilocybin may be a safe and efficacious intervention with rapid-acting antidepressant properties. Psilocybin is thought to exert therapeutic benefits by altering brain network connectivity and inducing neuroplastic changes that endure for weeks post-treatment. Although early clinical results are encouraging, psilocybin’s acute neurobiological effects on neuroplasticity have not been fully investigated. We aim to examine for the first time how psilocybin acutely (intraday) and subacutely (weeks) alters functional brain networks implicated in depression.MethodsFifty participants diagnosed with MDD or persistent depressive disorder (PDD) will be recruited from a tertiary mood disorders clinic and undergo 1:1 randomization into either an experimental or control arm. Participants will be given either 25 mg psilocybin or 25 mg microcrystalline cellulose (MCC) placebo for the first treatment. Three weeks later, those in the control arm will transition to receiving 25 mg psilocybin. We will investigate whether treatments are associated with changes in arterial spin labelling and blood oxygenation level-dependent contrast neuroimaging assessments at acute and subacute timepoints. Primary outcomes include testing whether psilocybin demonstrates acute changes in (1) cerebral blood flow and (2) functional brain activity in networks associated with mood regulation and depression when compared to placebo, along with changes in MADRS score over time compared to placebo. Secondary outcomes include changes across complementary clinical psychiatric, cognitive, and functional scales from baseline to final follow-up. Serum peripheral neurotrophic and inflammatory biomarkers will be collected at baseline and follow-up to examine relationships with clinical response, and neuroimaging measures.DiscussionThis study will investigate the acute and additive subacute neuroplastic effects of psilocybin on brain networks affected by depression using advanced serial neuroimaging methods. Results will improve our understanding of psilocybin’s antidepressant mechanisms versus placebo response and whether biological measures of brain function can provide early predictors of treatment response.Trial registrationClinicalTrials.gov Identifier: NCT06072898. Registered on 6 October 2023.

Up-to-Date on clinical and preclinical studies of psilocybin therapy

Major Depressive Disorder (MDD) poses a significant global health burden, with 30-40% patients developing resistance to standard clinical antidepressants, such as selective serotonin reuptake inhibitors and tricyclic antidepressants. In 2016, Carhart-Harris and colleagues reported that psilocybin, the hallucinogenic compound derived from magic mushrooms, exhibits rapid and enduring antidepressant effects in patients with treatment-resistant depression. Subsequent clinical studies have found the therapeutic potential of psilocybin in MDD, depressive episode in bipolar disorder, anorexia, and drug addiction. In 2018 and 2019, the U.S. Food and Drug Administration designated psilocybin as a "breakthrough medicine" for treatment-resistant depression and MDD, respectively. Notably, the side effects of psilocybin are limited to transient and mild issues, such as headache and fatigue, suggesting its safety. In 2023, we published a review on the role of serotonin 5-HT2A receptors in the antidepressant effects of serotonergic psychedelics (Nihon Yakurigaku Zasshi, Volume 158, Issue 3, Page 229-232). Here, we present our study alongside the latest clinical and preclinical research on the antidepressant effects of psilocybin and provide an overview of the potential and issues related to psilocybin therapy.

Effects of psilocybin on uncertain punishment learning

Psilocybin may provide a useful treatment for mood disorders including anxiety and depression but its mechanisms of action for these effects are not well understood. While recent preclinical work has begun to assess psilocybin’s role in affective behaviors through innate anxiety or fear conditioning, there is scant evidence for its role in conflict between reward and punishment. The current study was designed to determine the impact of psilocybin on the learning of reward-punishment conflict associations, as well as its effects after learning, in male and female rats. We utilized a chained schedule of reinforcement that involved execution of safe and risky reward-guided actions under uncertain punishment. Different patterns of behavioral suppression by psilocybin emerged during learning versus after learning of risky action-reward associations. Psilocybin increased behavioral suppression in female rats as punishment associations were learned. After learning, psilocybin decreased behavioral suppression in both sexes. Thus, psilocybin produces divergent effects on action suppression during approach-avoidance conflict depending on when the conflict is experienced. This observation may have implications for its therapeutic mechanism of action.

Effects of psilocin and psilocybin on human 5-HT4 serotonin receptors in atrial preparations of transgenic mice and humans

Several fungi belonging to the genus Psilocybe, also called “magic mushrooms”, contain the hallucinogenic drugs psilocybin and psilocin. They are chemically related to serotonin (5-HT). In addition to being abused as drugs, they are now also being discussed or used as a treatment option for depression. Here, we hypothesized that psilocybin and psilocin may act also on cardiac serotonin receptors and studied them in vitro in atrial preparations of our transgenic mouse model with cardiac myocytes-specific overexpression of the human 5-HT4 receptor (5-HT4-TG) as well as in human atrial preparations. Both psilocybin and psilocin enhanced the force of contraction in isolated left atrial preparations from 5-HT4-TG, increased the beating rate in isolated spontaneously beating right atrial preparations from 5-HT4-TG and augmented the force of contraction in the human atrial preparations. The inotropic and chronotropic effects of psilocybin and psilocin at 10 µM were smaller than that of 1 µM 5-HT on the left and right atria from 5-HT4-TG, respectively. Psilocybin and psilocin were inactive in WT. In the human atrial preparations, inhibition of the phosphodiesterase III by cilostamide was necessary to unmask the positive inotropic effects of psilocybin or psilocin. The effects of 10 µM psilocybin and psilocin were abrogated by 10 µM tropisetron or by 1 µM GR125487, a more selective 5-HT4 receptor antagonist. In summary, we demonstrated that psilocin and psilocybin act as agonists on cardiac 5-HT4 receptors.

Medical Uses and Adverse Effects of Psilocybin.

Medical Uses and Adverse Effects of Psilocybin.