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Pharmacological Research Aug 2023Major depressive disorder (MDD) is a chronic relapsing psychiatric disorder. Conventional antidepressants usually require several weeks of continuous administration to... (Review)
Review
Major depressive disorder (MDD) is a chronic relapsing psychiatric disorder. Conventional antidepressants usually require several weeks of continuous administration to exert clinically significant therapeutic effects, while about two-thirds of the patients are prone to relapse of symptoms or are completely ineffective in antidepressant treatment. The recent success of the N-methyl-D-aspartic acid (NMDA) receptor antagonist ketamine as a rapid-acting antidepressant has propelled extensive research on the action mechanism of antidepressants, especially in relation to its role in synaptic targets. Studies have revealed that the mechanism of antidepressant action of ketamine is not limited to antagonism of postsynaptic NMDA receptors or GABA interneurons. Ketamine produces powerful and rapid antidepressant effects by affecting α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptors, adenosine A1 receptors, and the L-type calcium channels, among others in the synapse. More interestingly, the 5-HT2A receptor agonist psilocybin has demonstrated potential for rapid antidepressant effects in depressed mouse models and clinical studies. This article focuses on a review of new pharmacological target studies of emerging rapid-acting antidepressant drugs such as ketamine and hallucinogens (e.g., psilocybin) and briefly discusses the possible strategies for new targets of antidepressants, with a view to shed light on the direction of future antidepressant research.
Topics: Animals; Mice; Ketamine; Depressive Disorder, Major; Psilocybin; Antidepressive Agents; Disease Models, Animal; Receptors, N-Methyl-D-Aspartate
PubMed: 37379962
DOI: 10.1016/j.phrs.2023.106837 -
Chinese Medical Journal Dec 2023Posttraumatic stress disorder (PTSD) and depression are highly comorbid. Psilocybin exerts substantial therapeutic effects on depression by promoting neuroplasticity....
BACKGROUND
Posttraumatic stress disorder (PTSD) and depression are highly comorbid. Psilocybin exerts substantial therapeutic effects on depression by promoting neuroplasticity. Fear extinction is a key process in the mechanism of first-line exposure-based therapies for PTSD. We hypothesized that psilocybin would facilitate fear extinction by promoting hippocampal neuroplasticity.
METHODS
First, we assessed the effects of psilocybin on percentage of freezing time in an auditory cued fear conditioning (FC) and fear extinction paradigm in mice. Psilocybin was administered 30 min before extinction training. Fear extinction testing was performed on the first day; fear extinction retrieval and fear renewal were tested on the sixth and seventh days, respectively. Furthermore, we verified the effect of psilocybin on hippocampal neuroplasticity using Golgi staining for the dendritic complexity and spine density, Western blotting for the protein levels of brain derived neurotrophic factor (BDNF) and mechanistic target of rapamycin (mTOR), and immunofluorescence staining for the numbers of doublecortin (DCX)- and bromodeoxyuridine (BrdU)-positive cells.
RESULTS
A single dose of psilocybin (2.5 mg/kg, i.p.) reduced the increase in the percentage of freezing time induced by FC at 24 h, 6th day and 7th day after administration. In terms of structural neuroplasticity, psilocybin rescued the decrease in hippocampal dendritic complexity and spine density induced by FC; in terms of neuroplasticity related proteins, psilocybin rescued the decrease in the protein levels of hippocampal BDNF and mTOR induced by FC; in terms of neurogenesis, psilocybin rescued the decrease in the numbers of DCX- and BrdU-positive cells in the hippocampal dentate gyrus induced by FC.
CONCLUSIONS
A single dose of psilocybin facilitated rapid and sustained fear extinction; this effect might be partially mediated by the promotion of hippocampal neuroplasticity. This study indicates that psilocybin may be a useful adjunct to exposure-based therapies for PTSD and other mental disorders characterized by failure of fear extinction.
Topics: Humans; Mice; Animals; Psilocybin; Fear; Extinction, Psychological; Brain-Derived Neurotrophic Factor; Bromodeoxyuridine; Hippocampus; Neuronal Plasticity; TOR Serine-Threonine Kinases
PubMed: 37000971
DOI: 10.1097/CM9.0000000000002647 -
Journal of Psychopharmacology (Oxford,... Jan 2022Microdoses of psychedelics (i.e. a sub-hallucinogenic dose taken every third day) can reduce symptoms of depression, anxiety and stress according to anecdotal reports... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Microdoses of psychedelics (i.e. a sub-hallucinogenic dose taken every third day) can reduce symptoms of depression, anxiety and stress according to anecdotal reports and observational studies. Research with medium to high doses of psilocybin points towards potential underlying mechanisms, including the modulation of emotion and interoceptive processing.
AIMS
In this preregistered study, we investigated whether psilocybin microdoses alter self-reported interoceptive awareness and whether repeated microdosing over 3 weeks modulates emotion processing and reduces symptoms of anxiety and depression.
METHODS
We used a double-blind, placebo-controlled, within-subject crossover design. Participants completed the Multidimensional Assessment of Interoceptive Awareness Questionnaire 1½ h after self-administering their second dose (or placebo), and the emotional go/no-go task and the shortened Depression Anxiety Stress Scale 1½ h after self-administering their seventh dose.
RESULTS
Our confirmatory analyses revealed that psilocybin microdosing did not affect emotion processing or symptoms of anxiety and depression compared with placebo. Our exploratory analyses revealed that psilocybin microdosing did not affect self-reported interoceptive awareness, that symptoms of depression and stress were significantly reduced in the first block compared with baseline, that participants broke blind in the second block and that there was no effect of expectations. Further research in a substance-naïve population with clinical range anxiety and depressive symptoms is needed to substantiate the potential beneficial effects of microdosing.
Topics: Adult; Anxiety; Cross-Over Studies; Depression; Dose-Response Relationship, Drug; Double-Blind Method; Emotions; Female; Hallucinogens; Humans; Male; Middle Aged; Psilocybin; Surveys and Questionnaires; Young Adult
PubMed: 34915762
DOI: 10.1177/02698811211050556 -
Laeknabladid Sep 2022The hallucinogen psilocybin is a potential novel treatment for treatment-resistant depression (TRD). Our goal is to review current knowledge on psilocybin and its...
The hallucinogen psilocybin is a potential novel treatment for treatment-resistant depression (TRD). Our goal is to review current knowledge on psilocybin and its efficacy in TRD. Literature searches were done on PubMed, Web of Science and Google Scholar, references reviewed in identified articles and other articles found on the website of COMPASS Pathways. Psilocybin treatment consists usually of a single oral administration of 25 mg of psilocybin along with psychological support for 5-8 hours during the ensuing hallucinogenic trip. Common side-effects include headache, nausea, fatigue and insomnia. A systematic review has demonstrated significant antidepressant efficacy in certain groups and a double-blind randomized study found antidepressant efficacy of psilocybin comparable to the SSRI escitalopram. In the phase 2 study of COMPASS Pathways, the psilocybin-COMP360 treatment led to a rapid response and remission as early as three weeks following the treatment for around one third of participants. Recent studies have shown that psilocybin significantly decreases the severity of depressive symptoms and is generally well tolerated. Further research will reveal whether it will be granted a license to treat treatment-resistant depression in the near future. There remains an urgent need for novel treatments for those who do not respond to current antidepressant therapies.
Topics: Antidepressive Agents; Depression; Depressive Disorder, Treatment-Resistant; Hallucinogens; Humans; Psilocybin; Randomized Controlled Trials as Topic
PubMed: 36040772
DOI: 10.17992/lbl.2022.09.706 -
Psychopharmacology Dec 2011This dose-effect study extends previous observations showing that psilocybin can occasion mystical-type experiences having persisting positive effects on attitudes,... (Comparative Study)
Comparative Study Randomized Controlled Trial
RATIONALE
This dose-effect study extends previous observations showing that psilocybin can occasion mystical-type experiences having persisting positive effects on attitudes, mood, and behavior.
OBJECTIVES
This double-blind study evaluated psilocybin (0, 5, 10, 20, 30 mg/70 kg, p.o.) administered under supportive conditions.
METHODS
Participants were 18 adults (17 hallucinogen-naïve). Five 8-h sessions were conducted individually for each participant at 1-month intervals. Participants were randomized to receive the four active doses in either ascending or descending order (nine participants each). Placebo was scheduled quasi-randomly. During sessions, volunteers used eyeshades and were instructed to direct their attention inward. Volunteers completed questionnaires assessing effects immediately after and 1 month after each session, and at 14 months follow-up.
RESULTS
Psilocybin produced acute perceptual and subjective effects including, at 20 and/or 30 mg/70 kg, extreme anxiety/fear (39% of volunteers) and/or mystical-type experience (72% of volunteers). One month after sessions at the two highest doses, volunteers rated the psilocybin experience as having substantial personal and spiritual significance, and attributed to the experience sustained positive changes in attitudes, mood, and behavior, with the ascending dose sequence showing greater positive effects. At 14 months, ratings were undiminished and were consistent with changes rated by community observers. Both the acute and persisting effects of psilocybin were generally a monotonically increasing function of dose, with the lowest dose showing significant effects.
CONCLUSIONS
Under supportive conditions, 20 and 30 mg/70 kg psilocybin occasioned mystical-type experiences having persisting positive effects on attitudes, mood, and behavior. Implications for therapeutic trials are discussed.
Topics: Adult; Affect; Attitude; Cross-Over Studies; Dose-Response Relationship, Drug; Double-Blind Method; Female; Follow-Up Studies; Hallucinogens; Humans; Male; Middle Aged; Psilocybin; Spirituality; Surveys and Questionnaires; Time Factors
PubMed: 21674151
DOI: 10.1007/s00213-011-2358-5 -
Ugeskrift For Laeger Aug 2023This review aims at RCT's of psychedelics used in the treatment of depression and PTSD. Psilocybin has shown an antidepressant effect in cancer patients that was... (Review)
Review
This review aims at RCT's of psychedelics used in the treatment of depression and PTSD. Psilocybin has shown an antidepressant effect in cancer patients that was sustained at 6- and 12-months follow-up. The effect of psilocybin was comparable to escitalopram in one study. Ketamine has shown effect for the treatment of resistant depression. Phase 2 and 3 trials have shown the effect of MDMA on PTSD. No serious adverse events were reported in controlled settings, but larger studies are needed to establish safety and long-term effects.
Topics: Humans; Hallucinogens; Psilocybin; Ketamine; Mental Disorders; Escitalopram
PubMed: 37615227
DOI: No ID Found -
Cell Apr 2020After a legally mandated, decades-long global arrest of research on psychedelic drugs, investigation of psychedelics in the context of psychiatric disorders is yielding...
After a legally mandated, decades-long global arrest of research on psychedelic drugs, investigation of psychedelics in the context of psychiatric disorders is yielding exciting results. Outcomes of neuroscience and clinical research into 5-Hydroxytryptamine 2A (5-HT2A) receptor agonists, such as psilocybin, show promise for addressing a range of serious disorders, including depression and addiction.
Topics: Hallucinogens; Humans; Mental Disorders; Neuropharmacology; Psilocybin; Psychiatry; Serotonin 5-HT2 Receptor Agonists
PubMed: 32243793
DOI: 10.1016/j.cell.2020.03.020 -
Journal of Psychopharmacology (Oxford,... Mar 2022Despite an increasing body of research highlighting their efficacy to treat a broad range of medical conditions, psychedelic drugs remain a controversial issue among the... (Review)
Review
BACKGROUND
Despite an increasing body of research highlighting their efficacy to treat a broad range of medical conditions, psychedelic drugs remain a controversial issue among the public and politicians, tainted by previous stigmatisation and perceptions of risk and danger.
OBJECTIVE
This narrative review examines the evidence for potential harms of the classic psychedelics by separating anecdotes and misinformation from systematic research.
METHODS
Taking a high-level perspective, we address both psychological and psychiatric risks, such as abuse liability and potential for dependence, as well as medical harms, including toxicity and overdose. We explore the evidence base for these adverse effects to elucidate which of these harms are based largely on anecdotes versus those that stand up to current scientific scrutiny.
RESULTS
Our review shows that medical risks are often minimal, and that many - albeit not all - of the persistent negative perceptions of psychological risks are unsupported by the currently available scientific evidence, with the majority of reported adverse effects not being observed in a regulated and/or medical context.
CONCLUSIONS
This highlights the importance for clinicians and therapists to keep to the highest safety and ethical standards. It is imperative not to be overzealous and to ensure balanced media reporting to avoid future controversies, so that much needed research can continue.
Topics: Communication; Drug Overdose; Hallucinogens; Humans; Lysergic Acid Diethylamide; Psilocybin
PubMed: 35107059
DOI: 10.1177/02698811211069100 -
EClinicalMedicine Feb 2023Psilocybin has been suggested as a novel, rapid-acting treatment for depression. Two consecutive doses have been shown to markedly decrease symptom severity in an...
BACKGROUND
Psilocybin has been suggested as a novel, rapid-acting treatment for depression. Two consecutive doses have been shown to markedly decrease symptom severity in an open-label setting or when compared to a waiting list group. To date, to our knowledge, no other trial compared a single, moderate dose of psilocybin to a placebo condition.
METHODS
In this double-blind, randomised clinical trial, 52 participants diagnosed with major depressive disorder and no unstable somatic conditions were allocated to receive either a single, moderate dose (0.215 mg/kg body weight) of psilocybin or placebo in conjunction with psychological support. MADRS and BDI scores were assessed to estimate depression severity, while changes from baseline to 14 days after the intervention were defined as primary endpoints. The trial took place between April 11th, 2019 and October 12th, 2021 at the psychiatric university hospital in Zürich, Switzerland and was registered with clinicaltrials.gov (NCT03715127).
FINDINGS
The psilocybin condition showed an absolute decrease in symptom severity of -13.0 points compared to baseline and were significantly larger than those in the placebo condition (95% CI -15.0 to -1.3; Cohens' = 0.97; P = 0.0011; MADRS) and -13.2 points (95% CI; -13.4 to -1.3; Cohens' = 0.67; P = 0.019; BDI) 14 days after the intervention. 14/26 (54%) participants met the MADRS remission criteria in the psilocybin condition.
INTERPRETATION
These results suggest that a single, moderate dose of psilocybin significantly reduces depressive symptoms compared to a placebo condition for at least two weeks. No serious adverse events were recorded. Larger, multi-centric trials with longer follow-up periods are needed to inform further optimisation of this novel treatment paradigm.
FUNDING
The study was funded by the Swiss National Science Foundation, Crowdfunding, the Swiss Neuromatrix Foundation, and the Heffter Research Institute.
PubMed: 36636296
DOI: 10.1016/j.eclinm.2022.101809 -
The Journal of Neuroscience : the... Nov 2023Serotonergic psychedelics, such as psilocybin and LSD, have garnered significant attention in recent years for their potential therapeutic effects and unique mechanisms... (Review)
Review
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-HT 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-HT 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-HT and 5-HT 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.
Topics: Humans; Hallucinogens; Serotonin; Receptor, Serotonin, 5-HT2A; Psilocybin; Anxiety
PubMed: 37940583
DOI: 10.1523/JNEUROSCI.1384-23.2023