Cureus
January 29, 2025
Sorcha O'Connor, Kate Godfrey, Sara Reed et al.
2 citations
The study aims to uncover the neural mechanisms by which psilocybin-assisted therapy affects obsessive-compulsive disorder (OCD) and whether those brain changes align with improvements in cognitive symptoms. A secondary goal is to test whether a low, tolerable dose is both practical and effective as a clinical treatment. The results will provide essential data for designing a future randomized controlled trial.
arXiv (Cornell University)
November 29, 2024
Claudio Agnorelli, Meg J. Spriggs, Kate Godfrey et al.
2 citations
Classic psychedelics (LSD, psilocybin, N,N-DMT) and non-classic psychedelics (ketamine, MDMA) enhance neuroplasticity, the nervous system's ability to adapt. Animal studies indicate these drugs induce meta-plasticity, heightening sensitivity to environmental stimuli, and hyper-plasticity, reopening developmental windows for long-term structural changes that affect mood and behavior. Translating these findings to humans is challenged by limitations in current imaging techniques, but emerging approaches like novel PET radioligands, non-invasive brain stimulation, and multimodal methods offer promising directions. This review informs development of targeted interventions for neuropsychiatric disorders and advances understanding of psychedelics' therapeutic potential.
October 19, 2022
Stefan Baumann, Robin Carhart-Harris, David Nutt et al.
2 citations
preprint
In a placebo-controlled citizen science trial with 240 participants, microdosing tolerance was assessed by tracking whether correct guesses of receiving a microdose decreased with more doses taken. Correct guess probability declined overall, indicating tolerance developed. This tolerance was specific to LSD and LSD-analogue microdoses, not psilocybin microdoses. The findings suggest that microdosers may need to periodically suspend their routine to avoid tolerance and that psilocybin may be better suited for long-term protocols.
Prometheus
September 1, 2010
David Nutt
2 citations
In October 2009, the UK home secretary requested David Nutt's resignation as chair of the government's advisory council on the misuse of drugs after the publication of his paper arguing that ecstasy and LSD are less dangerous than alcohol. Nutt had previously clashed with the Home Office over an editorial comparing the harms of ecstasy unfavorably to those of horse riding. The incident highlighted tensions between academic publication and scientific advice to government. Nutt now chairs the Independent Scientific Committee on Drugs.
bioRxiv (Cold Spring Harbor Laboratory)
June 16, 2026
Paulina Clara Dagnino, Irene Acero-Pousa, Gorka Zamora‐lópez et al.
1 citation
Psilocybin and the conventional antidepressant escitalopram produce opposite changes in the brain's hierarchical non-equilibrium dynamics when treating major depressive disorder. Using resting-state fMRI before and after treatment, researchers built whole-brain models and measured how much each patient's brain activity deviated from the fluctuation-dissipation theorem. Baseline measures distinguished treatment responders from non-responders within each group. The deviation from the fluctuation-dissipation theorem may serve as a marker to differentiate the brain effects of psilocybin and escitalopram, contributing to understanding how these treatments work for depression.
Psychological Medicine
July 19, 2023
Brandon Weiss, Induni Ginige, Lu Shannon et al.
1 citation
No Summary
BMJ
May 2, 2023
Leslie A. King, David Nutt, David E. Nichols
1 citation
The authors argue that regulations governing clinical research on Schedule 1 drugs, which are classified as having high abuse potential and no accepted medical use, should be reassessed. They contend that such classification unnecessarily impedes scientific investigation into substances with therapeutic potential, such as certain psychedelics. The piece advocates for a review of the scheduling system to facilitate research that could lead to medical treatments, while maintaining appropriate controls to prevent misuse.
Neuroscience Applied
January 1, 2023
Hannah Douglass, Merle Spriggs, Kate Godfrey et al.
1 citation
No Summary
June 30, 2022
Sandeep M. Nayak, Bilal A. Bari, David B. Yaden et al.
1 citation
preprint
A Bayesian reanalysis of a trial comparing psilocybin (COMP360) to escitalopram for major depressive disorder found that psilocybin outperformed escitalopram, but not by a clinically meaningful amount. The analysis also found extremely strong evidence that psilocybin is non-inferior to escitalopram. Evidence for psilocybin's superiority varied by depression scale: indeterminate for one, strong for two, and extremely strong for another. For a clinically meaningful difference, evidence was moderate against it on one scale, indeterminate on two, and moderate supporting it on one. These results provide a more nuanced interpretation and support further research.
December 11, 2020
Balázs Szigeti, Laura Kärtner, Allan Blemings et al.
1 citation
A self-blinding citizen science study tested whether psychedelic microdosing improves well-being and cognition beyond placebo. 191 participants who already planned to microdose were randomly assigned to receive four weeks of microdoses, placebos, or a mix. All psychological outcomes—including well-being, mindfulness, and life satisfaction—improved from baseline in the microdose group, but the placebo group also improved, and no significant differences emerged between groups. Small acute differences in mood, energy, and creativity were observed, but these could be explained by participants correctly guessing whether they took a microdose. The findings suggest that the anecdotal benefits of microdosing are likely due to the placebo effect.
bioRxiv (Cold Spring Harbor Laboratory)
Hanna M. Tolle, Andrea I Luppi, Timothy Lawn et al.
1 citation
preprint
A geometric deep learning model called graphTRIP predicts post-treatment depression severity from pretreatment clinical and brain imaging data. Trained on a clinical trial comparing psilocybin and escitalopram, it achieves strong predictive accuracy (r = 0.75) and generalizes to an independent dataset. The model links better outcomes to reduced functional coupling within serotonin systems and broader serotonergic integration with sensory-motor networks. Causal analysis shows a group-level advantage of psilocybin over escitalopram but identifies individuals with specific stress-related neuromodulatory profiles who may benefit more from escitalopram, advancing precision medicine and biomarker discovery in depression.
bioRxiv (Cold Spring Harbor Laboratory)
June 26, 2026
Paulina Clara Dagnino, Irene Acero-Pousa, Robin Carhart‐Harris et al.
A central challenge in neuroscience is understanding how the human brain is organised to support optimal functioning and adaptability. One approach to characterise complex brain dynamics is by artificially perturbing whole-brain models. Here, we asked whether whole-brain organisation under perturbation in major depressive disorder (MDD) changes after intervention with psilocybin and escitalopram. First, we built whole-brain models of pre- and post-treatment resting-state functional magnetic resonance imaging (fMRI) and obtained an initial generative effective connectivity (GEC) matrix for each individual.
Research Square
June 19, 2026
Aline Frick, Grace Blest‐hopley, Manesh Grin et al.
In a reanalysis of a six-week randomized controlled trial comparing psilocybin with escitalopram for moderate-to-severe major depressive disorder, sex-related patterns emerged for anxiety and anhedonia. Women receiving psilocybin showed greater reductions in anxiety than men, while women receiving escitalopram showed greater reductions in anhedonia than men. For other depressive symptoms, thought suppression, and well-being, sex differences were small and uncertain. Sexual dysfunction severity was lower overall in the psilocybin group than in the escitalopram group and lower in women than in men, though the treatment-by-sex interaction was not significant. These preliminary findings suggest that responses to these serotonergic treatments may differ between women and men, supporting the need for adequately powered, sex-balanced trials.
Translational Psychiatry
November 13, 2025
Bruna Giribaldi Cunha, David Nutt, Marieke Martens et al.
In a double-blind randomized trial, patients with long-standing moderate-to-severe depression received either two doses of 25 mg psilocybin plus daily placebo or two doses of 1 mg psilocybin plus daily escitalopram over six weeks. Both treatments comparably reduced negative bias in recognizing facial emotions, a measure of emotional information processing. However, changes in this bias were not linked to concurrent depression score changes. Only in the escitalopram group did a decrease in misclassifying positive faces as negative correlate with lower depression scores at a one-month follow-up. The findings suggest overlapping cognitive mechanisms between psilocybin and escitalopram, notable given psilocybin's short dosing regimen.
bioRxiv Preprint Server
May 1, 2025
Claudio Agnorelli, Joseph Peill, Gabriela Sawicka et al.
preprint
A single psychedelic dose of ketamine (1 mg/kg, intravenous) alters brain chemistry and connectivity in healthy people for at least one to eight days. After the dose, glutamate levels in the anterior cingulate cortex rose significantly. Functional connectivity decreased within high-order networks such as the default mode network, while integration between low- and high-order networks increased. Increases in a PET marker of synaptic plasticity correlated with reduced intrinsic activity in default mode network regions and a diminished influence of the posterior cingulate cortex on global network dynamics. The posterior cingulate cortex appears to be a central hub through which ketamine may reshape brain hierarchies over the long term.
Cureus
January 1, 2025
Sorcha O'Connor, Kate Godfrey, Sara Reed et al.
correction
A protocol describes a planned study testing whether a low-moderate dose of psilocybin (10 mg), combined with non-interventional therapy, can improve cognitive flexibility and neuroplasticity in people with obsessive-compulsive disorder (OCD). Twenty blinded participants will receive an active placebo (1 mg psilocybin) in a first session and 10 mg in a second session four weeks later. Cognitive flexibility will be measured with the intradimensional-extradimensional shift task two days after each session, and neuroplasticity will be assessed via electroencephalography immediately after each session. Secondary outcomes include OCD symptom severity and patient-reported measures. The results are expected to clarify neural mechanisms and guide a future randomized controlled trial.
Biological Psychiatry
April 10, 2023
David Nutt
No Summary
Psychedelics as Psychiatric Medications
March 1, 2023
David Castle, Nicole Ledwos, David Nutt
The renewed scientific interest in psychedelics and related drugs is promising for treating mental health disorders and addictions, but many questions remain unanswered. Key uncertainties include how these drugs work in the brain, how their biological effects interact with psychological support to produce therapeutic change, the duration of benefits, and long-term safety. The necessity of the psychedelic experience for therapeutic benefit, safe delivery of psychological support, integration into mainstream healthcare, funding, therapist training, and gold-standard trial designs addressing blinding, placebo response, and expectancy bias are all outstanding issues that need resolution as research expands across more disorders.
May 10, 2022
Robin Carhart‐Harris, Richard E. Daws, David Nutt
preprint
The authors respond to a critique of their earlier work that questioned whether psilocybin truly opens depressed minds. They address the skeptic's arguments, defending their original evidence and conclusions about psilocybin's effects on depression. The response clarifies methodological points and reaffirms the potential of psilocybin as a treatment for depression, while acknowledging the need for further research to address lingering doubts.
Journal of Psychopharmacology
July 14, 2019
Livia Ng, Luca Pani, Anaïs Soula et al.
Claims about the positive effects of microdosing psychedelics on mood and cognition have entered public discussion, but scientific studies are scarce and no consensus on what microdosing means exists. This critique identifies questions future research must answer and offers guidelines, focusing on psilocybin due to its potential clinical approval and short-lasting effects. While anecdotal reports emphasize benefits, the paper concludes that future studies should also investigate potential risks of repeated low-dose administrations. Preclinical and clinical research examining biological measures like heart rate and receptor turnover, as well as cognitive parameters such as memory and attention, is needed to uncover possible negative consequences.
May 23, 2018
David Nutt
Recent findings on the neurobiology of serotonin receptors and the mechanisms by which psychedelics have therapeutic potential in psychiatry are summarized. The text describes these topics but does not present specific results, data, or conclusions.
ChemRxiv
Vito Federico Palmisano, Claudio Agnorelli, Andrea Fagiolini et al.
The ability of classic psychedelics to permeate neuronal membranes and reach intracellular 5-HT2A receptors is critical for their therapeutic effects. Using molecular dynamics simulations, this computational study examined how structural modifications to tryptamines affect membrane permeability. Dimethylation of the primary amine group and adding a methoxy group at position 5 increased permeability. In contrast, substitutions at other positions on the indole ring and protonation of the molecules raised the energy barrier at the bilayer center, making the compounds highly impermeable. These findings can guide future drug design to develop psychedelics with enhanced activity.
arXiv Preprint Archive
November 29, 2024
Claudio Agnorelli, Meg Spriggs, Kate Godfrey et al.
Psychedelics like LSD and psilocybin can rewire brain connections after just one dose, unlike traditional psychiatric medications. These compounds boost the brain's natural plasticity, helping neurons form new pathways and adapt to change. Studies show they create a window of enhanced learning and adaptation, leading to lasting improvements in mood and behavior.
arXiv Preprint Archive
May 26, 2014
Enzo Tagliazucchi, Robin Carhart-Harris, Robert Leech et al.
Psilocybin, the active compound in magic mushrooms, dramatically expands the brain's repertoire of connectivity states, revealing how consciousness can be altered. Using advanced brain imaging, researchers tracked neural activity before and after psilocybin administration. Results showed increased signal variability in memory and emotion-processing regions, while higher brain networks displayed enhanced flexibility in their communication patterns.