Major depressive disorder (MDD) shows marked sex differences in prevalence, symptomatology, and treatment response. However, females remain underrepresented in many clinical trials, and sex-specific treatment outcomes are rarely examined. This study reanalyzed data from a randomized controlled trial comparing psilocybin and escitalopram for MDD to evaluate sex differences across multiple...
Neuroplasticity, the brain's capacity to reorganise its structure and function, is a transdiagnostic feature across psychiatric and neurodegenerative diseases and a putative mechanism of action for pharmacological interventions. [11C]-UCBJ positron emission tomography (PET), which quantifies synaptic vesicle glycoprotein 2A (SV2A) density, offers the most direct in vivo measure of human...
Abstract Ketamine is known to have anti-depressant effects and is suggested to reduce substance use. However, little is known about the mechanism of these effects. Given evidence from studies in depression of a greater therapeutic effect in those with a family history of AUD, this latter factor was also investigated as a moderating factor. We used data from the KARE trial, a randomised...
In the KARE trial, 96 adults with severe alcohol use disorder, abstinent following detoxification, were randomised in a 2×2 factorial design to 3 weekly infusions of ketamine (0.8 mg/kg) or saline, each combined with mindfulness-based psychological support (PS) or alcohol psychoeducation (PE). We re-expressed the trial data on endpoints acceptable to regulators and compared the most and least...
Background Anorexia nervosa is a debilitating eating disorder with high mortality and chronicity rates owing to the paucity of effective existing treatments. Several clinical trials using psilocybin therapy have demonstrated therapeutic efficacy and safety in psychiatric conditions, including anorexia nervosa. Aims This study aimed to further assess the safety, feasibility and potential...
Psilocybin has been shown to induce fast and sustained symptoms improvements across various psychiatric conditions, yet its long-term mechanisms of action are not fully understood. Initial evidence suggests that longitudinal functional and structural brain changes implicate fronto-striatal-thalamic (FST) circuitry, a broad system involved in goal-directed behavior and motivational states. Here,...
Abstract 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...
Abstract Rationale: Major depressive disorder (MDD) shows marked sex differences in prevalence, symptomatology, and treatment response. However, women remain underrepresented in many clinical trials, and sex-specific treatment outcomes are rarely examined. Objectives This study reanalyzed data from a randomized controlled trial comparing psilocybin and escitalopram for MDD to evaluate sex...
INTRODUCTION: Methylenedioxymethamphetamine (MDMA)-assisted psychotherapy (MDMA-AP) is a potentially transformative intervention for post-traumatic stress disorder (PTSD). Despite encouraging Phase III trial results, the psychological mechanisms underpinning MDMA's therapeutic effects remain insufficiently understood. Existing research on MDMA has emphasised neurobiological processes but has...
Abstract In recent decades, the psychedelic psilocybin has been studied as a potential treatment for major depressive disorder (MDD), offering an alternative to traditional antidepressants. However, the brain changes underlying the clinical effects of different interventions remain unclear. Here, we investigated the effects of psilocybin and a conventional antidepressant, escitalopram, from the...
Rates of mental illness in young people are increasing, whereas the development of novel mental health treatments has not significantly progressed. Psychedelic-assisted therapy, using substances such as psilocybin and 3,4-methylenedioxymethamphetamine (MDMA), has shown potential in the treatment of mental illnesses in the adult population, including depression, anxiety and post-traumatic stress...
May 4, 2026Victoria Burmester, Laura Aggett, David Nutt et al.
preprint
Background3,4-Methylenedioxymethamphetamine (MDMA) is associated with distinctive prosocial and empathogenic effects, yet the consistency and scope of its impact on social functioning in humans remain unclear. Although numerous placebo-controlled studies have examined MDMA’s acute social effects, findings vary widely across subjective and behavioural domains.MethodsWe conducted a systematic...
Psychedelic drugs are re-emerging as promising scientific and clinical tools. However, despite a rapidly expanding literature on their therapeutic value, the neural mechanisms underlying psychedelic effects remain unclear. Resting-state functional magnetic resonance imaging studies of acute psychedelic effects, conducted independently by several research groups, have so far yielded fragmented...
We investigated ketamine's neuroplastic effects in healthy human subjects using integrated Positron Emission Tomography (PET)/Magnetic Resonance Imaging (MRI) measures before and 1-8 days after a single psychedelic dose of ketamine (1 mg/kg, intravenous). Eleven male participants underwent two PET/MRI scans with [11C]-UCBJ (synaptic density/plasticity), 1H-MRS (glutamate and GABA) and...
Major depressive disorder (MDD) is a leading cause of disability worldwide, yet many patients have inadequate responses to current treatments. Dimethyltryptamine (DMT), a serotonergic psychedelic with rapid onset and short duration, shows promise as a potential antidepressant (AD), although clinical evidence in MDD remains limited. We conducted a phase IIa, double-blind, placebo-controlled,...
Without parallel public health action, reclassifying ketamine risks being a symbolic gesture rather than a strategy to reduce harm, write Adam Winstock, David Nutt, and Caroline Copeland
Abstract Disorders of consciousness (DoC), including unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS), have limited treatment options and are characterized by low complexity of brain activity. Recent research suggests that psychedelic drugs, which enhance the complexity of brain activity, could offer promising therapies. Here, individualized whole‐brain computational...
Abstract Recent clinical trial data suggests that ratings on depression scales are lowered after psilocybin therapy compared to placebo, though it is unclear what neuropsychological mechanisms underpin these effects. This study compared psilocybin, with an established antidepressant, escitalopram, to investigate whether there are shared or distinct effects on emotional information processing....
Lysergic acid diethylamide (LSD) and 3,4-Methylenedioxymethamphetamine (MDMA) are widely used psychoactive drugs and their potential use in psychiatric medicine is currently generating interest. The mechanism by which these drugs may assist recovery in various disorders such as addiction and post-traumatic stress disorder (PTSD) is still not well understood. Most investigations of the effects...
It is 60 years since ketamine was first tested in humans as an alternative but safer anaesthetic to PCP (phencyclidine) (Corssen and Domino 1966). It became widely used as the “buddy drug” for combatants in the Vietnam War: because of its great safety margin, it could be injected into wounded personnel by their buddies to relieve pain before the arrival of the medical team. Because of...
Psychedelics are undergoing a clinical research renaissance, with compounds such as psilocybin advancing to Phase 3 trials for treatment-resistant depression and receiving fast-track or breakthrough designations from regulatory agencies. Despite this progress, the field lacks standardized terminology to guide clinical development, dosing, safety monitoring, and regulatory classification. Here,...
Abstract Determining the scale of neural representations is a central challenge in neuroscience. While localized representations have traditionally dominated, evidence suggests information is also encoded in distributed, hierarchical networks. Recent research indicates that the hierarchy of causal influences shaping functional patterns serves as a signature of distinct brain states, with...
Obsessive-compulsive disorder (OCD) is a common and disabling condition. A large proportion of patients fail to respond to first-line treatment with serotonin reuptake inhibitors either selective serotonin reuptake inhibitors (SSRIs) or clomipramine. Preliminary evidence suggests psilocybin, a serotonin receptor agonist, might be efficacious. We conducted a pharmacological challenge study to...
The following part of the abstract had a minor error: ‘Following PT, there was greater activation in the ventromedial prefrontal cortex and sensory regions, and reduced activation in the angular gyrus.’ This is now corrected to ‘Following PT, there was decreased activation in the ventromedial prefrontal cortex and angular gyrus, and greater activation in sensory regions.’ The original article...
Patients with Major Depressive Disorder (MDD) have more dysfunctional attitudes than healthy individuals and these pessimistic biases are correlated with depression severity. Psilocybin has demonstrated sustained remission in depression. Secondary analysis of a two-arm randomized controlled trial assessing the effect of psilocybin therapy versus escitalopram on 'maladaptive' cognitive biases...