Lysergic acid diethylamide (LSD) is a potent psychedelic with increasing therapeutic interest, yet qualification of target engagement using in vivo neuroimaging has not yet been performed. Using simultaneous positron emission tomography-magnetic resonance imaging technology, we describe multiple brain actions of LSD in seven healthy volunteers blinded to LSD dose received. Here we show that LSD...
The research, understanding, and implementation of psychedelic therapies is characterised by a layered complexity that arises from the dynamic interactions between pharmacological and extra-pharmacological factors, and the embeddedness of psychedelics within broader societal, legal, and regulatory systems ill-equipped to accommodate them. This complexity is compounded by an epistemic...
A prominent theory of psychedelics is that they increase brain entropy. Thirteen studies have evaluated psychedelic effects on fMRI brain entropy, each applying a distinct measure. Here we evaluated these metrics in an independent 28-participant healthy cohort with 121 pre- and post-psilocybin fMRI scans. We assessed relations between brain entropy and objective and subjective psychedelic drug...
Major depression is a prevalent condition among patients with life-threatening illnesses, such as cancer, and recent findings suggest that psilocybin may hold promising treatment potential. Contemporary trials of psilocybin generally employ a model that includes psychotherapeutic support consisting of preparation and integration sessions surrounding the dosing. However, there is limited...
A key distinction among clinical trials on psilocybin treatments, for example, those targeting depression, has been whether the psilocybin dosing session is combined with bona fide psychotherapy or with what is referred to as “psychological support” (1-3). The most developed model of psychological support is the Compass Psychological Support Model (CPSM; 1). Kirlić and colleagues specifically...
Abstract Psychedelics such as psilocybin have been linked to enhanced neuroplasticity and symptom relief in affective disorders, but the neurobiological mechanisms and impact of environmen-tal context remain unclear. Here, we tested whether a single dose of psilocybin alters synap-tic density in healthy individuals and whether setting-dependent subjective experience shapes this effect. Fifteen...
Classic psychedelics are increasingly studied as potential treatments for different psychiatric disorders. Current research protocols often require patients to discontinue antidepressants (ADs) for at least 2 weeks before psychedelic administration to decrease the risk of serotonin syndrome and limit their effect on efficacy and the acute subjective effects of psychedelics. Moreover, the...
In this study, we provide the first study to integrate molecular and functional neuroimaging during psychedelic drug effects in humans. Using simultaneous PET-MRI technology, we describe multiple brain actions of lysergic acid diethylamide (LSD) in healthy volunteers. We quantify the occupancy of LSD at cerebral serotonin 2A receptors and show that LSD increases global cerebral blood flow and...
Background: Psilocybin, a serotonin 2A receptor agonist with psychedelic properties, shows promise as a novel treatment for alcohol use disorder (AUD). While current studies involve two dosing sessions, the effects of a single dose have not been investigated. Aims: To investigate the pharmacokinetics, feasibility, safety and efficacy of single-dose psilocybin therapy in AUD. Methods: This...
Introduction: Serotonergic psychedelics, serotonin 2A receptor agonists such as psilocybin that can result in substantially altered states of consciousness, are used in recreational and research settings. The safety of psychedelic experiences in research settings is supported by controlled physical environments, presence of clinical and medical staff to address emergent issues, screening for...
Abstract Background Psilocybin, a serotonin 2A receptor agonist with psychedelic properties, shows promise as a novel treatment for alcohol use disorder (AUD). While current studies involve two dosing sessions, the effects a single dose have not been investigated. Aims To investigate the pharmacokinetics, feasibility, safety, and efficacy of single-dose psilocybin therapy in AUD. Methods This...
Background: Psychedelic substances reliably induce marked altered states of consciousness (ASC), which may be important for lasting effects and clinical outcomes of psychedelic intervention. Several instruments are available to measure the acute psychedelic experience, of which the Five Dimensional Altered States of Consciousness Questionnaire (5D-ASC) is commonly used. The questionnaire can be...
The serotonin 2A (5-HT2A) receptor is an important target for drug development and the main receptor through which classical psychedelics elucidate their hallucinogenic effects. The 5-HT2A receptor antagonist ketanserin has frequently been used as a tool to block the receptor. Here, we establish the dose-occupancy relation of ketanserin and the cerebral 5-HT2A receptor in healthy participants...
Research suggests positive changes in both well-being and psychiatric symptoms following a psychedelic experience. One explanation may be the ability of psychedelic compounds to occasion mystical-type experiences. The Revised Mystical Experiences Questionnaire (MEQ30) is designed to assess the intensity and quality of such experiences. We examined the validity, reliability, and factor structure...
Psychedelic drugs including psilocybin and LSD are undergoing clinical trials for a range of psychiatric and neurological conditions, and have particularly shown substantial promise in phase 2 studies of depression. In this article we outline key knowledge gaps that may be imperative for a successful implementation of psychedelic drugs as medicines as identified by members of the European...
Abstract Objective To evaluate the feasibility and prophylactic effect of psilocybin as well as its effects on hypothalamic functional connectivity (FC) in patients with chronic cluster headache (CCH). Background CCH is an excruciating and difficult‐to‐treat disorder with incompletely understood pathophysiology, although hypothalamic dysfunction has been implicated. Psilocybin may have...
A prominent theory of psychedelics is that they increase brain entropy. Twelve studies have evaluated psychedelic effects on fMRI brain entropy quantifications, no findings have been replicated. Here we evaluated these metrics in an independent 28-participant healthy cohort with 121 pre- and post-psilocybin fMRI scans. We assessed relations between brain entropy and plasma psilocin, brain...
Psilocybin is a serotonergic psychedelic that has gained prominent attention recently as a potential therapeutic for neuropsychiatric disorders including Major Depressive Disorder. Pre-clinical and initial studies in humans suggest that serotonin 2A receptor agonists, including serotonergic psychedelics, have anti-inflammatory effects. This may contribute to its therapeutic effects as previous...
The psychedelic drug psilocybin has been successfully explored as a novel treatment for a range of psychiatric disorders. Administration of psilocybin requires careful attention to psychological support and the setting in which the drug is administered. The use of music to support the acute psychoactive effects of psilocybin is recommended in current guidelines, but descriptions of how to...
Our findings suggest that the acute perceptual psychedelic effects induced by psilocybin may stem from drug-level associated decreases in the occurrence and duration of lateral and medial frontoparietal connectivity motifs. We apply and argue for a modified approach to modeling eigenvectors produced by LEiDA that more fully acknowledges their underlying structure. Together these findings...
Background Psilocybin-induced mystical-type experiences are associated with lasting positive psychological outcomes. Recent studies indicate that trait mindfulness is increased 3 months after psilocybin intake, preceded by decreases in neocortical serotonin 2A receptor (5-HT 2A R) binding. However, the association between psilocybin-induced mystical-type experiences and subsequent changes in...
Introduction Alcohol use disorder is a difficult-to-treat psychiatric disorder and a major burden on public health. Existing treatment efficacy is moderate, and relapse rates are high. Preliminary findings suggest that psilocybin, a psychedelic compound, can safely and reliably occasion highly meaningful experiences that may spur a positive change in drinking behaviour when administered in a...
Abstract Chronic cluster headache (CCH) is an excruciating disorder of unknown pathophysiology, but hypothalamic dysfunction has been implicated. CCH is difficult to treat but on a case-basis, the psychedelic compound psilocybin is said to have beneficial effects. In this first-ever clinical trial ( NCT04280055 ), we evaluate in a small open-label study of CCH patients the feasibility and...
Psychedelic drugs such as psilocybin have shown substantial promise for the treatment of several psychiatric conditions including mood and addictive disorders. They also have the remarkable property of producing persisting positive psychological changes in healthy volunteers for at least several months. In this study (NCT03289949), 35 medium-high doses of psilocybin were administered to 28...