For English, the validated part of Psychedelic Experience Scale (PES48) is a four-factor structure called the Mystical Experience Questionnaire (MEQ30). The other validated part of the PES48 consists of four more factors: two more mystical factors (paradoxicality and connectedness, which together with the MEQ30 form the MEQ40), and two more non-mystical factors (visual experience and...
The clinical trial NCT03866252 investigates the antidepressant effects of lysergic acid diethylamide (LSD) in 61 patients with major depressive disorder (MDD) randomized to low-dose LSD (LD-LSD; 2 × 25 μg) or moderate-to-high-dose LSD (HD-LSD; 100 μg followed by 200 μg) 4 weeks apart. Although the trial reports positive clinical outcomes, underlying mechanisms remain unclear. Here, we test...
Objectives: For English, the validated part of Psychedelic Experience Scale (PES48) is a four-factor structure called the Mystical Experience Questionnaire (MEQ30). The other validated part of the PES48 consists of four more factors: two more mystical factors (paradoxicality and connectedness, which together with the MEQ30 form the MEQ40), and two more non-mystical factors (visual experience...
Mystical dynamics—the notion that mystical oneness may unfold involving ego disintegration, renewal, and luminous light—has been discussed anecdotally by psychedelic researchers and therapists but has not yet been empirically examined in controlled settings. This study investigated the occurrence and dose-dependency of mystical dynamics in healthy participants after administration of...
Classical psychedelics have regained interest for their potential to treat psychiatric and neurological disorders, and explore neural mechanisms supporting perception, cognition, and mood. Acute psychedelic effects have been linked to increases in brain complexity and entropy, but it is unclear if these changes are specific to psychedelics or reflect more general psychoactive effects. Here, we...
Mystical dynamics-the notion that mystical oneness may unfold involving ego disintegration, renewal, and luminous light-has been discussed anecdotally by psychedelic researchers and therapists but has not yet been empirically examined in controlled settings. This study investigated the occurrence and dose-dependency of mystical dynamics in healthy participants after administration of...
The Altered States of Consciousness Scale (3/5D-ASC or 11-ASC) is widely used to assess non-ordinary states of consciousness, particularly for psychedelic research. However, its original dimensional model (3D-ASC within 5D-ASC) and later 11-subscale structure (11-ASC) have a hierarchically incompatible higher/lower-order structure. Although the 11-ASC offers superior model fit, the 3D-ASC...
Mescaline is a classic serotonergic psychedelic with a long history of human use. The present study analyzed the pharmacokinetics, pharmacokinetic-pharmacodynamic relationship, and urinary recovery of oral mescaline hydrochloride. Data from 105 single-dose administrations (100-800 mg) in 49 participants from two phase I trials were analyzed with compartmental pharmacokinetics and...
This trial aimed to assess the efficacy of lysergic acid diethylamide (LSD)-assisted therapy in patients with moderate-to-severe major depressive disorder. This was a randomized, parallel, double-blind, low-dose controlled trial (Clinicaltrials.gov: NCT03866252). Patients were randomly assigned in a 1:1 ratio to receive supportive psychotherapy and either 100 μg + 200 μg LSD or 25 μg + 25 μg...
Psychedelics have recently attracted significant attention for their potential to mitigate symptoms associated with various psychiatric disorders. However, the precise neurobiological mechanisms responsible for these effects remain incompletely understood. A valuable approach to gaining insights into the specific mechanisms of action involves comparing psychedelics with substances that have...
Little is known about motives of healthy volunteers to participate in psychedelic trials and how they appraise their study experience retrospectively. This paper explored reasons why healthy people register for psychedelic trials, factors that they considered to contribute to either positive or negative study experiences, and under which circumstances they would seek a psychedelic experience...
Background: The Altered States of Consciousness Scale (3/5D-ASC or 11-ASC) is widely used to assess non-ordinary states of consciousness, particularly for psychedelic research. However, its original dimensional model (3D-ASC within 5D-ASC) and later 11-subscale structure (11-ASC) have a hierarchically incompatible higher/lower-order structure. Although the 11-ASC offers superior model fit, the...
Psychedelics, including mescaline, may serve as novel treatments for depression and anxiety. However, data is scarce on the safety of mescaline. The present pooled analysis included two double-blind, randomized, placebo-controlled studies with a total of 48 participants and 96 mescaline administrations. Single oral-dose administrations (n = 16/dose) of mescaline at doses of 100-800 mg were...
The pharmacodynamic effects of lysergic acid diethylamide (LSD) are diverse and different in different individuals. Effects of other psychoactive substances have been shown to be critically influenced by non-pharmacological factors such as personality traits and mood states. The aim of this study was to determine pharmacological and psychological predictors of the LSD effects in healthy human...
While the exploration of serotonergic psychedelics as psychiatric medicines deepens, so does the pressure to better understand how these compounds act on the brain. We used a double-blind, placebo-controlled, crossover design and administered lysergic acid diethylamide (LSD), 3,4-methylenedioxymethamphetamine (MDMA), and d-amphetamine in 25 healthy participants. By using spectral dynamic causal...
Psilocybin is being studied for its therapeutic potential in various mental health disorders, such as depression, anxiety, and addiction. Initial studies suggested that psilocybin is generally safe when used under controlled conditions, but more research is needed to better understand its safety profile. We report safety pharmacology data from a pooled analysis of three randomized crossover...
There is renewed interest in the use of lysergic acid diethylamide (LSD) in psychiatric research and practice. Although acute subjective effects of LSD are mostly positive, negative subjective effects, including anxiety, may occur. The induction of overall positive acute subjective effects is desired in psychedelic-assisted therapy because positive acute experiences are associated with greater...
Background: Research with the Psychedelic Experience Questionnaire/Scale (PES) focuses on questions relating to mystical experience (Mystical Experience Questionnaire (MEQ)). The psychometric potential of the non-MEQ items of the PES remains largely unexplored. Aims: We investigated whether the PES also yields subscales besides the MEQ30 subscales. Methods: Data from 239 PES measurements (140...
Mescaline, lysergic acid diethylamide (LSD), and psilocybin are classic serotonergic psychedelics. A valid, direct comparison of the effects of these substances is lacking. The main goal of the present study was to investigate potential pharmacological, physiological and phenomenological differences at psychoactive-equivalent doses of mescaline, LSD, and psilocybin. The present study used a...
N,N-dimethyltryptamine (DMT) is distinct among classic serotonergic psychedelics because of its short-lasting effects when administered intravenously. Despite growing interest in the experimental and therapeutic use of intravenous DMT, data are lacking on its clinical pharmacology. We conducted a double-blind, randomized, placebo-controlled crossover trial in 27 healthy participants to test...
Abstract Psychedelics have emerged as promising candidate treatments for various psychiatric conditions, and given their clinical potential, there is a need to identify biomarkers that underlie their effects. Here, we investigate the neural mechanisms of lysergic acid diethylamide (LSD) using regression dynamic causal modelling (rDCM), a novel technique that assesses whole-brain effective...
Psychedelics, empathogens, and psychostimulants evoke thalamocortical hyperconnectivity with sensorimotor areas, akin to findings in patients with psychotic disorders.
Abstract Growing interest has been seen in using lysergic acid diethylamide (LSD) and psilocybin in psychiatric research and therapy. However, no modern studies have evaluated differences in subjective and autonomic effects of LSD and psilocybin or their similarities and dose equivalence. We used a double-blind, randomized, placebo-controlled, crossover design in 28 healthy subjects (14 women,...
Abstract Background LSD and psilocybin are increasingly used in phase I trials and evaluated as therapeutic agents for mental disorders. The phenomenon of reoccurring drug-like experiences after the acute substance effects have worn off was described for both substances and especially attributed to LSD. According to the DSM-V, the persisting and distressing manifestation of these experiences is...
Background: 3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”) is used both recreationally and therapeutically. Little is known about the factors influencing inter- and intra-individual differences in the acute response to MDMA. Effects of other psychoactive substances have been shown to be critically influenced by personality traits and mood state before intake. Methods: We pooled data from...