Psychedelic-assisted therapy for treating anxiety, depression, and existential distress in people with life-threatening diseases.

BACKGROUND: Psychedelic-assisted therapy refers to a group of therapeutic practices involving psychedelics taken under therapeutic supervision from physicians, psychologists, and others. It has been hypothesised that psychedelic-assisted therapy may reduce symptoms of anxiety, depression, and existential distress in patients facing life-threatening diseases (e.g. cancer). However, these substances are illegal in most countries and have been associated with potential risks. OBJECTIVES: To assess the benefits and harms of psychedelic-assisted therapy compared to placebo or active comparators (e.g. antidepressants) for treatment of anxiety, depression, and existential distress in people with life-threatening diseases. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, and two trial registers on 30 March 2024. In addition, we undertook reference checking, citation searching, and contact with study authors to identify additional studies. We used no language or date restrictions. SELECTION CRITERIA: We included randomised controlled trials (RCTs), with no restrictions regarding comorbidity, sex, or ethnicity. Interventions comprised a substance-induced psychedelic experience preceded by preparatory therapeutic sessions and followed by integrative therapeutic sessions. DATA COLLECTION AND ANALYSIS: We used the standard methodological procedures expected by Cochrane. MAIN RESULTS: We included six studies in the review, which evaluated two different interventions: psychedelic-assisted therapy with classical psychedelics (psilocybin ('magic mushrooms') and lysergic acid diethylamide (LSD)), and psychedelic-assisted therapy with 3,4-methylenedioxymethamphetamine (MDMA or 'Ecstasy'). The studies randomised 149 participants with life-threatening diseases and analysed data for 140 of them. The age range of participants was 36 to 64 years. The studies lasted between 6 and 12 months, and were conducted in outpatient settings in the USA and in Switzerland. Drug companies were not involved in study funding, but funding was provided by organisations that promote psychedelic-assisted therapy. Primary outcomes (at 1 to 12 weeks) Anxiety Psychedelic-assisted therapy using classical psychedelics (psilocybin, LSD) may result in a reduction in anxiety when compared to active placebo (or low-dose psychedelic): State Trait Anxiety Inventory (STAI-Trait, scale 20 to 80) mean difference (MD) -8.41, 95% CI -12.92 to -3.89; STAI-State (scale 20 to 80) MD -9.04, 95% CI -13.87 to -4.21; 5 studies, 122 participants; low-certainty evidence. The effect of psychedelic-assisted therapy using MDMA on anxiety, compared to placebo, is very uncertain: STAI-T MD -14.70, 95% CI -29.45 to 0.05; STAI-S MD -16.10, 95% CI -33.03 to 0.83; 1 study, 18 participants; very low certainty evidence. Depression Psychedelic-assisted therapy using classical psychedelics (psilocybin, LSD) may result in a reduction in depression when compared to active placebo (or low-dose psychedelic): Beck Depression Inventory (BDI, scale 0 to 63) MD -4.92, 95% CI -8.97 to -0.87; 4 studies, 112 participants; standardised mean difference (SMD) -0.43, 95% CI -0.79 to -0.06; 5 studies, 122 participants; low-certainty evidence. The effect of psychedelic-assisted therapy using MDMA on depression, compared to placebo, is very uncertain: BDI-II (scale: 0 to 63) MD -6.30, 95% CI -16.93 to 4.33; 1 study, 18 participants; very low certainty evidence. Existential distress Psychedelic-assisted therapy using classical psychedelics (psilocybin, LSD) compared to active placebo (or low-dose psychedelic) may result in a reduction in demoralisation, one of the most common measures of existential distress, but the evidence is very uncertain (Demoralisation Scale, 1 study, 28 participants): post treatment scores, placebo group 39.6 (SEM 3.4), psilocybin group 18.8 (3.6), P ≤ 0.01). Evidence from other measures of existential distress was mixed. Existential distress was not measured in people receiving psychedelic-assisted therapy with MDMA. Secondary outcomes (at 1 to 12 weeks) Quality of life When classical psychedelics were used, one study had inconclusive results and two reported improved quality of life, but the evidence is very uncertain. MDMA did not improve quality of life measures, but the evidence is also very uncertain. Spirituality Participants receiving psychedelic-assisted therapy with classical psychedelics rated their experience as being spiritually significant (2 studies), but the evidence is very uncertain. Spirituality was not assessed in participants receiving MDMA. Adverse events No treatment-related serious adverse events or adverse events grade 3/4 were reported. Common minor to moderate adverse events for classical psychedelics were elevated blood pressure, nausea, anxiety, emotional distress, and psychotic-like symptoms (e.g. pseudo-hallucination where the participant is aware they are hallucinating); for MDMA, common minor to moderate adverse events were anxiety, dry mouth, jaw clenching, and headaches. Symptoms subsided when drug effects wore off or up to one week later. Certainty of the evidence Although all six studies had intended to blind participants, personnel, and assessors, blinding could not be achieved as this is very difficult in studies investigating psychedelics. Using GRADE criteria, we judged the certainty of evidence to be low to very low, mainly due to high risk of bias and imprecision (small sample size). AUTHORS' CONCLUSIONS: Implications for practice Psychedelic-assisted therapy with classical psychedelics (psilocybin, LSD) may be effective for treating anxiety, depression, and possibly existential distress, in people facing a life-threatening disease. Psychedelic-assisted therapy seemed to be well tolerated, with no treatment-emergent serious adverse events reported in the studies included in this review. However, the certainty of evidence is low to very low, which means that we cannot be sure about these results, and they might be changed by future research. At the time of this review (2024), psychedelic drugs are illegal in many countries. Implications for research The risk of bias due to 'unblinding' (participants being aware of which intervention they are receiving) could be reduced by measuring expectation bias, checking blinding has been maintained before cross-over, and using active placebos. More studies with larger sample sizes are needed to reduce imprecision. As the US Drug Enforcement Administration (DEA) currently classifies psychedelics as Schedule I substances (i.e. having no accepted medical use and a high potential for abuse), research involving these drugs is restricted, but is steadily increasing.

Hallucinogens in Mental Health: Preclinical and Clinical Studies on LSD, Psilocybin, MDMA, and Ketamine.

A revamped interest in the study of hallucinogens has recently emerged, especially with regard to their potential application in the treatment of psychiatric disorders. In the last decade, a plethora of preclinical and clinical studies have confirmed the efficacy of ketamine in the treatment of depression. More recently, emerging evidence has pointed out the potential therapeutic properties of psilocybin and LSD, as well as their ability to modulate functional brain connectivity. Moreover, MDMA, a compound belonging to the family of entactogens, has been demonstrated to be useful to treat post-traumatic stress disorders. In this review, the pharmacology of hallucinogenic compounds is summarized by underscoring the differences between psychedelic and nonpsychedelic hallucinogens as well as entactogens, and their behavioral effects in both animals and humans are described. Together, these data substantiate the potentials of these compounds in treating mental diseases.

Increased sensitivity to strong perturbations in a whole-brain model of LSD.

Lysergic acid diethylamide (LSD) is a potent psychedelic drug, which has seen a revival in clinical and pharmacological research within recent years. Human neuroimaging studies have shown fundamental changes in brain-wide functional connectivity and an expansion of dynamical brain states, thus raising the question about a mechanistic explanation of the dynamics underlying these alterations. Here, we applied a novel perturbational approach based on a whole-brain computational model, which opens up the possibility to externally perturb different brain regions in silico and investigate differences in dynamical stability of different brain states, i.e. the dynamical response of a certain brain region to an external perturbation. After adjusting the whole-brain model parameters to reflect the dynamics of functional magnetic resonance imaging (fMRI) BOLD signals recorded under the influence of LSD or placebo, perturbations of different brain areas were simulated by either promoting or disrupting synchronization in the regarding brain region. After perturbation offset, we quantified the recovery characteristics of the brain area to its basal dynamical state with the Perturbational Integration Latency Index (PILI) and used this measure to distinguish between the two brain states. We found significant changes in dynamical complexity with consistently higher PILI values after LSD intake on a global level, which indicates a shift of the brain's global working point further away from a stable equilibrium as compared to normal conditions. On a local level, we found that the largest differences were measured within the limbic network, the visual network and the default mode network. Additionally, we found a higher variability of PILI values across different brain regions after LSD intake, indicating higher response diversity under LSD after an external perturbation. Our results provide important new insights into the brain-wide dynamical changes underlying the psychedelic state - here provoked by LSD intake - and underline possible future clinical applications of psychedelic drugs in particular psychiatric disorders.

Decreased directed functional connectivity in the psychedelic state.

Neuroimaging studies of the psychedelic state offer a unique window onto the neural basis of conscious perception and selfhood. Despite well understood pharmacological mechanisms of action, the large-scale changes in neural dynamics induced by psychedelic compounds remain poorly understood. Using source-localised, steady-state MEG recordings, we describe changes in functional connectivity following the controlled administration of LSD, psilocybin and low-dose ketamine, as well as, for comparison, the (non-psychedelic) anticonvulsant drug tiagabine. We compare both undirected and directed measures of functional connectivity between placebo and drug conditions. We observe a general decrease in directed functional connectivity for all three psychedelics, as measured by Granger causality, throughout the brain. These data support the view that the psychedelic state involves a breakdown in patterns of functional organisation or information flow in the brain. In the case of LSD, the decrease in directed functional connectivity is coupled with an increase in undirected functional connectivity, which we measure using correlation and coherence. This surprising opposite movement of directed and undirected measures is of more general interest for functional connectivity analyses, which we interpret using analytical modelling. Overall, our results uncover the neural dynamics of information flow in the psychedelic state, and highlight the importance of comparing multiple measures of functional connectivity when analysing time-resolved neuroimaging data.

Role of the 5-HT2A Receptor in Self- and Other-Initiated Social Interaction in Lysergic Acid Diethylamide-Induced States: A Pharmacological fMRI Study.

Distortions of self-experience are critical symptoms of psychiatric disorders and have detrimental effects on social interactions. In light of the immense need for improved and targeted interventions for social impairments, it is important to better understand the neurochemical substrates of social interaction abilities. We therefore investigated the pharmacological and neural correlates of self- and other-initiated social interaction. In a double-blind, randomized, counterbalanced, crossover study 24 healthy human participants (18 males and 6 females) received either (1) placebo + placebo, (2) placebo + lysergic acid diethylamide (LSD; 100 µg, p.o.), or (3) ketanserin (40 mg, p.o.) + LSD (100 µg, p.o.) on three different occasions. Participants took part in an interactive task using eye-tracking and functional magnetic resonance imaging completing trials of self- and other-initiated joint and non-joint attention. Results demonstrate first, that LSD reduced activity in brain areas important for self-processing, but also social cognition; second, that change in brain activity was linked to subjective experience; and third, that LSD decreased the efficiency of establishing joint attention. Furthermore, LSD-induced effects were blocked by the serotonin 2A receptor (5-HT2AR) antagonist ketanserin, indicating that effects of LSD are attributable to 5-HT2AR stimulation. The current results demonstrate that activity in areas of the "social brain" can be modulated via the 5-HT2AR thereby pointing toward this system as a potential target for the treatment of social impairments associated with psychiatric disorders.SIGNIFICANCE STATEMENT Distortions of self-representation and, potentially related to this, dysfunctional social cognition are central hallmarks of various psychiatric disorders and critically impact disease development, progression, treatment, as well as real-world functioning. However, these deficits are insufficiently targeted by current treatment approaches. The administration of lysergic acid diethylamide (LSD) in combination with functional magnetic resonance imaging and real-time eye-tracking offers the unique opportunity to study alterations in self-experience, their relation to social cognition, and the underlying neuropharmacology. Results demonstrate that LSD alters self-experience as well as basic social cognition processing in areas of the "social brain". Furthermore, these alterations are attributable to 5-HT2A receptor stimulation, thereby pinpointing toward this receptor system in the development of pharmacotherapies for sociocognitive deficits in psychiatric disorders.

Spectral signatures of serotonergic psychedelics and glutamatergic dissociatives.

Classic serotonergic psychedelics are remarkable for their capacity to induce reversible alterations in consciousness of the self and the surroundings, mediated by agonism at serotonin 5-HT2A receptors. The subjective effects elicited by dissociative drugs acting as N-methyl-D-aspartate (NMDA) antagonists (e.g. ketamine and phencyclidine) overlap in certain domains with those of serotonergic psychedelics, suggesting some potential similarities in the brain activity patterns induced by both classes of drugs, despite different pharmacological mechanisms of action. We investigated source-localized magnetoencephalography recordings to determine the frequency-specific changes in oscillatory activity and long-range functional coupling that are common to two serotonergic compounds (lysergic acid diethylamide [LSD] and psilocybin) and the NMDA-antagonist ketamine. Administration of the three drugs resulted in widespread and broadband spectral power reductions. We established their similarity by using different pairs of compounds to train and subsequently evaluate multivariate machine learning classifiers. After applying the same methodology to functional connectivity values, we observed a pattern of occipital, parietal and frontal decreases in the low alpha and theta bands that were specific to LSD and psilocybin, as well as decreases in the low beta band common to the three drugs. Our results represent a first effort in the direction of quantifying the similarity of large-scale brain activity patterns induced by drugs of different mechanism of action, confirming the link between changes in theta and alpha oscillations and 5-HT2A agonism, while also revealing the decoupling of activity in the beta band as an effect shared between NMDA antagonists and 5-HT2A agonists. We discuss how these frequency-specific convergences and divergences in the power and functional connectivity of brain oscillations might relate to the overlapping subjective effects of serotonergic psychedelics and glutamatergic dissociative compounds.

Motives and Side-Effects of Microdosing With Psychedelics Among Users.

BACKGROUND: Microdosing with psychedelics has gained considerable media attention where it is portrayed as a performance enhancer, especially popular on the work floor. While reports are in general positive, scientific evidence about potential negative effects is lacking aside from the prevalence and motives for use. The present study addressed this gap by surveying psychedelic users about their experience with microdosing including their dosing schedule, motivation, and potential experienced negative effects. METHODS: An online questionnaire was launched on several websites and fora between March and July 2018. Respondents who had consented, were 18 years of age or older, and had experience with microdosing were included in the analyses. RESULTS: In total, 1116 of the respondents were either currently microdosing (79.5%) or microdosed in the past (20.5%). Lysergic acid diethylamide (10 mcg) and psilocybin (0.5 g) were the most commonly used psychedelics with a microdosing frequency between 2 and 4 times per week. The majority of users, however, were oblivious about the consumed dose. Performance enhancement was the main motive to microdose (37%). The most reported negative effects were of psychological nature and occurred acutely while under the influence. CONCLUSION: In line with media reports and anecdotes, the majority of our respondents microdosed to enhance performance. Negative effects occurred mostly acutely after substance consumption. However, the main reason to have stopped microdosing was that it was not effective. Future experimental placebo-controlled studies are needed to test whether performance enhancement can be quantified and to assess potential negative effects after longer term microdosing.

Pharmacokinetics and subjective effects of a novel oral LSD formulation in healthy subjects.

AIMS: The aim of the present study was to characterize the pharmacokinetics and exposure-subjective response relationship of a novel oral solution of lysergic acid diethylamide (LSD) that was developed for clinical use in research and patients. METHOD: LSD (100 µg) was administered in 27 healthy subjects using a placebo-controlled, double-blind, cross-over design. Plasma levels of LSD, nor-LSD, and 2-oxo-3-hydroxy-LSD (O-H-LSD) and subjective drug effects were assessed up to 11.5 hours. RESULTS: First-order elimination kinetics were observed for LSD. Geometric mean maximum concentration (Cmax ) values (range) of 1.7 (1.0-2.9) ng/mL were reached at a tmax (range) of 1.7 (1.0-3.4) hours after drug administration. The plasma half-life (t1/2 ) was 3.6 (2.4-7.3) hours. The AUC∞ was 13 (7.1-28) ng·h/mL. No differences in these pharmacokinetic parameters were found between male and female subjects. Plasma O-H-LSD but not nor-LSD (< 0.01 ng/mL) concentrations could be quantified in all subjects. Geometric mean O-H-LSD Cmax values (range) of 0.11 (0.07-0.19) ng/mL were reached at a tmax (range) of 5 (3.2-8) hours. The t1/2 and AUC∞ values of O-H-LSD were 5.2 (2.6-21) hours and 1.7 (0.85-4.3) ng·h/mL, respectively. The subjective effects of LSD lasted (mean ± SD) for 8.5 ± 2.0 hours (range: 5.3-12.8 h), and peak effects were reached 2.5 ± 0.6 hours (range 1.6-4.3 h) after drug administration. EC50 values were 1.0 ± 0.5 ng/mL and 1.9 ± 1.0 ng/mL for "good" and "bad" subjective drug effects, respectively. CONCLUSION: The present study characterized the pharmacokinetics of LSD and its main metabolite O-H-LSD. The subjective effects of LSD were closely associated with changes in plasma concentrations over time.

Serotonin 2A Receptor Signaling Underlies LSD-induced Alteration of the Neural Response to Dynamic Changes in Music.

Classic psychedelic drugs (serotonin 2A, or 5HT2A, receptor agonists) have notable effects on music listening. In the current report, blood oxygen level-dependent (BOLD) signal was collected during music listening in 25 healthy adults after administration of placebo, lysergic acid diethylamide (LSD), and LSD pretreated with the 5HT2A antagonist ketanserin, to investigate the role of 5HT2A receptor signaling in the neural response to the time-varying tonal structure of music. Tonality-tracking analysis of BOLD data revealed that 5HT2A receptor signaling alters the neural response to music in brain regions supporting basic and higher-level musical and auditory processing, and areas involved in memory, emotion, and self-referential processing. This suggests a critical role of 5HT2A receptor signaling in supporting the neural tracking of dynamic tonal structure in music, as well as in supporting the associated increases in emotionality, connectedness, and meaningfulness in response to music that are commonly observed after the administration of LSD and other psychedelics. Together, these findings inform the neuropsychopharmacology of music perception and cognition, meaningful music listening experiences, and altered perception of music during psychedelic experiences.

Twenty percent better with 20 micrograms? A qualitative study of psychedelic microdosing self-rapports and discussions on YouTube.

BACKGROUND: Psychedelic microdosing is the trending practice of using tiny repeated doses of psychedelic substances to facilitate a range of supposed benefits. With only a few published studies to date, the subject is still under-researched, and more knowledge is warranted. Social media and internet discussion forums have played a vital role in the growing visibility of the microdosing phenomenon, and the present study utilized YouTube contents to improve comprehension of the microdosing practice as well as the social interactions and discussions around microdosing. METHODS: Microdosing self-disclosure in YouTube videos and their following comments were qualitatively analyzed by inductive thematic analysis. Various software was utilized to enable gathering and sorting relevant data. RESULTS: Microdosing of psychedelic substances, primarily LSD and psilocybin, was used for therapeutic and enhancement purposes, and predominantly beneficial effects were reported. Many different applications and outcomes were discussed, and therapeutic effects for depression appeared especially noteworthy. Intentions for use were recognized as an influencing factor for the progression and outcomes of microdosing. The function of social interactions was mainly to discuss views on the microdosing phenomenon, strategies for optimal results, minimize risks, and share emotional support. CONCLUSIONS: Potentially, microdosing could provide some of the same benefits (for certain conditions) as full-dose interventions with less risk of adverse reactions related to the sometimes intense experiences of higher doses. Microdosing may well also mean additional benefits, as well as risks, through the repeated exposure over extended periods.

Psychedelic microdosing benefits and challenges: an empirical codebook.

BACKGROUND: Microdosing psychedelics is the practice of consuming very low, sub-hallucinogenic doses of a psychedelic substance, such as lysergic acid diethylamide (LSD) or psilocybin-containing mushrooms. According to media reports, microdosing has grown in popularity, yet the scientific literature contains minimal research on this practice. There has been limited reporting on adverse events associated with microdosing, and the experiences of microdosers in community samples have not been categorized. METHODS: In the present study, we develop a codebook of microdosing benefits and challenges (MDBC) based on the qualitative reports of a real-world sample of 278 microdosers. RESULTS: We describe novel findings, both in terms of beneficial outcomes, such as improved mood (26.6%) and focus (14.8%), and in terms of challenging outcomes, such as physiological discomfort (18.0%) and increased anxiety (6.7%). We also show parallels between benefits and drawbacks and discuss the implications of these results. We probe for substance-dependent differences, finding that psilocybin-only users report the benefits of microdosing were more important than other users report. CONCLUSIONS: These mixed-methods results help summarize and frame the experiences reported by an active microdosing community as high-potential avenues for future scientific research. The MDBC taxonomy reported here informs future research, leveraging participant reports to distil the highest-potential intervention targets so research funding can be efficiently allocated. Microdosing research complements the full-dose literature as clinical treatments are developed and neuropharmacological mechanisms are sought. This framework aims to inform researchers and clinicians as experimental microdosing research begins in earnest in the years to come.

Psychedelics and music: neuroscience and therapeutic implications.

From the beginning of therapeutic research with psychedelics, music listening has been consistently used as a method to guide or support therapeutic experiences during the acute effects of psychedelic drugs. Recent findings point to the potential of music to support meaning-making, emotionality, and mental imagery after the administration of psychedelics, and suggest that music plays an important role in facilitating positive clinical outcomes of psychedelic therapy. This review explores the history of, contemporary research on, and future directions regarding the use of music in psychedelic research and therapy, and argues for more detailed and rigorous investigation of the contribution of music to the treatment of psychiatric disorders within the novel framework of psychedelic therapy.

Current perspectives on psychedelic therapy: use of serotonergic hallucinogens in clinical interventions.

Humans have used serotonergic hallucinogens (i.e. psychedelics) for spiritual, ceremonial, and recreational purposes for thousands of years, but their administration as part of a structured therapeutic intervention is still a relatively novel practice within Western medical and psychological frameworks. In the mid-20th century, considerable advances were made in developing therapeutic approaches integrating administration of low (psycholytic) and high (psychedelic) doses of serotonergic hallucinogens for treatment of a variety of conditions, often incorporating psychoanalytic concepts prevalent at that time. This work contributed seminal insights regarding how these substances may be employed with efficacy and safety in targeted therapeutic interventions, including the importance of optimizing set (frame of mind) and setting (therapeutic environment). More recently, clinical and pharmacological research has revisited the effects and therapeutic potential of psychedelics utilizing a variety of approaches. The current article provides an overview of past and present models of psychedelic therapy, and discusses important considerations for future interventions incorporating the use of psychedelics in research and clinical practice.

Therapeutic use of classic psychedelics to treat cancer-related psychiatric distress.

Cancer is highly prevalent and one of the leading causes of global morbidity and mortality. Psychological and existential suffering is common in cancer patients, associated with poor psychiatric and medical outcomes. Promising early-phase clinical research (1960s to early 1970s) suggested a therapeutic signal for serotoninergic psychedelics (e.g. psilocybin, LSD) in treating cancer-related psychiatric distress. After several decades of quiescence, research on psychedelic-assisted therapy to treat psychiatric disorders in cancer patients has resumed within the last 2 decades in the US and Europe. This review article is based on a systematic search of clinical trials from 1960-2018 researching the therapeutic use of psychedelic treatment in patients with serious or terminal illnesses and related psychiatric illness. The search found 10 eligible clinical trials, with a total of 445 participants, with the vast majority of the patients having advanced or terminal cancer diagnoses. Six open label trials, published between 1964 and 1980 (n = 341), suggested that psychedelic therapy (mostly with LSD) may improve cancer-related depression, anxiety, and fear of death. Four RCTs trials were published between 2011 and 2016 (n = 104), mostly with psilocybin treatment (n = 92), and demonstrated that psychedelic-assisted treatment can produce rapid, robust, and sustained improvements in cancer-related psychological and existential distress.

The paradoxical psychological effects of lysergic acid diethylamide (LSD).

BACKGROUND: Lysergic acid diethylamide (LSD) is a potent serotonergic hallucinogen or psychedelic that modulates consciousness in a marked and novel way. This study sought to examine the acute and mid-term psychological effects of LSD in a controlled study. METHOD: A total of 20 healthy volunteers participated in this within-subjects study. Participants received LSD (75 µg, intravenously) on one occasion and placebo (saline, intravenously) on another, in a balanced order, with at least 2 weeks separating sessions. Acute subjective effects were measured using the Altered States of Consciousness questionnaire and the Psychotomimetic States Inventory (PSI). A measure of optimism (the Revised Life Orientation Test), the Revised NEO Personality Inventory, and the Peter's Delusions Inventory were issued at baseline and 2 weeks after each session. RESULTS: LSD produced robust psychological effects; including heightened mood but also high scores on the PSI, an index of psychosis-like symptoms. Increased optimism and trait openness were observed 2 weeks after LSD (and not placebo) and there were no changes in delusional thinking. CONCLUSIONS: The present findings reinforce the view that psychedelics elicit psychosis-like symptoms acutely yet improve psychological wellbeing in the mid to long term. It is proposed that acute alterations in mood are secondary to a more fundamental modulation in the quality of cognition, and that increased cognitive flexibility subsequent to serotonin 2A receptor (5-HT2AR) stimulation promotes emotional lability during intoxication and leaves a residue of 'loosened cognition' in the mid to long term that is conducive to improved psychological wellbeing.

Acid Brothers: Henry Beecher, Timothy Leary, and the psychedelic of the century.

Henry Knowles Beecher, an icon of human research ethics, and Timothy Francis Leary, a guru of the counterculture, are bound together in history by the synthetic hallucinogen lysergic acid diethylamide (LSD). Both were associated with Harvard University during a critical period in their careers and of drastic social change. To all appearances the first was a paragon of the establishment and a constructive if complex hero, the second a rebel and a criminal, a rogue and a scoundrel. Although there is no evidence they ever met, Beecher's indirect struggle with Leary over control of the 20th century's most celebrated psychedelic was at the very heart of his views about the legitimate, responsible investigator. That struggle also proves to be a revealing bellwether of the increasingly formalized scrutiny of human experiments that was then taking shape.

From Tusko to Titin: the role for comparative physiology in an era of molecular discovery.

As we approach the centenary of the term "comparative physiology," we reexamine its role in modern biology. Finding inspiration in Krogh's classic 1929 paper, we first look back to some timeless contributions to the field. The obvious and fascinating variation among animals is much more evident than is their shared physiological unity, which transcends both body size and specific adaptations. The "unity in diversity" reveals general patterns and principles of physiology that are invisible when examining only one species. Next, we examine selected contemporary contributions to comparative physiology, which provides the context in which reductionist experiments are best interpreted. We discuss the sometimes surprising insights provided by two comparative "athletes" (pronghorn and rattlesnakes), which demonstrate 1) animals are not isolated molecular mechanisms but highly integrated physiological machines, a single "rate-limiting" step may be exceptional; and 2) extremes in nature are rarely the result of novel mechanisms, but rather employ existing solutions in novel ways. Furthermore, rattlesnake tailshaker muscle effectively abolished the conventional view of incompatibility of simultaneous sustained anaerobic glycolysis and oxidative ATP production. We end this review by looking forward, much as Krogh did, to suggest that a comparative approach may best lend insights in unraveling how skeletal muscle stores and recovers mechanical energy when operating cyclically. We discuss and speculate on the role of the largest known protein, titin (the third muscle filament), as a dynamic spring capable of storing and recovering elastic recoil potential energy in skeletal muscle.

Pharmacokinetics and Concentration-Effect Relationship of Oral LSD in Humans.

BACKGROUND: The pharmacokinetics of oral lysergic acid diethylamide are unknown despite its common recreational use and renewed interest in its use in psychiatric research and practice. METHODS: We characterized the pharmacokinetic profile, pharmacokinetic-pharmacodynamic relationship, and urine recovery of lysergic acid diethylamide and its main metabolite after administration of a single oral dose of lysergic acid diethylamide (200 µg) in 8 male and 8 female healthy subjects. RESULTS: Plasma lysergic acid diethylamide concentrations were quantifiable (>0.1 ng/mL) in all the subjects up to 12 hours after administration. Maximal concentrations of lysergic acid diethylamide (mean±SD: 4.5±1.4 ng/mL) were reached (median, range) 1.5 (0.5-4) hours after administration. Concentrations then decreased following first-order kinetics with a half-life of 3.6±0.9 hours up to 12 hours and slower elimination thereafter with a terminal half-life of 8.9±5.9 hours. One percent of the orally administered lysergic acid diethylamide was eliminated in urine as lysergic acid diethylamide, and 13% was eliminated as 2-oxo-3-hydroxy-lysergic acid diethylamide within 24 hours. No sex differences were observed in the pharmacokinetic profiles of lysergic acid diethylamide. The acute subjective and sympathomimetic responses to lysergic acid diethylamide lasted up to 12 hours and were closely associated with the concentrations in plasma over time and exhibited no acute tolerance. CONCLUSIONS: These first data on the pharmacokinetics and concentration-effect relationship of oral lysergic acid diethylamide are relevant for further clinical studies and serve as a reference for the assessment of intoxication with lysergic acid diethylamide.

Safety and efficacy of lysergic acid diethylamide-assisted psychotherapy for anxiety associated with life-threatening diseases.

A double-blind, randomized, active placebo-controlled pilot study was conducted to examine safety and efficacy of lysergic acid diethylamide (LSD)-assisted psychotherapy in 12 patients with anxiety associated with life-threatening diseases. Treatment included drug-free psychotherapy sessions supplemented by two LSD-assisted psychotherapy sessions 2 to 3 weeks apart. The participants received either 200 µg of LSD (n = 8) or 20 µg of LSD with an open-label crossover to 200 µg of LSD after the initial blinded treatment was unmasked (n = 4). At the 2-month follow-up, positive trends were found via the State-Trait Anxiety Inventory (STAI) in reductions in trait anxiety (p = 0.033) with an effect size of 1.1, and state anxiety was significantly reduced (p = 0.021) with an effect size of 1.2, with no acute or chronic adverse effects persisting beyond 1 day after treatment or treatment-related serious adverse events. STAI reductions were sustained for 12 months. These results indicate that when administered safely in a methodologically rigorous medically supervised psychotherapeutic setting, LSD can reduce anxiety, suggesting that larger controlled studies are warranted.

Microdosing Psychedelics: Current Evidence From Controlled Studies.

Taking regular low doses of psychedelic drugs (microdosing) is a practice that has drawn recent scientific and media attention for its potential psychotherapeutic effects. Yet, controlled studies evaluating this practice have lagged. Here, we review recent evidence focusing on studies that were conducted with rigorous experimental control. Studies conducted under laboratory settings using double-blind placebo-controlled procedures and investigator-supplied drug were compiled. The review includes demographic characteristics of participants and dependent measures such as physiological, behavioral, and subjective effects of the drugs. Review criteria were met by 14 studies, all of which involved acute or repeated low (5-20 µg) doses of lysergic acid diethylamide (LSD). Acute microdoses of LSD dose-dependently altered blood pressure, sleep, neural connectivity, social cognition, mood, and perception of pain and time. Perceptible drug effects were reported at doses of 10 to 20 µg but not 5 µg. No serious adverse effects were reported. Repeated doses of LSD did not alter mood or cognition on any of the measures studied. The findings suggest that low doses of LSD are safe and produce acute behavioral and neural effects in healthy adults. Further studies are warranted to extend these findings to patient samples and to other psychedelic drugs and to investigate microdosing as a potential pharmacological treatment for psychiatric disorders.