Phenomenology and content of the inhaled N, N-dimethyltryptamine (N, N-DMT) experience

Brain substates induced by DMT relate to sympathetic output and meaningfulness of the experience

N,N-Dimethyltryptamine (DMT) is a serotonergic psychedelic, known to rapidly induce short-lasting alterations in conscious experience, characterized by a profound and immersive sense of physical transcendence alongside rich and vivid auditory distortions and visual imagery. Multimodal neuroimaging data paired with dynamic analysis techniques offer a valuable approach for identifying unique signatures of brain activity - and linked autonomic physiology - naturally unfolding during the altered state of consciousness induced by DMT. We leveraged simultaneous fMRI and EKG data acquired in 14 healthy volunteers prior to, during, and after intravenous administration of DMT, and, separately, placebo. fMRI data was preprocessed to derive individual dynamic activity matrices, reflecting the similarity of brain activity in time, and community detection algorithms were applied on these matrices to identify brain activity substates; EKG data was used to derive continuous heart rate. We identified a brain substate occurring immediately after DMT injection, characterized by increased superior temporal lobe activity, and hippocampal and medial parietal deactivations under DMT. Results revealed that hippocampus and medial parietal cortex hypoactivity correlated with scores of meaningfulness of the experience. During this first post-injection substate, increased heart rate under DMT correlated negatively with the meaningfulness of the experience and positively with hippocampus/medial parietal deactivation. These results suggest a chain of influence linking sympathetic regulation to hippocampal and medial parietal deactivations under DMT, which combined, may contribute to positive mental health outcomes related to self-referential processing following psychedelic administration.

Safety and tolerability of inhaled N,N-Dimethyltryptamine (BMND01 candidate): A phase I clinical trial

Psychedelics are being increasingly examined for their therapeutic potential in mood disorders. While the acute effects of ayahuasca, psilocybin, and lysergic acid diethylamide (LSD) last over several hours, inhaled N,N-Dimethyltryptamine (DMT) effects last around 10 min, which might provide a cost- and time-effective alternative to the clinical application of oral psychedelics. We aimed at investigating the safety and tolerability of inhaled DMT (BMND01 candidate). We recruited 27 healthy volunteers to receive a first, lower dose and a second, higher dose (5/20 mg, 7.5/30 mg, 10/40 mg, 12.5/50 mg, or 15/60 mg) of inhaled DMT in an open-label, single-ascending, fixed-order, dose-response study design. We investigated subjective experiences (intensity, valence, and phenomenology), physiological effects (blood pressure, heart rate, respiratory rate, blood oxygen saturation, body temperature), biochemical markers (liver, kidney, and metabolic functions), and adverse events during the acute and post-acute effects of DMT. DMT dose-dependently increased intensity, valence and perceptual ratings. There was a mild, transient, and self-limited increase in blood pressure and heart rate. There were no changes in safety blood biomarkers and no serious adverse events. DMT dose-dependently enhanced subjective experiences and positive valence. Inhaled DMT might be an efficient, non-invasive, safe route of administration, which might simplify the clinical use of this substance. This is the first clinical trial to test the effects of inhaled DMT (BMND01 candidate).

Development and psychometric validation of a novel scale for measuring 'psychedelic preparedness'

Preparing participants for psychedelic experiences is crucial for ensuring these experiences are safe and, potentially beneficial. However, there is currently no validated measure to assess the extent to which participants are well-prepared for such experiences. Our study aimed to address this gap by developing, validating, and testing the Psychedelic Preparedness Scale (PPS). Using a novel iterative Delphi-focus group methodology ('DelFo'), followed by qualitative pre-test interviews, we incorporated the perspectives of expert clinicians/researchers and of psychedelic users to generate items for the scale. Psychometric validation of the PPS was carried out in two large online samples of psychedelic users (N = 516; N = 716), and the scale was also administered to a group of participants before and after a 5-7-day psilocybin retreat (N = 46). Exploratory and confirmatory factor analysis identified four factors from the 20-item PPS: Knowledge-Expectations, Intention-Preparation, Psychophysical-Readiness, and Support-Planning. The PPS demonstrated excellent reliability (ω = 0.954) and evidence supporting convergent, divergent and discriminant validity was also obtained. Significant differences between those scoring high and low (on psychedelic preparedness) before the psychedelic experience were found on measures of mental health/wellbeing outcomes assessed after the experience, suggesting that the scale has predictive utility. By prospectively measuring modifiable pre-treatment preparatory behaviours and attitudes using the PPS, it may be possible to determine whether a participant has generated the appropriate mental 'set' and is therefore likely to benefit from a psychedelic experience, or at least, less likely to be harmed.

Effects of DMT on mental health outcomes in healthy volunteers

Psilocybin, a serotonergic psychedelic, is being increasingly researched in clinical studies for the treatment of psychiatric disorders. The relatively lengthy duration of oral psilocybin's acute effects (4-6 h) may have pragmatic and cost-effectiveness limitations. Here, we explored the effects of intravenous (IV) N,N-Dimethyltryptamine (DMT), a closely related, but faster-acting psychedelic intervention, on mental health outcomes in healthy volunteers. Data is reported from two separate analyses: (1) A comparison of mental health-related variables 1 week after 7, 14, 18, and 20 mg of IV DMT versus IV saline placebo (n = 13) and, (2) A prospective dataset assessing effects before versus 2 weeks after 20 mg of IV DMT (n = 17). Mental health outcomes included measures of depression severity (QIDS-SR16), trait anxiety (STAI-T), Neuroticism (NEO-FFI), wellbeing (WHO-5), meaning in life (MLQ), optimism (LOT-R), and gratitude (GQ-6). In both the prospective and placebo-controlled datasets, significant improvements in scores of depression were found 1-2 weeks after DMT administration. Significant reductions in trait Neuroticism were only found for the placebo-controlled sample. Finally, changes in depression and trait anxiety correlated with acute peak experiences (assessed via 'Oceanic Boundlessness'). While the use of two separate cohorts in pooled analysis limits the generalizability of these correlational findings, these results suggest that DMT may reduce depressive symptomatology by inducing peak experiences. The short half-life of IV DMT and its potential for flexible dosing via controlled infusions makes it an appealing candidate for psychedelic medicine. Further research in clinical samples is needed to corroborate the therapeutic potential of DMT.

Potential therapeutic effects of an ayahuasca-inspired N,N-DMT and harmine formulation: a controlled trial in healthy subjects

Background

There is growing scientific evidence for the therapeutic benefits of the Amazonian plant-based psychedelic "ayahuasca" for neuropsychiatric disorders such as depression and anxiety. However, there are certain challenges when incorporating botanical ayahuasca into biomedical research and clinical therapy environments. Formulations inspired by ayahuasca, which contain specific and standardized active components, are a potential remedy.

Methods

We investigated subjective acute and persisting effects of a novel formulation containing the reversible monoamine oxidase inhibitor harmine (orodispersible tablet containing 100 mg MAO-I) and N,N-dimethyltryptamine (incremental intranasal dosing of up to 100 mg DMT), compared with two other conditions, namely harmine alone and placebo, in a crossover RCT in 31 healthy male subjects.

Results

DMT + harmine, but not harmine alone, induced a psychedelic experience assessed with the 5D-ASC rating scale [global score: F(2,60) = 80.21, p < 0.001] and acute experience sampling items over time, characterized by psychological insights [PIQ, F(2,58.5) = 28.514, p < 0.001], emotional breakthroughs [EBI, F(2,60) = 26.509, p < 0.001], and low scores on the challenging experience questionnaire [CEQ, F(2,60) = 12.84, p < 0.001]. Participants attributed personal and spiritual significance to the experience (GSR) with mainly positive persisting effects (PEQ) at 1- and 4-months follow-up. Acute drug effects correlated positively with persisting effects. We found no changes in trait measures of personality, psychological flexibility, or general well-being, and no increases in psychopathology (SCL-90-R) were reported.

Discussion and Conclusion

Our results suggest that the experience induced by the standardized DMT + harmine formulation induces a phenomenologically rich psychedelic experience, demonstrates good psychological safety and tolerability, is well tolerated, and induces beneficial psychological processes that could possibly support psychotherapy. Further studies are required to investigate the psychotherapeutic potential in patients.

Psychological and physiological effects of extended DMT

N,N-Dimethyltryptamine (DMT) is a serotonergic psychedelic that induces a rapid and transient altered state of consciousness when inhaled or injected via bolus administration. Its marked and novel subjective effects make DMT a powerful tool for the neuroscientific study of consciousness and preliminary results show its potential role in treating mental health conditions. In a within-subjects, placebo-controlled study, we investigated a novel method of DMT administration involving a bolus injection paired with a constant-rate infusion, with the goal of extending the DMT experience. Pharmacokinetic parameters of DMT estimated from plasma data of a previous study of bolus intravenous DMT were used to derive dose regimens necessary to keep subjects in steady levels of immersion into the DMT experience over an extended period of 30 min, and four dose regimens consisting of a bolus loading dose and a slow-rate infusion were tested in eleven healthy volunteers (seven male, four female, mean age ± SD = 37.09 ± 8.93 years). The present method is effective for extending the DMT experience in a stable and tolerable fashion. While subjective effects were maintained over the period of active infusion, anxiety ratings remained low and heart rate habituated within 15 min, indicating psychological and physiological safety of extended DMT. Plasma DMT concentrations increased consistently starting 10 min into DMT administration, whereas psychological effects plateaued into the desired steady state, suggesting the development of acute psychological tolerance to DMT. Taken together, these findings demonstrate the safety and effectiveness of continuous IV DMT administration, laying the groundwork for the further development of this method of administration for basic and clinical research.

Ayahuasca-induced personal death experiences: prevalence, characteristics, and impact on attitudes toward death, life, and the environment

Introduction

Despite an emerging understanding regarding the pivotal mechanistic role of subjective experiences that unfold during acute psychedelic states, very little has been done in the direction of better characterizing such experiences and determining their long-term impact. The present paper utilizes two cross-sectional studies for spotlighting - for the first time in the literature - the characteristics and outcomes of self-reported past experiences related to one's subjective sense of death during ayahuasca ceremonies, termed here Ayahuasca-induced Personal Death (APD) experiences.

Methods

Study 1 (n = 54) reports the prevalence, demographics, intensity, and impact of APDs on attitudes toward death, explores whether APDs are related with psychopathology, and reveals their impact on environmental concerns. Study 2 is a larger study (n = 306) aiming at generalizing the basic study 1 results regarding APD experience, and in addition, examining whether APDs is associated with self-reported coping strategies and values in life.

Results

Our results indicate that APDs occur to more than half of those participating in ayahuasca ceremonies, typically manifest as strong and transformative experiences, and are associated with an increased sense of transcending death (study 1), as well as the certainty in the continuation of consciousness after death (study 2). No associations were found between having undergone APD experiences and participants' demographics, personality type, and psychopathology. However, APDs were associated with increased self-reported environmental concern (study 1). These experiences also impact life in profound ways. APDs were found to be associated with increases in one's self-reported ability to cope with distress-causing life problems and the sense of fulfillment in life (study 2).

Discussion

The study's findings highlight the prevalence, safety and potency of death experiences that occur during ayahuasca ceremonies, marking them as possible mechanisms for psychedelics' long-term salutatory effects in non-clinical populations. Thus, the present results join other efforts of tracking and characterizing the profound subjective experiences that occur during acute psychedelic states.

Acute Subjective Effects of Psychedelics within and Beyond WEIRD Contexts

Reports of psychedelic experiences may contain similarities and differences across cultural contexts, but most current characterizations and quantifications of psychedelic experiences come from Western medical and naturalistic settings. In this article, we begin with a brief history of the diversity of psychedelic use in non-Western settings. We then compare and contrast accounts of psychedelic experiences within and beyond Western, educated, industrialized, rich, and democratic (WEIRD) contexts. We focus on specific reports of direct testimony of the acute subjective effects of psychedelics experienced across these contexts. We compare themes from each of these various contexts, with special emphasis on psychometric measures such as the mystical experiences questionnaire (MEQ), the five-dimensional altered states of consciousness (5D-ASC) scale, the Survey of God Encounters, and the Survey of Entity Encounters, the Challenging Experiences Questionnaire, and the Inventory of Nonordinary Experiences (INOE). Finally, we offer recommendations for future research to quantify these similarities and differences across cultures to assess them empirically in the future.

Electroencephalographic Signature of Out-of-Body Experiences Induced by Virtual Reality: A Novel Methodological Approach

Out-of-body experiences (OBEs) are subjective experiences of seeing one's own body and the environment from a location outside the physical body. They can arise spontaneously or in specific conditions, such as during the intake of dissociative drug. Given its unpredictable occurrence, one way to empirically study it is to induce subjective experiences resembling an OBE using technology such as virtual reality. We employed a complex multisensory method of virtual embodiment in a virtual reality scenario with seven healthy participants to induce virtual OBE-like experiences. Participants performed two conditions in a randomly determined order. For both conditions, the participant's viewpoint was lifted out of the virtual body toward the ceiling of the virtual room, and real body movements were (visuo-tactile ON condition) or were not (visuo-tactile OFF condition) translated into movements on the virtual body below-the latter aiming to maintain a feeling of connection with the virtual body. A continuous 128-electrode EEG was recorded. Participants reported subjective experiences of floating in the air and of feeling high up in the virtual room at a strong intensity, but a weak to moderate feeling of being "out of their body" in both conditions. The EEG analysis revealed that this subjective experience was associated with a power shift that manifested in an increase of delta and a decrease of alpha relative power. A reduction of theta complexity and an increase of beta-2 connectivity were also found. This supports the growing body of evidence revealing a prominent role of delta activity during particular conscious states.

A Qualitative Analysis of First-Hand Accounts of Diphenhydramine Misuse Available on YouTube

Deliriants are the least studied class of hallucinogens and display noticeable subjective effects, including dysphoria, hallucinations, and substantial alterations in thought. High doses of diphenhydramine (DPH), an over-the-counter antihistamine medication, can produce deliriant effects due to secondary anticholinergic activity. We sought to characterize the subjective experiences produced by DPH misuse to better understand deliriants more broadly and the context under which DPH misuse occurs. To conduct our analysis, 32 first-hand accounts of DPH misuse publicly available in YouTube videos were analyzed using inductive thematic analysis. Video makers discussed alterations in most sensory modalities, confusion, and a tendency for strongly unpleasant experiences. Occasionally, video makers reported positive effects, although these were rare and often overshadowed by negative aspects of the experience. Video makers frequently warned against misusing DPH, and these individuals occasionally reported adverse post-acute effects. Despite the prevalence of adverse experiences, patterns of repeated misuse were sometimes discussed. Motives for misusing DPH, when mentioned, included accessibility, affordability, and legality. Overall, findings suggest DPH misuse can produce substantial psychoactive effects that are often distressing and share some phenomenological overlap with experiences produced by psychosis.

N, N-Dimethyltryptamine (DMT)-Occasioned Familiarity and the Sense of Familiarity Questionnaire (SOF-Q)

This study investigated the sense of familiarity attributed to N, N-dimethyltryptamine (DMT) experiences. 227 naturalistic inhaled-DMT experiences reporting a sense of familiarity were included. No experiences referenced a previous DMT or psychedelic experience as the source of the familiarity. A high prevalence of concomitant features discordant from ordinary consciousness were identified: features of a mystical experience (97.4%), ego-dissolution (16.3%), and a "profound experience of death" (11.0%). The Sense of Familiarity Questionnaire (SOF-Q) was developed assessing 19 features of familiarity across 5 themes: (1) Familiarity with the Feeling, Emotion, or Knowledge Gained; (2) Familiarity with the Place, Space, State, or Environment; (3) Familiarity with the Act of Going Through the Experience; (4) Familiarity with Transcendent Features; and (5) Familiarity Imparted by an Entity Encounter. Bayesian latent class modeling yielded two stable classes of participants who shared similar SOF-Q responses. Class 1 participants responded, "yes" more often for items within "Familiarity Imparted by an Entity Encounter" and "Familiarity with the Feeling, Emotion, or Knowledge Gained." Results catalogued features of the sense of familiarity imparted by DMT, which appears to be non-referential to a previous psychedelic experience. Findings provide insights into the unique and enigmatic familiarity reported during DMT experiences and offer a foundation for further exploration into this intriguing phenomenon.

Paradoxical pharmacological dissociations result from drugs that enhance delta oscillations but preserve consciousness

Low-frequency (<4 Hz) neural activity, particularly in the delta band, is generally indicative of loss of consciousness and cortical down states, particularly when it is diffuse and high amplitude. Remarkably, however, drug challenge studies of several diverse classes of pharmacological agents-including drugs which treat epilepsy, activate GABA_B receptors, block acetylcholine receptors, or produce psychedelic effects-demonstrate neural activity resembling cortical down states even as the participants remain conscious. Of those substances that are safe to use in healthy volunteers, some may be highly valuable research tools for investigating which neural activity patterns are sufficient for consciousness or its absence.

Time-resolved network control analysis links reduced control energy under DMT with the serotonin 2a receptor, signal diversity, and subjective experience

Psychedelics offer a profound window into the functioning of the human brain and mind through their robust acute effects on perception, subjective experience, and brain activity patterns. In recent work using a receptor-informed network control theory framework, we demonstrated that the serotonergic psychedelics lysergic acid diethylamide (LSD) and psilocybin flatten the brain's control energy landscape in a manner that covaries with more dynamic and entropic brain activity. Contrary to LSD and psilocybin, whose effects last for hours, the serotonergic psychedelic N,N-dimethyltryptamine (DMT) rapidly induces a profoundly immersive altered state of consciousness lasting less than 20 minutes, allowing for the entirety of the drug experience to be captured during a single resting-state fMRI scan. Using network control theory, which quantifies the amount of input necessary to drive transitions between functional brain states, we integrate brain structure and function to map the energy trajectories of 14 individuals undergoing fMRI during DMT and placebo. Consistent with previous work, we find that global control energy is reduced following injection with DMT compared to placebo. We additionally show longitudinal trajectories of global control energy correlate with longitudinal trajectories of EEG signal diversity (a measure of entropy) and subjective ratings of drug intensity. We interrogate these same relationships on a regional level and find that the spatial patterns of DMT's effects on these metrics are correlated with serotonin 2a receptor density (obtained from separately acquired PET data). Using receptor distribution and pharmacokinetic information, we were able to successfully recapitulate the effects of DMT on global control energy trajectories, demonstrating a proof-of-concept for the use of control models in predicting pharmacological intervention effects on brain dynamics.