Intensity of Mystical Experiences Occasioned by 5-MeO-DMT and Comparison With a Prior Psilocybin Study

5-MeO-DMT is a psychoactive indolealkylamine found in high concentrations in the bufotoxin of the Colorado River toad (Bufo alvarius), in various plants, and can be synthesised. Earlier work and survey reports have suggested that inhaled 5-MeO-DMT can occasion profound mystical-type experiences that are similar in quality to those produced by better-studied psychedelics such as psilocybin, but with a markedly shorter duration of action. Because mystical experiences occasioned by psilocybin have been linked to therapeutic outcomes in conditions such as depression, anxiety and substance use disorders, understanding the intensity and character of mystical effects induced by 5-MeO-DMT bears on its potential clinical usefulness. Gallimore and colleagues set out to address two primary gaps. First, they aimed to quantify the intensity of acute mystical effects following administration of vaporised bufotoxin containing 5-MeO-DMT in participants attending a residential psychospiritual retreat. Second, they sought to compare those effects with previously reported mystical-effect ratings from a laboratory study in which healthy volunteers received moderate/high and high doses of psilocybin. The authors hypothesised that 5-MeO-DMT would produce moderate-to-strong mystical effects, comparable to high-dose psilocybin and greater than moderate/high-dose psilocybin.

This was a retrospective analysis of anonymised survey data collected from residents of a four-day psychospiritual retreat in Baja California, Mexico, between August 2015 and May 2017. The analytic sample comprised 20 participants (11 male) who elected to complete the Mystical Experience Questionnaire (MEQ30) after their 5-MeO-DMT session. The 20 respondents were drawn from a larger group of 76 residents who completed an exit survey; the completion rate for the MEQ30 was 26.3% (20/76). The extracted text does not clearly report whether any procedures were used to compare responders and non-responders. The retreat operator provided the archival, de-identified survey data for secondary analysis. Participants were reported as medically healthy on the basis of medical history, physical examination, electrocardiography and urine drug testing. The sample had a mean age of 38 years (range 21–57). Educational and demographic descriptors included 40% with a college degree and 25% with a graduate degree; 85% identified as White/Caucasian. Most participants (80%) were from the United States. Religious affiliation was reported by 45% of participants and included a range of traditions. Intervention and setting details: each resident received a single administration of 50 mg of vaporised bufotoxin obtained from wild toads; the bufotoxin was estimated to contain approximately 5–7 mg of 5-MeO-DMT (reported 5–15% 5-MeO-DMT content, described as a "light" to "common" dose). The bufotoxin was vaporised in a handheld device and inhaled according to facilitated instructions: participants fully exhaled, inhaled to capacity, held the breath for a minimum of 10 seconds, then lay down. A medical doctor and a facilitator/guide were present during sessions. The retreat programme also included preparatory and integration practices, but procedural details beyond the administration protocol are limited in the extracted text. Outcome measures and analysis: acute mystical effects were assessed using the 30-item Mystical Experience Questionnaire (MEQ30), scored on a 0–5 scale per item and yielding a total score (item-mean reporting appears in the results). The MEQ30 comprises four subscales (mystical, positive mood, transcendence of time/space, ineffability). A "complete mystical experience" was defined as endorsing at least 60% of the maximum possible score on each of the four MEQ30 subscales. Demographics were summarised with frequency counts; correlations tested associations between demographics and MEQ30 scores. Independent-samples t-tests compared MEQ30 ratings from this sample with published data from a laboratory psilocybin study (moderate/high 20 mg/70 kg, n = 18; high 30 mg/70 kg, n = 18). A conventional alpha of 0.05 was used and Cohen's d effect sizes were reported to aid interpretation. The text reports that the analysis was exploratory and that corrected alpha approaches were not applied. Ethical oversight: the secondary analysis of de-identified archival survey data was deemed exempt from IRB review and informed consent for the retrospective analysis was not required.

No significant correlations were found between MEQ30 scores and demographic variables (the extracted text states these data are available on request but does not present them). On the MEQ30, 15 of 20 participants (75%) met the criterion for a "complete mystical experience" (≥60% of maximum scores on all four subscales). Mean item-level scores on the MEQ30 subscales were reported as follows (means ± SD): mystical 3.96 ± 0.92; positive mood 4.43 ± 0.58; transcendence of time/space 4.28 ± 0.69; ineffability 4.43 ± 0.63. The MEQ30 total (reported as an item-mean) was 4.17 ± 0.64. Comparisons to previously published psilocybin data showed that MEQ30 ratings in the 5-MeO-DMT sample were statistically equivalent to ratings from the high-dose psilocybin group (30 mg/70 kg) across MEQ30 scales (all p-values > 0.11). When compared with the moderate/high-dose psilocybin group (20 mg/70 kg), the 5-MeO-DMT sample had significantly higher scores on the positive mood subscale (p = 0.004, Cohen's d = 1.01), the transcendence of time/space subscale (p = 0.015, d = 0.85), and the MEQ30 total score (p = 0.02, d = 0.81). Proportions of participants reporting a complete mystical experience were 75% for 5-MeO-DMT, 66.7% for 30 mg/70 kg psilocybin, and 61.1% for 20 mg/70 kg psilocybin; these proportional differences were not statistically significant (p-values > 0.36). The extracted text does not present confidence intervals for the means or tests, nor detailed table values beyond the figures and p-values noted.

Gallimore and colleagues interpret the findings as evidence that a single inhaled administration of bufotoxin containing an estimated 5–7 mg of 5-MeO-DMT occasioned moderate-to-strong mystical-type experiences in the majority of retreat participants, and that the overall intensity of those experiences was comparable to the effects reported after high-dose psilocybin in a laboratory study. The authors note that 75% of respondents met criteria for a complete mystical experience and that several MEQ30 subscales and the total score were significantly higher than those from the moderate/high-dose psilocybin comparison. The investigators position these results as extending prior survey and anecdotal reports about 5-MeO-DMT, emphasising that a comparatively low (light/common) inhaled dose produced effects of similar intensity to a high laboratory psilocybin dose but with a substantially shorter duration of action, which the authors suggest could be advantageous for clinical applications and for experimental characterisations of mystical-type experiences. The authors acknowledge multiple important limitations. The study is retrospective, non-randomised and lacked placebo or control conditions. Only 20 of 76 retreat residents completed the MEQ30, introducing potential self-selection bias, and the archival sample was demographically homogeneous (predominantly educated Caucasian participants from the United States), limiting generalisability. The bufotoxin preparations were obtained from wild toads, so 5-MeO-DMT concentration likely varied across doses and the toxin contains other tryptamines that could modulate subjective effects. Crucially, participants underwent a four-day programme that included ibogaine administration 48 hours before 5-MeO-DMT for some residents; because noribogaine (ibogaine's active metabolite) has a long half-life, potential pharmacological interactions that might have potentiated 5-MeO-DMT effects cannot be ruled out. The extracted text also notes that extensive psychiatric histories were not collected, so the sample cannot be assumed to match healthy laboratory volunteers. Given these limitations, the authors call for further controlled research, including prospective and Phase I trials, to characterise safety, dose–response, and therapeutic potential. They also suggest that the short action of 5-MeO-DMT and its apparent capacity to occasion intense mystical experiences make it a candidate for future investigation in clinical and experimental settings. The authors refrain from making clinical recommendations and frame their conclusions as a rationale for further controlled study rather than proof of therapeutic efficacy.