Database

This online survey (n=233) of autistic participants with high autism quotient scores examines their experiences with psychedelic drugs and perceived changes attributed to their most 'impactful' psychedelic experience. It finds that the majority of participants reported reductions in psychological distress (82%) and social anxiety (78%), and increases in social engagement (70%), while 20% reported undesirable effects such as increased anxiety.

This preprint, naturalistic EEG study (n=29) examines the effects of inhaled synthetic 5-MeO-DMT (12mg) on brain activity in healthy individuals. It finds that 5-MeO-DMT radically reorganises low-frequency neural activity flows, making them incoherent, heterogeneous, and nonrecurring. It also causes broadband activity to exhibit slower, more stable, low-dimensional behaviour with increased energy barriers to rapid global shifts.

This meta-analysis (2024, s=31) examines the correlation between subjective effects and therapeutic outcomes for ketamine (s=23, n=471) and psilocybin (s=8, n=183) in depression and substance use disorder (SUD) treatment. It finds modest mediating effects of subjective experiences on therapeutic outcomes, with psilocybin showing a stronger mediating effect (R² = 24%) compared to ketamine (R² = 5-10%), and a greater mediating effect observed in SUD compared to depression regardless of the substance used.

This preprint open-label study (n=20) examines the effects of ketamine infusions (35mg/70kg, 6x) on biological ageing markers in individuals with depression (MDD) or PTSD. It finds reductions in epigenetic age as measured by OMICmAge, GrimAge V2, and PhenoAge biomarkers, as well as significant changes in Epigenetic Biomarker Proxies (EBPs) and surrogate protein markers following a 2-3 week treatment course. The study also reports expected decreases in depression and PTSD scores as measured by PHQ-9 and PCL-5.

Psychedelic research in September 2024 covered mescaline dosing, meditation, psilocybin for veterans, harmine dosing, and more

This single-blind, cross-over study (n=28) using MRI in healthy participants found that psilocybin (18.2mg/70kg) significantly decreased cerebral blood flow (CBF) and internal carotid artery (ICA) diameter. In contrast, ketanserin (20mg) had no significant effect. This finding suggests an asymmetric 5-HT2AR modulatory effect on CBF and provides the first in vivo human evidence of psilocybin-induced ICA constriction.

This randomized, double-blind, placebo-controlled, crossover study (n=16) investigates the dose-dependent acute effects, pharmacokinetics, and mechanism of action of mescaline (100-800mg; 5x) in healthy subjects. It finds that mescaline induces dose-dependent subjective effects, increases blood pressure and heart rate, and has dose-proportional pharmacokinetics, with effects primarily mediated by 5-HT2A receptors as demonstrated by ketanserin co-administration.

This open-label trial (n=15) evaluates the efficacy and safety of psilocybin (25mg) in veterans with severe treatment-resistant depression (TRD). It finds that 60% of participants met response criteria and 53% met remission criteria at 3 weeks post-treatment, with 47% maintaining response and 40% maintaining remission at 12 weeks.

This randomized, double-blind, placebo-controlled study (n=68) assesses the prosocial, entactogen effects of ketamine (35mg/70kg) in participants with treatment-resistant depression (TRD). Ketamine increased pleasure from social interactions and helping others, lasting for one week post-treatment. In a rodent experiment, ketamine-treated rats showed increased protective behaviour towards their cage mates, indicating entactogen effects.

This double-blind, placebo-controlled study (n=40) investigates the effect of DMT-harmine ('pharmahuasca') on meditative states during a 3-day retreat with experienced meditators. It finds that participants who received DMT-harmine reported greater mystical-type experiences, non-dual awareness, and emotional breakthrough during acute effects, as well as greater psychological insight one day later, compared to the placebo group.