Psychedelic therapy is transforming treatment for treatment-resistant depression (TRD) by increasing benefits and reducing risks. Psilocybin shows promise as a potential game-changer, with initial evidence indicating a rapid antidepressant effect that lasts at least three months for some responders. However, more rigorous, double-blind, comparator-controlled trials with adequate statistical power are needed to understand how psychedelics work and their long-term effects in TRD. Psychedelics may also benefit other psychiatric conditions like bipolar depression and post-traumatic stress disorder.
A systematic review of 32 trials in healthy adults found that LSD and psilocybin show dose-proportional peak concentrations (Cmax), while DMT's oral and intravenous formulations differ in ways that may be clinically significant. LSD was the most studied psychedelic, followed by DMT and psilocybin; mescaline appeared in only two trials. Single studies examined intravenous LSD, intravenous psilocybin, inhaled 5-MEO-DMT, and intranasal 5-MEO-DMT. Variations in absorption, distribution, and elimination among the compounds may have important implications for clinical and research settings.