Psychedelic drugs like LSD, mescaline, and psilocybin are gaining renewed scientific and clinical interest due to the need for new mental health treatments, progress in research, and changing drug policies. The FDA's designation of psilocybin as a "Breakthrough Therapy" for treatment-resistant depression has opened a path for these drugs to be used in clinical settings. However, a clearer understanding of how these drugs work at the molecular level is essential for developing such applications. This review examines current knowledge about the molecular details of psychedelic drug actions and suggests that these discoveries can provide new insights into their hallucinogenic and therapeutic mechanisms.
Classical psychedelics like LSD, psilocybin, and mescaline produce their mind-altering effects by activating the 5-HT2A serotonin receptor. Recent clinical studies indicate they may also help treat depression, anxiety, migraines, cluster headaches, drug abuse, and PTSD. This work examined 41 psychedelics from three chemical classes, testing them against 318 human G-protein-coupled receptors and, for LSD, over 450 human kinases. The compounds potently activated nearly every serotonin, dopamine, and adrenergic receptor. They also stimulated multiple signaling pathways through the 5-HT2A receptor, each linked to psychedelic-like effects in animals. The findings suggest that many molecular targets contribute to the overall actions of psychedelics.
Random genetic variations in the serotonin 2A receptor can modestly alter how four commonly used psychedelic drugs activate this receptor, with effects that differ depending on the specific drug. Seven naturally occurring receptor variants were tested in the lab; each showed small but statistically significant changes in drug potency and efficacy. These findings suggest that individual genetic differences may influence responses to psychedelic medications.