Psilocybin, a psychedelic compound, has fast-acting antidepressant-like effects in mice. Using tests of hedonic behavior and a drug that blocks hallucinogenic 5-HT2A receptors, the results suggest that altered perception may not be required for its therapeutic benefits. Psilocybin also strengthens connections between brain cells in regions involved in reward and emotion processing. These findings indicate it may be possible to retain psilocybin's antidepressant actions while minimizing alterations in consciousness.
Psychedelic compounds like psilocybin show promise for treating neuropsychiatric disorders, with clinical trials demonstrating rapid (within days) and persistent (3-12 months) improvement in treatment-resistant depression. This review examines preclinical models and experimental approaches used to study the neurobiological actions of psychedelic drugs, summarizing insights into mechanisms underlying therapeutic effects, including receptor binding and second messenger signaling cascades. It also discusses potential biological processes such as improvements in synaptic structure and function and suppression of inflammation that may produce lasting symptom amelioration. Better mechanistic understanding will advance these medicines.