Why basic science is needed to understand psychedelics neurobiology: mechanisms for clinical promise, sex differences, and 5-HT2A versus hallucinations

Psychedelics have growing promise in treating psychiatric diseases, but scientists still do not fully understand how these drugs work in the brain. Because clinical trials face major obstacles, including hard-to-blind subjective effects and the influence of expectancy and psychotherapy, the article argues that preclinical basic science is the most viable path to identify causal neurobiological mechanisms. It highlights how animal and human imaging studies point to long-lasting changes in brain connectivity and network activity, while mouse studies suggest psychedelics can remodel corticolimbic circuitry involved in executive control and emotional processing. The piece also focuses on two unresolved questions: whether psychedelics act differently across sexes, and whether therapeutic effects can be separated from hallucinogenic effects mediated by serotonergic 5-HT2A receptor activation. It notes mixed behavioral results across labs and proposes better standardization, improved translational experimental design, and deeper integration of human and preclinical findings.