Analyzing the clinical evolution and regulatory challenges of psychedelic-assisted psychotherapy (PAT), focusing on the neurobiological mechanisms of substances like psilocybin, MDMA, and esketamine. Research highlights that classic psychedelics promote neural plasticity by activating intracellular receptors, whereas entactogens like MDMA facilitate social reward learning and trauma processing. However, the field faces a significant methodological crisis because the intense subjective effects of these drugs lead to functional unblinding, which complicates traditional double-blind study designs and inflates expectancy bias. High-profile regulatory setbacks, such as the FDA’s rejection of MDMA for PTSD, underscore critical concerns regarding trial integrity, therapist standardization, and historical research misconduct. To address these hurdles, th ...