For a user named ketamine_ are you really questioning the well known efficacy of few-shot therapies for treatment resistant depression and PTSD?
Psychedelic-Assisted Psychotherapy: A Paradigm Shift in Psychiatric Research and Development: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6041963/
Reviewing the Potential of Psychedelics for the Treatment of PTSD: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7311646/
etc.