It's starting to happen, ecstasy was recently designated a "breakthrough therapy" for people with PTSD in early trials.
https://www.axios.com/ecstasy-to-treat-ptsd-fast-trackedl-24...
https://www.axios.com/ecstasy-to-treat-ptsd-fast-trackedl-24...
MDMA was orignally used heavily in psychological experimentation in the 70s and then later became popular recreationally in the 80s