In the recent last few years the FDA has approved several studies on the effects of psychedelics. All that I know of seem to have had very interesting results. Before this, research was banned for the prior 30 years approx. This is a link to a research paper by Roland Griffiths of Johns Hopkins University. It was published in May 2006 and is called:
"Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance".
https://neuroscience.jhu.edu/griffit...ocybin2006.pdf