I know people personally that psilocybin, LSD, and other substances do nothing for. All of them also have existing mental health disorders (extreme generalized anxiety, depression, bipolar, etc.).
Nothing as in there is no outside noticeable change in behavior and they report no change in speaking, or nothing as it relates to the topic of this thread, in that they have no profound or spiritual experiences?
Fwiw I find that, due to my antidepressants, i need 3x the dose to have the equivalent experience as my friends.
Many psych meds diminish/block psychedelic effects.
That could be an interaction with the meds they take for those conditions, couldn't it? I seem to recall that SSRIs in particular could mitigate the effects of the hallucinogen.