Psychosis is an episodic condition caused by metabolic failure. Contributing factors include malnourishment, alcohol withdrawal, chronic stress, certain prescription and OTC drugs, street drugs, etc. People would recover from psychosis if given supportive treatment - good nutrition, B-vitamins (liver, yeast, etc), appropriate pro-metabolic prescriptions, naltrexone to keep them off alcohol, etc.
My observations of the standard treatments forced on "psychotic" patients is that they are only useful for preventing the patient's recovery. My aunt's friend was always sort of 'off', now she's dying of liver failure. Didn't know until now that she's been on maintenance antipsychotics for decades, even though the trigger for her episode concluded decades ago.
I would suggest that psychedelics cannot take a person with zero risk of developing psychosis, and make them psychotic. There are many apparent triggers for mental illness eg a failed relationship, a drug binge, losing your job, giving birth etc, and we don’t treat these as causal events. Psychedelics are most likely no different. People at risk of developing psychosis may have a greater willingness to try psychedelics as well, creating a biased sample.
If we ever do get regulated access to psychedelics, it will need some process to exclude ‘at risk’ persons. This will be crude and highly exclusionary at the start. Over time, genomics and brain imaging may allow more careful selection of those who can take psychedelics safely.