I personally know someone who has suffered visual distortions post trip for 20 years and counting at this point.
There is a foundation looking to understand why/how this happens and what we can do to moderate/manage it: https://www.perception.foundation/
No, there is a lot of strong evidence that psychadelic trips can trigger underlying issues such as schizophrenia, etc.
However, some portion of these people would have it triggered these latent illnesses regardless of the use of these substances. The hard to answer question is how many people would develop these conditions without the drug use, if the drug use significantly accelerated it, etc.
On the subject of HPPD, I am more skeptical. It's very poorly understood, and there's been correlation shown for just about any sort of psychoactive substance, SSRIs, etc. Studies have claimed that anywhere from 5% to 25% of people who have taken recreational psychoactive drugs are impacted by it. Which, well, I have not done and am not qualified to do such a study, but having spoken to hundreds of users of psychadelic drugs over several decades and never encountering a single person who claimed to experience HPPD, it's hard to square up my anecdotal experiences with some of the reports.
Something is going on there - there's enough people that report the symptoms that I don't believe it's made up or anything like that - but it doesn't seem to be nearly as simply as "Anyone that does recreational drugs has a chance of developing HPPD"
Think that through.
Schizophrenia was already there, the trip made it apparent.
Associating “psychedelics” with CAUSATION is absolutely irresponsible
That is exactly what they are saying.
However I work with doctors, and through that have had the ability to discuss the site with various medical doctors. In general, they have also noted it as a good resource. They've also noted there is limited ability for them as medical doctors to assess the medical side effects of various drugs due to the illegality of them in their jurisdictions. Thus, the need for resources such as Erowid. If you want your medical doctor to be able to give you medical advice about psychedelic drug use then help push for continued legal reclassification of and access to psychedelics for medical researchers.
The fact of the matter is that a lot of researchers depend on the folk knowledge that is stuffed into Erowid for their own research because it's one of the higest quality sources of information on the actual effects of various substances that people have been putting into their bodies. Much of the research on these substances cannot be funded easily (federal law in the US bans the use of federal funds to research LSD, marijuana, etc due to their classification by the DEA of "intractably bad for society, useless for medicine, and not worthy of academic study.") This means that researchers have to turn to these contemporaneous accounts.
Nobody calls Erowid "medical advice." It's the tripper's notebook, shared and amalgamated by many a substance user. It's the closest thing we have to a Merck Manual for things that alter your mind.
I think I may have read this exact post 10+ years ago. Reminds me of old homes that have since been sold. What links to this Q&A?
This is an example of some of the better sources of info on that site: https://www.erowid.org/chemicals/lsd/lsd.shtml
In fact they have an answer specific to your question on mushrooms: https://www.erowid.org/ask/ask.php?ID=1606
In short, there is very little risk but whether or not someone should choose to take something should still be an informed choice. As far as risk to life, there's been few or no reported deaths purely due to ingesting psilocybin. However, there are small risks around operating heavy machinery (e.g. driving) after as well as small risks around ensuring you are actually ingesting a safe psilocybe mushroom as opposed to a different toxic mushroom.