I was explicitly told to read up on several topics from Erowid by my psychiatrist upon starting an antidepressant. Her comment was: "I can't tell you what you'll experience, but if you're willing, here's some resources". I read the comments, including quite a bit of medical research that I would have been otherwise unaware of, and was prepared for some of the weirder effects that can come with it (the drug itself is a dopamine receptor augmenter).

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.