Yes, I know someone directly that had suicidal tendencies for months after a couple of years of binging on weed, some lsd precursor I'm forgetting and mushrooms. He's fine now thankfully but he went through hell.
"Years of binging on weed and 'some lsd precursor'" are not exactly the same thing as traditional plant based psychedelics. The only LSD precursor you could be referring to is Ergotamine (rye fungus), which is pretty well known to be toxic.
If you're talking about years of binging on mind altering substances, it's a virtual certainty that there were underlying psychiatric issues causing that. You can't simply conclude that because one thing came after the other, the drugs caused it, when we're talking about years of abuse.
I've known him for 20 years, he didn't have any psychiatric issues at all before he started doing psychedelics often. He went deep into Terrance McKenna videos and had high ambitions to bend reality through his will and drug trips, this was fueled by magick videos and the like, got into crystals, all that crap. The "lsd" was ald-52.
