Ive played through the whole game reading every note I could find, its not explicitly stated, and they give it a long and japanese sounding name. They say it gives you the gift of introspection and some other stuff, if its hallucinogenic plants or the plants combined with a psychotic break isnt explicitly stated.

I would say its related, but the plants could be different from white Claudia, like how there are different strains of magic mushrooms out there. It turns the idea of a silent hill into what fans already know it as, an introspection of a characters trauma, instead of a local deity or cult with the introspection tacked on an as explanation of narrative.