They cite one such study right there in the article, and there are others: https://pubmed.ncbi.nlm.nih.gov/38775165/
This isn't new information either, the experience I related above was a decade ago, and the impact of weed on people prone to psychotic disorders was already well known to the medical community at that time.
Alcohol can make you feel like shit and can do great damage if used too often, but meth and K2 can fuck someone's brain up after even one use due to lack of quality control