Thanks for sharing; it appears to be this 1995 paper:
https://pubmed.ncbi.nlm.nih.gov/8747157/
Something remains unclear about that; there's a more recent relevant paper that criticizes the consistency in such studies (see the Conclusions section at the end):
https://pulmonology.cureus.com/articles/278236-elevated-endogenous-psychedelic-bufotenine-in-the-urine-of-patients-diagnosed-with-a-mental-illness-a-systematic-review