There's a relationship between smoking cigarettes and schizophrenia too. I think this may be a case of people trying to self medicate for their conditions.

> "There has been emerging evidence of an association between tobacco smoking and schizophrenia spectrum disorders (SSD). Two meta-analyses have reported that people who smoke tobacco have an ~2-fold increased risk of incident schizophrenia or psychosis, even after adjusting for confounding factors."

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6255982/#:~:tex....