This isn't news. The link between schizophrenia and cannabis use was known in mental health world before it was ever made illegal. The legalization crowd wouldn't promote that. The news is the problem is increasing and a 3 in 10 chance of males becoming schizophrenic is a reason to avoid it. Now I wonder what the correlation of cannabis use to active shooter incidents is?
Uh, is it even reasonable to try and find these correlations? We could probably say that the vast majority of mass shootings were conducted by somebody who had previously used ibuprofen or drank alcohol. Is that meaningful or even useful information?