And now it is bad drugs.. AFAIK the argument against most environmental factors was that schizophrenia frequency seems similar globally after accounting for ways societies handle cases.

Given the ethical limitations on this kind of research, I think a research group that wants to talk about probable causation really needs a cross cultural method to randomly sample and demonstrate active case prevalence changes and to run that sampling over many years.

This is the old, and silly, nature vs nurture debate. Its debunked because we now know that its a combination of genetics and environment (such bad parenting) that can bring about issues

Such that someone generally needs to have the genetic predisposition for <mental_health_issue> in order for the bad parenting to surface it. In some cases the genetic predisposition is stronger such that we need less (or more) environmental influence to being about <issue>

While it's not entirely incorrect to say that <environmental_factor> (such as parenting or cannabis) can bring about <issue>, its also misleading because we don't get the full picture of cause and effect And as such we have people who go around on the internet claiming they know the ~one true cause~ because they read some mischaracterized study reported on by <media_institution>

Never listen to media institutions about singular scientific studies, the reporting is almost always entirely trash