Spurious argument. But assuming that it is legitimate, you'd still have to admit that pot IS THE TRIGGER.
It’s not spurious.
There are some documented cases of people showing the early warning signs of schizophrenia who go full-on nuts after smoking weed.
Of course one could argue they were headed there anyway. Or perhaps not.
But without controlled experiments it’s unlikely to be known for certain.
Disclosure: I support the legalization of marijuana by any state who so chooses.