What drug can cause schizophrenia?

Its not a pretty site. My mother has suffered from schizophrenia for years and never would admit it. She also self medicated which just made the matter worse. it basically causes the level of paranoia to elevate to an unbelievable degree. And then the person seams to just live in their own little world and there is nothing anyone can do to persuade them other wise. I would advise against the drug use if you are asking for yourself and get help for someone if you are worried about their condition plus drug use before its too late.