Dr. Sukhi Shergill discusses some of the risk factors that can cause schizophrenia.
There’s no association between personality, the parenting that you have, the kind of parents you have, and the development of schizophrenia. So it’s just a question largely of being unlucky or being silly enough to use drugs when you don’t need to, or being unfortunate enough to have a particular genetic makeup but that will only contribute a very small amount.