JB hadn't known very much about schizophrenia the same as it's not fully known about in the world of the mentally ill. His knowledge came from reading books about it while in prison. Initially it was just a word which was bandied about, to him without any depth of meaning.
I've pretty well answered why Sheila was violent. And I think everyone knows about her punching walls ----which isn't normal, for a woman in any case, besides putting her hand through plate glass .
Talking about him any knowledge of Sheila bring violent , not her Schizophrenia
Who said punching walls isnt normal for women in ANY case? Ah but here you go Lookout, she wasn't in normal case/state , was she? t was during one of her episode!