In light of the Bondi Junction attack, there's been a lot of commentary about mental illness - including schizophrenia. So what is schizophrenia? While the exact cause isn't known, it's a serious mental illness that can affect how a person behaves.  It might also surprise you to learn that someone with a diagnosis is more likely to be harmed, than to harm others. On this special episode of Health Report, Dr Norman Swan talks about the medical facts about the disorder, how common it is and some of the successful treatments.