professor of psychiatry at the university of maryland school of medicine and dr. e. fuller torrey, psychiatrist and founder of the advocacy center. thank you for joining us, doctors. i want to take a look at loughner, because you've watched it as we all have watched it, you haven't examined him and we understand that. how do you tell, because the first thing whenever i talk to anyone in the mental health industry they say, just remember that the vast in a jort of schizophrenics and anyone with a serious mental illness, they're not dangerous. how do you tell? >> the strongest predictors of violence are, number one, past history of violence, candy, that's true of people who don't have schizophrenia, too. number two, substance abuse. these are the two biggest predictors. being a male is also a predictor. there are a few symptoms that increase the violence a little