Is there a link between mental illness and violence? The answer is complex and doesn't quite fit popular conceptions, says Ronald Pies, MD, a professor emeritus of psychiatry at Upstate Medical University. Pies discusses his research on this subject and factors that appear to raise the risk of violence. Regarding mass shooters, he says many have "the three R's": rage, resentment and a desire for revenge. Pies is also a clinical professor of psychiatry at Tufts University School of Medicine in Boston. Click here for a paper about mass shootings that he co-wrote with James Knoll IV, MD, associate professor of psychiatry and director of forensic psychiatry at Upstate.