The Sept. 11, 2001, terrorist attacks brought violence “home,” but changes in how society reacts to violence more recently cause more common and more frequent anxiety and worry, three college professors say. Many Americans are “more heightened, more aware” of potential violence since more than 3,000 people were killed in the attacks 15 years ago today, said Harrison Davis, associate professor of clinical mental health counseling at the University of North Georgia. Davis speculated some people may be more suspicious and fear large crowds now than just after 9/11 because of increased news coverage of violent events.