Roxane Cohen Silver, Professor of Psychology and Social Behavior and an expert on PTSD (Post Traumatic Stress Disorder), was quoted in Agence France Presse."The attacks of 9/11 did far more than destroy buildings and kill thousands of innocent people. They interrupted routine patterns and tugged our social fabric" in the United States, Silver said. "Even those individuals who did not know anyone who died that day have been touched by the tragedy. We are different now... We sometimes gaze askance at young men carrying backpacks on public transportation," she added.