A risk factor is a condition or behavior that increases the likelihood of developing a disease or other condition or behavior that is harmful to your health. It now turns out that attention-deficit hyperactivity disorder is a risk factor for depression, anorexia, post-traumatic stress disorder (PTSD), and even suicidal behavior. To support this thesis, two epidemiologists from the University of Augsburg in Germany published a study on the available data British medical journal Mental Health.