Post-traumatic stress disorder (PTSD) is a kind of problem that can happen after a person has gone through a scary or dangerous event. People who have PTSD can feel very frightened, sad, or worried even when there is nothing bad happening. They might have nightmares, feelings of being on edge, or find it hard to trust people or focus on things for a long time. It can be hard to cope and it can last for a long time after the event. PTSD can be managed with different kinds of counselling or therapy.