The first thing to say about physical trauma is that it is usually apparent. Damage to the body will result in pain as well as other common signs, such as bleeding. By contrast, psychological trauma is often unseen. However, it will often manifest itself in certain behaviours – or the lack of them. People who have been traumatised psychologically will sometimes find it difficult to express their emotional well-being, suffer from bouts of anger or moodiness and will also sometimes have bad dreams. A common form of this phenomenon is known as post-traumatic stress disorder (PTSD) which will mean that a person continues to suffer long after a traumatic event and well after physical traumas can have been expected to heal.