Trauma is the Greek word for "wound". Although the Greeks used the term only for physical injuries, nowadays trauma is just as likely to refer to emotional wounds. We now know that a traumatic event can leave psychological symptoms long after any physical injuries have healed. The psychological reaction to emotional trauma now has an established name: post-traumatic stress disorder, or PTSD. It usually occurs after an extremely stressful event, such as wartime combat, a natural disaster, or sexual or physical abuse; its symptoms include depression, anxiety, flashbacks, and recurring nightmares.