Post-traumatic stress disorder (PTSD) is a mental health condition that can develop after experiencing or witnessing a traumatic event. The condition is characterized by intense, disturbing thoughts and feelings related to the experience that last long after the traumatic event has ended. People with PTSD may relive the event through flashbacks or nightmares, feel sadness, fear, or anger, and feel detached or estranged from other people. Symptoms of PTSD fall into four categories: intrusion, avoidance, negative alterations in cognition and mood, and alterations in arousal and reactivity. Examples of traumatic events that can lead to PTSD include combat exposure, childhood physical abuse, sexual violence, physical assault, being threatened with a weapon, an accident, and many other traumatic events. PTSD can disrupt a persons whole life, including their job, relationships, health, and enjoyment of everyday activities. People with PTSD may also have an increased risk of other mental health problems, such as depression, anxiety, issues with drugs or alcohol use, eating disorders, and suicidal thoughts and actions.