Post-Traumatic Stress Disorder (PTSD) occurs as a result of exposure to a traumatic event or events -- whether a single ordeal, such as a car accident, natural disaster, or act of violence, or years of abuse or neglect. People with PTSD may re-experience the trauma as flashbacks, or just maintain a state of heightened alertness, leading to headaches, stomach problems and other debilitating symptoms. Cognitive-behavior therapy is often effective in treating PTSD.

