**4. Classification**

Posttraumatic stress disorder is classified as an anxiety disorder, characterized by aversive anxiety-related experiences, behaviors, and physiological responses that develop after exposure to a psychologically traumatic event (sometimes months after). Its features persist for longer than 30 days, which distinguishes it from the briefer acute stress disorder. These persisting posttraumatic stress symptoms cause significant disruptions in one or more important areas of life function. It has three sub-forms: acute, chronic, and delayed-onset; based on onset of symptoms after the traumatic event. Acute is of < 1 month, chronic between 1-3 months and delayed is after 3 months.

Complex Post Traumatic Stress Disorder (C-PTSD) is a condition that results from chronic or long-term exposure to emotional trauma over which a victim has little or no control and from which there is little or no hope of escape, such as in cases of domestic emotional, physical or sexual abuse; childhood emotional, physical or sexual abuse; entrapment or kidnapping; slavery or enforced labor and long term imprisonment and torture. When people have been trapped in a situation over which they had little or no control at the beginning, middle or end, they can carry an intense sense of dread even after that situation is removed. This is because they know how bad things can possibly be. And they know that it could possibly happen again. And they know that if it ever does happen again, it might be worse than before. C-PTSD results more from chronic repetitive stress from which there is little chance of escape. PTSD can result from single events, or short term exposure to extreme stress or trauma.
