Posttraumatic stress disorder (PTSD) is a psychiatric condition that may occur in people who have experienced or witnessed a traumatic event or series of traumatic events. The individual often experience the event or events as emotionally or physically harmful or life-threatening.

Complex post-traumatic stress disorder (CPTSD, cPTSD, or hyphenated C-PTSD) is a stress-related mental disorder generally occurring in response to complex traumas (i.e., commonly prolonged or repetitive exposure to a traumatic event (or traumatic events), from which one sees little or no chance to escape).

CPTSD is a category of post-traumatic stress disorder (PTSD) with three additional clusters of significant symptoms: emotional dysregulation, negative self-beliefs (e.g., shame, guilt, failure for wrong reasons), and interpersonal difficulties. C-PTSD’s symptoms include prolonged feelings of terror, worthlessness, helplessness, distortions in identity or sense of self, and hypervigilance.

a condition in which the nervous system is inaccurately and rapidly filtering sensory information and the individual is in an enhanced state of sensory sensitivity. This appears to be linked to a dysregulated nervous system which can often be caused by traumatic events or complex PTSD.

In hypervigilance, there is a perpetual scanning of the environment to search for sights, sounds, people, behaviors, smells, or anything else that is reminiscent of activity, threat or trauma. The individual is placed on high alert in order to be certain danger is not near. Hypervigilance can lead to a variety of obsessive behavior patterns, as well as producing difficulties with social interaction and relationships.

A trauma trigger is a psychological stimulus that prompts involuntary recall of a previous traumatic experience. The stimulus itself need not be frightening or traumatic and may be only indirectly or superficially reminiscent of an earlier traumatic incident, such as a scent or a piece of clothing. Triggers can be subtle, individual, and difficult for others to predict. A trauma trigger may also be called a trauma stimulus, a trauma stressor or a trauma reminder.