Acute trauma results from a single critical incident, such as a car accident, being a victim of a crime, witnessing a violent event, or surviving a natural disaster. These incidents can have a profound impact on one's daily functioning and interpersonal relationships.
Chronic trauma is repeated and prolonged, such as domestic violence or physical abuse. Chronic trauma may also result from the accumulation of multiple unrelated traumatic events. People struggling with chronic trauma may relive the trauma through flashbacks and nightmares, avoid situations that remind them of the trauma, experience hyperarousal (living in a continual state of high alert), develop a belief that the world is a dangerous place or that they can not trust in themselves or others.
Complex trauma [also referred to as Developmental Trauma] describes both children's exposure to multiple traumatic events--often of an invasive, interpersonal nature--and the wide-ranging, long-term effects of this exposure. These events are severe and pervasive, such as abuse or profound neglect. They usually occur early in life and can disrupt many aspects of the child's development and the formation of a sense of self. Since these events often occur with a caregiver, they interfere with the child's ability to form a secure attachment. Many aspects of a child's healthy physical and mental development rely on this primary source of safety and stability.--The National Child Traumatic Stress Network
When a child grows up afraid or under constant or extreme stress, the body's immune system and body's stress response systems may not develop normally. An absence of mental stimulation in neglectful environments may limit the brain from developing to its full potential. Stress in the environment, or experienced threat, can impair the development of the brain and nervous system. Later on, when the child or adult is exposed to even ordinary levels of stress, these systems may automatically respond as if the individual is under extreme stress. For example, an individual may experience significant physiological reactivity such as rapid breathing or heart pounding, or may "shut down" entirely when presented with stressful situations. Individuals who have experienced complex trauma often have difficulty identifying, expressing, and managing emotions, and may have limited language or feeling states.--The National Child Traumatic Stress Network
Dissociation is often seen in individuals with histories of complex trauma. When children encounter an overwhelming and terrifying experience, they may dissociate, or [automatically] mentally separate themselves from their experience. They may perceive themselves as being detached from their bodies, on the ceiling, or somewhere else in the room watching what is happening to their bodies. They may feel as if they are in a dream or some altered state that is not quite real or as if the experience is happening to someone else. Or they may lose all memory or sense of the experiences having happened to them, resulting in gaps of time or even gaps in their personal history. At its extreme, a child may cut off or lose touch with various aspects of self .--The National Child Traumatic Stress Network
Dissociative Disorders are often called a self-protection or survival technique because they allow individuals to endure "hopeless" circumstances and preserve some healthy functioning. For a child who has been repeatedly physically and sexually assaulted, however, dissociation becomes a reinforced and conditioned response. Because it is so effective, children who are very practiced at dissociating may automatically use it whenever they feel threatened--even if the anxiety producing situation is not extreme or abusive. Even after the traumatic circumstances are long past, the left-over pattern of defensive dissociation sometimes remains into adulthood. Habitual defensive dissociation may lead to serious dysfunction in school, work, social, and daily activities.--Traumatic Stress Institute (Formerly Sidran Institute)