psychiatric disorders
Dissociative Subtype of Posttraumatic Stress Disorder
Introduction
The diagnosis of dissociative subtype of posttraumatic stress disorder (PTSD) is made in patients who meet all the diagnostic criteria for PTSD and also experience persistent or recurrent dissociative symptoms (specifically, depersonalization and derealization) in response to a stressor. Diagnosis is based on history. Treatment consists of psychotherapy and medications. (See also Overview of Dissociative Disorders and refers to incomplete integration of aspects of identity, memory, and consciousness, and is associated with unresponsive parenting and psychologic trauma, as well as with PTSD ( General references ). As with PTSD, dissociation commonly occurs in the aftermath of exposure to trauma, which may include experiencing the trauma firsthand, witnessing physical trauma experienced by someone else, learning of trauma suffered by loved ones, or being involved in the aftermath of trauma done to others (eg, as is required of emergency responders). Complex trauma, particularly that which occurs early in life and involves an intimate relationship (eg, with a caregiver), increases the likelihood of a patient developing PTSD with dissociative symptoms ( General references ). In addition to a history of childhood sexual and physical abuse, other factors associated with dissociative symptoms later in life include physical violence, shame, and guilt ( General references ). A population-based survey from 16 countries reported that almost 15% of those with PTSD also had the dissociative symptoms of depersonalization and derealization ( General references ). Patients with dissociative symptoms and PTSD were characterized by higher levels of re-experiencing symptoms, onset of PTSD in childhood, high exposure to trauma and childhood adversities (prior to PTSD onset), severe role impairment (eg, difficulties in performing job responsibilities and completing work around the house) and suicidality. The neurologic mechanisms of different responses to trauma are being investigated. Experiencing sudden physical injury or the threat of it dysregulates emotion, causes hyperarousal of autonomic responses, and disrupts the continuity of a person's experience and expectations for the future. An analysis of functional MRI (fMRI) and PET findings among patients shows that the more common hyperarousal type of PTSD involves increased amygdala and anterior insula activity and decreased medial prefrontal and rostral anterior cingulate activity ( General references ). As a result, cognition is overwhelmed by affect. In the dissociative subtype of PTSD, activations are reversed, leading to oversuppression of emotion consistent with depersonalization and derealization. Although not all individuals who meet criteria for PTSD have high levels of dissociation, most patients with high levels of dissociative symptomatology meet criteria for PTSD ( General references ). 