Posttraumatic Stress Disorder, Repression and Memory Impairment
Survivors of PTSD suffer from a persistent and aversive tendency to reexperience the traumatic event, as manifested by symptoms of intrusion, dissociation and hyperarousal. These symptoms can include recurrently intrusive images or dreams, hallucinatory flashbacks, intense psychological distress (caused by symbolic re-exposure), blunted affect, social withdrawal, hopelessness, amne-sia, avoidant behavior, irritability, insomnia, hypervigilance and impaired concentration. When experienced in combination, these symptoms may often result in a highly debilitating syndrome that operates to the exclusion of adaptive coping behavior.
PSSD by definition involves a pathological response to memories that are so traumatic as to be at once unforgettable (hence the intrusive symptoms) and intolerable to remember (hence the dissociation). The resulting heterostasis is posited to lead to emotional and physical dysregulation and presents a challenge to fundamental beliefs regarding security, efficacy and prospect for future well-being (Herman, 1992).
It is currently unclear whether PTSD memory deficits de-rive from some (unidentified) neuropsychological sequelae of extreme stress exposure or are simply concomitant to prolonged symptoms of hypervigilance, emotional distress, or comorbid de-pression. It is clear that PTSD is associated with significant pro-active interference in memory, such that survivors are impaired in their ability to encode and to retrieve new information.
The second type of memory deficit in PTSD involves symptoms of amnesia for, and intrusion of, memories for the initial traumatic event. These symptoms represent a functional deficit in memory, such that the survivor is alternately confronted with emotionally disturbing recollections and unable to access the traumatic memory.
In addition to deficits in memory, individuals with PTSD complain about the intrusion of memories for the traumatic event. In a pattern similar to that observed in MDD, individuals with PTSD appear to demonstrate both overgeneral autobiographical recall and a negativistic memory bias.
Questions about the accuracy (or inaccuracy) of repressed memory are difficult to address. Although the prevalence of am-nesic and dissociative symptoms in PTSD has been validated by studies of trauma survivors (Herbst, 1992; Zimering et al., 1993), these studies do not address the validity of more contro-versial cases that reportedly involve complete (and asymptom-atic) repression over long periods. Empirical efforts to document long-term traumatic repression continue to meet with signifi-cant methodological and conceptual criticisms (Williams, 1994; Loftus et al., 1994).
The practicing psychiatrist must recognize the possibil-ity of suggestibility and bias in retrieval of traumatic memories (Loftus, 1993; Berliner and Loftus, 1992; Gutheil, 1993), while maintaining a stance of openness and compassion in helping trauma survivors to clarify and to reintegrate their memories of traumatic events (Alloy et al., 1990). In sum, PTSD is a disorder of unbearable and inescapable recollection, and both research and therapy will continue to focus on the elucidation of memory for trauma.