Dissociative Amnesia and DSM-IV-TR Cluster C Personality Traits

Abstract

Dissociative amnesia is a disorder characterized by retrospectively reported memory gaps. These gaps involve an inability to recall personal information, usually of a traumatic or stressful nature. Dissociative amnesia most commonly occurs in the presence of other psychiatric conditions, particularly personality disorders. In the literature and in clinical practice, it is often associated with DSM-IV-TR Cluster B personality disorders. However, there is evidence to suggest that dissociative amnesia may be more likely to occur among individuals with Cluster C personality disorders. Presented here is a discussion of the types of memory loss, two cases of dissociative amnesia occurring in patients with Cluster C psychopathology, and a focused literature review.

Introduction

As defined by Tulving, humans have three major types of memory.¹ Episodic memory is remembering events as one would recall a movie. Semantic memory is knowledge about the world and memory of words, dates, and facts. Procedural memory is the ability to remember motor routines, such as combing one's hair. Loss of any of these types of memory can arise from organic damage to the neocortex, as in the case of a traumatic brain injury, a cerebral vascular accident (CVA), a space-occupying lesion, or a toxic exposure. Alternatively, memory deficits can result from extreme psychological stress, as seen in dissociative disorders.

Dissociative amnesia (DA) is generally considered the most common dissociative disorder² and is defined in the Diagnostic and Statistical Manual (Fourth Edition), Text Revision (DSM-IV-TR) as “one or more episodes of inability to recall important personal information, usually of a traumatic or stressful nature, that is too extensive to be explained by ordinary forgetfulness” (Table 1).³

Table 1.

DSM-IV-TR diagnostic criteria for dissociative amnesia

The predominant disturbance is one or more episodes of inability to recall important personal information, usually of a traumatic or stressful nature, that is too extensive to be explained by ordinary forgetfulness. The disturbance does not occur exclusively during the course of dissociative identity disorder, dissociative fugue, posttraumatic stress disorder, acute stress disorder, or somatization disorder and is not due to the direct physiologic effects of a substance (e.g., drug abuse or medication) or a neurological or other general medical condition (e.g., amnestic disorder due to head trauma). The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.

DA can present a very confusing clinical picture.^4,5 Differentiating between organic and dissociative memory loss is the first step to accurate diagnosis (Table 2). Unlike dementia, in which an individual may remember personal information but not recall general topics, a common presentation for DA is amnesia for personal identity and traumatic details, but intact memory for general information. Other amnesias, such as transient global amnesia and postconcussion amnesia, present with both retrograde and ongoing anterograde amnesia and demonstrate problems learning new information.⁶ In contrast, the amnesia associated with DA is usually only anterograde, restricted to the period following the trauma, and is without problems learning new information.³ Except for the amnesia, individuals with DA seem cognitively intact and function coherently.

Table 2.

Characteristics of organic and dissociative memory loss

Organic Memory Loss

Dissociative Memory Loss

History suggestive of CNS injury Abnormal physical/neurological exam Abnormal laboratory values Abnormal EEG, LP, head CT, and MRI Older age Rare loss of autobiographical information Tends to be irreversible Both retrograde and anterograde Cognitive abilities impaired Difficulty encoding new memories Patient concerned about memory loss Baseline emotional responsiveness

History of an emotional trauma Normal physical/neurological exam Normal laboratory values Normal EEG, LP, head CT, and MRI Younger age Frequent loss of autobiographical information Is mostly reversible Usually anterograde* Cognitive abilities preserved Ability to encode new memories Patient not concerned about memory loss Heightened emotional responsiveness High hypnotizability &dissociative capacity

^*Except in the case of generalized amnesia, in which retrograde memory loss occurs as well

Recent advances in neurophysiology have clarified the process of memory from a biologic perspective, but DA also has a significant psychological component.⁷ There is a large body of literature on peritraumatic dissociation, which is too extensive to be covered here. However, it is worthwhile noting how several experts in the field conceptualize DA. Van der Hart described the Janetian view of dissociation as “the process and the product of psychological and somatic splitting, which result from the impact of trauma emotions.”⁸ Posttraumatic amnesia can be thought of as faulty ego integrative functioning in the setting of traumatic emotions. Gabbard conceptualizes DA in the following way: “Memories of the traumatized self must be dissociated because they are inconsistent with the everyday self that appears to be in full control.”⁹ Unlike repression, which can be thought of as horizontal split in the memory system, dissociation involves a vertical split.¹⁰ This results in the loss of memory for discrete periods of time rather than for discrete events.

Nearly all individuals with DA have significant comorbid psychiatric diagnoses, which if not treated will predispose the individual to recurrent eposides of amnesia.^2,9 Frequently, these diagnoses include personality disorders, which are described in the DSM-IV-TR as “enduring subjective experiences and behavior that deviate from cultural standards, are rigidly pervasive with onset in late adolescence or early adulthood, are stable through time, and result in unhappiness and impairment.” The 10 recognized personality disorders are divided into three groups or clusters with Cluster A (paranoid, schizoid, schizotypal) perceived as odd and eccentric; Cluster B (antisocial, borderline, histrionic, narcissistic) being dramatic, emotional, and erratic; and Cluster C (avoidant, dependent, obsessive compulsive) described as anxious and fearful.³

Dissociative symptomology is most commonly associated with Cluster B personality disorders, presumably because these individuals often have a history of psychic or physical trauma.^2,3 However, there is evidence to suggest that the relationship between Cluster C personality disorders, specifically avoidant and dependent personality disorders, and DA is also prominent. In an effort to demonstrate this relationship, two cases of DA occurring in patients with avoidant and dependent personality traits are presented, followed by a focused review of the current literature.

Case 1

The patient was a 19-year-old male military service member who was hospitalized on two separate occasions after he was found to have toxic salicylate levels. Both times, he presented to a primary care clinic with complaints of nausea, disequilibrium, labored breathing, diaphoresis, and hemetemesis. Laboratory evaluations revealed toxic salicylate levels, but the patient denied ingesting any medication, denied memory loss, and was without psychiatric complaint.

He was admitted to the psychiatric ward, where he was noted to be polite but anxious, speaking with a stutter, appearing inhibited in the milieu, and avoiding most interpersonal contact. He continued to deny ingestion of aspirin, despite physical signs and laboratory evidence of overdose.

At the time of his second hospitalization, he reported finding an empty aspirin bottle in his room. He was also more forthcoming with some of his current stressors. He shared that he had joined the military after September 11 with a sense of patriotism and the fantasy of serving with “heroes.” He had not anticipated the difficulty he would have separating from his family, nor the disappointment he would experience upon finding that his military peers did not meet his expectations of the idealized hero. He disclosed that he had previously witnessed an assault on his roommate by other service members, who had then made threats against his life. Poisoning was considered, but was deemed unlikely since the perpetrators were in jail pending trial.

A benzodiazepine-assisted interview was conducted, but it failed to elicit memories of either ingestion. The patient underwent psychological testing to assist in diagnosis. The Minnesota Multiphasic Personality Inventory, Second Edition (MMPI-2) indicated that he was experiencing a significant level of distress. The validity profile suggested over-reporting of symptoms, which was thought to be related to an inability to express his needs in a more sophisticated manner. The Structured Interview of Reported Symptoms (SIRS) suggested that there was a low probability that he was feigning symptoms, and the most prominent theme in the patient's Rotter Incomplete Sentence Blank (RISB) involved feelings of interpersonal rejection and alienation.

The patient was discharged from the inpatient psychiatric ward with an Axis I diagnosis of dissociative amnesia and an Axis II diagnosis of avoidant personality disorder. He remained unable to recall details of the ingestions while hospitalized and in the months that followed, and was eventually discharged from active duty service with no further psychiatric sequelae.

Case 2

The second patient was a 24-year-old man who suffered an episode of global amnesia while driving. Authorities found him sitting at a gas station in a disheveled, exhausted, and disoriented state. They brought him to the nearest hospital, where he was identified by means of his military identification (“dog”) tags, and was admitted for evaluation.

At the hospital, he underwent a comprehensive medical work-up that was completely normal. His medical team consulted psychiatry for further diagnostic assistance. Following a thorough review of his history, including collateral data from his friends and family, he was diagnosed with DA and was transferred to the inpatient psychiatry ward for treatment.

In the psychiatric milieu, he was cooperative and pleasant, but had no memory of his life or the events leading to his hospitalization. He could identify his emotional states, including “scared,” “frustrated,” “worn out,” and “a little sad,” but had no idea why he was experiencing such feelings. He received hypnosis two to three times a week in addition to the standard milieu therapies, and regained most of his memory over the course of three weeks.

Collateral information from his friends and family revealed him to be “easygoing,” “hardworking,” and “a nice guy to be around.” They reported that he liked to please others and was very uncomfortable with confrontation or interpersonal conflict, traits that also became evident in the psychiatric ward milieu. It was eventually discovered that these aspects of his personality greatly contributed to the events leading up to his hospitalization.

The patient had recently completed Army basic training. While in training, he had left his car and other personal possessions in the hands of his girlfriend, whom many of his friends felt took unfair advantage of him. Not surprisingly, she depleted his bank account, took his car, and relocated while he was away. He was angry and had taken leave to find her, break up with her, and reclaim his possessions. However, when he found her, she was very apologetic and affectionate. She suggested they get married, citing concerns about her children's health and her lack of medical insurance. The patient recalled having reservations about marriage, but he felt guilty about wanting to end the relationship in light of the children's medical problems. Over the course of the evening, they became intimate and she accidentally called him by another man's name.

Feeling devastated by this event, the patient went to a park, where he spent the remainder of the night contemplating whether or not he should take his life. The next morning, he began the drive back to his duty station. Along the way, he ruminated over the events of the previous evening and experienced conflicting feelings of guilt and rage. For reasons he could not explain, he pulled over to the side of the road and started walking toward what he described as “home,” the town where his girlfriend lived. The gas station where he was found was 12 miles away from his car. Despite comprehensive milieu treatment, he never fully regained the memories of that day.

Following discharge from the hospital, he participated in weekly insight-oriented psychotherapy sessions. Additional suggestions of character pathology became increasingly evident. Psychological testing supported the diagnosis of DA and suggested “dependent and passive-aggressive [personality] features.” Additionally, the examining psychologist reported that the patient “doesn't appear capable of healthy intimacy and may continually choose partners with similar difficulties.” He was discharged from the military five months after his amnestic episode with the diagnoses of DA and dependent personality traits.

Discussion

The DSM-IV-TR does not mention dissociation as either a diagnostic criterion or an associated finding among Cluster C personality disorders.³ At the authors' institution, an informal discussion with mental health clinicians revealed that greater than 90 percent of the clinicians associated dissociation with only Cluster B personality disorders. However, the case reports presented and a review of the literature summarized below support a correlation between Cluster C personality traits and dissociation.

Simeon found that people who dissociate were likely to have a harm-avoidant temperament, along with frequent disconnection and overconnection schemata. Disconnection schemata involve themes of abuse, neglect, and deprivation, while overconnection schemata contain themes of dependency, vulnerability, and incompetence.¹¹ Dell found the following breakdown of Minnesota Multiphasic Personality Inventory-2 (MMPI-2) personality scales among 42 outpatients with dissociative identity disorder: Seventy-six–percent avoidant, 68-percent self-defeating, 53-percent borderline, and 50-percent passive-aggressive. He concluded that “the core personality pathology in severe dissociative disorders…is avoidant and self-defeating.”¹² Marmar found that rescue workers who are shy, inhibited, and uncertain about their identity are at higher risk for acute dissociative responses to trauma.¹³ Using the reliable and well-validated Dissociative Experiences Scale,¹⁴ Wise found that high dissociators were more neurotic, less able to identify feelings, and more likely to daydream than low dissociators.¹⁵ In another study by Simeon evaluating 49 patients with depersonalization disorder, Cluster C personality disorders (48%) were more prevalent than Cluster A (13%) and Cluster B (38%).¹⁶

Not all Cluster C personality disorders appear to carry the same degree of risk. Exaggerated standards schemata, which are seen in obsessive-compulsive personality disorder and “reflect self-sacrifice, perfectionism, and exaggerated self-expectations,” were less likely to be found among patients with depersonalization disorder than among controls.⁶ Additionally, there is evidence to suggest that increasing severity of overall psychopathology is associated with both an increased incidence of dissociation and with non-Cluster C pathology, specifically borderline, passive-aggressive, schizotypal, schizoid, and paranoid personality traits.¹⁷

Both of the cases presented involved DSM-IV-TR Cluster C personality traits contributing to episodes of DA. In the first case, the patient presented as a very shy and anxious young man who was eager to please. He was in the midst of significant stressors, including loss of his immediate family support system, joining the military, being rejected by his military peers, and experiencing his own anger and disappointment in the military experience. His subsequent overdoses were related to extrusion from his military peer group in the form of physical threats and likely experienced as a significant rejection. This peer rejection may have lead to further fears of rejection by family and friends. The amnesia for the overdose may have been a way for him not only to tolerate the ego-dystonic act of suicide but also an attempt to defend against the shame he anticipated from family and friends for his perceived military failure. Finally, the patient's personality structure prevented him from expressing anger toward the military, which he felt had disappointed him. The act of suicide may have been a way for him to act out this aggression. The DA served to make the anger and aggression unknown to him.

The second patient was passive and overly trusting, exercising poor judgment in allowing an uncaring girlfriend unlimited access to his valuables. He demonstrated an appropriate anger response when he found out that she had taken advantage of him, but this response quickly dissipated when she seduced him and appealed to his guilty tendencies by mentioning her children's health problems. After she called him by another man's name during intercourse, the patient was able to momentarily revive his anger, but due to his harm-avoidant nature and discomfort with interpersonal conflict, directed it erroneously toward himself. He accepted her mistake as evidence of his worthlessness, impotence, and inability to make a lasting impact on people. The resultant suicidal ideations conflicted with his natural survival instincts. This unresolved conflict, as well as the conflict involving alternating feelings of guilt and rage toward his girlfriend, led ultimately to the dissociative response.

Summary

In clinical practice, dissociation is often associated with DSM-IV-TR Cluster B personality disorders. However, the literature contains evidence of a correlation between certain Cluster C character pathology and dissociation, which is not commonly stressed in psychiatric teachings. The cases presented highlight this correlation, as well as demonstrate the importance of identifying and treating underlying Cluster C personality traits to reduce the risk of future dissociative episodes. Further study of this correlation is needed to promote accurate diagnosis and improve treatment outcomes.