Dissociative states in multiple personality disorder: a quantitative study

Dissociative Identity Disorder CPAP Adherence: An Uncommon Factor in Obstructive Sleep Apnea

ABSTRACT

We present a case of a patient with dissociative identity disorder and symptomatic sleep apnea who was treated with continuous positive airway pressure (CPAP). CPAP use depended upon which personality the patient exhibited but apnea reduction did not. This case illustrates in one individual how personality can positively or negatively affect CPAP adherence.

Interidentity amnesia in dissociative identity disorder

INTRODUCTION

Patients diagnosed with dissociative identity disorder (DID) usually present with alternative personality states (alters) who take separate control of consciousness. Commonly, one alter will claim they have no awareness of events which took place when another alter was in control. However, some kinds of material are transferred across the alter boundary. Huntjens et al. devised an objective method of demonstrating such transfer.

METHODS

In the main study, following Huntjens et al., for three patients, two alters were taught different sets of nouns. The following week, one of the alters was given a recognition memory test including both sets plus distractor words. The patients in the Huntjens experiment responded in the same way to words in both sets.

RESULTS

In the present experiemnt, two of the patients tested had pairs of alters where there was no interference from the material which was presented to the other alter. In one of these cases, there was breakthrough with one pairing of alters, a pattern matched in a subsidiary experiment.

CONCLUSIONS

The population of individuals with DID are not homogeneous with respect to the depth of the blocking of episodic material from one alter to another.

Neurobiological mechanisms of state-dependent learning

State-dependent learning (SDL) is a phenomenon relating to information storage and retrieval restricted to discrete states. While extensively studied using psychopharmacological approaches, SDL has not been subjected to rigorous neuroscientific study. Here we present an overview of approaches historically used to induce SDL, and highlight some of the known neurobiological mechanisms, in particular those related to inhibitory neurotransmission and its regulation by microRNAs (miR). We also propose novel cellular and circuit mechanisms as contributing factors. Lastly, we discuss the implications of advancing our knowledge on SDL, both for most fundamental processes of learning and memory as well as for development and maintenance of psychopathology.

Trauma-related self-defining memories and future goals in Dissociative Identity Disorder

This study examined the content of self-defining autobiographical memories in different identities in patients with Dissociative Identity Disorder (DID) and comparison groups of patients with PTSD, healthy controls, and DID simulators. Consistent with the DID trauma model, analyses of objective ratings showed that DID patients in trauma identities retrieved more negative and trauma-related self-defining memories than DID patients in avoidant identities. Inconsistent with the DID trauma model, DID patients' self-rated trauma-relatedness of self-defining memories and future life goals did not differ between trauma identities and trauma avoidant identities. That is, the DID patients did not seem to be "shut off" from their trauma while in their avoidant identity. Furthermore, DID patients in both identities reported a higher proportion of avoidance goals compared to PTSD patients, with the latter group scoring comparably to healthy controls. The simulators behaved according to the instructions to respond differently in each identity (i.e., to report memories and goals consistent with the identity tested). The discrepant task behavior by DID patients and simulators indicated that DID patients did not seem to intentionally produce the hypothesized differences in performance between identities. In conclusion, for patients with DID (i.e., in both identities) and patients with PTSD, trauma played a central role in the retrieval of self-defining memories and in the formulation of life goals.

Memory, Amnesia, and Dissociative Identity Disorder

Virtually all patients with dissociative identity (or multiple personality) disorder manifest interpersonality amnesia, whereby events experienced by a particular personality state or identity are retrievable by that same identity but not by a different one Though considered a hallmark of dissociative identity disorder (DID), interpersonality amnesia has to date attracted little empirical attention. Further, the few studies on the topic typically include just 1 DID patient and a single index of retention In contrast the current experiment involved 9 DID patients and several measures of either explicit or implicit memory Replicating and extending the single-case study of Nissen, Ross, Willingham, MacKenzie, and Schacter (1988), the present results revealed that implicit testing is a necessary but not a sufficient condition for demonstrating transfer of information from one identity to another Specifically, whereas priming in word-stem completion occurred only if the same personality state performed at both study and at test, priming in picture-fragment completion was as robust between different identities as it was within the same identity Discussion focuses on prospects for future research aimed at understanding the nature and scope of interpersonality amnesia

GABAergic mechanisms regulated by miR-33 encode state-dependent fear

Fear-inducing memories can be state dependent, meaning that they can best be retrieved if the brain states at encoding and retrieval are similar. Restricted access to such memories can present a risk for psychiatric disorders and hamper their treatment. To better understand the mechanisms underlying state-dependent fear, we used a mouse model of contextual fear conditioning. We found that heightened activity of hippocampal extrasynaptic GABAA receptors, believed to impair fear and memory, actually enabled their state-dependent encoding and retrieval. This effect required protein kinase C-βII and was influenced by miR-33, a microRNA that regulates several GABA-related proteins. In the extended hippocampal circuit, extrasynaptic GABAA receptors promoted subcortical, but impaired cortical, activation during memory encoding of context fear. Moreover, suppression of retrosplenial cortical activity, which normally impairs retrieval, had an enhancing effect on the retrieval of state-dependent fear. These mechanisms can serve as treatment targets for managing access to state-dependent memories of stressful experiences.

Simulation of multiple personalities: a review of research comparing diagnosed and simulated dissociative identity disorder

Dissociative Identity Disorder (DID) has long been surrounded by controversy due to disagreement about its etiology and the validity of its associated phenomena. Researchers have conducted studies comparing people diagnosed with DID and people simulating DID in order to better understand the disorder. The current research presents a systematic review of this DID simulation research. The literature consists of 20 studies and contains several replicated findings. Replicated differences between the groups include symptom presentation, identity presentation, and cognitive processing deficits. Replicated similarities between the groups include interidentity transfer of information as shown by measures of recall, recognition, and priming. Despite some consistent findings, this research literature is hindered by methodological flaws that reduce experimental validity.

Inter-identity autobiographical amnesia in patients with dissociative identity disorder

Background

A major symptom of Dissociative Identity Disorder (DID; formerly Multiple Personality Disorder) is dissociative amnesia, the inability to recall important personal information. Only two case studies have directly addressed autobiographical memory in DID. Both provided evidence suggestive of dissociative amnesia. The aim of the current study was to objectively assess transfer of autobiographical information between identities in a larger sample of DID patients.

Methods

Using a concealed information task, we assessed recognition of autobiographical details in an amnesic identity. Eleven DID patients, 27 normal controls, and 23 controls simulating DID participated. Controls and simulators were matched to patients on age, education level, and type of autobiographical memory tested.

Findings

Although patients subjectively reported amnesia for the autobiographical details included in the task, the results indicated transfer of information between identities.

Conclusion

The results call for a revision of the DID definition. The amnesia criterion should be modified to emphasize its subjective nature.

Dissociative disorders

The dissociative disorders, including "psychogenic" or "functional" amnesia, fugue, dissociative identity disorder (DID, also known as multiple personality disorder), and depersonalization disorder, were once classified, along with conversion disorder, as forms of hysteria. The 1970s witnessed an "epidemic" of dissociative disorder, particularly DID, which may have reflected enthusiasm for the diagnosis more than its actual prevalence. Traditionally, the dissociative disorders have been attributed to trauma and other psychological stress, but the existing evidence favoring this hypothesis is plagued by poor methodology. Prospective studies of traumatized individuals reveal no convincing cases of amnesia not attributable to brain insult, injury, or disease. Treatment generally involves recovering and working through ostensibly repressed or dissociated memories of trauma; at present, there are few quantitative or controlled outcome studies. Experimental studies are few in number and have focused largely on state-dependent and implicit memory. Depersonalization disorder may be in line for the next "epidemic" of dissociation.

Memory transfer for emotionally valenced words between identities in dissociative identity disorder

The present study aimed to determine interidentity retrieval of emotionally valenced words in dissociative identity disorder (DID). Twenty-two DID patients participated together with 25 normal controls and 25 controls instructed to simulate DID. Two wordlists A and B were constructed including neutral, positive and negative material. List A was shown to one identity, while list B was shown to another identity claiming total amnesia for the words learned by the first identity. The identity claiming amnesia was tested for intrusions from list A words into the recall of words from list B and recognition of the words learned by both identities. Test results indicated no evidence of total interidentity amnesia for emotionally valenced material in DID. It is argued that dissociative amnesia in DID may more adequately be described as a disturbance in meta-memory functioning instead of an actual retrieval inability.

Identity state-dependent attentional bias for facial threat in dissociative identity disorder

Biased attention for threatening stimuli has been associated with many forms of psychopathology. Attention to threatening faces presented below perceptual thresholds was assessed in patients diagnosed with dissociative identity disorder using a pictorial emotional Stroop task. Patients were tested in two different identity states, in one of which they claimed strong awareness of trauma. Attentional bias for social threat proved state-dependent in the patients and deviated from the patterns observed in controls.

Procedural memory in dissociative identity disorder: When can inter-identity amnesia be truly established?

In a serial reaction time task, procedural memory was examined in Dissociative Identity Disorder (DID). Thirty-one DID patients were tested for inter-identity transfer of procedural learning and their memory performance was compared with 25 normal controls and 25 controls instructed to simulate DID. Results of patients seemed to indicate a pattern of inter-identity amnesia. Simulators, however, were able to mimic a pattern of inter-identity amnesia, rendering the results of patients impossible to interpret as either a pattern of amnesia or a pattern of simulation. It is argued that studies not including DID-simulators or simulation-free memory tasks, should not be taken as evidence for (or against) amnesia in DID.

Transfer of newly acquired stimulus valence between identities in dissociative identity disorder (DID)

Patients with Dissociative Identity Disorder (DID) frequently report episodes of interidentity amnesia, that is amnesia for events experienced by other identities. The goal of the present experiment was to test the implicit transfer of trauma-related information between identities in DID. We hypothesized that whereas declarative information may transfer from one identity to another, the emotional connotation of the memory may be dissociated, especially in the case of negative, trauma-related emotional valence. An evaluative conditioning procedure was combined with an affective priming procedure, both performed by different identities. In the evaluative conditioning procedure, previously neutral stimuli come to refer to a negative or positive connotation. The affective priming procedure was used to test the transfer of this acquired valence to an identity reporting interidentity amnesia. Results indicated activation of stimulus valence in the affective priming task, that is transfer of emotional material between identities.

Interidentity amnesia for neutral, episodic information in dissociative identity disorder

Interidentity amnesia is considered a hallmark of dissociative identity disorder (DID) in clinical practice. In this study, objective methods of testing episodic memory transfer between identities were used. Tests of both recall (interference paradigm) and recognition were used. A sample of 31 DID patients was included. Additionally, 50 control subjects participated, half functioning as normal controls and the other half simulating interidentity amnesia. Twenty-one patients subjectively reported complete one-way amnesia for the learning episode. However, objectively, neither recall nor recognition scores of patients were different from those of normal controls. It is suggested that clinical models of amnesia in DID may be specified to exclude episodic memory impairments for emotionally neutral material.

Directed forgetting between, but not within, dissociative personality states

To investigate amnesia between identities in dissociative identity disorder (DID), the authors assessed explicit and implicit memory performance on a directed-forgetting task in 12 DID patients who switched from one state to an "amnesic" state between presentation and memory testing. DID patients were instructed either to remember or to forget neutral and emotional words. Besides an overall decrease in explicit memory, patients demonstrated selective forgetting of to-be-forgotten, but not of to-be-remembered words in the amnesic state. Patients did not exhibit any directed forgetting within the same state. Implicit memory was fully preserved across states. Independent of state, patients recalled more emotional than neutral information. These results may extend the conceptualization of memory processes in DID, suggesting an important role for retrieval inhibition.

Toward an etiology of dissociative identity disorder: a neurodevelopmental approach

This article elaborates on Putnam's "discrete behavioral states" model of dissociative identity disorder (Putnam, 1997) by proposing the involvement of the orbitalfrontal cortex in the development of DID and suggesting a potential neurodevelopmental mechanism responsible for the development of multiple representations of self. The proposed "orbitalfrontal" model integrates and elaborates on theory and research from four domains: the neurobiology of the orbitalfrontal cortex and its protective inhibitory role in the temporal organization of behavior, the development of emotion regulation, the development of the self, and experience-dependent reorganizing neocortical processes. The hypothesis being proposed is that the experience-dependent maturation of the orbitalfrontal cortex in early abusive environments, characterized by discontinuity in dyadic socioaffective interactions between the infant and the caregiver, may be responsible for a pattern of lateral inhibition between conflicting subsets of self-representations which are normally integrated into a unified self. The basic idea is that the discontinuity in the early caretaking environment is manifested in the discontinuity in the organization of the developing child's self.

Dissociative identity disorder and memory dysfunction: the current state of experimental research and its future directions

Memory dysfunction is a central feature of dissociative identity disorder (DID). Following the memorial anomalies outlined by Putnam [Putnam, F. W. (1994). Dissociation and disturbances of self. In: D. Cicchetti & S. L. Toth (Eds.), Disorders and dysfunctions of the self, vol. 5 (pp. 251-265). Rochester, NY: University of Rochester Press; Putnam, F. W. (1995). Development of dissociative disorders. In: D. Chicchetti & D. J. Cohen (Eds.), Developmental psychopathology, vol. 2 (pp. 581-608). New York: Wiley], the experimental research using DID case studies and samples is reviewed. As a whole, research suggests that amnesic barriers between alter personalities are typically impervious to explicit stimuli, as well as conceptually driven implicit stimuli. Autobiographical memory deficits are also experimentally evident in DID. Although no experimental studies have addressed the issue of source amnesia or pseudomemories, there is some evidence that pseudomemories are an infrequent but real phenomenon in DID patients. Finally, potential deficits in working memory are outlined, including those relating to cognitive inhibition. Research directions are discussed throughout to further elucidate the nature of memory dysfunction in DID.

Apparent amnesia on experimental memory tests in dissociative identity disorder: an exploratory study

Dissociative identity disorder (DID; called multiple personality disorder in DSMIII-R) is a psychiatric condition in which two or more identity states recurrently take control of the person's behavior. A characteristic feature of DID is the occurrence of apparently severe amnestic symptoms. This paper is concerned with experimental research of memory function in DID and focuses on between-identity transfer of newly learned neutral material. Previous studies on this subject are reviewed and a pilot study with four subjects is described. This study is specifically concerned with the question whether self-reported asymmetries in between-identity transfer can be replicated on experimental memory tests. A secondary aim was to examine whether, in the absence of explicit transfer, implicit transfer of information would occur. The results showed that the apparent amnestic asymmetry for explicit information was substantiated in the laboratory, although at least some leakage was present between the apparently amnestic identities. No evidence was found for better performance on implicit than on explicit memory tests in the apparently amnestic identities. In the discussion, parallels between apparent amnesia in DID and state-dependent memory are drawn, and the question of simulated amnesia is addressed.

Multiple personality disorder

Five aspects of the diagnosis and treatment of multiple personality disorder (MPD) were examined. The following five conclusions were made: the contemporary diagnostic criteria are vague and overinclusive; the recent alleged increase in prevalence of the disorder is almost certainly artefactual; legal proceedings involving MPD patients raise disturbing questions about personal responsibility; there is little literature support for the theory that MPD results from childhood trauma; and many of the techniques used to diagnose and treat the condition reinforce its symptoms. A careful revision of diagnostic criteria for the disorder is recommended.

Reflections on multiple personality disorder as a developmentally complex adaptation

Recent advances in the understanding of multiple personality disorder provide the groundwork for its creative reconciliation with psychoanalysis. This paper uses psychoanalytic, modern developmental, and psychological assessment perspectives to conceptualize multiple personality disorder as a developmentally protective response to chronic childhood trauma. Implications of this theory for clinical work with these patients are discussed.

Relation of dissociative phenomena to levels of cerebrospinal fluid monoamine metabolites and beta-endorphin in patients with eating disorders: a pilot study

Dissociation is made manifest by a failure to integrate thoughts, feelings, memories, and actions into a unified sense of consciousness. Although dissociation is presumed to be a special state of consciousness manifested by state-dependent memory and physiology, the psychobiology of dissociation is poorly understood. In this study, we examined cerebrospinal fluid levels of the major monoamine metabolites and beta-endorphin in patients with eating disorders (11 with anorexia nervosa, 16 with bulimia nervosa), while they were acutely ill. Dissociative capacity was measured using the Dissociative Experiences Scale (DES). We provide evidence that neurochemical changes in dopaminergic, serotonergic, and opioid systems may be associated with the clinical expression of dissociation in patients with eating disorders during the acute phase of their illness. These preliminary results are compatible with previous studies of neurochemical disturbances in the eating disorders and suggest that future work in dissociation should specifically include examination of these neurobiologic systems.

Dissociative disorders in children: behavioral profiles and problems

Transient dissociative episodes are a common and normative phenomenon during childhood that generally decrease during adolescence to relatively low levels in adults. Retrospective clinical research has firmly established a connection between childhood trauma and the development of dissociative disorders in adults. A growing number of clinicians are now identifying dissociative symptoms in abused children, and there is increasing evidence that dissociative disorders represent a significant and hitherto unrecognized form of psychopathology in traumatized children. Pathological dissociation is a complex psychobiological process that results in a failure to integrate information into the normal stream of consciousness. It produces a range of symptoms and behaviors including: (a) amnesias; (b) disturbances in sense of self; (c) trance-like states; (d) rapid shifts in mood and behavior; (e) perplexing shifts in access to knowledge, memory, and skills; (f) auditory and visual hallucinations; and (g) vivid imaginary companionship in children and adolescents. Many of these symptoms and behaviors are misdiagnosed as attention, learning or conduct problems, or even psychoses. Early identification and therapeutic intervention appear to be particularly efficacious in children in contrast to adults, although systematic studies of treatment and outcome are presently lacking.

Differential autonomic nervous system activity in multiple personality disorder

The cardinal feature of multiple personality disorder (MPD) is the existence of two or more alter personality states that exchange control over the behaviour of an individual. Numerous clinical reports suggest that these alter personality states exhibit distinct physiological differences. We investigated differential autonomic nervous system (ANS) activity across nine subjects with MPD and five controls, who produced "alter" personality states by simulation and by hypnosis or deep relaxation. Eight of the nine MPD subjects consistently manifested physiologically distinct alter personality states. Three of the five controls were also produced physiologically distinct states, but these differed from those of the MPD subjects. A habituation paradigm demonstrated carryover effects at the ANS levels from one state to the next for both groups.

The diagnosis of multiple personality disorder. A critical review

Recently, there has been a dramatic rise in the number of case reports of multiple personality disorder (MPD). The phenomenology of the disorder is described and theories on aetiology are discussed. A review of the recent literature reveals a poverty of information on reliability of diagnosis, prevalence, or the role of selection bias. It is argued that iatrogenic factors may contribute to the development of the syndrome. There is little evidence from genetic or physiological studies to suggest that MPD represents a distinct psychiatric disorder. It is assumed that MPD is an hysterical symptom, and an attempt is made to catalogue the predisposing factors and influences that may lead to the clinical presentation.

Memory and awareness in a patient with multiple personality disorder

We studied an individual with multiple personality disorder in whom each of several personalities claimed to have no direct awareness of the others and to be unable to consciously remember the experiences of other personalities. A broad selection of implicit and explicit memory tests was used to determine the extent to which one personality had access to knowledge acquired by another and the circumstances in which that knowledge would be expressed. The implicit assessment of memory was a necessary but not sufficient condition for demonstrating interpersonality access. The degree of compartmentalization of knowledge in this patient depended largely on whether the interpretation of presented information was likely to differ across personalities.