Inter-identity amnesia in dissociative identity disorder resolved: A behavioural and neurobiological study.

INTRODUCTION: Dissociative identity disorder (DID) is characterised by, among others, subjectively reported inter-identity amnesia, reflecting compromised information transfer between dissociative identity states. Studies have found conflicting results regarding memory transfer between dissociative identity states. Here, we investigated inter-identity amnesia in individuals with DID using self-relevant, subject specific stimuli, and behavioural and neural measures. METHODS: Data of 46 matched participants were included; 14 individuals with DID in a trauma-avoidant state, 16 trauma-avoiding DID simulators, and 16 healthy controls. Reaction times and neural activation patterns related to three types of subject specific words were acquired and statistically analysed, namely non-self-relevant trauma-related words (NSt), self-relevant trauma-related words from a trauma-avoidant identity state (St), and trauma-related words from a trauma-related identity state (XSt). RESULTS: We found no differences in reaction times between XSt and St words and faster reaction times for XSt over NSt. Reaction times of the diagnosed DID group were the longest. Increased brain activation to XSt words was found in the frontal and parietal regions, while decreased brain activity was found in the anterior cingulate cortex in the diagnosed DID group. DISCUSSION: The current study reproduces and amalgamates previous behavioural reports as well as brain activation patterns. Our finding of increased cognitive control over self-relevant trauma-related knowledge processing has important clinical implications and calls for the redefinition of "inter-identity amnesia" to "inter-identity avoidance".

Inter-identity amnesia for neutral episodic self-referential and autobiographical memory in Dissociative Identity Disorder: An assessment of recall and recognition.

Amnesia is a core diagnostic criterion for Dissociative Identity Disorder (DID), however previous research has indicated memory transfer. As DID has been conceptualised as being a disorder of distinct identities, in this experiment, behavioral tasks were used to assess the nature of amnesia for episodic 1) self-referential and 2) autobiographical memories across identities. Nineteen DID participants, 16 DID simulators, 21 partial information, and 20 full information comparison participants from the general population were recruited. In the first study, participants were presented with two vignettes (DID and simulator participants received one in each of two identities) and asked to imagine themselves in the situations outlined. The second study used a similar methodology but with tasks assessing autobiographical experience. Subjectively, all DID participants reported amnesia for events that occurred in the other identity. On free recall and recognition tasks they presented a memory profile of amnesia similar to simulators instructed to feign amnesia and partial information comparisons. Yet, on tests of recognition, DID participants recognized significantly more of the event that occurred in another identity than simulator and partial information comparisons. As such, results indicate that the DID performance profile was not accounted for by true or feigned amnesia, lending support to the idea that reported amnesia may be more of a perceived than actual memory impairment.

Dissociative identity as a continuum from healthy mind to psychiatric disorders: Epistemological and neurophenomenological implications approached through hypnosis.

The topic of multiple personality, redefined as Dissociative Identity Disorders (DIDs) in the DSM-5, is an intriguing and still debated disorder with a long history and deep cultural and epistemological implications, extending up to the idea of possession. Hypnosis is an appealing and valuable model to manipulate subjective experience and get an insight on both the physiology and the pathophysiology of the mind-brain functioning; it and has been closely connected with DIDs and possession since its origin in 18th century and as recently proved the capacity to yield a loss of sense of agency, mimicking delusions of alien control and spirit possession. In this study we report on five very uncommon "hypnotic virtuosos" (HVs) free from any psychiatric disorder, spontaneously undergoing the emergence of multiple identities during neutral hypnosis; this allowed us to check the relationship between their experience and fMRI data. During hypnosis the subjects underwent spontaneous non-intrusive experiences of other selves which were not recalled after the end of the session, due to post-hypnotic amnesia. The fMRI showed a significant decrease of connectivity in the Default Mode Network (DMN) especially between the posterior cingulate cortex and the medial prefrontal cortex. Our results and their contrast with the available data on fMRI in DIDs allows to draw the hypothesis of a continuum between healthy mind - where multiple identities may coexist at unconscious level and may sometimes emerge to the consciousness - and DIDs, where multiple personalities emerge as dissociated, ostensibly autonomous components yielding impaired functioning, subject's loss of control and suffering. If this is the case, it seems more reasonable to refrain from seeking for a clear-cut limit between normality (anyway a conventional, statistical concept) and pathology, and accept a grey area in between, where ostensibly odd but non-pathological experiences may occur (including so-called non-ordinary mental expressions) without calling for treatment but, rather, for being properly understood.

El papel de la desregulación emocional en el Trastorno Conversivo / The role of emotion dysregulation in Conversion Disorder

Introducción. El papel que juega la regulación de las emociones en la etiopatogénesis del Trastorno Conversivo (TC) es todavía poco conocido. Esta investigación pretende profundizar en este tema, buscando describir las diferencias principales que existen entre un grupo de pacientes con TC y un grupo control en lo que concierne a la forma de regular sus emociones así como a otras variables clínicas fundamentales. Métodos. Se ha realizado un estudio de tipo casos (n=43) y controles (n=42). Ambos grupos se sometieron a dos entrevistas psiquiátricas y completaron 6 cuestionarios autoadministrados evaluando la depresión, ansiedad, alexitimia, desregulación emocional, intensidad efectiva, así como la disociación psicomorfa y somatomorfa. Resultados. Los pacientes con TC puntuaron significativamente más alto en las seis variables estudiadas a través de los cuestionarios (p<0.001). La reactividad y la intensidad emocional negativas fueron mayores en el grupo de pacientes (p<0.01) mientras que ambos grupos puntuaron de manera similar en afectividad positiva y serenidad. La ansiedad, la alexitimia y la desregulación emocional fueron los factores de riesgo más importantes identificados (OR=5.85/3.50/3.23 respectivamente). La ansiedad y las dificultades en la regulación de las emociones fueron las variables que mejor explicaron la pertenencia al grupo de pacientes en los modelos de regresión logística calculados. Entre los 5 factores que midieron diferentes dificultades en la regulación emocional los más relevantes fueron la falta de control emocional y la interferencia en conductas orientadas a una meta. La sintomatología conversiva positiva y la sintomatología conversiva negativa se correlacionaron con distintos patrones de regulación emocional. Conclusiones. Los pacientes con TC sufrieron múltiples dificultades a la hora de regular sus emociones, comparados con el grupo control. La desregulación emocional puede ser considerada un factor de riesgo para padecer un TC. Se discute la posibilidad de que existan diferentes patrones de regulación emocional en pacientes con distintos tipos de sintomatología conversiva

Introduction. The role that emotion regulation plays in Conversion Disorders (CD) is not well known. This research deepens in this subject and describes the main differences between a group of conversion patients and a control group on different measures of emotion regulation and other clinical variables. Methods. A case-control study was conducted including 43 patients suffering from CD and 42 healthy controls. Both groups went thought two psychiatric interviews and fulfilled 6 questionnaires assessing depression, anxiety, alexithymia, emotion dysregulation, affect intensity, psychoform and somatoform dissociation. Results. Patients suffering from CD scored significantly higher on all the six questionnaires (p<0.001). Negative reactivity and negative intensity were also higher in patients (p<0.01) while cases and controls did not show any significant differences on positive affectivity and serenity. Anxiety, alexithymia and emotional dysregulation were the most relevant factors (OR=5.85/3.50/3.23 respectively). Anxiety and difficulties in emotion regulation were the most explicative variables for conversion in the regression analysis performed. Within the five factors assessing difficulties in emotion regulation, lack of emotional control and interference in goal directed behaviors were the most relevant. Positive and negative conversion where correlated to different emotional impairments. Conclusions. People suffering from CD show several emotional impairments when compared to healthy controls. Emotion dysregulation can be considered a relevant aspect in CD. The existence of specific emotional patterns for different conversion manifestations is suspected

Neurodevelopmental origins of abnormal cortical morphology in dissociative identity disorder.

OBJECTIVE: To examine the two constitutes of cortical volume (CV), that is, cortical thickness (CT) and surface area (SA), in individuals with dissociative identity disorder (DID) with the view of gaining important novel insights into the underlying neurobiological mechanisms mediating DID. METHODS: This study included 32 female patients with DID and 43 matched healthy controls. Between-group differences in CV, thickness, and SA, the degree of spatial overlap between differences in CT and SA, and their relative contribution to differences in regional CV were assessed using a novel spatially unbiased vertex-wise approach. Whole-brain correlation analyses were performed between measures of cortical anatomy and dissociative symptoms and traumatization. RESULTS: Individuals with DID differed from controls in CV, CT, and SA, with significantly decreased CT in the insula, anterior cingulate, and parietal regions and reduced cortical SA in temporal and orbitofrontal cortices. Abnormalities in CT and SA shared only about 3% of all significantly different cerebral surface locations and involved distinct contributions to the abnormality of CV in DID. Significant negative associations between abnormal brain morphology (SA and CV) and dissociative symptoms and early childhood traumatization (0 and 3 years of age) were found. CONCLUSIONS: In DID, neuroanatomical areas with decreased CT and SA are in different locations in the brain. As CT and SA have distinct genetic and developmental origins, our findings may indicate that different neurobiological mechanisms and environmental factors impact on cortical morphology in DID, such as early childhood traumatization.

Elena: A case of dissociative identity disorder from the 1920s.

In 1930, Italian psychiatrist Giovanni Enrico Morselli described the history, diagnosis, and treatment of his patient Elena. The case of Elena has been considered in literature as one of the most remarkable cases of multiple personality ever published. In fact, before treatment, Elena showed alternating French- and Italian-speaking personalities, with the Italian personality knowing nothing of her French counterparts. After a difficult treatment involving recovered memories of incestuous attacks by her father, which were proven to be true, Elena fully recovered from her symptoms. In this article, the author presents details of the case that were not available in the international literature before. He also discusses Elena's psychological and somatoform symptoms according to a contemporary perspective on the relationally traumatic origins of dissociation and dissociative identity disorder.

Sight and blindness in the same person: Gating in the visual system.

We present the case of a patient having dissociative identity disorder (DID) who-after 15 years of misdiagnosed cortical blindness--step-by-step regained sight during psychotherapeutic treatment. At first only a few personality states regained vision whereas others remained blind. This could be confirmed by electrophysiological measurement, in which visual evoked potentials (VEPs) were absent in the blind personality states but were normal and stable in the seeing states. A switch between these states could happen within seconds. We assume a top-down modulation of activity in the primary visual pathway as a neural basis of such psychogenic blindness, possibly at the level of the thalamus. VEPs therefore do not allow separating psychogenic blindness from organic disruption of the visual pathway. In summary, psychogenic blindness seems to suppress visual information at an early neural stage.

Meet Dr Jekyll: a case of a psychiatrist with dissociative identity disorder.

OBJECTIVE: Dissociative identity disorder (DID) is a controversial psychiatric diagnosis. This case review presents a retired psychiatrist with a history of DID. CONCLUSIONS: This case is used to illustrate current thinking about the characteristics and aetiology of DID. It also argues for the importance of being aware of both our personal and professional biases in our own clinical practice.

Autobiographical memory specificity in dissociative identity disorder.

A lack of adequate access to autobiographical knowledge has been related to psychopathology. More specifically, patients suffering from depression or a history of trauma have been found to be characterized by overgeneral memory, in other words, they show a relative difficulty in retrieving a specific event from memory located in time and place. Previous studies of overgeneral memory have not included patients with dissociative disorders. These patients are interesting to consider, as they are hypothesized to have the ability to selectively compartmentalize information linked to negative emotions. This study examined avoidance and overgeneral memory in patients with dissociative identity disorder (DID; n = 12). The patients completed the autobiographical memory test (AMT). Their performance was compared with control groups of posttraumatic stress disorder (PTSD) patients (n = 26), healthy controls (n = 29), and DID simulators (n = 26). Specifically, we compared the performance of separate identity states in DID hypothesized to diverge in the use of avoidance as a coping strategy to deal with negative affect. No significant differences in memory specificity were found between the separate identities in DID. Irrespective of identity state, DID patients were characterized by a lack of memory specificity, which was similar to the lack of memory specificity found in PTSD patients. The converging results for DID and PTSD patients add empirical evidence for the role of overgeneral memory involved in the maintenance of posttraumatic psychopathology.

Dissociative part-dependent resting-state activity in dissociative identity disorder: a controlled FMRI perfusion study.

BACKGROUND: In accordance with the Theory of Structural Dissociation of the Personality (TSDP), studies of dissociative identity disorder (DID) have documented that two prototypical dissociative subsystems of the personality, the "Emotional Part" (EP) and the "Apparently Normal Part" (ANP), have different biopsychosocial reactions to supraliminal and subliminal trauma-related cues and that these reactions cannot be mimicked by fantasy prone healthy controls nor by actors. METHODS: Arterial spin labeling perfusion MRI was used to test the hypotheses that ANP and EP in DID have different perfusion patterns in response to rest instructions, and that perfusion is different in actors who were instructed to simulate ANP and EP. In a follow-up study, regional cerebral blood flow of DID patients was compared with the activation pattern of healthy non-simulating controls. RESULTS: Compared to EP, ANP showed elevated perfusion in bilateral thalamus. Compared to ANP, EP had increased perfusion in the dorsomedial prefrontal cortex, primary somatosensory cortex, and motor-related areas. Perfusion patterns for simulated ANP and EP were different. Fitting their reported role-play strategies, the actors activated brain structures involved in visual mental imagery and empathizing feelings. The follow-up study demonstrated elevated perfusion in the left temporal lobe in DID patients, whereas non-simulating healthy controls had increased activity in areas which mediate the mental construction of past and future episodic events. CONCLUSION: DID involves dissociative part-dependent resting-state differences. Compared to ANP, EP activated brain structures involved in self-referencing and sensorimotor actions more. Actors had different perfusion patterns compared to genuine ANP and EP. Comparisons of neural activity for individuals with DID and non-DID simulating controls suggest that the resting-state features of ANP and EP in DID are not due to imagination. The findings are consistent with TSDP and inconsistent with the idea that DID is caused by suggestion, fantasy proneness, and role-playing.

Dissociative identity disorder: An empirical overview.

OBJECTIVE: Despite its long and auspicious place in the history of psychiatry, dissociative identity disorder (DID) has been associated with controversy. This paper aims to examine the empirical data related to DID and outline the contextual challenges to its scientific investigation. METHODS: The overview is limited to DID-specific research in which one or more of the following conditions are met: (i) a sample of participants with DID was systematically investigated, (ii) psychometrically-sound measures were utilised, (iii) comparisons were made with other samples, (iv) DID was differentiated from other disorders, including other dissociative disorders, (v) extraneous variables were controlled or (vi) DID diagnosis was confirmed. Following an examination of challenges to research, data are organised around the validity and phenomenology of DID, its aetiology and epidemiology, the neurobiological and cognitive correlates of the disorder, and finally its treatment. RESULTS: DID was found to be a complex yet valid disorder across a range of markers. It can be accurately discriminated from other disorders, especially when structured diagnostic interviews assess identity alterations and amnesia. DID is aetiologically associated with a complex combination of developmental and cultural factors, including severe childhood relational trauma. The prevalence of DID appears highest in emergency psychiatric settings and affects approximately 1% of the general population. Psychobiological studies are beginning to identify clear correlates of DID associated with diverse brain areas and cognitive functions. They are also providing an understanding of the potential metacognitive origins of amnesia. Phase-oriented empirically-guided treatments are emerging for DID. CONCLUSIONS: The empirical literature on DID is accumulating, although some areas remain under-investigated. Existing data show DID as a complex, valid and not uncommon disorder, associated with developmental and cultural variables, that is amenable to psychotherapeutic intervention.

De la respuesta a la locura, a la locura como respuesta / From the answer to madness and madness as an answer

Se presenta el caso clínico de una mujer de cuarenta años de edad que es atendida en el Servicio de Urgencias (por recomendación de su hija) al contactar con su difunto cuñado, y sentirlo “como si estuviera dentro de ella”. La paciente comentó que el fallecido le había trasmitido que deseaba que su viuda rehiciera su vida de pareja y familiar. Durante la observación psicopatológica se aprecia, entre otros datos, verbalizaciones de ideas de perjuicio. La hija de la paciente especifica reiteradamente que existía una asociación entre la toma de tratamiento anticonceptivo con dispositivo intrauterino hormonal (levonorgestrel) y síntomas premórbidos (caracterizados por apatía, abulia y abandono parcial de sus tareas cotidianas). Se planteó el diagnóstico diferencial entre un trastorno psicótico de debut o un trastorno disociativo, a descartar una posible inducción del tratamiento hormonal. La evolución clínica y el conocimiento de la situación vital de la paciente permitirá discernir el cuadro (AU)

A case involving a 40-years old woman attended by the Emergency Service (at the request of her daughter). The woman claimed she had had contact with her late brother-in-law and felt “as if he had been inside her”. The patient also said that the deceased had expressed his desire to see his widow recover her intimate personal and family life. During the psychopathological observation, vocalizations of prejudicial ideas, among other data, were noted. The patient’s daughter repeatedly specified an association between the intake of contraceptive treatment with hormonal intrauterine device (levonorgestrel) and premorbid symptoms (characterized by apathy, abulia and partial abandonment of her routine activities). A differential diagnosis was proposed among which, a psychotic disorder, a dissociative disorder, or a possible induction by the hormonal treatment, was presented. The clinical progress and the knowledge of the patient’s vital situation will help determine the linical picture (AU)

An eye for an I: a 35-year-old woman with fluctuating oculomotor deficits and dissociative identity disorder.

Physiologic changes, including neurological or pseudo-neurological symptoms, occur across identity states in dissociative identity disorder DID) and can be objectively measured. The idea that dissociative phenomena might be associated with changes in brain function is consistent with research on the brain effects of hypnosis. The authors report a case of psycho-physiologic differences among 4 alter personalities manifested by a 35-year-old woman with DID. Differences in visual acuity, frequency of pendular nystagmus, and handedness were observed in this patient both when the alter personalities appeared spontaneously and when elicited under hypnosis. The authors consider several diagnostic possibilities for these findings and discuss whether prevailing treatment recommendations for DID patients could possibly be modified to ameliorate such visual and neurologic symptoms.

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.

Fact or factitious? A psychobiological study of authentic and simulated dissociative identity states.

BACKGROUND: Dissociative identity disorder (DID) is a disputed psychiatric disorder. Research findings and clinical observations suggest that DID involves an authentic mental disorder related to factors such as traumatization and disrupted attachment. A competing view indicates that DID is due to fantasy proneness, suggestibility, suggestion, and role-playing. Here we examine whether dissociative identity state-dependent psychobiological features in DID can be induced in high or low fantasy prone individuals by instructed and motivated role-playing, and suggestion. METHODOLOGY/PRINCIPAL FINDINGS: DID patients, high fantasy prone and low fantasy prone controls were studied in two different types of identity states (neutral and trauma-related) in an autobiographical memory script-driven (neutral or trauma-related) imagery paradigm. The controls were instructed to enact the two DID identity states. Twenty-nine subjects participated in the study: 11 patients with DID, 10 high fantasy prone DID simulating controls, and 8 low fantasy prone DID simulating controls. Autonomic and subjective reactions were obtained. Differences in psychophysiological and neural activation patterns were found between the DID patients and both high and low fantasy prone controls. That is, the identity states in DID were not convincingly enacted by DID simulating controls. Thus, important differences regarding regional cerebral bloodflow and psychophysiological responses for different types of identity states in patients with DID were upheld after controlling for DID simulation. CONCLUSIONS/SIGNIFICANCE: The findings are at odds with the idea that differences among different types of dissociative identity states in DID can be explained by high fantasy proneness, motivated role-enactment, and suggestion. They indicate that DID does not have a sociocultural (e.g., iatrogenic) origin.

Diagnóstico diferencial mediante EEG entre cuadro disociativo y estatus epiléptico no convulsivo / Differential diagnosis by EEG of dissociative status versus nonconvulsive status epilepticus

Introducción. El estatus epiléptico no convulsivo (EENC) incluye diferentes formas clínicas, desde una mínima confusión hasta alteraciones complejas del comportamiento, la psicosis o el coma. Por ello a veces el paciente puede ser mal diagnosticado y etiquetado como psiquiátrico. Caso clínico. Consciente y desorientada en el tiempo, episodios de desconexión, lentitud generalizada, bradipsíquia, lenguaje entrecortado y con lentitud en las respuestas. Se planteó el diagnóstico diferencial entre estado disociativo y EENC. Tanto la exploración física general como la neurológica fueron normales. El TC craneal fue normal. Sólo el EEG aportó el dato definitivo al presentar descargas de punta-onda generalizadas entre 2-3 Hz y desincronización del trazado de base. Conclusiones. El diagnóstico de EENC requiere la disponibilidad de EEG. A menudo se presentan pacientes en la frontera entre la patología médica y los trastornos mentales, la observación de la evolución y una actitud abierta por partede los profesionales es necesaria para un correcto diagnóstico y tratamiento (AU)

Introduction. Nonconvulsive status epilepticus (NCSE)has different clinical presentations, from minimal confusion to bizarre behavioral manifestations, psychosis or coma. As a result, patients can sometimes be misdiagnosed and labeled as psychiatric cases. Clinical case. The patient was alert and disoriented in time, with disconnection episodes, generalized slowness, slow mental response, faltering language and slow answers. A differential diagnosis between dissociative status and NCSE was proposed. The physical and neurological examinations were normal. The cranial CT scan findings were normal. Only the EEG provided the definitive diagnostic data, consisting of generalized spike and wave discharges of2-3 Hz against a desynchronized background. Conclusions. Diagnosis of NCSE requires the availability of an EEG. Often patients are on the border between medical conditions and mental disorders. Observation of the disease evolution and an open-minded attitude of physicians are necessary for the correct diagnosis and treatment (AU)

Dissociative identity disorder: Medicolegal challenges.

Persons with dissociative identity disorder (DID) often present in the criminal justice system rather than the mental health system and perplex experts in both professions. DID is a controversial diagnosis with important medicolegal implications. Defendants have claimed that they committed serious crimes, including rape or murder, while they were in a dissociated state. Asserting that their alter personality committed the bad act, defendants have pleaded not guilty by reason of insanity (NGRI). In such instances, forensic experts are asked to assess the defendant for DID and provide testimony in court. Debate continues over whether DID truly exists, whether expert testimony should be allowed into evidence, and whether it should exculpate defendants for their criminal acts. This article reviews historical and theoretical perspectives on DID, presents cases that illustrate the legal implications and controversies of raising an insanity defense based on multiple personalities, and examines the role of forensic experts asked to comment on DID with the goal of assisting clinicians in the medicolegal assessment of DID in relation to crimes.

Are major dissociative disorders characterized by a qualitatively different kind of dissociation?

A total of 66 patients with a major dissociative disorder, 54 patients with nondissociative disorders, and 30 nonclinical controls were administered the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised, the Dissociative Experiences Scale, the Multidimensional Inventory of Dissociation, and the Symptom Checklist 90-Revised. Dissociative patients reported significantly more dissociative and nondissociative symptoms than did nondissociative patients and nonclinical controls. When general psychopathology was controlled, the dissociation scores of dissociative patients were still significantly higher than those of both other groups, whereas the dissociation scores of nondissociative patients and nonclinical controls no longer differed. These findings appear to be congruent with a typological model of dissociation that distinguishes between 2 qualitatively different kinds of dissociation. Specifically, the results of this study suggest that the dissociation that occurs in major dissociative disorders (i.e., dissociative identity disorder [DID] and dissociative disorder not otherwise specified, Type 1 [DDNOS-1]) is qualitatively different from the dissociation that occurs in persons who do not have a dissociative disorder. In contrast to previous research, the dissociation of persons who do not have a dissociative disorder is not limited to absorption; it covers a much wider range of phenomena. The authors hypothesize that different mechanisms produce the dissociation of persons with DID and DDNOS-1 as opposed to the dissociation of persons who do not have a dissociative disorder.

Cross-examining dissociative identity disorder: neuroimaging and etiology on trial.

Dissociative identity disorder (DID) is probably the most disputed of psychiatric diagnoses and of psychological forensic evaluations in the legal arena. The iatrogenic proponents assert that DID phenomena originate from psychotherapeutic treatment while traumagenic proponents state that DID develops after severe and chronic childhood trauma. In addition, DID that is simulated with malingering intentions, but not stimulated by psychotherapeutic treatment, may be called pseudogenic. With DID gaining more interest among the general public it can be expected that the number of pseudogenic cases will grow and the need to distinguish between traumagenic, iatrogenic or pseudogenic DID will increase accordingly. This paper discusses whether brain imaging studies can inform the judiciary and/or distinguish the etiology of DID.

Frontal and occipital perfusion changes in dissociative identity disorder.

The aim of the study was to investigate if there were any characteristics of regional cerebral blood flow (rCBF) in dissociative identity disorder. Twenty-one drug-free patients with dissociative identity disorder and nine healthy volunteers participated in the study. In addition to a clinical evaluation, dissociative psychopathology was assessed using the Structured Clinical Interview for DSM-IV Dissociative Disorders, the Dissociative Experiences Scale and the Clinician-Administered Dissociative States Scale. A semi-structured interview for borderline personality disorder, the Hamilton Depression Rating Scale, and the Childhood Trauma Questionnaire were also administered to all patients. Normal controls had to be without a history of childhood trauma and without any depressive or dissociative disorder. Regional cerebral blood flow (rCBF) was studied with single photon emission computed tomography (SPECT) with Tc99m-hexamethylpropylenamine (HMPAO) as a tracer. Compared with findings in the control group, the rCBF ratio was decreased among patients with dissociative identity disorder in the orbitofrontal region bilaterally. It was increased in median and superior frontal regions and occipital regions bilaterally. There was no significant correlation between rCBF ratios of the regions of interest and any of the psychopathology scale scores. An explanation for the neurophysiology of dissociative psychopathology has to invoke a comprehensive model of interaction between anterior and posterior brain regions.