Examination of the pathological dissociation taxon in depersonalization disorder

The Treatment of Depersonalization-Derealization Disorder: A Systematic Review

Depersonalization-derealization disorder (DPD) is characterized by persistent or recurrent experiences of detachment from oneself and surroundings, as well as a sense of unreality. Considering the inadequacy of current research on treatment, we performed a systematic review of the available pharmacotherapies, neuromodulations, and psychotherapies for DPD. The systematic review protocol was based on PRISMA 2020 guidelines and pre-registered. The PubMed, Web of Science, PsycINFO, Embase, the Cochrane Library, Scopus, and ScienceDirect databases were searched from inception to June 2021. All treatments for DPD and all study types, including controlled and observational studies as well as case reports, were assessed. Of the identified 17,540 studies, 41 studies (four randomized controlled trials, one non-randomized controlled trial, 10 case series, and 26 case reports) involving 300 participants met the eligibility criteria. We identified 30 methods that have been applied independently or in combination to treat DPD since 1955. The quality of these studies was considered. The relationship between individual differences, such as symptoms, comorbidities, history, and duration since onset, and treatment effects was explored. The results suggest that a series of treatments, such as pharmacotherapies, neuromodulation, and psychotherapies, could be considered in combination. However, the quality and quantity of studies were generally low considering the high prevalence of DPD. The review concludes with suggestions for future research and an urgent call for more high-quality research.

Pathological Dissociation in The National Comorbidity Survey Replication (NCS-R): Prevalence, Morbidity, Comorbidity, and Childhood Maltreatment

Our aim was to examine U.S. national prevalence of pathological dissociation (PD) likely indicative of dissociative disorder, and associated morbidity, comorbidity, and childhood maltreatment. PD was assessed in 6,644 participants in the National Comorbidity Survey Replication, a nationally representative adult survey. Seven of the eight pathological dissociation taxon items were inquired about over the past month and scored on a 4-point scale. A conservative PD cutoff score was applied, with 100% specificity against healthy individuals and 84% sensitivity for Depersonalization Disorder which lies at the less severe end of the dissociative disorder spectrum; it yielded a national PD prevalence of 4.1%. The PD group had diminished physical and mental health, marked comorbidity with most major psychiatric disorders, and high likelihood of psychiatric hospitalization. Over half of PD members had attempted suicide, significantly more than individuals with lifetime major depression. Childhood maltreatment was quantified for physical abuse, witnessing domestic violence, physical neglect, emotional abuse, and emotional neglect. Total childhood trauma significantly positively predicted PD severity, as well as severity of all three pathological dissociative experiences (amnesia, depersonalization / derealization, identity alteration). Furthermore, each childhood trauma category significantly predicted PD severity uniquely and additively. Childhood maltreatment in the PD group was significantly greater than in lifetime major depression, except for similar emotional neglect, and was comparable to lifetime PTSD. The study reinforces the validity of prior PD findings across clinical and community samples, and highlights the need for increased attention toward diagnosing and treating these quite common and highly morbid disorders and their traumatic antecedents.

The Dissociative Taxon and Dissociative Identity Disorder

A total of 491 participants from four previous studies, 443 of whom were diagnosed with dissociative identity disorder (DID) on the Dissociative Disorders Interview Schedule, completed the Dissociative Experiences Scale (DES). Their results were analyzed to determine how many were in the dissociative taxon (DES-T) on the DES. Of the 443 individuals with DID, 419 (94.6%) were in the taxon, 13 (2.9%) were out of the taxon and 11 (2.5%) were indeterminate. The DES-T is therefore very effective at identifying people with DID as being in the dissociative taxon, although it does have a false negative rate of 5.4%. Out of 48 people with no dissociative disorder on the Dissociative Disorders Interview Schedule, the DES-T identified 26 (54.2%) as being in the taxon and 22 (45.8%) as being out of the taxon with no indeterminate cases. The clinical diagnoses of these 48 individuals are unknown: all were inpatients in the same Trauma Program. Thus, the sensitivity of the DES-T for confirming that individuals with DID are in the dissociative taxon was 94.6% and the specificity of the DES-T for confirming that individuals with no dissociative disorder are not in the dissociative taxon was 45.8%. It is possible that the DES-T yields false positives for taxon membership; this possibility should be investigated in future research.

Dissociation and false memory: the moderating role of trauma and cognitive ability

The term dissociation is often used to refer to a diverse range of psychological symptoms, including perceptual impairments, emotional detachment, and memory fragmentation. In the present study, we examined whether there was a relation between participants' self-reports of dissociative experiences and their memory performance in the Deese-Roediger-McDermott (DRM) paradigm-a laboratory-based procedure that is frequently used to investigate false memory. University students (N = 298) completed the Dissociative Experiences Scale (DES) and the Traumatic Life Events Questionnaire (TLEQ). Participants were also administered a standardised intelligence test (Shipley-2), and they were tested in the DRM paradigm. Overall, experiencing trauma and dissociation, as well as lower levels of cognitive ability, were associated with higher false memory. These findings are discussed in the context of the activation monitoring theory of DRM false memory.

The Association between General and Pathological Dissociation and Disaster-Related Psychopathology in Directly Exposed Survivors

Objective: Dissociation and trauma have a well-documented relationship, and dissociation is assumed to result from trauma exposure. If trauma generates dissociative psychopathology, it should be observed after exposure to disaster and be associated with disaster-related psychopathology. Few studies have focused specifically on dissociation as an outcome of disaster trauma. This study examined dissociation and its association with disaster-related psychopathology in survivors of five different disasters. Methods: In the first 6 postdisaster months, directly exposed survivors (N = 216) of mass shootings, floods, or a firestorm completed structured diagnostic interviews providing lifetime predisaster and postdisaster prevalent/incident psychiatric diagnoses and the Dissociative Experiences Scale (DES) 1-3 years after baseline. Results: DES scores were very low; only 1% met the DES Taxon signifying pathological dissociation. In multivariate models including predisaster lifetime major depression, lifetime panic disorder, lifetime generalized anxiety disorder, and lifetime alcohol use disorder; disaster-related PTSD; and number of incident somatoform symptoms as independent covariates, predisaster lifetime major depression and alcohol use disorder were independently associated with both general (DES score) and pathological (DES Taxon) dissociation, and postdisaster incident somatization symptoms were also associated with general dissociation, but postdisaster psychopathology including disaster-related PTSD was not associated with general or pathological dissociation. Conclusions: Neither general nor pathological dissociation was independently associated with disaster-related PTSD or other incident psychopathology. The only psychiatric disorders associated with dissociation were present before the disasters. Coupled with the low dissociation rates, these findings indicate that dissociation does not appear to be a mental health outcome of disaster trauma.

Dissociation and disasters: A systematic review

BACKGROUND

Dissociation, which is defined as the failure to associate consciousness, memory, identity, emotion, perception, body representation, motor control, and behavior into an integrated whole, has long been assumed to be generated by trauma. If dissociation is a product of trauma exposure, then dissociation would be a major mental health outcome observed in studies of disaster survivors. Although some studies have examined dissociation in disasters, no systematic literature reviews have been conducted to date on the topic.

AIM

To systematically evaluate the literature on the association between disaster and dissociation to determine the prevalence and incidence of dissociation after exposure to disaster and further examine their relationship.

METHODS

EMBASE, Medline, and PsychINFO were searched from inception to January 1, 2019 to identify studies examining dissociative disorders or symptoms related to a disaster in adult or child disaster survivors and disaster responders. Studies of military conflicts and war, articles not in English, and those with samples of 30 or more participants were excluded. Search terms used were “disaster*” and dissociation (“dissociat*,” “multiple personality,” “fugue,” “psychogenic amnesia,” “derealization,” and “depersonalization”). Reference lists of identified articles were scrutinized to identify studies for additional articles.

RESULTS

The final number of articles in the review was 53, including 36 articles with samples of adults aged 18 and above, 5 of children/adolescents under age 18, and 12 of disaster workers. Included articles studied several types of disasters that occurred between 1989 and 2017, more than one-third (38%) from the United States. Only two studies had a primary aim to investigate dissociation in relation to disaster and none reported data on dissociative disorders. All of the studies used self-report symptom scales; none used structured interviews providing full diagnostic assessment of dissociative disorders or other psychopathology. Several studies mixed exposed and unexposed samples or did not differentiate outcomes between exposure groups. Studies examining associations between dissociation and disaster exposure have been inconclusive. The majority (75%) of the studies compared dissociation with posttraumatic stress, with inconsistent findings. Dissociation was found to be associated with a wide range of other psychiatric disorders, symptoms, and negative emotional, cognitive, and functional states.

CONCLUSION

The studies reviewed had serious methodological limitations including problems with measurement of psychopathology, sampling, and generation of unwarranted conclusions, precluding conclusions that dissociation is an established outcome of disaster.

The Detachment and Compartmentalization Inventory (DCI): An assessment tool for two potentially distinct forms of dissociation

While evidence suggests a division between two qualitatively distinct forms of dissociation, no scale has been specifically designed to differentiate between them. This study describes the development and validation of the Detachment and Compartmentalization Inventory (DCI). The DCI was developed from dissociation theory, 29 existing dissociation scales and expert opinion. An initial pilot study was conducted which assessed readability, explored validity and reduced items before the DCI was administered online to 89 nonclinical and 105 clinical participants. The Dissociative Experiences Scale (DES), Somatoform Dissociation Questionnaire (SDQ), and Mindfulness Attention Awareness Scale (MAAS) were included in the survey battery. The DCI exhibited good internal reliability, discriminant validity, convergent validity, construct validity and concurrent validity. The final version containing 22-items, is self-administered, grounded in the theoretical literature and supported by initial psychometric evaluation. It has 10 items assessing compartmentalization, 10 items assessing detachment and two items examining valid responding. The DCI could detect compartmentalization and detachment, and was designed for clinical research and for screening patients.

A study of dissociation in survivors of 5 disasters

This study examined dissociation as an outcome to disaster in dissociative data collected from 423 highly-exposed survivors of 5 different disasters using consistent methodology. Ten items selected for conceptual relevance to disaster experience were administered from the Dissociative Disorders Interview Schedule, a structured interview for lifetime dissociative disorders. Structured psychiatric interviews provided data on incident somatization symptoms, disaster-related PTSD, and lifetime predisaster psychopathology. The Temperament and Character Inventory assessed personality. Observed levels of dissociation were low and not usually postdisaster. Dissociation level was associated with female sex, number of incident somatization symptoms, personality (underdeveloped executive functioning), PTSD, and predisaster psychopathology in bivariate analyses. In multiple linear regression models, dissociation was associated with the low number of incident somatoform symptoms observed independent of the effects of PTSD, hyperarousal specifically (but not intrusion or avoidance/numbing), personality, predisaster psychopathology, and demographic variables which were not independently associated with dissociation. The low levels of dissociation found in this study and the lack of association between dissociation and indicators of psychopathology point to a largely nonpathological nature of the dissociative phenomena measured. These findings do not indicate the development of dissociative psychopathology as a prevalent mental health outcome of disasters.

Strange-face illusions during eye-to-eye gazing in dyads: specific effects on derealization, depersonalization and dissociative identity

Experimentally induced strange-face illusions can be perceived when two individuals look at each other in the eyes under low illumination for about 10 minutes. This task of subject-other eye-to-eye gazing produces the following perceptions by the subject: (i) mild to huge deformations and color/shape changes of face and facial features; (ii) lifeless, unmoving faces and immaterial presences akin to out-of-body experiences; (iii) pseudo-hallucinations, enlightened 'idealized' faces and personalities - rather than the other's actual face. Dissociative phenomena seem to be involved, whereas the effects of non-pathological dissociation on strange-face illusions have not yet been directly investigated. In the present study, dissociative perceptions and strange-face illusions were measured through self-report questionnaires on a large sample (N = 90) of healthy young individuals. Results of correlation and factor analyses suggest that strange-face illusions can involve, respectively: (i) strange-face illusions correlated to derealization; (ii) strange-face illusions correlated to depersonalization; and (iii) strange-face illusions of identity, which are supposedly correlated to identity dissociation. The findings support the separation between detachment and compartmentalization in dissociative processes. Effects of gender show that strange-face illusions are more frequent in men with respect to women if dyads are composed of individuals of different-gender. Furthermore, drawings of strange-faces, which were perceived by portrait artists in place the others' faces, allowed a direct illustration of examples of dissociative identities. Findings are discussed in relation to the three-level model of self-referential processing.

Depersonalization, adversity, emotionality, and coping with stressful situations

Depersonalization is defined as persistent or recurrent episodes of feeling detached or estranged from a sense of self and the world. This study addressed the primary question: Do nonclinical individuals who endorse high symptomatic depersonalization have inherently more intense emotional responses, along with more childhood adversity and past trauma? In this IRB approved study, participants who met clinical levels of depersonalization (n = 43, 16.3%) were compared to a group without clinical levels of depersonalization (n = 221, 83.7%). Adverse childhood experiences, adult traumatic events, emotional overexcitability, coping strategies under stress, and anxiety were examined in both groups. The variables to assess depersonalization severity included the Dissociative Experience Scale-II, Cambridge Depersonalization Scale, and Multiscale Dissociation Inventory. The results indicated that clinical levels of depersonalization were identified in 16.3% of the sample. The high depersonalization group had significantly more adverse childhood experiences, in particular, emotional abuse and neglect. They also experienced more adult traumatic events, higher levels of anxiety, more emotional overexcitability, and they employed a less adaptive emotion-oriented coping strategy under stress. It is recommended that treating depersonalization symptoms should include examining childhood adversity, especially emotional abuse and neglect. Based on study findings, emotion regulation skills should be promoted to help individuals with elevated depersonalization manage their emotion-oriented coping strategies, anxiety, and emotional overexcitability.

Misattributing the Source of Self-Generated Representations Related to Dissociative and Psychotic Symptoms

Objective: An intertwined relationship has been found between dissociative and psychotic symptoms, as the two symptom clusters frequently co-occur, suggesting some shared risk factors. Using a source monitoring paradigm, previous studies have shown that patients with schizophrenia made more errors in source monitoring, suggesting that a weakened sense of individuality may be associated with psychotic symptoms. However, no studies have verified a relationship between sense of individuality and dissociation, and it is unclear whether an altered sense of individuality is a shared sociocognitive deficit underlying both dissociation and psychosis.

Method: Data from 80 acute psychiatric patients with unspecified mental disorders were analyzed to test the hypothesis that an altered sense of individuality underlies dissociation and psychosis. Behavioral tasks, including tests of intelligence and source monitoring, as well as interview schedules and self-report measures of dissociative and psychotic symptoms, general psychopathology, and trauma history, were administered.

Results: Significant correlations of medium effect sizes indicated an association between errors attributing the source of self-generated items and positive psychotic symptoms and the absorption and amnesia measures of dissociation. The associations with dissociative measures remained significant after the effects of intelligence, general psychopathology, and trauma history were excluded. Moreover, the relationships between source misattribution and dissociative measures remained marginally significant and significant after controlling for positive and negative psychotic symptoms, respectively.

Limitations: Self-reported measures were collected from a small sample, and most of the participants were receiving medications when tested, which may have influenced their cognitive performance.

Conclusions: A tendency to misidentify the source of self-generated items characterized both dissociation and psychosis. An altered sense of individuality embedded in self-referential representations appears to be a common sociocognitive deficit of dissociation and psychosis.

Is the Dissociative Experiences Scale able to identify detachment and compartmentalization symptoms? Factor structure of the Dissociative Experiences Scale in a large sample of psychiatric and nonpsychiatric subjects

BACKGROUND

In this study, we explored the ability of the Dissociative Experiences Scale (DES) to catch detachment and compartmentalization symptoms.

PARTICIPANTS AND METHODS

The DES factor structure was evaluated in 768 psychiatric patients (546 women and 222 men) and in 2,403 subjects enrolled in nonpsychiatric settings (1,857 women and 546 men). All participants were administered the Italian version of DES. Twenty senior psychiatric experts in the treatment of dissociative symptoms independently assessed the DES items and categorized each of them as follows: "C" for compartmentalization, "D" for detachment, and "NC" for noncongruence with either C or D.

RESULTS

Confirmatory factor analysis supported the three-factor structure of DES in both clinical and nonclinical samples and its invariance across the two groups. Moreover, factor analyses results overlapped with those from the expert classification procedure.

CONCLUSION

Our results showed that DES can be used as a valid instrument for clinicians to assess the frequency of different types of dissociative experiences including detachment and compartmentalization.

Cumulative traumatization associated with pathological dissociation in acute psychiatric inpatients

Clinical studies of patients with dissociative disorders and prospective studies of childhood trauma survivors show inconsistent findings regarding the relationship between childhood trauma and dissociation. This study aims to resolve this inconsistency by investigating how dissociation is related to parental dysfunctions, general psychopathology, childhood trauma, and adulthood trauma. Specifically, we focus on the role of cumulative traumatization in pathological and non-taxon dissociation. Eighty acute psychiatric inpatients were administrated standardized measures on dissociation, perceived parental dysfunctions, traumatizing events, and general psychopathology. Parental dysfunctions and trauma correlated with both types of dissociation and general psychopathology. When general psychopathology and parental dysfunctions were controlled, a unique link between trauma and dissociation remained significant. Moreover, the pattern of relationships differed for non-taxon and pathological dissociations. The effect of childhood but not adulthood trauma was significant on non-taxon dissociation. In contrast, an interactive model incorporating both childhood and adulthood trauma was the best model for explaining pathological dissociation. Childhood trauma is important for developing non-taxon dissociation, and adulthood trauma exacerbates its effects on the emergence of pathological dissociation. Cumulative traumatization from childhood to adulthood should be incorporated into the trauma hypothesis of pathological dissociation.

Abnormal cardiovascular sympathetic and parasympathetic responses to physical and emotional stimuli in depersonalization disorder

Background

Depersonalization disorder (DPD) is characterized by a subjective sense of unreality, disembodiment, emotional numbing and reduced psychogenic (sudomotor) sympathoexcitation.

Aims

Three related experiments utilized escalating physical and emotional challenges in 14 DPD participants and 16 controls aimed to elucidate (i) whether the cardiovascular sympathetic (SNS) and parasympathetic (PNS) nervous systems are implicated in DPD pathophysiology and (ii) if possible, to determine whether the blunted sympathoexcitation in DPD is peripherally or centrally mediated.

Method

Participants completed the Beck Anxiety Inventory (BAI), Dissociative Experience Scale (DES), and Cambridge Depersonalization Scale (CDS). Study I recorded heart rate (HR) and blood pressure (BP) during 5 min supine baseline, 3 min sustained handgrip (HG), 3 min cold pressor (CP) and 5 min 60° head-up tilt (HUT). In study II, HR, BP, and heart rate variability (HRV) were recorded during 5 min simultaneous 60° HUT and continuous presentation of unpleasant images (5 s per image). Study III examined HR and BP orienting responses (ORs) to simultaneous 60° HUT and pseudorandom presentation of unpleasant, neutral and pleasant images (5 s per image 3 min 25 s). OR data was grouped by image valence post hoc.

Results

DPD BAI (p = 0.0004), DES (p = 0.0002), and CDS (p ≤ 0.0001) scores were higher than controls. The DPD group produced diminished diastolic BP (DBP) (p = 0.045) increases to HG. Other indices were comparable between groups. DPD participants produced diminished systolic BP (SBP) (p = 0.003) and DBP (p = 0.002) increases, but greater (p = 0.004) HR increases to CP. In study II, DPD high frequency HRV (HF-HRV)—indicating parasympathetic vagal activity–was reduced (p = 0.029). In study III, DPD DBP was higher throughout the 5 s duration of HUT/pseudorandom unpleasant image presentation (1 s, p = 0.002, 2 s p = 0.033, 3 s p = 0.001, 4 s p = 0.009, 5 s p = 0.029).

Conclusions

Study I's BP pressor data supports previous findings of suppressed sympathoexcitation in DPD. The greater HR increases to CP, decreased HF-HRV in study II, and increased DBP during unpleasant ORs in study III implicates the SNS and PNS in DPD pathophysiology. These studies suggest the cardiovascular autonomic dysregulation in DPD is likely to be centrally-mediated.

Dissociative disorders in medical settings

Despite the challenges of conducting research on dissociation and the dissociative disorders, our understanding has grown greatly over the past three decades, including our knowledge of the often overlooked sensorimotor manifestations of dissociation, more commonly referred to as somatoform dissociation. This article will first review the definitions and presentations of dissociation in general along with recent research on the concept of somatoform dissociation. Then, each of the dissociative disorders and conversion disorder will be discussed in further detail as well as how they might present in a medical setting. Current recommendations for diagnosis and treatment will also be provided.

Dissociative disorders in DSM-5

BACKGROUND

We present recommendations for revision of the diagnostic criteria for the Dissociative Disorders (DDs) for DSM-5. The periodic revision of the DSM provides an opportunity to revisit the assumptions underlying specific diagnoses and the empirical support, or lack of it, for the defining diagnostic criteria.

METHODS

This paper reviews clinical, phenomenological, epidemiological, cultural, and neurobiological data related to the DDs in order to generate an up-to-date, evidence-based set of DD diagnoses and diagnostic criteria for DSM-5. First, we review the definitions of dissociation and the differences between the definitions of dissociation and conceptualization of DDs in the DSM-IV-TR and the ICD-10, respectively. Also, we review more general conceptual issues in defining dissociation and dissociative disorders. Based on this review, we propose a revised definition of dissociation for DSM-5 and discuss the implications of this definition for understanding dissociative symptoms and disorders.

RESULTS

We make the following recommendations for DSM-5: 1. Depersonalization Disorder (DPD) should include derealization symptoms as well. 2. Dissociative Fugue should become a subtype of Dissociative Amnesia (DA). 3. The diagnostic criteria for DID should be changed to emphasize the disruptive nature of the dissociation and amnesia for everyday as well as traumatic events. The experience of possession should be included in the definition of identity disruption. 4. Dissociative Trance Disorder should be included in the Unspecified Dissociative Disorder (UDD) category.

CONCLUSIONS

There is a growing body of evidence linking the dissociative disorders to a trauma history, and to specific neural mechanisms.

Dissociative disorders in DSM-5

BACKGROUND

We present recommendations for revision of the diagnostic criteria for the Dissociative Disorders (DDs) for DSM-5. The periodic revision of the DSM provides an opportunity to revisit the assumptions underlying specific diagnoses and the empirical support, or lack of it, for the defining diagnostic criteria.

METHODS

This paper reviews clinical, phenomenological, epidemiological, cultural, and neurobiological data related to the DDs in order to generate an up-to-date, evidence-based set of DD diagnoses and diagnostic criteria for DSM-5. First, we review the definitions of dissociation and the differences between the definitions of dissociation and conceptualization of DDs in the DSM-IV-TR and the ICD-10, respectively. Also, we review more general conceptual issues in defining dissociation and dissociative disorders. Based on this review, we propose a revised definition of dissociation for DSM-5 and discuss the implications of this definition for understanding dissociative symptoms and disorders.

RESULTS

We make the following recommendations for DSM-5: 1. Depersonalization Disorder (DPD) should derealization symptoms as well. 2. Dissociative Fugue should become a subtype of Dissociative Amnesia (DA). 3. The diagnostic criteria for DID should be changed to emphasize the disruptive nature of the dissociation and amnesia for everyday as well as traumatic events. The experience of possession should be included in the definition of identity disruption. 4. Should Dissociative Trance Disorder should be included in the Unspecified Dissociative Disorder (UDD) category.

CONCLUSIONS

There is a growing body of evidence linking the dissociative disorders to a trauma history, and to specific neural mechanisms.

Quality of early care and childhood trauma: a prospective study of developmental pathways to dissociation

Kihlstrom (2005) has recently called attention to the need for prospective longitudinal studies of dissociation. The present study assesses quality of early care and childhood trauma as predictors of dissociation in a sample of 56 low-income young adults followed from infancy to age 19. Dissociation was assessed with the Dissociative Experiences Scale; quality of early care was assessed by observer ratings of mother-infant interaction at home and in the laboratory; and childhood trauma was indexed by state-documented maltreatment, self-report, and interviewer ratings of participants' narratives. Regression analysis indicated that dissociation in young adulthood was significantly predicted by observed lack of parental responsiveness in infancy, while childhood verbal abuse was the only type of trauma that added to the prediction of dissociation. Implications are discussed in the context of previous prospective work also pointing to the important contribution of parental emotional unresponsiveness in the development of dissociation.

Demographic and mental health factors associated with pathological dissociation in a Portuguese sample

Pathological dissociation has been extensively studied in many countries; however, little is known about it in Portugal. This research examined the role of demographic variables and mental health on dissociation in Portugal. We assessed 505 participants from 6 samples consisting of dissociative patients (n = 37), conversive patients (n = 26), somaticizing patients (n = 59), posttraumatic stress disorder patients (n = 50), other psychiatric patients (n = 174), and nonclinical subjects (n = 159). Dissociation was measured by Portuguese versions of the Dissociative Experiences Scale and Somatoform Dissociation Questionnaire; the LEAD procedure and subscales of the Brief Symptom Inventory indicated mental health. Pathological psychological dissociation was significantly more frequent in women, in the youngest of the participants, and in those with less education. Multiple logistic regression revealed that psychoticism, paranoid ideation, and depression symptoms made both men and women more vulnerable to psychological dissociation. Furthermore, psychological dissociation was more probable in men having symptoms of obsession and paranoid ideation and in women having symptoms of psychoticism and paranoid ideation. Pathological somatoform dissociation was significantly more probable in women with less education. Moreover, somatoform dissociation was more likely in women with somatization symptoms and more likely in men with symptoms of somatization and psychoticism. Even though significant associations were found, causal relations could not be established because the study was cross-sectional.

Somatoform dissociation in depersonalization disorder

Along with psychoform dissociation, somatoform dissociation has been put forth as a core aspect of dissociative states, possibly as reliable as psychoform dissociation in the screening for dissociative disorders. The goal of this study was to investigate the prominence and correlates of somatoform dissociation in one of the major Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.) dissociative disorders, depersonalization disorder (DPD). A total of 54 adults with DPD and 47 healthy control participants free of lifetime Axis I and II disorders were administered the 20-item Somatoform Dissociation Questionnaire (SDQ) as well as the Dissociative Experiences Scale, the Cambridge Depersonalization Scale, and the Childhood Trauma Questionnaire-Short Form. Somatoform dissociation scores were statistically significantly, but clinically only modestly, elevated in the DPD as compared to the healthy control group. SDQ items significantly elevated in the DPD group were mostly perceptual in nature. Depersonalization scores were significantly correlated with somatoform dissociation in the DPD group, whereas absorption and amnesia scores were not. With respect to childhood interpersonal trauma, although emotional abuse was significantly associated with depersonalization severity, none of the 5 categories of trauma were significantly associated with somatoform dissociation in the DPD group. In conclusion, somatoform dissociation is modest in DPD, and the SDQ is a weak instrument for the screening of dissociation in this disorder, detecting only one third of the sample when using the traditional SDQ cutoff score of 30.

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.

Dissociation and pain perception: an experimental investigation

Dissociative symptoms and abnormalities in pain perception have been associated with a range of disorders. The authors tested whether experimentally induced increases in state dissociation would cause an analgesic response. Participants (N = 120) were randomized to a dissociation induction condition via audiophotic stimulation or a credible control condition and were compared on pre- and postchanges in subjective pain and immersion time in response to a standard cold pressor test. Unexpectedly, the dissociation induction led to small, but significant increases in subjective pain and did not lead to greater immersion time. An exploratory analysis revealed that increases in absorption and derealization significantly predicted increased subjective pain and increased immersion time, respectively.

Depersonalization in psychiatric patients: a transcultural study

There is evidence suggesting that the prevalence of depersonalization in psychiatric patients can vary across cultures. To explore the possible influence of culture on the prevalence of depersonalization, we compared psychiatric inpatient samples from the United Kingdom (N = 31), Spain (N = 68), and Colombia (N = 41) on standardized and validated self-rating measures of dissociation and depersonalization: the Cambridge Depersonalization Scale and the Dissociative Experiences Scale (DES). Colombian patients were found to have lower global scores on the Cambridge Depersonalization Scale and the DES and all its subscales, with the exception of DES-Absorption. No differences were found for measures of depression or anxiety. These findings seem to support the view that depersonalization is susceptible to cultural influences. Attention is drawn to the potential relevance of the sociological dimension "individualism-collectivism" on the experience of the self, and it is proposed that cultures characterized by high individualism may confer vulnerability to depersonalization experiences.