Dissociative symptoms and dissociative disorder comorbidity in patients with obsessive-compulsive disorder

Dissociative Identity Disorder: A Review of Research From 2011 to 2021

ABSTRACT

Dissociative identity disorder (DID) has historically been one of the most controversial topics in the study of psychopathology. Building on a previous review of empirical research on DID from 2000 to 2010, the present review examined DID research from 2011 to 2021. The research output included 56 case studies and 104 empirical studies. Within the empirical studies, approximately 1354 new cases of DID emerged, which resulted in an average samples of approximately 20. Reanalysis of previous samples was standard in the literature with only 40% of reported cases being new. Studies emerged from dozens of countries across the world, but the majority of cases were from Western counties, especially the United States. Diagnosis primarily relied upon validated measures, but 74% of all new cases came from six research groups. Overall, research on DID is steady but methodologically limited in ways that make generalization, especially about etiology, difficult.

Obsessive-compulsive symptoms and dissociative experiences: Suggested underlying mechanisms and implications for science and practice

A strong and specific link between obsessive-compulsive disorder or symptoms (OCD/S) and a tendency for dissociative experiences (e.g., depersonalization-derealization, absorption and imaginative involvement) cannot be explained by trauma and is poorly understood. The present theoretical formulation proposes five different models conceptualizing the relationship. According to Model 1, dissociative experiences result from OCD/S through inward-focused attention and repetition. According to Model 2, dissociative absorption causally brings about both OCD/S and associated cognitive risk factors, such as thought-action fusion, partly through impoverished sense of agency. The remaining models highlight common underlying causal mechanisms: temporo-parietal abnormalities impairing embodiment and sensory integration (Model 3); sleep alterations causing sleepiness and dreamlike thought or mixed sleep-wake states (Model 4); and a hyperactive, intrusive imagery system with a tendency for pictorial thinking (Model 5). The latter model relates to Maladaptive Daydreaming, a suggested dissociative syndrome with strong ties to the obsessive-compulsive spectrum. These five models point to potential directions for future research, as these theoretical accounts may aid the two fields in interacting with each other, to the benefit of both. Finally, several dissociation-informed paths for further developing clinical intervention in OCD are identified.

The Prevalence of Depersonalization-Derealization Disorder: A Systematic Review

Depersonalization-Derealization disorder (DDD) is a psychiatric condition characterized by persistent feelings of detachment from one's self and of unreality about the outside world. This review aims to examine the prevalence of DDD amongst different populations. A systematic review protocol was developed before literature searching. Original articles were drawn from three electronic databases and included only studies where prevalence rates of DDD were assessed by standardized diagnostic tools. A narrative synthesis was conducted. Twenty-three papers were identified and categorized into three groups of participants: general population, mixed in/outpatient samples, and patients with specific disorders. The prevalence rates ranged from 0% to 1.9% amongst the general population, 5-20% in outpatients and 17.5-41.9% in inpatients. In studies of patients with specific disorders, prevalence rates varied: 1.8-5.9% (substance abuse), 3.3-20.2% (anxiety), 3.7-20.4% (other dissociative disorders), 16.3% (schizophrenia), 17% (borderline personality disorder), ~50% (depression). The highest rates were found in people who experienced interpersonal abuse (25-53.8%). The prevalence rate of DDD is around 1% in the general population, consistent with previous findings. DDD is more prevalent amongst adolescents and young adults as well as in patients with mental disorders. There is also a possible relationship between interpersonal abuse and DDD, which merits further research.

Absorption and dissociation mediate the relationship between direct verbal suggestibility and impulsivity/compulsivity

Direct verbal suggestibility refers to the capacity for an individual to experience perceptual, motor, affective and cognitive changes in response to verbal suggestions. Suggestibility is characterized by pronounced, yet reliable, inter-individual differences. Previous research and theoretical considerations suggest that greater impulsivity and compulsivity is associated to higher suggestibility, but the characteristics and mediating factors of this association are poorly understood. Using established psychometric measures in an online sample, we found positive correlations between the domain comprising impulsivity, compulsivity and behavioural activation, and the domain of suggestibility, dissociation and absorption. We also observed that dissociation and absorption mediated the link between suggestibility and impulsivity, and between suggestibility and behavioural activation, respectively. These results confirm the positive link between suggestibility and the impulsivity/compulsivity domain and shed new light on the characterisation of traits associated with suggestibility.

Does the Presence of Dissociative Symptoms Affect the Response to Venlafaxine Treatment for Major Depression? An Open-Label, Prospective Study

Many psychiatric diseases may be accompanied by dissociative symptoms and disorders. This study examined whether dissociative symptoms affect the response to venlafaxine treatment for major depressive disorder (MDD). The study included 40 patients who had a diagnosis of MDD according toDiagnostic and Statistical Manual of Mental Disorders(fifth edition) criteria. Venlafaxine was administered to each patient (37.5 mg to 150 mg daily) for 10 weeks. The researchers used the Beck Depression Inventory (BDI) and the Dissociation Questionnaire (DIS-Q) on cases with MDD at the beginning of the study. The researchers divided the patients into two groups according to DIS-Q scores and conducted the BDI again at the end of the 10-week period.

The authors detected the difference between the values of decrease in BDI scores as a percentage. They found these values to be 48.03% ± 29.03 in the low DIS-Q group and 27.06% ± 32.91 in the high DIS-Q group. They also found a significant difference between the groups (z = −2.167; P = .030). This study showed that, in patients with MDD, intense dissociative experiences reduced the response to venlafaxine therapy.

[Psychiatr Ann2022;52(3):119–125.]

Maladaptive Daydreaming and Obsessive-Compulsive Symptoms: A confirmatory and exploratory investigation of shared mechanisms

Maladaptive Daydreaming (MD) is a newly proposed mental disorder characterized by excessive, vivid fantasy activity impairing functioning. There is a high comorbidity of MD with Obsessive-Compulsive Spectrum Symptoms (OCSS), yet the mechanisms responsible for this relationship are still unclear. The present study set out to explore the relationship between MD and OCSS by: (1) examining dissociation, trauma, sense of control, and mind-wandering as potential mediators; (2) exploring whether MD is more strongly related to obsessions or compulsions; and (3) identifying patterns of specific obsessions and/or compulsions common in an MD sample. A group of 510 participants with self-identified MD completed a battery of online questionnaires. Dissociation and sense of control significantly mediated the MD-OCSS association. MD was moderately related to both obsessions and compulsions but was significantly more strongly related to the former. Frequently endorsed obsessions and compulsions among MD participants included checking and repetition compulsions, intrusive obsessions, and body-related obsessions and compulsions. We conclude that dissociative mechanisms, including dissociative absorption, play a major role in the relationship between MD and OCSS and may lead to consequent checking when transitioning back to reality, altered embodiment, intrusive images, and thoughts, and an impaired sense of mental control. Clinicians working with OCSS should be aware of the possible role of MD in the development or maintenance of symptoms. Future work should develop useful interventions for this type of shared psychopathology.

"Was it real or did I imagine it?" Perfectionistic beliefs are associated with dissociative absorption and imaginative involvement in obsessive-compulsive disorder

Background and objectives

In the literature there are inconsistent data regarding the role of dissociation in OCD. No study explored the association between obsessive beliefs and dissociative symptoms in OCD. It is important to understand which clinical factors are related to dissociation in OCD as more severe dissociative symptoms, particularly absorption, have been found to be predictors of treatment non-response. In the present short report we describe the results of an exploratory study aimed to investigate the role of the obsessive beliefs as predictors of the different dissociative symptoms controlling for anxiety and OCD severity in a group of OCD patients.

Methods

Sixty treatment-seeking patients consecutively referred to psychiatric services were included (mean age=31.17 years, 53.30% females). The Dissociative Experiences Scale-II, the Obsessive Beliefs Questionnaire-46, the Yale-Brown Obsessive-Compulsive Scale, and the Beck Anxiety Inventory were administered.

Results

Higher anxious symptoms predicted higher Dissociative Amnesia, Depersonalization/Derealization, and Absorption/Imaginative Involvement. Higher OCD severity predicted higher Dissociative Amnesia. More severe Perfectionism predicted higher Absorption/Imaginative Involvement.

Conclusion

Perfectionism in OCD patients may be associated with a higher tendency to absorption and imaginative involvement. Future research should explore whether a psychotherapeutic intervention on perfectionism might improve the outcomes of the OCD patients with higher absorption tendencies.

Development and Preliminary Psychometric Properties of an Instrument for the Measurement of Obsessional Dissociative Experiences: The Van Obsessional Dissociation Questionnaire (VOD-Q)

A growing body of research evidence documents the substantial associations between obsessive-compulsive disorder (OCD) and dissociation. This article describes the development and preliminary psychometric properties of the Van Obsessional Dissociation Questionnaire (VOD-Q). Obsessional dissociation is defined as a tendency to dissociate in reaction to distressing, unwanted and intrusive thoughts, images and impulses. The screening tool is conceptualized to tap obsessional dissociation across three dimensions: obsessional absorption, obsessional depersonalization/ derealization and obsessional amnesia. The VOD-Q, the Padua Inventory-Revised (PI-R), the Dissociative Experiences Scale (DES), and the Obsessive Belief Questionnaire (OBQ-44) were administered in this study. The results showed that the VOD-Q had excellent test-retest reliability (ranging from 0.73 to 0.90) and internal consistency (ranging from 0.90 to 0.97). The VOD-Q total and subscale scores were significantly associated with measures of obsessive-compulsive symptoms and dissociative experiences. OCD patients scored significantly higher on the VOD-Q than community participants. Based on the present findings, the VOD-Q appears to be a reliable and valid instrument for the measurement of obsessional dissociative experiences.

Evaluation of Relationship between Obsessive-compulsive Disorder and Dissociative Experiences

Objective

The aim of the study is to evaluate the relationship between obsessive-compulsive disorder (OCD) symptoms and dissociative experiences and the effect of childhood traumatic experiences on this relationship in OCD patients.

Methods

Fifty consecutive OCD patients and 50 healthy controls are enrolled for this study. Sociodemographic and Clinical Data Form, Dissociative Experiences Scale (DES), Padua Inventory (PI) and Childhood Trauma Questionnaire (CTQ) are applied to participants.

Results

Average DES total score in the patient group is 20.58 and in the control group it is 4.87. In the patient group, when we evaluate the relation strengths of DES total and subscale scores with PI total score, we found out that amnesia subscale has r=0.361 (p<0.01), absorption subscale has r=0.611 (p<0.01), depersonalization/derealization subscale has r=0.574 (p<0.01), and DES total score has r=0.55 (p<0.01) relation strengths with PI total score. In patient group both DES total score and CTQ total score have influence on PI total score independently from each other. In addition to this, the level of the influence of DES total scores on PI total scores is, R²=0.399 (p<0.01) and the level of the influence of CTQ total scores on PI total scores is R²=0.343 (p<0.01).

Conclusion

Dissociative experiences are seen more frequently in OCD patients than healthy controls. Among dissociative experiences, absorption has stronger relation with OCD symptoms. The relation between OCD and dissociation is independent from and stronger than the relation between childhood traumatic experiences and OCD.

Neurological soft signs, dissociation and alexithymia in patients with obsessive-compulsive disorder (OCD) and healthy subjects

A body of evidence has supported that patients with obsessive-compulsive disorder (OCD) have increased rates of various neurological soft signs (NSS) compared to controls. Various lines of research has documented robust relationships between OCD and dissociative symptomatology. The study aimed to examine the associations between obsessive-compulsive symptoms, dissociative experiences alexithymia, and NSS. The study included thirty OCD patients and thirty healthy controls, matched for age, marital status, education, and income. The Neurological Evaluation Scale (NES), Padua Inventory-Revised (PI-R), Dissociative Experiences Scale (DES) and Toronto Alexithymia Scale (TAS-20) were administered. In comparison to healthy controls, patients with OCD had difficulty sequencing for complex motor acts and greater absorption/ imaginative involvement. Using latent class analysis, the study sample was classified into two homogenous subsets as mild NSS (n = 45) and severe NSS (n = 15). Majority of the participants who were grouped into severe NSS latent class were OCD patient (n = 14, 93.3%). Furthermore, those with severe NSS reported greater levels of alexithymia and more severe obsessive-compulsive symptoms, particularly precision. We concluded that relationships between OCD severity and NSS appear to be of crucial importance. Our data along with accumulated evidence suggest that OCD associated with pronounced NSS may represent a specific subtype of the disorder.

Complexity in obsessive-compulsive and body dysmorphic disorder – a functional approach to complex difficulties

Obsessive-compulsive disorder (OCD) and related disorders such as body dysmorphic disorder (BDD) can take many different forms of presentations. The term ‘complex’ is common and inconsistently used in both OCD and BDD. Practitioners often refer to complex OCD or BDD when patients present with severe co-morbid problems, often in the context of personality difficulties, dissociation, difficult early relationships and trauma; or when the illness is chronic and debilitating with previous multiple treatment failures. Current best-evidence treatment protocols for both disorders focus heavily on exposure and response prevention (E/RP) but with moderate success, particularly in patients who are deemed ‘complex’, and often those with relevant shame and/or disgust-based past experiences. The aim of the present paper is to (a) describe factors that contribute to complexity in OCD and BDD, and (b) link these with theory and practice. We emphasize the importance of understanding both the function of OCD and BDD-related behaviours (rather than the content of obsessions or compulsion), and the context in which they occur such as the family. We illustrate complexity in OCD and BDD using real case material, using a functional and contextual approach to formulate the client's difficulties, and demonstrate how E/RP can be enhanced successfully with imagery rescripting, family work, and compassion-focused therapy.

Dissociative Experiences and Psychopathology Among Inmates in Italian and Portuguese Prisons

The association between dissociation and psychopathological symptoms is well established, yet studies with inmates are lacking. If higher rates of dissociation and psychiatric symptoms are reported in inmate samples, it is not clear whether they represent two separate, albeit related, characteristics. We examined the association between dissociation and psychopathological symptoms among 320 Italian subjects (122 inmates and 198 community participants) and a Portuguese inmate sample ( n = 67). Then, we tested whether dissociation and psychopathology levels were higher among inmates. Both hypotheses were supported, confirming the relevance of dissociative, paranoid, and psychotic symptoms among inmates, as well as their interrelations. Notably, the group difference in dissociation remained significant after partialing out the variance associated with other psychopathological symptoms. Conversely, only the difference in paranoid symptoms remained-marginally-significant when controlling for the influence of dissociation. This finding suggests that dissociation may have unique relevance for the psychological functioning of inmates.

The link between dissociation and both suicide attempts and non-suicidal self-injury: Meta-analyses

Dissociative disorders (DD) are frequently associated with suicidal behaviors. We performed the first meta-analysis of studies comparing rates of suicide attempts (SA) and non-suicidal self-injury (NSSI) in psychiatric individuals with and without DD. We included: 1) studies comparing SA and NSSI rates in psychiatric individuals with and without DD; 2) studies comparing Dissociative Experiences Scale (DES) scores in both SA and NSSI psychiatric patients versus non SA and non NSSI ones. Cochrane Collaboration Review Manager Software and STROBE statement were used. Nineteen studies were included in the analyses. DD patients were more likely to report both previous SA and NSSI in comparison to non DD patients. Importantly, results remained highly significant in both outcomes but with no more heterogeneity when including studies using a DSM-based method to diagnose DD. Both SA and NSSI patients reported higher DES scores in comparison to non SA and non NSSI patients. The presence of DD diagnosis or higher DES scores seems to be related to both SA and NSSI in psychiatric patients. Hence, it may be reasonable to hypothesize the presence of a dissociative subtype in a subset of these patients, which should be considered as a transdiagnostic factor and should be carefully assessed.

Is there a complex relation between social anxiety disorder, childhood traumatic experiences and dissociation?

BACKGROUND

A possible relationship has been suggested between social anxiety and dissociation. Traumatic experiences, especially childhood abuse, play an important role in the aetiology of dissociation.

AIM

This study assesses childhood trauma history, dissociative symptoms, and dissociative disorder comorbidity in patients with social anxiety disorder (SAD).

METHOD

The 94 psychotropic drug-naive patients participating in the study had to meet DSM-IV criteria for SAD. Participants were assessed using the Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D), the Dissociation Questionnaire (DIS-Q), the Liebowitz Social Anxiety Scale (LSAS), and the Childhood Trauma Questionnaire (CTQ). Patients were divided into two groups using the DIS-Q, and the two groups were compared.

RESULTS

The evaluation found evidence of at least one dissociative disorder in 31.91% of participating patients. The most prevalent disorders were dissociative disorder not otherwise specified (DDNOS), dissociative amnesia, and depersonalization disorders. Average scores on LSAS and fear and avoidance sub-scale averages were significantly higher among the high DIS-Q group (p < .05). In a logistic regression taking average LSAS scores as the dependent variable, the five independent variables DIS-Q, CTQ-53 total score, emotional abuse, sexual abuse, and emotional neglect were associated with average LSAS scores among patients with SAD (p < .05).

CONCLUSIONS

It is concluded that, on detecting SAD symptoms during hospitalization, the clinician should not neglect underlying dissociative processes and traumatic experiences among these patients.

Open-longitudinal study of the effect of dissociative symptoms on the response of patients with panic disorder to venlafaxine

The relationship between Panic Disorder (PD) and dissociation is well known. In this study we aimed to investigate whether or not dissociative experiences affect the response to PD drug treatment. For this purpose, standart dose of venlafaxine was preferred for treatment. 63 patients with PD were included in the study. Venlafaxine treatment with increasing dose was administered to each patient during a 10-week period. The Panic Disorder Severity Scale (PDSS) and the Dissociation Questionnaire (DIS-Q) were applied to the patients at the beginning of the study. Patients were divided into two groups based on DIS-Q scores. PDSS was applied again to both groups at the end of 10-week treatment. No difference between sociodemographic data and PDSS scores of two groups - patients with low DIS-Q scores (<2.5) and high DIS-Q scores (>2.5) - was found at the beginning. At the end of the study, a significant decrease in PDSS scores measured in both groups was detected. However, the decrease in PDSS score for the group with lower DIS-Q score was at a higher percentage (z=-3.822, p=0.0001). These results depict that dissociative symptoms accompanying PD affect psychopharmacological treatment in a negative way. Reevaluation of dissociative symptoms at the beginning and end of treatment would help in planning personal therapy.

Childhood Traumatic Experiences, Dissociative Symptoms, and Dissociative Disorder Comorbidity Among Patients With Panic Disorder: A Preliminary Study

This study assessed childhood trauma history, dissociative symptoms, and dissociative disorder comorbidity in patients with panic disorder (PD). A total of 92 psychotropic drug-naive patients with PD, recruited from outpatient clinics in the psychiatry department of a Turkish hospital, were involved in the study. Participants were assessed using the Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D), Dissociation Questionnaire, Panic and Agoraphobia Scale, Panic Disorder Severity Scale, and Childhood Trauma Questionnaire. Of the patients with PD, 18 (19%) had a comorbid dissociative disorder diagnosis on screening with the SCID-D. The most prevalent disorders were dissociative disorder not otherwise specified, dissociative amnesia, and depersonalization disorders. Patients with a high degree of dissociation symptoms and dissociative disorder comorbidity had more severe PD than those without (p < .05). All of the childhood trauma subscales used were correlated with the severity of symptoms of dissociation and PD. Among all of the subscales, the strongest relationship was with childhood emotional abuse. Logistic regression analysis showed that emotional abuse and severity of PD were independently associated with dissociative disorder. In our study, a significant proportion of the patients with PD had concurrent diagnoses of dissociative disorder. We conclude that the predominance of PD symptoms at admission should not lead the clinician to overlook the underlying dissociative process and associated traumatic experiences among these patients.

Dissociative Experiences are Associated with Obsessive-Compulsive Symptoms in a Non-clinical Sample: A Latent Profile Analysis

INTRODUCTION

There has been a burgeoning literature considering the significant associations between obsessive-compulsive symptoms and dissociative experiences. In this study, the relationsips between dissociative symtomotology and dimensions of obsessive-compulsive symptoms were examined in homogeneous sub-groups obtained with latent class algorithm in an undergraduate Turkish sample.

METHOD

Latent profile analysis, a recently developed classification method based on latent class analysis, was applied to the Dissociative Experiences Scale (DES) item-response data from 2976 undergraduates. Differences in severity of obsessive-compulsive symptoms, anxiety and depression across groups were evaluated by running multinomial logistic regression analyses. Associations between latent class probabilities and psychological variables in terms of obsessive-compulsive sub-types, anxiety, and depression were assessed by computing Pearson's product-moment correlation coefficients.

RESULTS

The findings of the latent profile analysis supported further evidence for discontinuity model of dissociative experiences. The analysis empirically justified the distinction among three sub-groups based on the DES items. A marked proportion of the sample (42%) was assigned to the high dissociative class. In the further analyses, all sub-types of obsessive-compulsive symptoms significantly differed across latent classes. Regarding the relationships between obsessive-compulsive symptoms and dissociative symptomatology, low dissociation appeared to be a buffering factor dealing with obsessive-compulsive symptoms; whereas high dissociation appeared to be significantly associated with high levels of obsessive-compulsive symptoms.

CONCLUSION

It is concluded that the concept of dissociation can be best understood in a typological approach that dissociative symptomatology not only exacerbates obsessive-compulsive symptoms but also serves as an adaptive coping mechanism.

Dissociative symptoms and dissociative disorders comorbidity in obsessive compulsive disorder: Symptom screening, diagnostic tools and reflections on treatment

Borderline personality disorder, conversion disorder and obsessive compulsive disorder frequently have dissociative symptoms. The literature has demonstrated that the level of dissociation might be correlated with the severity of obsessive compulsive disorder (OCD) and that those not responding to treatment had high dissociative symptoms. The structured clinical interview for DSM-IV dissociative disorders, dissociation questionnaire, somatoform dissociation questionnaire and dissociative experiences scale can be used for screening dissociative symptoms and detecting dissociative disorders in patients with OCD. However, a history of neglect and abuse during childhood is linked to a risk factor in the pathogenesis of dissociative psychopathology in adults. The childhood trauma questionnaire-53 and childhood trauma questionnaire-40 can be used for this purpose. Clinicians should not fail to notice the hidden dissociative symptoms and childhood traumatic experiences in OCD cases with severe symptoms that are resistant to treatment. Symptom screening and diagnostic tools used for this purpose should be known. Knowing how to treat these pathologies in patients who are diagnosed with OCD can be crucial.

Are trauma and dissociation related to treatment resistance in patients with obsessive-compulsive disorder?

OBJECTIVE

Previous research has indicated a relation between obsessive-compulsive disorder (OCD), childhood traumatic experiences and higher levels of dissociation that appears to relate to negative treatment outcome for OCD. The aim of the present study is to investigate whether childhood trauma and dissociation are related to severity of OCD in adulthood. We also intend to examine the association between treatment resistance, dissociation, and each form of trauma.

METHODS

Participants included 120 individuals diagnosed with OCD; 58 (48.3 %) of them met the criteria for treatment-resistant OCD (resistant group), whereas the other 62 (51.7 %) were labeled as responder group. The intensity of obsessions and compulsions was evaluated using Yale-brown obsessive-compulsive scale (Y-BOCS). All patients were assessed with the traumatic experiences checklist, dissociative experiences scale, beck depression inventory, and beck anxiety inventory.

RESULTS

Controlling for clinical variables, resistant group had significantly higher general OCD severity, anxiety, depression, trauma, and dissociation scores than the responders. Correlation analyses indicated that Y-BOCS scores were significantly related to severity of dissociation, anxiety, depression, and traumatic experiences. In a logistic regression analysis with treatment resistance as a dependent variable, high dissociation levels, long duration of illness, and poor insight emerged as relevant predictors, but gender, levels of anxiety, depression, and traumatic experiences did not.

CONCLUSIONS

Our results suggest that dissociation may be a predictor of poorer treatment outcome in patients with OCD; therefore, a better understanding of the mechanisms that underlie this phenomenon may be useful. Future longitudinal studies are warranted to verify if this variable represents predictive factors of treatment non-response.

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 depression among women in the community

This study screened the prevalence and correlates of dissociative disorders among depressive women in the general population. The Dissociative Disorders Interview Schedule and the posttraumatic stress disorder (PTSD) and borderline personality disorder sections of the Structured Clinical Interview for DSM-IV were administered to 628 women in 500 homes. The prevalence of current major depressive episode was 10.0%. Of the women, 26 (40.6%) had the lifetime diagnosis of a DSM-IV, dissociative disorder, yielding a prevalence of 4.1% for dissociative depression. This group was younger (mean age = 30.7 years) than the nondissociative depression women (mean age = 39.6 years). There was no difference between the 2 groups on comorbid somatization disorder, PTSD, or borderline personality disorder. Besides suicide attempts, the dissociative group was characterized by secondary features of dissociative identity disorder; Schneiderian symptoms; borderline personality disorder criteria; and extrasensory perceptions, including possession experiences. They reported suicidality, thoughts of guilt and worthlessness, diminished concentration and indecisiveness, and appetite and weight changes more frequently than the nondissociative group. Early cessation of school education and childhood sexual abuse were frequently reported by the dissociative depression group. With its distinct features, the concept of dissociative depression may facilitate understanding of treatment resistance in, development of better psychotherapy strategies for, and new thinking on the neurobiology and pharmacotherapy of depressive disorders.