ABSTRACT
Introduction: The Dissociative Experiences Scale (DES-II) is a widely used psychometric tool to assess dissociative symptoms. Over the years, it has been the subject of numerous studies and research in various fields of psychology and psychiatry. Numerous studies have supported the validity and reliability of the DES-II as a reliable measure of dissociative experiences. The most problematic aspect of the DES-II is the inconsistency in its factor structure. Objective: This research aimed to examine the psychometric properties of the DES-II in a clinical and non-clinical sample from Puerto Rico. Method: This research had an instrumental design. An availability sampling of 341 adult participants was used. Several competing models of the DES-II were analyzed, including a bifactor model. Result: Psychometric analyses concluded that the scale has a unidimensional structure, strong reliability, and construct validity. All 28 items met adequate discrimination values. Participants with dissociative disorders obtained higher means on the DES-II than the other diagnostic groups. Furthermore, the more adverse experiences in childhood, the more dissociative experiences in adulthood. Conclusion: The DES-II should be treated and interpreted as a unidimensional dissociation index rather than a multidimensional instrument. This study will advance further research on dissociation and dissociative disorders in Puerto Rico and Latin America.
Introducción: La Escala de Experiencias Disociativas (DES-II) es una herramienta psicométrica ampliamente utilizada para evaluar síntomas disociativos. A lo largo de los años, ha sido objeto de numerosos estudios e investigaciones en diversos campos de la psicología y la psiquiatría. Numerosos estudios han respaldado la validez y la fiabilidad de la DES-II como una medida confiable de las experiencias disociativas. El aspecto más problemático del DES-II es la inconsistencia de su estructura factorial. Objetivo: Esta investigación tuvo como objetivo examinar las propiedades psicométricas de la DES-II en una muestra clínica y no clínica de Puerto Rico. Método: Esta investigación tuvo un diseño instrumental. Se utilizó un muestreo por disponibilidad compuesto por 341 participantes adultos. Se analizaron varios modelos competitivos de la DES-II, incluyendo un modelo bifactorial. Resultados: Los análisis psicométricos concluyeron que la escala posee una estructura unidimensional y una sólida confiabilidad y validez de constructo. Los 28 ítems cumplieron con valores adecuados de discriminación. Los participantes con trastornos disociativos obtuvieron medias más altas en la DES-II que los otros grupos diagnósticos. Además, a mayores experiencias adversas en la infancia, mayores experiencias disociativas en la adultez. Conclusión: La DES-II debería tratarse e interpretarse como un índice unidimensional de disociación y no como un instrumento multidimensional. Este estudio permitirá el avance de nuevas investigaciones sobre disociación y trastornos disociativos en Puerto Rico y América Latina.
ABSTRACT
OBJECTIVES: Dissociative Experiences Scale (DES) is the most widely used and studied instrument for measuring dissociative symptoms with its favorable psychometric properties well described in the literature. However, recent debate on factor structure and multidimensionality has brought attention to factorial validity of the scale. This study tested the factor structure of a Korean translation of the scale (KDES-II) with confirmatory factor analysis in a clinical population. METHODS: Exploratory principal component analysis were conducted with data from 340 psychiatric patients and confirmatory factor analysis (maximum likelihood estimation) with 262 psychiatric outpatients. RESULTS: Exploratory analysis revealed four factor structure of the scale with total variance of 55.9% : Depersonalization/derealization (Factor 1), Amnestic dissociation (Factor 2), Absorption (Factor 3), and Pseudopsychotic symptoms (Factor 4). However, original three- and one- factor model were also acceptable considering the goodness-of-fit indices. CONCLUSION: Despite heterogeneity of the sample, KDES-II showed factorial validity and supported a cross cultural stability of DES. We suggest use of original three factor solution for Korean clinical population.
Subject(s)
Humans , Absorption , Factor Analysis, Statistical , Outpatients , Population Characteristics , Principal Component Analysis , PsychometricsABSTRACT
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Abstract: Introduction: Dissociative disorders are characterized by impaired conscious integration functions, personal identity, memory and environment perception. Their frequent psychopathological manifestations are amnesia, depersonalization, fugue states, extra sensorial experiences, trance states and total personality changes. They usually appear under different life stressors, and their clinical course is highly variable. Prevalence estimates give figures ranging from 5 to 10% among general population, and reach 10.2 to 41.4% among psychiatric populations. This wide variation is one of the indicators of the complexity of this diagnostic entities and of its difficulty to be studied. Culture is a key factor in functionality of subjects with a dissociative disorder, because the acceptance of many of its clinical features varies. It is accepted that these diagnostic categories are barely-recognized, not only by general physicians, but by experienced mental health specialists. The original Structured Diagnostic Interviews (SCID, CIDI, SADS, SCAN), did not include them in their widely distributed packages, and many of them decided to create a separate appendix to address them. Unfortunately, structured interviews face an important limitation as there is a lack of trained, and some times, experienced psychopathologist, a fact that difficults to use them in large samples. Self-report instruments, when they show good reliability and validity, are of great value in terms of time, costs and feasibility. Their major limitation is the low reliability that they show in psychiatric conditions in which lack of insight is present (psychotic disorders). To evaluate the psychometric properties of translated versions of instruments is highly desirable. This is specially important when elusive disorders are being evaluated. Given that the cultural environment of Mexico is surrounded by several factors that influence this kind of disorders, the availability of reproducible research instruments is of outmost relevance. Therefore, the Dissociative Experiences Scale (DES) -the most widely used measure in this field- in contrast with the Dissociative Disorders Interview Schedule (DDIS), was evaluated, with the purpose to give a first approach to a 12 month prevalence of some Dissociative disorders in Mexican psychiatric patients. Methods: Subjects: A non-random, consecutive sample of male and female patients, between 18 and 63 years old were included. They were receiving treatment, regardless of the diagnosis, at the Institute of Mental Health of Jalisco, from the State's Ministry of the Health in Mexico. The ethics committee authorized the study, and they all gave informed consent. Translation: The Spanish version of the DES, has a Spanish translation, and a Mexican Spanish idiomatic adaptation was performed by consensus. The DDIS was translated by one bilingual psychiatrist, and independently reviewed by another. Consensus was reached in controverted items. Once a final translated version was obtained, it was given to 10 subjects (mainly with primary school level), to assess item understanding. A second review was performed to reach a culturally compatible version, concentrating in respecting item content validity. Back translation was not considered, because this method does not capture common language of low school population, which is the case of most Mexicans. Measures: Dissociative Experiences Scale (DES): This is a 28 items, self-report scale, designed to evaluate different kinds and severity of Dissociative conditions, in a 0 to 100 range. Most populations without a psychiatric condition or with a non-Dissociative disorder, scored under 20. A cut-off point of 30, usually indicates the possibility of a Dissociative disorder diagnosis. Given that a Spanish version of the DES is available from Spain, only an idiomatic adaptation to Mexican Spanish was performed (changes in slang or word content differences between countries). Dissociative Disorder Interview Scale (DDIS): This is a structured diagnostic interview, of 132 yes/no items, designed to assess the presence of DSM-IV Dissociative disorders entities. It is to be applied by mental health professionals, properly trained on its use. It does not give a total score, it assesses each disorder independently. As previous studies performed in different languages, it has adequate psychometric properties, and is the usual golden standard for Dissociative categories. Previous reports on DDIS correlation with DES have shown variations between disorders, with Kappa values for Identity Dissociative Disorder ranging 0.68 to 0.95. Procedures: A 4th year general psychiatry residency doctor was trained in the DDIS, and, after obtaining the patient's consent, applied the DDIS interview, and then gave the patient the DES to be completed. Demographic and clinical variables were obtained, as well as the diagnosis assigned in the patient chart. To analyze results two procedures were planned: 1) compare DES total score punctuation between positive and negative presence of Dissociative disorders according with the DDIS and 2)compare between patients with a Dissociative disorder with or without concomitant major depression. Results: A total of 100 subjects were included, 63% female, with a mean age of 32.4±12.5 (range 18 - 63) years old. The DES internal consistency index was 0.96. Patients with a Dissociative Disorder (according to the DDIS), showed clinically and significantly higher DES values than non-Dissociative patients (34.7±24.8 n= 38 vs. 10.7±9.6 n=62; T -6.8, d.f. 98, p< 0.001). Frequency of Dissociative disorders and symptoms: Mean DES total score was 19.8±20.6. According to DDIS criteria, 38 subjects fulfilled DSM IV diagnostic criteria for a Dissociative disorder: Dissociative identity disorder 24, Depersonalization Disorder 6, psychogenic fugue 3. The most common concomitant diagnosis as assessed in the patient chart was unipolar major depression (17 44.7%. When a Dissociative disorder was comorbid with major depression, comparing it with Dissociative disorders only, the difference was greater (34.7±24.2 n= 38, 9.3±8.55, T 6.3, d.f. 80, p<000.1. Discussion: Dissociative disorder measurements evaluated, seem to work adequately in Mexican population. Prevalence of dissociative disorders found in this psychiatric population, is consistent with other studies. Further research in the field is needed, to evaluate the influence of cultural factors, including rural and indigenous samples.