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Dive into the research topics where Vedat Sar is active.

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Featured researches published by Vedat Sar.


PLOS ONE | 2016

Minimization of childhood maltreatment is common and consequential: results from a large, multinational sample using the childhood trauma questionnaire

Kai MacDonald; Michael L. Thomas; Andres F. Sciolla; Beacher Schneider; Katherine Pappas; Gijs Bleijenberg; Martin Bohus; Bradley Bekh; Linda L. Carpenter; Alan Carr; Udo Dannlowski; Martin J. Dorahy; Claudia Fahlke; Tobi Karu; Arne Gerdner; Heide Glaesmer; Hans J. Grabe; Marianne Heins; Daeho Kim; Hans Knoop; Jill Lobbestael; Christine Lochner; Grethe Lauritzen; Edle Ravndal; Shelley A. Riggs; Vedat Sar; Ingo Schäfer; Nicole Schlosser; Melanie L. Schwandt; Murray B. Stein

Childhood maltreatment has diverse, lifelong impact on morbidity and mortality. The Childhood Trauma Questionnaire (CTQ) is one of the most commonly used scales to assess and quantify these experiences and their impact. Curiously, despite very widespread use of the CTQ, scores on its Minimization-Denial (MD) subscale—originally designed to assess a positive response bias—are rarely reported. Hence, little is known about this measure. If response biases are either common or consequential, current practices of ignoring the MD scale deserve revision. Therewith, we designed a study to investigate 3 aspects of minimization, as defined by the CTQ’s MD scale: 1) its prevalence; 2) its latent structure; and finally 3) whether minimization moderates the CTQ’s discriminative validity in terms of distinguishing between psychiatric patients and community volunteers. Archival, item-level CTQ data from 24 multinational samples were combined for a total of 19,652 participants. Analyses indicated: 1) minimization is common; 2) minimization functions as a continuous construct; and 3) high MD scores attenuate the ability of the CTQ to distinguish between psychiatric patients and community volunteers. Overall, results suggest that a minimizing response bias—as detected by the MD subscale—has a small but significant moderating effect on the CTQ’s discriminative validity. Results also may suggest that some prior analyses of maltreatment rates or the effects of early maltreatment that have used the CTQ may have underestimated its incidence and impact. We caution researchers and clinicians about the widespread practice of using the CTQ without the MD or collecting MD data but failing to assess and control for its effects on outcomes or dependent variables.


Psychopathology | 2010

Childhood Trauma and Dissociation in Schizophrenia

Vedat Sar; Okan Taycan; Nurullah Bolat; Mine Ozmen; Alaattin Duran; Erdinc Ozturk; Hayriye Ertem-Vehid

Background: This study is concerned with relationships between childhood trauma history, dissociative experiences, and the clinical phenomenology of chronic schizophrenia. Sampling and Methods: Seventy patients with a schizophrenic disorder were evaluated using the Structured Clinical Interview for DSM-IV, Dissociative Experiences Scale, Dissociative Disorders Interview Schedule, Positive and Negative Symptoms Scales, and Childhood Trauma Questionnaire. Results: Childhood trauma scores were correlated with dissociation scale scores and dissociative symptom clusters, but not with core symptoms of the schizophrenic disorder. Cluster analysis identified a subgroup of patients with high dissociation and childhood trauma history. The dissociative subgroup was characterized by higher numbers of general psychiatric comorbidities, secondary features of dissociative identity disorder, Schneiderian symptoms, somatic complaints, and extrasensory perceptions. A significant majority of the dissociative subgroup fit the diagnostic criteria of DSM-IV borderline personality disorder concurrently. Among childhood trauma types, only physical abuse and physical neglect predicted dissociation. Conclusions: A trauma-related dissociative subtype of schizophrenia is supported. Childhood trauma is related to concurrent dissociation among patients with schizophrenic disorder. A duality model based on the interaction of 2 qualitatively distinct psychopathologies and a dimensional approach are proposed as possible explanations for the complex relationship between these 2 psychopathologies and childhood trauma.


Journal of Trauma & Dissociation | 2003

The Axis-I Dissociative Disorder Comorbidity of Borderline Personality Disorder Among Psychiatric Outpatients

Vedat Sar; Turgut Kundakci; Emre Kiziltan; Ilhan Yargic; Hamdi Tutkun; Bahadir Bakim; Oya Bozkurt; Tuba Özpulat; Vehbi Keser; Özay Özdemir

ABSTRACT The aim of this study was to determine the frequency of dissociative disorders among psychiatric outpatients with borderline personality disorder (BPD). In order to ascertain the extent of the overlap between two diagnostic groups, the overall prevalence of both disorders were evaluated. Two hundred and forty (240) consecutive patients who presented to a university outpatient psychiatry unit were screened using the self-report questionnaire version of the BPD section of Structured Clinical Interview for DSM-III-R Personality Disorders (SCID-II), the Dissociative Experiences Scale (DES) and the Somatoform Dissociation Questionnaire (SDQ). One hundred and twenty-nine (129) participants who had a score above the cut-off point on at least one of these instruments were evaluated using the interview version of the BPD section of the SCID-II, the Dissociative Disorders Interview Schedule (DDIS), and the PTSD module of the Structured Clinical Interview for DSM-III-R (SCID-I). All participants who were diagnosed as having BPD or a dissociative disorder were evaluated then with the Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D). Twenty-five (25; 10.4%) participants had BPD and 33 participants (13.8%) had dissociative disorder in the final evaluation. Sixteen participants (64.0%) with BPD had the Axis I diagnosis of a dissociative disorder; all six participants (2.5%) with dissociative identity disorder were among them. The findings demonstrate that a significant part of psychiatric outpatients who fit the criteria of BPD have a DSM-IV dissociative disorder on Axis I. The presence of dissociative symptoms as a part of BPD should not lead to overlooking the possibility of a co-occurring dissociative disorder.


Journal of Trauma & Dissociation | 2001

Differentiating Dissociative Disorders from Other Diagnostic Groups Through Somatoform Dissociation in Turkey

Vedat Sar; Turgut Kundakci; Emre Kiziltan; Bahadır Bakım; Oya Bozkurt

Abstract This study aimed to assess the reliability, validity, and psychometric characteristics of the Turkish version of the Somatoform Dissociation Questionnaire (SDQ-20). In this context, it investigated whether somatoform dissociation differentiates dissociative disorders from other diagnostic groups and non-clinical individuals. The Turkish Version of the SDQ-20 was administered to 50 patients with a dissociative disorder, 94 patients with psychiatric disorders other than dissociative disorder, and 175 non-clinical participants. To confirm the clinical diagnosis, all patients in the dissociative disorder group had been evaluated using the Structured Clinical Interview for DSM-IV Dissociative Disorders. The internal consistency and the test-retest correlation of the SDQ-20 were excellent. The scale had strong correlations with the DES and the DIS-Q. There was a statistically significant difference between dissociative patients and other diagnostic groups on the SDQ-20 total score. The discriminative power of the SDQ-20 was as robust as that of the DES. There was no significant difference between the mean SDQ-20 total scores of Turkish and Dutch patients, but Turkish dissociative patients reported pseudoseizures more frequently than Dutch patients. The specificity of the short version of the scale (SDQ-5) was weak among Turkish patients. Dissociative disorders can be differentiated from other diagnostic groups through somatoform dissociation. The good psychometric characteristics of the SDQ-20 among Turkish participants support its cross-cultural validity.


European Journal of Psychotraumatology | 2011

Developmental trauma, complex PTSD, and the current proposal of DSM-5.

Vedat Sar

This paper evaluates representation of clinical consequences of developmental psychological trauma in the current proposal of DSM-5. Despite intensive efforts by its proponents for two decades, it is not known yet if Complex PTSD will take a place in the final version of DSM-5. Recognition of dissociative character of several symptom dimensions and introduction of items about negative affects such as shame and guilt imply an indirect improvement toward better coverage of the consequences of developmental trauma in the existing category of PTSD. As disorders with highest prevalence of chronic traumatization in early years of life, dissociative disorders and personality disorder of borderline type are maintained as DSM-5 categories; however, recognition of a separate type of trauma-related personality disorder is unlikely. While a preschooler age variant of PTSD is under consideration, the proposed diagnosis of Developmental Trauma Disorder (child version of Complex PTSD) has not secured a place in the DSM-5 yet. We welcome considerations of subsuming Adjustment Disorders, Acute Stress Disorder, PTSD, and Dissociative Disorders under one rubric, i.e., Section of Trauma, Stress, or Event Related Disorders. Given the current conceptualization of DSM-5, this paper proposes Complex PTSD to be a subtype of the DSM-5 PTSD. Composition of a trauma-related disorders section would facilitate integration of knowledge and expertise about interrelated and overlapping consequences of trauma. For the abstract or full text in other languages, please see Supplementary files under Reading Tools online


Psychiatry Research-neuroimaging | 2011

Lifetime PTSD and quality of life among alcohol-dependent men: Impact of childhood emotional abuse and dissociation

Cuneyt Evren; Vedat Sar; Ercan Dalbudak; Rabia Cetin; Mine Durkaya; Bilge Evren; Selime Celik

The aim of this study was to investigate the impact of lifetime posttraumatic stress disorder (PTSD), dissociation and a history of childhood trauma on quality of life (QoL) among men with alcohol dependency. A consecutive series of alcohol-dependent men (N=156) admitted to an inpatient treatment unit were screened using the Michigan Alcoholism Screening Test, the Clinician Administered PTSD Scale, the Dissociative Experiences Scale, and the Childhood Trauma Questionnaire. QoL was assessed using the Medical Outcomes Study Short-Form 36-item health survey. Fifty (32.1%) patients had lifetime diagnosis of PTSD. Besides problems related to severity of alcohol use, the lifetime PTSD group was impaired on several physical and mental components of QoL. While the lifetime PTSD group and remaining patients did not differ on reports of childhood trauma and dissociation, in lifetime PTSD group, dissociative patients had higher scores of childhood emotional abuse than those of the non-dissociative patients. In multivariate covariance analysis, both dissociation and lifetime PTSD predicted impairment in physical functioning, general health, vitality, and mental health components of QoL. Among alcohol-dependent men with lifetime PTSD, a history of childhood emotional abuse contributes to impairment of QoL through its relationship with dissociation.


Psychiatry Research-neuroimaging | 2007

Frontal and occipital perfusion changes in dissociative identity disorder

Vedat Sar; Seher Unal; Erdinc Ozturk

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.


Epidemiology Research International | 2011

Epidemiology of Dissociative Disorders: An Overview

Vedat Sar

General psychiatric assessment instruments do not cover DSM-IV dissociative disorders. Many large-scale epidemiological studies led to biased results due to this deficit in their methodology. Nevertheless, screening studies using diagnostic tools designed to assess dissociative disorders yielded lifetime prevalence rates around 10% in clinical populations and in the community. Special populations such as psychiatric emergency ward applicants, drug addicts, and women in prostitution demonstrated the highest rates. Data derived from epidemiological studies also support clinical findings about the relationship between childhood adverse experiences and dissociative disorders. Thus, dissociative disorders constitute a hidden and neglected public health problem. Better and early recognition of dissociative disorders would increase awareness about childhood traumata in the community and support prevention of them alongside their clinical consequences.


Psychiatry and Clinical Neurosciences | 2008

Childhood emotional abuse, dissociation, and suicidality among patients with drug dependency in Turkey

Defne Tamar-Gurol; Vedat Sar; Figen Karadag; Cuneyt Evren; Mustafa Karagoz

Aim:  The aim of the present study was to determine the prevalence and correlates of dissociative disorders among patients with drug dependency.


Psychiatry and Clinical Neurosciences | 2008

Dissociation and alexithymia among men with alcoholism

Cuneyt Evren; Vedat Sar; Bilge Evren; Ümit Başar Semiz; Ercan Dalbudak; Duran Cakmak

Aim:  The aim of the present study was to evaluate the relationship between alexithymia and dissociation among men with alcoholism.

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