La schizophrénie dissociative : nouvelle entité clinique, trouble comorbide ou autres considérations nosographiques
The existence of a dissociative subtype of schizophrenia has been suggested by several authors to account for the symptomatology of a group of people whose primary diagnosis is in the schizophrenia spectrum but have in addition dissociative symptoms (Ross, 2004; Sar et al, 2010; Van der Hart, Witztum, & Friedman, 1993). Of traumatic origin, this type of clinical picture where psychotic and dissociative symptoms are intertwined was first described more than a century ago (Janet & Raymond, 1898) but disappeared in the 30’s, having been incorporated to the concept of "schizophrenia" (Rosenbaum, 1980). It is in a new nosographic context that the concept of dissociative schizophrenia resurfaced. Indeed, psychiatric nosography took a turn in 1980 when the approach advocated by the DSM became descriptive rather than based on psychoanalytic conceptualizations. The psychiatric conditions of the time were divided into disorders whose symptoms tended to occur together (Cooper, 2004). Consequently, the presence of comorbid disorders increased. Given the frequently reported co-occurrence of psychotic and dissociative disorders, the phenomenological similarity of their symptoms and their potential traumatic etiology, Ross (2004) proposed a criteria set for the diagnosis of dissociative schizophrenia. The main objective of this thesis is to determine whether the dissociative schizophrenia, as defined by Ross (2004), exists. The first article focuses on the problem and the theoretical background that led to the research question. It aims at providing an overview of the issues surrounding the question of dissociative schizophrenia. It also reports on the literature pertaining to symptoms found in both psychotic and dissociative disorders, their traumatic etiology and studies on dissociation and schizophrenia. The second article is of empirical nature and reports the methodology used to answer the research question. Indeed, no study to date has systematically tested the criteria for dissociative schizophrenia. Our results show that 24 % of our sample (N = 50) could receive a diagnosis of schizophrenia with dissociative criteria proposed by Ross (2004). However, the criteria set was problematic so a modification was proposed and a prevalence of 14% was then found. Clinical vignettes are presented to compare our participants with those reported elsewhere. The links between psychotic and dissociative symptoms are discussed in trying to conceptualize dissociative schizophrenia in different ways, either as a new clinical entity, as a comorbid disorder or in a psychodynamic nosographic context.
Dissociation Schizophrenia Dissociative disorders Psychotic disorders Comorbidity Dissociative schizophrenia Diagnostic validity Nosography