Abstract
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