Psychotraumatology and Innovation in Schizophrenia Research: Does a New Subtyping of Schizophrenic Disorder Matter?

Abstract

DSM-5 [1] cancelled the classical subtypes of schizophrenic disorder after a century of their introduction but did not replace these clinically informed traditional categories with others. Subtypes and specifiers continue to be added to other diagnostic categories of the DSM-5 in condition that they are supported by external validators such as biological markers or treatment response. In consideration of this development, new subtypes and/or specifiers are expected to be set for schizophrenia in the near future after a period of rest and refreshment of ideas. Hence, to be pro-active here, I would like to unleash the burning question: Does current research inspire any subtyping already? My answer is: Yes. A trauma-related dissociative subtype of schizophrenia as proposed by Colin Ross originally [2] deserves to be warranted this status.

Historically, schizophrenia has been considered as a heterogenous category composed of "a group of disorders" as Bleuler preferred to call it in his inaugural work on the subject [3]. He has been successful in replacing Kraepelin's obdurate "dementia praecox" by the more gracious but broader concept of the "split mind"; i.e. he was implying the presence of "healthy" aspects in the individual's mind who was affected by the illness. This compelling proposal took effect immediately to be challenged only in 1980'ies first (the so called neo- Kraepelinian period) after having dominated the field for almost a century: Being overinclusive, the Bleulerian concept of schizophrenia had possibly led to misdiagnosis of diverse psychiatric conditions and related research interfered with appropriate treatment of the affected patients as a confounding factor [4].

Curious enough, dissociation and dissociative disorders have been perhaps those among all psychiatric conditions which were influenced by this overinclusive concept of schizophrenia rather negatively. In fact, dissociative disorders have been almost totally erased from psychiatry for a century throughout this period. Although the overinclusive schizophrenia concept may not have been the major force behind the omission of dissociative disorders from psychiatric research, it served as a niche for this purpose. Ironically, "split mind" and "schizophrenia" would fit the very core of dissociation nicely if they would not be implemented to psychotic disorders [2].

While the research on psychosis also suffered from this unrealistic delineation, in fact, it was the concept of "psychological trauma" which lost its ground [5]. Namely, the concept of "hysteria" and "hysterical neurosis" continued to live in this era, however, no more as a dissociative or trauma-related disorder but as a reaction style based allegedly on a specific personality type. In my view, the re-emergence of dissociation in psychiatric research in 1980'ies has been counterbalanced by the "overinclusive" borderline personality disorder a la Kernberg [6] which has been proven as overlapping with dissociative disorders including traumatic antecents later on [7,8]. Unlike the one of psychotraumatologists, Kernberg's well received notion minimizes the concept of dissociation to a epiphenomenon of the "personality disorder" spectrum. Nevertheless, PTSD joined the field as a further major player simultaneously.

To make the issue more complex, an increasing number of studies have begun to document that also patients with schizophrenia [9] or psychosis [10,11] report childhood traumas more frequently than controls. Ten out of eleven general population studies have shown, even after controlling for other factors (including family history of psychosis), that child maltreatment is significantly related to psychosis [12]. Although consideration of psychological trauma as a direct cause of a pervasive mental illness like schizophrenia is controversial [13], a traumagenic neurodevelopmental model has been proposed to explain a potential relationship [14,15].

In addition to this general trend of stress research, there are studies inquiring dissociative symptoms in schizophrenia [16- 18]. The more than expected prevalence of dissociative symptoms and even dissociative disorders in schizophrenic patients led the authors to think whether there was continuity between two psychopathologies [19]. Others propose a type of comorbidity usually related to an adverse childhood among a subgroup of schizophrenic patients [18]. There are intriguing phenomenological similarities between dissociative and schizophrenic symptoms indeed: e.g. Schneiderian hallucinations and passive influence phenomena as well as depersonalization and disturbances of self-identity. There are even patients for whom a correct differential diagnosis is very hard to achieve that the possibility of a schizo-dissociative disorder should also be considered. This is not merely a matter of "academic curiosity" but a serious problem for clinicians because such cases are known to be relatively treatment-resistant both in terms of psychotherapy and pharmacotherapy. On the other hand, the disavowal of the special place in DSM-5 which was given to the Schneiderian halluciations as pathogonomic symptoms of schizophrenia previously is a major and well done step forward in dissecting schizotypy from dissociation.

Knowing this historical background is useful in pondering on the contemporary question: Would it be feasible to introduce a subtype of schizophrenic disorder based on the accumulated data of psychotraumatology during the last three decades? Should this be in regard of the childhood adversity or better, phenomenological; i.e. on the basis of dissociative symptoms? As childhood traumata have been shown to have an impact on several psychiatric disorders already, such a subtyping should be based on the latter. Several studies have shown that a dissociative subgroup exists in schizophrenia and is usually related to a high frequency of childhood trauma reports, even subgroups of this subtype based on both phenomenological differences as well as different types of anteceding childhood appear. Hence, a dissociative subtype of schizophrenia [2] is warranted to be considered as the best studied and clinically valid proposal. It is hoped that such a step forward not only contributes to the modern psychotraumatology research but also to a refinement of the research in the spectrum of psychotic disorders. Last but not least, this would enhance innovations in psychiatry which would largely serve to the patients in terms of more effective treatment [20,21].

References

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