What is Bizarre in Bizarre Delusions? A Critical Review

Schizophrenia Bulletin vol. 36 no. 4 pp. 667–679, 2010 doi:10.1093/schbul/sbq001 Advance Access publication on February 8, 2010 What is Bizarre in Bizarre Delusions? A Critical Review M. Cermolacce1,2,3,*, L. Sass4, and J. Parnas3,5 *To whom correspondence should be addressed; tel: þ334 91 746 750, fax: þ334 91 745 578, e-mail: (DSM-IV), so long as dysfunction/suffering and lengthof-illness criteria are satisfied. Given the importance of this psychopathological concept, there is a surprising shortage of empirical and conceptual studies. Recently, however, Bell et al1 published a review of the reliability of BD. Their main conclusions were that reliability of BD was inferior to that for delusions ‘‘in general’’ and that the concept was inadequate for scientific usage.1 In any case, only a small fraction of patients receive their schizophrenia diagnosis because of the presence of BD (4%–8%).2,3 It seems to us that contemporary discussions of BD are articulated as a series of merely technical problems, independent of more fundamental conceptual issues in psychopathology. There has been a consequent failure to address certain basic questions concerning the concept of BD—questions concerning the empirical and intuitive sources of this psychopathological concept as well as its conceptual validity.4 We believe that ‘‘bizarreness’’ needs to be understood as linked not merely to delusional content but to a form of experiencing as well. Here, we use the term ‘‘content’’ to refer to the propositional aspect of the delusional claim (what the delusion is about) and the term ‘‘form’’ to refer to the mode of subjectivity that is associated with the delusion in question (the way it is experienced). This point is closely related to the broader issue of the conceptual validity of the schizophrenia diagnosis.5 A related problem is the proximity of BD to first rank symptoms (FRS). Discussion of reliability needs to clarify certain epistemological assumptions that underlie data collection. Specifically, one needs to consider the form of assessment and type of expertise that are required in order to make reliable judgments regarding BD. One problem is that a structured series of questions, especially if focused on content alone, may fail to disclose the way in which Diagnostic and Statistical Manual of Mental Disorder, Fourth Edition (DSM-IV) treats the presence of bizarre delusions (BD) as the heaviest-weighted clinical criterion of schizophrenia. Although BD play a major role in contemporary diagnostic systems, only a few empirical studies explore this issue. These studies provide highly heterogenous results because they are based on different experimental paradigms, in terms of definition, clinical sample, and number of raters. Here, we first discuss the psychopathological sources of the concept of BD, which were initially described as either nonsensical or incomprehensible. Then, we provide a critical review of contemporary studies on the reliability of BD and their methodological and conceptual limitations. Current approaches have focused intensely on BD’s reliability and have defined BD strictly in terms of delusional content—mainly in terms of the physical impossibility or the cultural or historical incomprehensibility of the delusional claims. These approaches have neglected formal features of experience that underlie BD and the crucial issue of the nature and validity of BD. In the discussion, we argue that clinical diagnosis of BD cannot be limited to delusional contents alone and requires taking into account the subjective side of BD (how altered experience manifests itself) as well as the conditions of intersubjective encounter (how BD are expressed to and experienced by the clinician). The notion of ‘‘bizarreness’’ in schizophrenia is not purely theoretical; it has practical relevance for the therapeutic encounter and implications on further empirical research and on diagnostic approaches. Key words: schizophrenia/delusions/bizarre delusions/ bizarreness/DSM-IV/diagnostic systems Introduction The presence of bizarre delusions (BD) is considered a sufficient criterion of schizophrenia in the Diagnostic and Statistical Manual of Mental Disorder, Fourth Edition Ó The Author 2010. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: . 667 1 University Department of Psychiatry, Hospital of Sainte Marguerite, University of Marseilles, Marseilles, France; 2Institut de Neurosciences Cognitives de la Méditerranée, CNRS, Marseilles, France; 3Danish National Research Foundation, Center for Subjectivity Research, University of Copenhagen, Denmark; 4Department of Clinical Psychology, Graduate School of Applied and Professional Psychology, Rutgers University, NJ, USA; 5University Psychiatric Center, Hvidovre, Copenhagen, Denmark M. Cermolacce et al. delusions develop and are experienced—factors of relevance for determining bizarreness. Below, we review historical and contemporary descriptions of BD as well as recent studies of the reliability of BD. Then, we consider limitations of studies on BD’s reliability and conceptual validity. We end by articulating some ideas concerning further research and diagnostic approaches and concerning the general significance of bizarreness in schizophrenia. The contemporary notion of BD originates in the Research Diagnostic Criteria (RDC).6 Recent notions formulate its essence variously: (1) ‘‘the content [is] patently absurd and has no possible basis in fact’’ (DSM-III); (2) ‘‘involving a phenomenon that the person’s culture would regard as totally implausible’’ (DSM-IIIR); and (3) ‘‘clearly implausible and not understandable and not derived from ordinary life experiences’’ (DSM-IV, DSM-IV TR). (All these terms defining bizarreness are, in turn, badly or not defined at all, thus in need of further specification. In other words, we are here far away from the operationalistic ideal formulated by Hempel.7) In brief, the DSMs have attempted to define bizarreness through the following notions: physical (or perhaps logical) impossibility, general acceptance in cultural context, and overall implausibility or incomprehensibility with emphasis on grounding in ordinary experience. According to Spitzer,8 a central figure in the development of the DSMs, the notion of BD stems jointly from Emil Kraepelin, who defined delusions in schizophrenia as ‘‘non-sensical,’’ and Karl Jaspers, who considered them ‘‘incomprehensible.’’ According to Kraepelin, the notion of ‘‘non-sensicality’’ (which, incidentally, seems unlikely to be reliable in itself) enables us to distinguish delusion in dementia praecox from delusion in paranoia or affective psychoses; whereas, the former presents ‘‘an extraordinary, sometimes wholly nonsensical stamp,’’ the latter, ‘‘with all the improbability and uncertainty of its foundation, does not usually contain any apparent impossibilities.’’8– (...truncated)