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ICOSR 2013—Schizophrenia in DSM-5 and ICD-11

21 May 2013

22 May 2013. Empty seats were few and far between and microphone lines were long on the morning of 23 April 2013 at the International Congress on Schizophrenia Research symposium entitled “Future Classification of Psychotic Disorders: DSM-5 and ICD-11.” With the May 17 publication date of the fifth revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) rapidly approaching, clinicians and researchers alike were eager to hear about the upcoming changes that session co-chair Wolfgang Gaebel noted will “shape our future professional lives.”

Describing DSM-5

The first speaker was Rajiv Tandon of the University of Florida, Gainesville, who recounted his experiences as a member of the DSM-5 Work Group on Psychotic Disorders and provided an overview of the group’s efforts. He discussed the objectives of the new revision: improvements in validity, reliability, and utility; simplification; and the incorporation of research. He also described the basic principles of the revision: 1) given that the DSM is a manual for clinicians, the changes made must be implementable in routine clinical practice; 2) any changes should be guided by research evidence; 3) continuity with previous versions should be preserved whenever possible; and 4) harmony with the International Classification of Diseases (ICD) should be maintained whenever possible.

From 2008 to 2012 the Work Group met twice a year in person and one to two times per month via teleconference. Additional tasks were assigned to small groups and to individuals. Throughout this time, the Work Group reviewed the scientific literature and relevant datasets, developed and discussed topic reviews, and, of course, debated the issues. They also interacted with related Work Groups such as the one on mood disorders. It was a tough and very time-consuming process, Tandon admitted.

Tandon then moved on to describe the major changes coming to the classification of psychotic disorders in DSM-5, noting their iterative nature. Due to a lack of long-term usability and stability, the current subtypes of schizophrenia will be eliminated. In an effort to better capture the heterogeneity of schizophrenia and other psychotic disorders, several dimensions—reality distortion, negative symptoms, disorganization, cognition, depression, mania, and psychomotor symptoms—have been added, though they will be located in the Appendix. The criteria for schizoaffective disorder have also been modified to better delineate it from schizophrenia, and instead of allowing for brief episodes of mood symptoms, now require these features to be present for a majority of the time (see SRF Webinar). Attenuated psychosis syndrome, characterized by mild symptoms that do not fulfill the criteria for full-blown psychosis, will be included in the Appendix (see SRF related news story and SRF Webinar). Finally, a consistent definition of catatonia will now be used across the DSM.

Symposium co-chair William Carpenter of the University of Maryland in Baltimore was next up to the podium. Carpenter, the chair of the DSM-5 Psychotic Disorders Work Group, discussed some of the more controversial revisions to the chapter, including its organization, whether or not catatonia should be a formal diagnosis in the psychotic disorders section, the de-emphasis of Scheiderian first-rank symptoms, and the changes to schizoaffective disorder. Another major controversy was the paradigm shift toward thinking about schizophrenia as a syndrome with domains of pathology. The Work Group recommended the addition of symptom dimensions in addition to the diagnostic classifications, but at the last minute the dimensions were relegated to the Appendix, a change Carpenter characterized as a “major disappointment.”

By far the most controversial issue within the Work Group, he said, surrounded the attenuated psychosis syndrome. External criticisms against its inclusion included the potential for false positives, more therapeutic harm than good, and stigmatization of young people. The Work Group heavily debated the reliability of the diagnosis during numerous field trials, Carpenter said, ultimately deciding that it was not reliable enough. Thus, they recommended the addition of the attenuated psychosis syndrome to the Appendix, marking it as a condition for further study. Although the upcoming changes to the DSM-5 have been the subject of much controversy, Carpenter noted that the manual will be “a living document,” with revisions likely happening much sooner than in the past.

Illuminating ICD-11

The topic then turned to the proposed changes coming to psychotic disorders in the newest version of the World Health Organization’s diagnostic tool for all medical disorders, the ICD-11. Wolfgang Gaebel of Germany’s Heinrich-Heine University in Düsseldorf is the chair of the ICD-11’s Working Group on the Classification of Psychotic Disorders, and also a member of the DSM-5 Psychotic Disorder Work Group. He described the major changes that have been proposed (Gaebel, 2012), noting that unlike the DSM-5, the ICD-11 criteria must be applicable worldwide, even in areas with limited resources. Unlike the DSM-5, the ICD-11 is in a much earlier stage, due to be presented to the World Health Assembly in 2015, and thus proposed changes are not yet finalized.

Similar to the DSM-5, first-rank symptoms will be de-emphasized. A diagnosis of schizoaffective disorder will now require that the symptom criteria of both schizophrenia and a mood disorder be met within a short timeframe. Schizophrenia subtypes will be replaced with a system of coded specifiers, added after diagnosis, that describe a patient’s symptoms and illness course. Two points of continuing debate, said Gaebel, are whether functional impairment should be included as a separate specifier, and whether it should be a mandatory component of the schizophrenia diagnosis. He noted that field trials will hopefully be completed in the second half of 2013.

The final speaker of the session was Michael Green of the University of California, Los Angeles, who addressed the issue of where cognition fits into the ICD-11, discussing both its placement as well as its implementation. The Working Group considered placing cognitive impairments in three different places within the manual—as part of the guidelines for diagnosis, as a coded specifier after diagnosis, or as part of the Appendix—and benefited substantially from the DSM-5 Work Group’s discussion of this issue. The ICD-11 group quickly eliminated the option of including cognitive impairments in the diagnosis based on the rationale that cognitive deficits would not substantially help with differentiating between different psychosis diagnoses (Bora et al., 2010). The Working Group also felt that inclusion of cognitive impairments in the Appendix would not substantially increase the awareness of cognition in psychotic disorders. However, they decided that including them as a coded specifier after diagnosis would both help clinicians to become aware of this core feature and guide treatment, and thus they recommended this option.

Green then described the practical implications of including cognitive impairments in the psychotic disorders section of ICD-11, describing the Working Group’s thought process regarding the range of cognitive domains (limited vs. broad) that should be included and how they should be measured (quantitative scale vs. presence/absence). The group ultimately suggested a five-point scale. The ICD International Advisory Group, a committee that is overseeing the new revisions, then recommended that a broad range of cognitive domains be included in the assessment. A second oversight committee, from the WHO’s Department of Mental Health and Substance Abuse, has subsequently recommended that the deficits should be rated as present or absent rather than quantified, in the interest of simplicity, although they noted that a scale could be evaluated in field trials. Remaining issues include determining the threshold for the presence of cognitive symptoms and how to evaluate a scale during field trials.—Allison A. Curley.