title: Deficit status in bipolar disorder: investigation on prevalence rate and description of seven cases.
abstract: OBJECTIVE
  While the Kraepelinian dichotomy explicitly distinguishes between schizophrenia and bipolar disorder, it remains unclear as to whether a deficit form of bipolar disorder exists.
  
  
  METHODS
  We conducted a study to investigate the prevalence rate of the deficit form of bipolar disorder; the criteria of which were basically adopted by the original proposal for schizophrenia that described the predominance of negative symptoms for over a year. Moreover, we presented a series of cases with "deficit" bipolar disorder to characterize its clinical pictures in detail.
  
  
  RESULTS
  Consecutive outpatients who visited one psychiatric hospital in Tokyo, Japan in March 2007 were evaluated cross-sectionally. Additionally, medical charts of inpatients who were hospitalized in the same hospital between April 2006 and March 2007 were also thoroughly reviewed. Of 494 patients, 7 patients (1.4%; 10.9% of 64 bipolar cases) fulfilled the criteria for bipolar disorder with deficit syndrome. Seven "deficit" cases had a mean±SD age of 61±5 year-old with the age at onset being 25±8 year-old. In addition to pervasive negative symptoms, they exhibited evidence of cognitive impairments close to the magnitude of what is usually noted in schizophrenia (i.e. a mean±SD total IQ score of 80±9 in the Wechsler Adult Intelligence Scale and 0.4±0.5 in the Wisconsin Card Sorting Test, categories achieved).
  
  
  CONCLUSIONS
  Although preliminary, the evidence on deficit status in patients with bipolar disorder that we found in this study appears more consistent with recent evidence and challenges the Kraepelinian dichotomy that reserves deficit status solely to schizophrenia patients.
authors: Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan. shin@dd.catv.ne.jp
authors: Shintaro
authors: S
authors: Nio
authors: Takefumi
authors: T
authors: Suzuki
authors: Hiroyuki
authors: H
authors: Uchida
authors: Koichiro
authors: K
authors: Watanabe
authors: Masaru
authors: M
authors: Mimura
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D001714:Bipolar Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D015995:Prevalence; D012189:Retrospective Studies; D012559:Schizophrenia / Q000175:diagnosis; D012565:Schizophrenic Psychology; D013577:Syndrome; D014041:Tokyo / Q000453:epidemiology; D014888:Wechsler Scales