title: A preliminary report: a new scale to identify the pseudodementia syndrome.
abstract: BACKGROUND
  The literature was reviewed to abstract items which were claimed to distinguish organic dementia from pseudodementia. Their discriminating powers were tested in a prospective study. Eighteen of these items were selected to create a questionnaire which should distinguish organic dementia from pseudodementia. The gold standard was the final diagnosis given by a consultant psychiatrist 12-14 months later.
  
  
  METHODS
  One hundred and twenty-eight patients referred to our service with a differential diagnosis of depressive pseudodementia were screened using a checklist of 44 characteristic features (in the form of questions with 'yes' or 'no' answers) which were claimed in the literature of differentiate between organic dementia and depressive pseudodementia. This checklist covers the areas of history, clinical data, insight and performance.
  
  
  RESULTS
  Forty points (questions) out of the 44 in the checklist showed significant discriminating power to differentiate dementia from depressive pseudodementia (p < 0.01). A principal component and factor analysis was performed from which 18 questions were extracted. The shortened questionnaire was able to classify (43/44 cases) 98% of dementia cases and (60/63) 95% of depression correctly. A new definition has been introduced for 'pseudodementia' as a syndrome of reversible subjective or objective cognitive problems caused by non-organic disorder. Thus depressive pseudodementia may be classified into two subtypes. Type I is a group of patients who have depressive symptoms with subject complaint of dysmnesia without measurable intellectual deficits. Type II is a group of patients who have depressive symptoms and show poor cognitive performance based on poor concentration not due to organic disorder.
authors.affiliation: St. Mary's Medical School Hospital, Department of Psychiatry, London, UK.
authors.forename: G
authors.initials: G
authors.lastname: Yousef
authors.forename: W J
authors.initials: WJ
authors.lastname: Ryan
authors.forename: T
authors.initials: T
authors.lastname: Lambert
authors.forename: B
authors.initials: B
authors.lastname: Pitt
authors.forename: J
authors.initials: J
authors.lastname: Kellett
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003704:Dementia / Q000175:diagnosis*; D003863:Depression / Q000150:complications / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005069:Evaluation Studies as Topic; D005163:Factor Analysis, Statistical; D005260:Female; D015577:Geriatric Assessment; D005852:Geriatric Psychiatry / Q000379:methods*; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales / Q000592:standards; D011594:Psychometrics / Q000379:methods* / Q000592:standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D013001:Somatoform Disorders / Q000175:diagnosis* / Q000209:etiology