title: Is processing speed a valid cognitive endophenotype for bipolar disorder?
abstract: OBJECTIVE
  The current study investigated whether a single brief cognitive assessment, processing speed, could be considered as a valid endophenotype for bipolar disorder (BD).
  
  
  METHODS
  Processing speed was assessed using the Digit Symbol Test (DST) in 53 euthymic BD probands (BD-P), 50 unaffected first-degree relatives (UFDR) and 60 unrelated healthy controls (HC).
  
  
  RESULTS
  Euthymic BD-P and the UFDR were significantly more impaired on DST performance even after controlling for demography and current mood symptoms (effect sizes 0.89 and 0.52). Clinically significant performance impairment was present in about 30% BD-P and 25% UFDR.
  
  
  CONCLUSIONS
  Pharmacotherapy was not controlled for.
  
  
  CONCLUSIONS
  Processing speed, as measured with the DST, is a brief reliable measure that could be used in clinical assessments of at risk populations. Our findings support the hypothesis that processing speed may be a valid endophenotype, highly specific for differentiating both euthymic BD-P and UFDR, from HC.
authors.affiliation: Inserm, U955, Créteil, 94000, France. claire.daban-huard@inserm.fr
authors.forename: Claire
authors.initials: C
authors.lastname: Daban
authors.forename: Flavie
authors.initials: F
authors.lastname: Mathieu
authors.forename: Aurelie
authors.initials: A
authors.lastname: Raust
authors.forename: Barbara
authors.initials: B
authors.lastname: Cochet
authors.forename: Jan
authors.initials: J
authors.lastname: Scott
authors.forename: Bruno
authors.initials: B
authors.lastname: Etain
authors.forename: Marion
authors.initials: M
authors.lastname: Leboyer
authors.forename: Frank
authors.initials: F
authors.lastname: Bellivier
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D003071:Cognition / Q000502:physiology; D003072:Cognition Disorders / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011581:Psychological Tests