title: Impaired sustained attention and executive dysfunction: bipolar disorder versus depression-specific markers of affective disorders.
abstract: OBJECTIVE
  To identify neurocognitive measures that could be used as objective markers of bipolar disorder.
  
  
  METHODS
  We examined executive function, sustained attention and short-term memory as neurocognitive domains in 18 participants with bipolar disorder in euthymic state (Beuth), 14 in depressed state (Bdep), 20 with unipolar depression (Udep) and 28 healthy control participants (HC). We conducted four-group comparisons followed by relevant post hoc analyses.
  
  
  RESULTS
  Udep and Bdep, but not Beuth showed impaired executive function (p=0.045 and p=0.046, respectively). Both Bdep and Beuth, but not Udep, showed impaired sustained attention (p=0.001 and p=0.045, respectively). The four groups did not differ significantly on short-term memory. Impaired sustained attention and executive dysfunction were not associated with depression severity, duration of illness and age of illness onset. Only a small number of abnormal neurocognitive measures were associated with medication in Bdep and Beuth.
  
  
  CONCLUSIONS
  Impaired sustained attention appears specific to bipolar disorder and present in both Beuth and Bdep; it may represent an objective marker of bipolar disorder. Executive dysfunction by contrast, appears to be present in Udep and Bdep and likely represents a marker of depression.
authors.affiliation: Western Psychiatric Institute and Clinic, Department of Psychiatry, University of Pittsburgh School of Medicine, USA. fm38@aub.edu.lb
authors.forename: Fadi T
authors.initials: FT
authors.lastname: Maalouf
authors.forename: Crystal
authors.initials: C
authors.lastname: Klein
authors.forename: Luke
authors.initials: L
authors.lastname: Clark
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Sahakian
authors.forename: Edmund J
authors.initials: EJ
authors.lastname: Labarbara
authors.forename: Amelia
authors.initials: A
authors.lastname: Versace
authors.forename: Stefanie
authors.initials: S
authors.lastname: Hassel
authors.forename: Jorge R C
authors.initials: JR
authors.lastname: Almeida
authors.forename: Mary L
authors.initials: ML
authors.lastname: Phillips
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001289:Attention Deficit Disorder with Hyperactivity / Q000209:etiology*; D001714:Bipolar Disorder / Q000150:complications*; D003072:Cognition Disorders / Q000209:etiology*; D003863:Depression / Q000150:complications*; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D009716:Numerical Analysis, Computer-Assisted; D011569:Psychiatric Status Rating Scales; D011930:Reaction Time / Q000502:physiology