title: Increased intrasubject variability in response time in youths with bipolar disorder and at-risk family members.
abstract: OBJECTIVE
  Deficits in sustained attention may represent an endophenotype for bipolar disorder (BD). One heritable measure of sustained attention is intrasubject variability in response time (ISV-RT). We tested the hypothesis that, compared with controls, both youths with BD and those at familial risk for the disorder would have increased ISV-RT.
  
  
  METHODS
  Subjects were 28 patients with BD, 26 unaffected youths with a first-degree relative with BD, and 24 control youths without an affected relative, all aged 7 to 17 years. Subjects completed the Flanker Continuous Performance Test.
  
  
  RESULTS
  Bipolar disorder and at-risk youths had increased ISV-RT, compared with the controls. Differences were independent of comorbid psychopathology in youths with BD and present in psychiatrically healthy at-risk youths.
  
  
  CONCLUSIONS
  Increased ISV-RT may be a risk marker for BD. Further research is needed to investigate the neural and genetic underpinnings of this deficit, as well as the specificity of the finding to BD.
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Brotman
authors.forename: Melissa H
authors.initials: MH
authors.lastname: Rooney
authors.forename: Martha
authors.initials: M
authors.lastname: Skup
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Pine
authors.forename: Ellen
authors.initials: E
authors.lastname: Leibenluft
mesh_terms: D000293:Adolescent; D001288:Attention; D001714:Bipolar Disorder / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D002648:Child; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics / Q000523:psychology; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010641:Phenotype; D011930:Reaction Time; D012307:Risk Factors