title: Total white matter hyperintensity volume in bipolar disorder patients and their healthy relatives.
abstract: OBJECTIVE
  White matter hyperintensities (WMH) are more common in subjects with bipolar disorder (BP) than in healthy subjects (HS). Few studies have examined the effect of the diagnostic type of bipolar illness on WMH burden, and none have approached this question through a direct measurement of the volume of affected white matter in relationship to familiality. In this pilot study, we utilized a volumetric measurement of WMH to investigate the relationship between the total volume of WMH and the familiality and type of BP.
  
  
  METHODS
  Forty-five individuals with bipolar I disorder (BP-I) with psychotic features, BP-I without psychotic features, or bipolar II disorder (BP-II), seven of their unaffected relatives, and 32 HS were recruited for participation. T-2 weighted magnetic resonance imaging scans were obtained on all subjects, and the total volume of all WMH for each subject was measured in cubic centimeters. The significance of difference between groups was tested using ANOVA with post-hoc adjustment for multiple comparisons. Further, we used logistic regression to test for trends between symptom load and total WMH volume.
  
  
  RESULTS
  The mean total volume of WMH in BP-I patients with psychotic features was significantly higher (p < 0.05) than that of HS. Further, we observed a positive linear trend by familiality and type of affectedness when comparing mean total WMH volume of HS, unaffected family members, subjects with BP-II, and BP-I with and without a history of psychosis (p < 0.05).
  
  
  CONCLUSIONS
  Based on a quantitative technique, WMH burden appears to be associated with familiality and type of BP. The significance of these findings remains to be fully elucidated.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA. stighe1@jhmi.edu
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Tighe
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Reading
authors.forename: Paul
authors.initials: P
authors.lastname: Rivkin
authors.forename: Brian
authors.initials: B
authors.lastname: Caffo
authors.forename: Barbara
authors.initials: B
authors.lastname: Schweizer
authors.forename: Godfrey
authors.initials: G
authors.lastname: Pearlson
authors.forename: James B
authors.initials: JB
authors.lastname: Potash
authors.forename: J Raymond
authors.initials: JR
authors.lastname: Depaulo
authors.forename: Susan S
authors.initials: SS
authors.lastname: Bassett
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001714:Bipolar Disorder / Q000150:complications / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D056784:Leukoencephalopathies / Q000150:complications*; D008279:Magnetic Resonance Imaging; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology*