title: The association of elevated body mass index with reduced brain volumes in first-episode mania.
abstract: BACKGROUND
  Compared with normal-weight patients, obese patients with bipolar I disorder (BD) suffer more manic and depressive episodes and make more suicide attempts. In the general population, obesity is associated with reduced total brain volume (TBV) and gray matter volume (GMV), but the neurobiology of obesity in BD has not been investigated.
  
  
  METHODS
  We used magnetic resonance imaging to examine TBV, GMV, white matter volume (WMV), as well as frontal, parietal, occipital, and temporal lobe volumes, in 55 healthy subjects (17 overweight/obese and 38 normal weight) and 57 patients with BD following their first manic episode (20 overweight/obese and 37 normal weight).
  
  
  RESULTS
  Linear regression analyses demonstrated that when other predictors of brain volume were accounted for, increased body mass index (BMI) in healthy subjects was significantly associated with decreased TBV and GMV. In contrast, increased BMI in patients with BD was significantly associated with decreased WMV and temporal lobe volume, areas of known vulnerability in early BD.
  
  
  CONCLUSIONS
  This is the first published report to show a relationship between elevated BMI and reduced brain volumes in BD, or any psychiatric illness. Our results suggest that obesity is associated with unique neurobiological changes in BD. They further imply a possible biological mechanism underlying the association between obesity and a more severe illness course in BD.
authors.affiliation: Mood Disorders Centre, University of British Columbia, Vancouver, Canada.
authors.forename: David J
authors.initials: DJ
authors.lastname: Bond
authors.forename: Donna J
authors.initials: DJ
authors.lastname: Lang
authors.forename: Melissa M
authors.initials: MM
authors.lastname: Noronha
authors.forename: Mauricio
authors.initials: M
authors.lastname: Kunz
authors.forename: Ivan J
authors.initials: IJ
authors.lastname: Torres
authors.forename: Wayne
authors.initials: W
authors.lastname: Su
authors.forename: William G
authors.initials: WG
authors.lastname: Honer
authors.forename: Raymond W
authors.initials: RW
authors.lastname: Lam
authors.forename: Lakshmi N
authors.initials: LN
authors.lastname: Yatham
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001714:Bipolar Disorder / Q000150:complications / Q000473:pathology*; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D009765:Obesity / Q000150:complications / Q000473:pathology; D011569:Psychiatric Status Rating Scales; D055815:Young Adult