title: A comparison of affected and unaffected relatives of patients with bipolar disorder using proton magnetic resonance spectroscopy.
abstract: OBJECTIVE
  Bipolar disorders have a strong genetic underpinning. Little is known about biological predispositions that convey vulnerability for the illness. We searched for biological vulnerability markers using proton magnetic resonance spectroscopy (MRS) in both affected and unaffected participants at high genetic risk for bipolar disorder.
  
  
  METHODS
  We recruited high-risk participants aged 15-30 years from families in which multiple members were affected with bipolar disorder. Our primary sample included 14 affected and 15 unaffected relatives of probands with bipolar I disorder. Our extended sample comprised 19 affected and 21 unaffected participants with a family history of either bipolar I or bipolar II disorders. We matched both samples by age and sex with 31 control participants without a personal or family history of psychiatric disorders. We performed single voxel proton MRS at 1.5 T in bilateral dorsal and ventral medial prefrontal cortices with correction for grey matter proportion.
  
  
  RESULTS
  We found comparable levels of choline, creatine, myo-inositol and N-acetylaspartate among the groups in both samples. There were no differences between regions of the medial prefrontal cortex or between hemispheres for any of the metabolites in any of the samples. The exclusion of 5 participants taking medication did not change our results.
  
  
  CONCLUSIONS
  Neurochemical changes in the medial prefrontal cortex that are measurable using proton MRS do not appear to be antecedent to the onset of mood disorders in genetically susceptible individuals.
authors.affiliation: Department of Psychiatry, Dalhousie University, Halifax, NS.
authors.forename: Tomas
authors.initials: T
authors.lastname: Hajek
authors.forename: Denise
authors.initials: D
authors.lastname: Bernier
authors.forename: Claire
authors.initials: C
authors.lastname: Slaney
authors.forename: Lukas
authors.initials: L
authors.lastname: Propper
authors.forename: Matthias
authors.initials: M
authors.lastname: Schmidt
authors.forename: Normand
authors.initials: N
authors.lastname: Carrey
authors.forename: Glenda
authors.initials: G
authors.lastname: MacQueen
authors.forename: Anne
authors.initials: A
authors.lastname: Duffy
authors.forename: Martin
authors.initials: M
authors.lastname: Alda
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers; D001714:Bipolar Disorder / Q000235:genetics* / Q000378:metabolism / Q000523:psychology; D001923:Brain Chemistry; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D019964:Mood Disorders / Q000378:metabolism / Q000523:psychology; D011569:Psychiatric Status Rating Scales
chemical_list: D015415:Biomarkers