title: Anterior cingulate glutamate-glutamine levels predict symptom severity in women with obsessive-compulsive disorder.
abstract: OBJECTIVE
  Abnormalities of the anterior cingulate cortex (ACC) have consistently been identified in obsessive-compulsive disorder (OCD), but very few studies have examined the biochemical basis of such changes. The purpose of the present study was to investigate how ACC biochemistry in OCD varies as a function of gender, hemisphere, subregion, and symptomatology.
  
  
  METHODS
  3 T proton-magnetic resonance spectroscopy (MRS) was used to probe ACC biochemistry in 20 OCD patients (10 male, 10 female) and a comparable group of 26 healthy comparison subjects. Data were acquired from the left and right dorsal and rostral subregions of the ACC. Metabolites assessed included N-acetylaspartate (NAA), glutamate-glutamine (Glx), choline-containing compounds (Cho), creatine/phosphocreatine (Cr), and myoinositol-containing compounds (mI).
  
  
  RESULTS
  Female OCD patients had significantly reduced levels of Glx in all but one subregion of the ACC when compared to matched controls. Levels of Glx were correlated with clinical measures of symptom severity in female but not male patients. State levels of anxiety and depression did not explain this association. In addition, both male and female OCD patients had relatively higher concentrations of mI in their right ACC (rostral and dorsal) compared with healthy controls. No other compounds had any statistically significant group differences, nor were the concentrations of any other compounds correlated with symptom measures.
  
  
  CONCLUSIONS
  To the authors' knowledge this is the first study to demonstrate gender-specific neurochemical changes in OCD. Although these findings are tentative and require replication, they raise the possibility that MRS techniques may be of use in objectively monitoring patient progress and assessing the effectiveness of various treatments.
authors.affiliation: Melbourne Neuropsychiatry Centre, National Neuroscience Facility, Carlton South, Australia. murat@unimelb.edu.au
authors.forename: Murat
authors.initials: M
authors.lastname: Yücel
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Wood
authors.forename: R Mark
authors.initials: RM
authors.lastname: Wellard
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Harrison
authors.forename: Alex
authors.initials: A
authors.lastname: Fornito
authors.forename: Jesus
authors.initials: J
authors.lastname: Pujol
authors.forename: Dennis
authors.initials: D
authors.lastname: Velakoulis
authors.forename: Christos
authors.initials: C
authors.lastname: Pantelis
mesh_terms: D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism*; D005973:Glutamine / Q000378:metabolism*; D006179:Gyrus Cinguli / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007294:Inositol / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods; D008297:Male; D009483:Neuropsychological Tests; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism*; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D012737:Sex Factors
chemical_list: D015415:Biomarkers; D005973:Glutamine; D001224:Aspartic Acid; D018698:Glutamic Acid; D007294:Inositol; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline