Anterior cingulate glutamate-glutamine levels predict symptom severity in women with obsessive-compulsive disorder.
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.
Yücel
Murat
M
Melbourne Neuropsychiatry Centre, National Neuroscience Facility, Carlton South, Australia. murat@unimelb.edu.au
Wood
Stephen J
SJ
Wellard
R Mark
RM
Harrison
Ben J
BJ
Fornito
Alex
A
Pujol
Jesus
J
Velakoulis
Dennis
D
Pantelis
Christos
C
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
D015415:Biomarkers; D005973:Glutamine; D001224:Aspartic Acid; D018698:Glutamic Acid; D007294:Inositol; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline