A proton MRSI study of brain N-acetylaspartate level after 12 weeks of citalopram treatment in drug-naive patients with obsessive-compulsive disorder

Am J Psychiatry. 2006 Jul;163(7):1202-7. doi: 10.1176/appi.ajp.163.7.1202.


Objective: Reductions in the level of N-acetylaspartate within subcortical structures of patients with obsessive-compulsive disorder (OCD) have been reported in several studies. However, there have been, as yet, no reports regarding N-acetylaspartate levels in the prefrontal cortex of adult drug-naive OCD patients. The authors used proton magnetic resonance spectroscopic imaging ((1)H-MRSI) to investigate regional N-acetylaspartate level abnormalities and changes after 12 weeks of pharmacotherapy with citalopram in drug-naive OCD patients.

Method: Thirteen drug-naive OCD patients and 13 age- and sex-matched healthy comparison subjects were included in this study. N-acetylaspartate levels (obtained from ratios of N-acetylaspartate with creatine, choline, and creatine plus choline) in the prefrontal cortex, parietal cortex, anterior cingulate, posterior cingulate, frontal white matter, and parietal white matter were measured by (1)H-MRSI. In OCD patients, measurements were taken before and after 12 weeks of citalopram treatment. Correlations between N-acetylaspartate concentrations in regions of interest and clinical measures were also assessed.

Results: Drug-naive OCD patients exhibited significantly lower N-acetylaspartate levels in the prefrontal cortex, frontal white matter, and anterior cingulate at baseline than did comparison subjects. Significant increases in N-acetylaspartate level were detected in the prefrontal cortex and frontal white matter in OCD patients after 12 weeks of citalopram treatment.

Conclusions: These data suggest that reductions in neuronal viability occur in the frontal region of OCD patients and that these reductions may be partly reversible.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aspartic Acid / analogs & derivatives*
  • Aspartic Acid / metabolism
  • Brain / drug effects
  • Brain / metabolism*
  • Brain Chemistry / drug effects
  • Choline / metabolism
  • Citalopram / pharmacokinetics*
  • Citalopram / therapeutic use*
  • Creatine / metabolism
  • Female
  • Frontal Lobe / drug effects
  • Frontal Lobe / metabolism
  • Gyrus Cinguli / drug effects
  • Gyrus Cinguli / metabolism
  • Humans
  • Longitudinal Studies
  • Magnetic Resonance Spectroscopy*
  • Male
  • Obsessive-Compulsive Disorder / diagnosis
  • Obsessive-Compulsive Disorder / drug therapy*
  • Obsessive-Compulsive Disorder / metabolism
  • Personality Inventory
  • Prefrontal Cortex / drug effects
  • Prefrontal Cortex / metabolism
  • Protons
  • Psychiatric Status Rating Scales
  • Serotonin Uptake Inhibitors / pharmacokinetics*
  • Serotonin Uptake Inhibitors / therapeutic use*


  • Protons
  • Serotonin Uptake Inhibitors
  • Citalopram
  • Aspartic Acid
  • N-acetylaspartate
  • Creatine
  • Choline