Longitudinal changes in neurometabolite concentrations in the dorsal anterior cingulate cortex after concentrated exposure therapy for obsessive-compulsive disorder

Niels T de Joode, Anders L Thorsen, Eline L Vester, Chris Vriend, Petra J W Pouwels, Kristen Hagen, Olga T Ousdal, Bjarne Hansen, Gerd Kvale, Odile A van den Heuvel

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BACKGROUND: The dorsal anterior cingulate cortex (dACC) plays an important role in the pathophysiology of obsessive-compulsive disorder (OCD) due to its role in error processing, cognitive control and emotion regulation. OCD patients have shown altered concentrations in neurometabolites in the dACC, particularly Glx (glutamate+glutamine) and tNAA (N-acetylaspartate+N-acetyl-aspartyl-glutamate). We investigated the immediate and prolonged effects of exposure and response prevention (ERP) on these neurometabolites.

METHODS: Glx and tNAA concentrations were measured using magnetic resonance spectroscopy (1H-MRS) in 24 OCD patients and 23 healthy controls at baseline. Patients received concentrated ERP over four days. A subset was re-scanned after one week and three months.

RESULTS: No Glx and tNAA abnormalities were observed in OCD patients compared to healthy controls before treatment or over time. Patients with childhood or adult onset differed in the change over time in tNAA (F(2,40) = 7.24, ɳ2p= 0.27, p = 0.004): concentrations increased between one week after treatment and follow-up in the childhood onset group (t(39) = -2.43, d = -0.86, p = 0.020), whereas tNAA concentrations decreased between baseline and follow-up in patients with an adult onset (t(42) = 2.78, d = 1.07, p = 0.008). In OCD patients with versus without comorbid mood disorders, lower Glx concentrations were detected at baseline (t(38) = -2.28, d = -1.00, p = 0.028). Glx increased after one week of treatment within OCD patients with comorbid mood disorders (t(30) = -3.09, d = -1.21, p = 0.004).

LIMITATIONS: Our OCD sample size allowed the detection of moderate to large effect sizes only.

CONCLUSION: ERP induced changes in neurometabolites in OCD seem to be dependent on mood disorder comorbidity and disease stage rather than OCD itself.

Original languageEnglish
Pages (from-to)344-352
Number of pages9
JournalJournal of affective disorders
Early online date15 Dec 2021
Publication statusPublished - 15 Feb 2022


  • Anterior cingulate cortex
  • Exposure and response prevention
  • Glutamate
  • Magnetic resonance spectroscopy
  • N-acetylaspartate
  • Obsessive-compulsive disorder

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