Repetitive transcranial magnetic stimulation (rTMS) applied in the orbitofrontal cortex (OFC) is not effective as add-on treatment in obsessive-compulsive disorder (OCD) in a relatively large patient group compared with previous studies conducted in this field .
Previous studies show that high-frequency stimulation of the anterior cingulate cortex (ACC) and medial prefrontal cortex (mPFC) is effective in treatment [2,3]. Dr Alper Zıblak (Pamukkale University, Turkey) explained the hypothesis for this treatment. OFC activation is increased by provoking symptoms in OCD patients. Moreover, improvement of OCD symptoms with selective serotonin reuptake inhibitors (SSRIs) or cognitive behavioural therapies is associated with decreased OFC activation. This indicates that methods to decrease OFC activation may be effective in the treatment of patients suffering from OCD. However, there is hardly any data available on this particular topic.
Dr Zıblak and his team investigated the effectiveness of low-frequency rTMS on the OFC of treatment-resistant OCD patients. Included were 34 treatment-resistant OCD patients, divided into 2 groups. Group A (n=19) received active rTMS during 2 weeks, and sham rTMS in the 2 consecutive weeks. The opposite schedule was applied in group B (n=15). There were no differences between the 2 groups regarding age, gender, marital status, education level, age of onset of disease, and the number of hospitalisations (P>0.05). However, disease duration was significantly higher in the group receiving sham rTMS first than in the group receiving active rTMS first (P=0.028). The decrease in total scores of Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores was not over 35% for any patient at the end of the 4-week study period. Additionally, no differences were found between the percentage change of the 0-2 week, 0-4 week, and the 2-4 week scores between the 2 groups regarding the Y-BOCS score (see Figure) .
Figure: Yale-Brown Obsessive Compulsive Scale after active or sham rTMS in treatment-resistant OCD patients 
- Zıblak A. Transcranial magnetic stimulation in obsessive-compulsive disorder: a double-blind, cross over, placebo-controlled trial. S.17.08. ECNP Congress 2020.
- Carmi et al. Brain Stimul. 2018;11(1):158-165.
- Carmi et al. Eur Neuropsychopharmacol. 2018;28(6):777-778.
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