Adjuvant Priming Repetitive Transcranial Magnetic Stimulation for Treatment-Resistant Obsessive-Compulsive Disorder: In Search of a New Paradigm!

Objectives: Repetitive transcranial magnetic stimulation (rTMS) is used as a therapeutic option for obsessive-compulsive disorder (OCD) in both clinical and research settings. There has been no consensus with regard to target area and other parameters, although 1-Hz rTMS over the supplementary motor area (SMA) is found to be promising. Priming stimulation, which involves high-frequency followed by low-frequency rTMS, has been shown to enhance neural response to low-frequency rTMS. Hence, this study was conducted to investigate the effect of adjunctive priming rTMS over the SMA in treatment-resistant OCD.

Methods: Thirty patients with OCD who were symptomatic after an adequate selective serotonin reuptake inhibitor trial were randomized into 2 groups: one group receiving active priming stimulation (6-Hz rTMS at 80% resting motor threshold) followed by 1-Hz rTMS (priming rTMS group) and the other receiving sham stimulation followed by 1-Hz rTMS (rTMS-only group). Both groups received 10 sessions of such interventions for 2 weeks. Both the rater and patients were blind to the treatment allocation. Assessments were done using the Yale-Brown Obsessive Compulsive Scale, Hamilton Rating Scale for Depression, Hamilton Rating Scale for Anxiety, and Clinical Global Impression-Improvement scale at baseline, 2 weeks, and 4 weeks.

Results: Both groups showed a significant improvement in all domains of psychopathology over time. The priming rTMS group was better than the rTMS-only group in reducing the Yale-Brown Obsessive Compulsive Scale compulsion score (P < 0.023) as well as scores of the Hamilton Rating Scale for Anxiety, Hamilton Rating Scale for Depression, and Clinical Global Impression-Improvement scale. None developed any adverse effects requiring medical attention.

Conclusions: Priming rTMS over the SMA is safe and has favorable effects in OCD. It seems to have a predominant effect on the reduction of compulsions, presumably rectifying the impaired response inhibition in patients with OCD.