Accelerated rTMS in the treatment of obsessive compulsive disorder: A pilot study on safety and feasibility

Introduction Obsessive Compulsive Disorder (OCD) is a disabling psychiatric disorder with a prevalence of approximately 1–3%. Next to disruptions within the orbitofronto-subcortical loops, regions within the salience network (SN) are related to specific OCD symptoms. Of interest, non-invasive brain stimulation has been documented to modulate SN cortical-subcortical loop disturbances. Therefore medial prefrontal regions (supplementary motor area (SMA), pre-SMA and the dorsomedial prefrontal cortex (dmPFC)) could be promising targets. Because accelerated rTMS (arTMS) has been showing fast clinical responses in depression, we applied arTMS (LF) in OCD patients. Methods Seven patients (4M, 3F, mean age: 33 years) with severe treatment resistant OCD, under treatment with stable medication regimen were enrolled. Patients received 20 sessions of 1Hz rTMS (1200 pulses) in an accelerated protocol (2 sessions a day) during 10 weekdays. Change from baseline to endpoint and to delayed endpoint (14 days after treatment) on the Y-BOCS were the primary outcome measure. Change as a direct and delayed effect on the IDS-SR were the secondary outcome measure. Side effects were carefully monitored. Results We found statistically significant reductions of the Y-BOCS scores from baseline to endpoint and to the delayed endpoint, however, without achieving clinical response (decline of≥35% at Y-BOCS). We also found a significant reduction on depression severity scores. The treatment was generally well tolerated. Headache was a common adverse effect. No epileptic insult occurred. Conclusion To our knowledge, this is the first accelerated rTMS protocol of the dmPFC in patients with OCD. These preliminary results indicate that accelerated rTMS may be safe, well-tolerated and capable of achieving significant improvement. Because this study is limited due to lack of sham condition and lack of power, further investigation is warranted.