High-frequency deep transcranial magnetic stimulation (dTMS) over the medial prefrontal cortex (mPFC) and the anterior cingulate cortex (ACC) with an H-coil has been approved by the Food and Drug Administration for use in treatment-resistant obsessive-compulsive disorder (OCD). However, there is not yet strong scientific evidence concerning the efficacy and safety of performing a similar procedure with a double-cone coil or in an accelerated manner. The aim of this study was evaluating the efficacy of dTMS over the medial prefrontal cortex (mPFC) and the anterior cingulate cortex (ACC) in an accelerated manner with double-cone coil.

The current study aimed to investigate the efficacy and safety of multiple deep stimulations per day with a double-cone coil to the mPFC and ACC in treatment-resistant patients with OCD. This study evaluated (I) the effectiveness of high-frequency stimulation of the mPFC and ACC with a double cone coil, and (II) the effectiveness of the application of this protocol in three weeks, not six weeks as approved by the FDA. The participants were randomized into two parallel groups in a double-blind manner. High frequency (20 Hz) dTMS was applied to the mPFC and ACC in one group and sham dTMS to the same regions in the other group, twice a day, for a total of 30 sessions. This application was for three weeks in total, excluding weekends.

Inclusion Criteria:

• Clinical diagnosis of obsessive-compulsive disorder
• Not having an adequate response to treatment despite using at least two selective serotonin reuptake inhibitors at a sufficient dose and duration for 12 weeks before the planned add-on treatment
• Aged 18-65 years
• Able to read and write

Exclusion Criteria:

• Not providing consent to participate in the study
• Diagnosis of a psychiatric disorder, such as psychotic disorder, bipolar disorder, major depressive disorder [Hamilton Depression Rating Scale (HDRS) score above 17], mental retardation, alcohol-substance use disorder, and organic mental disorder (dementia, delirium, and head trauma, etc.)
• Diagnosis of an important medical or neurological disease (e.g., epilepsy);
• Mental retardation
• Illiteracy
• Having received electroconvulsive therapy (ECT) or TMS within the last six months;
• Having any prosthesis, such as an implant and pacemaker.