A double blind randomized clinical trial of the effectiveness of low frequency rTMS over right DLPFC or OFC for treatment of obsessive-compulsive disorder

We compared the effectiveness of low frequency repetitive transcranial magnetic stimulation over right dorsolateral prefrontal cortex (DLPFC), right orbitofrontal cortex (OFC) and sham for treatment of obsessive-compulsive disorder (OCD) and sought to determine possible predictors of effective treatment. Sixty OCD patients participated and were randomly allocated to one of the 3 treatment groups. Treatment was administered daily for 10 days. Assessments were made at the beginning and end of therapy as well as three months later using the Yale-Brown obsessive compulsive scale (Y-BOCS), Hamilton Anxiety Rating Scale (HAM-A), Beck Depression Inventory (BDI), and Clinical Global Impression – Severity scale (CGI-S). There were no significant demographic or clinical differences between the groups at baseline. One-way repeated measures ANOVA showed that participants in all 3 groups improved their scores on all rating scales following treatment. A two-way repeated measures ANOVA revealed a significant time and group interaction due to the fact that both active treatment groups outperformed the sham group, although there was no significant difference between the two. Percent improvement had significant negative correlations with the following factors: duration of illness, baseline Y-BOCS, HAM-A, and BDI. We conclude that rTMS over either right DLPFC or OFC has a therapeutic effect on OCD symptoms. Patients with lower Y-BOCS and fewer comorbidities responded best to rTMS.