A meta-analysis of the effects of non-invasive brain stimulation on obsessive-compulsive disorder

• The results of this meta-analysis show that rTMS and tDCS are effective interventions for obsessive-compulsive disorder • This study is the first meta-analysis focusing on the efficacy of tDCS on obsessive-compulsive disorder • This meta-analysis provides evidence for the efficacy of non-invasive brain stimulation in the treatment of obsessive-compulsive disorder This study aims to assess the efficacy of non-invasive brain stimulation (NIBS) in randomized controlled clinical trials (RCTs) for obsessive-compulsive disorder (OCD). Relevant literature was searched from PubMed, Embase, and Cochrane Library as of March 14, 2021. The effect was evaluated using standard mean deviation (SMD), and the recommended grade of the evidence was analyzed. Finally, nineteen studies with 525 patients were included. Active repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) significantly reduced the scores of OCD. No eligible articles evaluated the effects of other NIBS techniques. The subgroup analyses indicated that both the high-frequency and the low-frequency stimulation showed significantly positive effects, with no statistical difference between the two stimulation frequencies. Targeting the dorsolateral prefrontal cortex (DLPFC) showed significant improvements over sham stimulation, but no such improvement was found in the supplementary motor area (SMA). Our study suggested that rTMS is effective in treating OCD, and it is likely that the same is true for tDCS. In addition, the site and frequency of stimulation may be potential factors affecting therapeutic effects. The results of this study not only validate previous findings but may inspire future research.