Repetitive transcranial magnetic stimulation and its role in suicidality - A systematic review

Background: Repetitive transcranial magnetic stimulation (rTMS) as a brain stimulation modality is approved for the treatment of resistant depression and its efficacy in depression is also well supported in several studies. However, its effect on suicidality is still unclear, unlike electroconvulsive therapy. Methodology: This paper provides a systematic review of the literature published till June 2021. Studies that used rTMS as either monotherapy or adjunctive treatment in patients with suicidality, irrespective of their diagnosis, were included. The Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines was followed. A total of 20 studies (N = 1584) were included for the qualitative synthesis. The quality of studies was assessed using the Cochrane Risk of Bias tool for Randomised control trials (RCT) and the Newcastle-Ottawa Scale tool for Non-Randomised studies (NRS). Results: Of the 20 articles selected for qualitative synthesis, 11 were RCTs and 9 were NRS. The results are categorized in domains of type of the study, size of population, type of population, diagnosis, assessment scales, mode of rTMS, stimulus parameters, safety and efficacy. Conclusions: The high frequency rTMS at left dorsolateral prefrontal cortex as an adjunct to antidepressant medication is promising in reducing suicidal behaviour in treatment resistant depression. However, role of TMS targeting other areas of stimulation in mitigating suicide risk in other disorders could not be established due to scarcity of such studies. The results should be interpreted cautiously as considerable risk of bias was present in the reviewed studies.