The Effectiveness of Transcranial Magnetic Stimulation in Suicidality: An Updated Systematic Review

Suicidal thoughts and behaviors (STB) have a substantial global burden, with over 14 million individuals attempting suicide annually. Existing biological therapies do not adequately reduce STB risk. Repetitive transcranial magnetic stimulation (rTMS) is an approved, non-invasive and low-risk treatment for several psychiatric disorders. Meta-analyses investigating TMS' effects on STB indicate therapeutic promise. Given the proliferation of TMS studies investigating its effect on STB, a repeat review of the literature is warranted.

A PRISMA-guided systematic review was conducted to evaluate the efficacy of rTMS in reducing STB. Studies assessing STB outcomes following rTMS to treat psychiatric disorders, either as monotherapy or adjunctive treatment, were included. Forty-five studies were identified (N=3515).

Studies generally applied rTMS to treat primary psychiatric disorders, particularly depression, with change in suicidality evaluated as a secondary outcome. rTMS protocols differed across studies. Most studies targeted the left dorsolateral prefrontal cortex (dlPFC), although significant improvements to STB were also reported with rTMS targeting the visual cortex, right dlPFC and the bilateral PFC. High frequency rTMS and intermittent theta burst stimulation (iTBS) protocols were superior in reducing STB compared to other stimulation protocols, with studies reporting 40-100% treatment response rates. Adverse events (AEs) were mostly mild and transient.

rTMS appears to be a safe and effective treatment option for STB, with significant reductions observed, particularly when rTMS or iTBS is applied to the dlPFC. Mechanistically informed randomized controlled trials specifically designed to evaluate rTMS' treatment effects on STB are needed to validate this promising treatment approach.