Therapeutic potential of non-invasive brain stimulation in alleviating suicidal ideation and depressive symptoms in major depressive disorder: A systematic review and meta-analysis.

IMPORTANCE

Suicidal ideation, intricately associated with depressive symptoms, poses a significant public health challenge. Previous clinical studies of non-invasive brain stimulation (NIBS) as a therapeutic modality have demonstrated encouraging efficacy, underscoring its potential to address both suicidal and depressive manifestations.

OBJECTIVE

The present study aims to integrate the anti-suicidal and antidepressant effects of NIBS in depressive patients and examined the complex interplay and underlying correlations between these effects.

METHODS

Adopting the PICOS framework and adhering to PRISMA guidelines, we conducted a comprehensive systematic review and meta-analysis, prospectively registered with PROSPERO (CRD42024506889). Our search, spanning six databases from inception to June 2025, targeted terms related to suicidal ideation, depression, and NIBS, with a focus on randomized controlled trials. Following independent screening by two assessors, we assessed the methodological rigor of the included studies using the Jadad score and the Cochrane Collaboration Risk of Bias Tool version 2 (RoB2).

FINDINGS: The meta-analysis included 21 clinical trials from 19 articles (with two articles each reporting two trials), totaling 1329 participants. Results revealed a small effect size for the anti-suicide effect (SMD = -0.28, 95 % CI [-0.43, -0.14], I2 = 38.8 %, p < 0.001) and a medium effect size for the antidepressant effect (SMD = -0.46, 95 % CI [-0.64, -0.28], I2 = 22.9 %, p < 0.001). Subgroup analysis and meta-regression highlighted cultural background (Western or Non-western) as the most significant contributor to the heterogeneity of suicidal outcomes (R2 = 100 %). Furthermore, a positive linear correlation was observed between the two therapeutic effects (R = 0.74, p < 0.001), suggesting a synergistic interplay.

INTERPRETATION: Our findings emphasized the dual therapeutic potential of NIBS in mitigating suicidality and depression, offering outcome-driven evidence for clinical practice and mathematical correlation into the underlying neurobiological mechanisms. Notably, the heterogeneity analysis revealed the profound influence of sociodemographic factors, particularly cultural context, on psychological states, indicating the need for culturally tailored interventions.