Efficacy of Theta Burst Stimulation in Bipolar Depression: A Systematic Review and Meta-analysis

Purpose: Repetitive transcranial magnetic stimulation (rTMS) has emerged as a promising alternative therapeutic modality for bipolar depression. Theta Burst Stimulation (TBS) a novel variant of rTMS is currently evolving as an effective and safe therapeutic tool in the management of bipolar depression, although it is still in the initial phase. In the present systematic review and meta-analysis, data from various studies investigating the effectiveness and tolerability of TBS in individuals with bipolar depression were synthesized.Data collection and analyses: Eight studies assessing the efficacy of TBS as a treatment for bipolar depression were included after a systematic search. The quality of the included studies was assessed using standard methods. Synthesized data included three uncontrolled clinical trials (non-randomized controlled trials [RCTs]; n = 48) and five RCTs (n = 201). While four studies used intermittent TBS, two studies used continuous TBS and bilateral TBS, each. Data from the five RCTs meta-analyzed using the random effects model showed the pooled odds ratio and effect size for response in the active group compared to the sham group were 1.01 (95%CI: 0.56, 1.83) and 1.64 (95%CI: -0.46, 3.74), respectively. Although both models showed no/minimal heterogeneity or publication bias, they were not statistically significant. A supplementary trial sequential analysis confirmed the need for more studies and suggested that the total sample required for drawing meaningful inferences was 918 samples.Conclusion: The available evidence suggests that more studies are required to draw conclusive inferences for the efficacy of TBS in the therapeutic management of bipolar depression.