Impact of deep transcranial magnetic stimulation on insomnia outcomes in patients with treatment-resistant depression: a retrospective study

Deep transcranial magnetic stimulation (dTMS) is an Food and Drug Administration-approved treatment for treatment-resistant depression (TRD). Our study aims to examine the impact of baseline insomnia severity on mood outcomes of dTMS and the impact of dTMS on comorbid insomnia in patients with treatment-resistant depression using a retrospective analysis. Twenty-five patients with treatment-resistant depression who underwent dTMS were divided into two groups: "low insomnia" and "high insomnia," depending on Insomnia Severity Index scores at baseline. Significant improvements in depression and anxiety from baseline to final dTMS session were noted in both groups. Baseline insomnia severity was not associated with poorer treatment outcomes after dTMS. Final insomnia scores of the two groups were not significantly different, suggesting dTMS alleviated insomnia symptoms in patients with treatment-resistant depression. Further research incorporating a prospective study design in a multicenter setting is warranted to replicate these findings and elucidate the mechanistic action of dTMS on insomnia outcomes.