Combination therapy with transcranial magnetic stimulation and ketamine for treatment-resistant depression: A long-term retrospective review of clinical use.

Background: Both transcranial magnetic stimulation (TMS) and infused ketamine are recognized treatments for patients suffering from major depressive disorder (MDD). A novel therapy named combination TMS with ketamine (CTK) is introduced. This retrospective review examined the safety and clinical benefits of CTK in patients suffering from treatment-resistant depression (TRD) during the routine practice of psychiatry in a private clinic.

Methods: TRD patients (N = 28) received a coincident application of high-output TMS (30 minutes) with biomarker-determined ketamine infusions (20 minutes). Frequency of treatment was dependent on patient responsiveness (10-30 sessions). Clinical global impression (CGI) data was collected pre- and post-treatment and then two years later.

Results: The mean reduction in CGI severity for the patient group following CTK was 4.46 ± 0.54 at a 99% confidence interval and was deemed statistically significant using a paired t-test (α = 0.01, t = 22.81 p < 0.0001). This reduction was sustained for two years following treatment completion and this remission was deemed statistically significant by a second paired t-test (α = 0.01, t = 27.36, p < 0.0001).

Limitations: Retrospective review of a limited number of patients undergoing CTK in a clinical practice.

Conclusions: This clinical review indicated that CTK is an effective, long-term therapy (after two years) and can be used for TRD patients. The coincident administration of ketamine allowed for higher TMS intensities than otherwise would be tolerated by patients. Further studies for optimization of CTK are warranted.