Objective: Major depressive disorder (MDD) which comes to transcranial magnetic stimulation (TMS) is prone to relapse. Cluster maintenance (CM) TMS is courses of 5 treatments delivered over 2.5-5 days, separated by monthly or greater non-treatment periods. Our aim was to characterize the outcomes of 100 courses of CM TMS.

Method: This was a Quality Assurance/Clinical Audit study. We studied consecutive CM TMS courses provided to private hospital inpatients. Mood was rated (on admission and discharge) using the six-item Hamilton depression rating (HAMD6) and the Clinical Global Impression - Severity (CGI-S) scales. We also applied recent STAR*D criteria which are designed to measure the 'clinical change' expected to impact patient function [16].

Results: For the total sample, using the HAMD6, 83% of courses featured relapse or partial relapse on admission, and 81% featured remission on discharge. Of 46 courses featuring HAMD6 relapse on admission, 74% featured remission on discharge. For the 100 courses the HAMD6 discharge scores were significantly lower than the admission scores (p = 2.0 × 10-24), as were the CGI-S scores (p = 1.8 × 10-25). Using STAR*D criteria for people in relapse or partial relapse on admission, CM TMS provided least a 'clinically meaningful' outcome in 82% of the cases.

Conclusion: For courses featuring relapse or partial relapse on admission, CM TMS converted greater than 70% to remission at discharge. It produced statistically significant reductions in HAMD6 and CGI-S scores, and using STAR*D criteria, at least 'clinically meaningful' change was extensively demonstrated. This evidence indicates CM TMS should be readily available to people living with relapsing MDD.