5 Hz Repetitive transcranial magnetic stimulation to left prefrontal cortex for major depression

•Patients who were unable to tolerate standard 10 Hz rTMS were switched to 5 Hz rTMS.•Higher baseline levels of depression and anxiety were found in 5 Hz patients.•5 Hz rTMS provided the same clinical outcomes as 10 Hz rTMS.•Power was sufficient to detect small differences between groups.

BackgroundRepetitive transcranial magnetic stimulation (rTMS) to left prefrontal cortex at 10 Hz is the most commonly utilized protocol for major depressive disorder (MDD). Published data suggests that left sided 5 Hz rTMS may be efficacious and well tolerated.ObjectiveWe analyzed outcomes in a naturalistic cohort of MDD patients who could not tolerate 10 Hz rTMS and were routinely switched to 5 Hz. We hypothesized that the efficacy of 5 Hz rTMS would be equivalent to 10 Hz.MethodsRecords were reviewed for patients (n=98) who received 15 or more acute rTMS treatments. The sample was split based upon the frequency (10 or 5 Hz) at which the majority of treatments were delivered. The Inventory of Depressive Symptoms (IDS-SR) and 9-Item Patient Health Questionnaire (PHQ-9) were used to evaluate outcomes.ResultsBaseline IDS-SR was higher in the 5 Hz (n=27) than in the 10 Hz (n=71) group (p<.05), as was frequency of comorbid anxiety (p=.002). Depression outcomes did not differ between groups, and there were no differences in response or remission rates (all p>.1). Statistical power was sufficient to detect small group differences (d=.26).LimitationsOpen-label data in a naturalistic setting.ConclusionOutcomes associated with 5 Hz rTMS did not differ from 10 Hz, despite higher baseline depressive symptom severity and anxiety in 5 Hz patients. 5 Hz stimulation may be an alternative treatment option for patients unable to tolerate 10 Hz rTMS.