Continuation transcranial direct current stimulation for the prevention of relapse in major depression

Background: Transcranial direct current stimulation (tDCS) is gaining attention as an effective new treatment for major depression. Little is known, however, of the duration of antidepressant effects following acute treatment. In this study, we describe the use of continuation tDCS treatment for up to 6 months following clinical response to an acute treatment course. Methods: Twenty-six participants pooled from two different studies involving different tDCS protocols received continuation tDCS treatment on a weekly basis for 3 months and then once per fortnight for the final 3 months. Mood ratings were completed at 3 and 6 months. Analyses examined clinical predictors of relapse during continuation tDCS treatment. Results: The cumulative probability of surviving without relapse was 83.7% at 3 months and 51.1% at 6 months. Medication resistance was found to be a predictor of relapse during continuation tDCS. Limitations: This was an open label prospective study with no control group. Two different forms of tDCS were used. Conclusion: Similar to other antidepressant treatments, continuation tDCS appears to be a useful strategy to prevent relapse following clinical response. These preliminary data suggest that the majority of patients maintained antidepressant benefit with a continuation schedule of at least weekly treatment. Future controlled studies are required to confirm these findings.