Time-course of the tDCS antidepressant effect: An individual participant data meta-analysis
Nikolin et al., 2023. Progress in Neuro-Psychopharmacology and Biological Psychiatry.
A meta-analysis of ten randomised controlled trials of tDCS in depression.
Data from 576 participants were analysed (tDCS: n = 311; sham: n = 265), of which 468 were unipolar, and 108 had bipolar disorder.
The analysis showed that tDCS is effective for depressive symptoms in both unipolar and bipolar depressive disorders.
tDCS effect sizes reached a peak at approximately 6 weeks and continued to diverge from sham up to 10 weeks.
Significant predictors associated with worse response included higher baseline depression severity and treatment resistance. Predictors associated with better response included bipolar disorder and anxiety disorder.
Compared to unipolar depression, participants with bipolar disorder may require additional maintenance sessions to prevent rapid relapse.
The findings suggest that longer treatment courses, lasting at least 6 weeks, may be indicated.