Efficacy of Transcranial Direct Current Stimulation in Reducing Symptoms in Patients with Major Depressive Disorder: A Randomized Controlled Trial

Introduction: In the recent years, transcranial direct current stimulation (tDCS) has been considered by researchers as one of the possible effective approach in the treatment of major depressive disorder. However, the results of these investigations are often contradictory. According to this, the purpose of this study was to determine the effectiveness of tDCS in reducing symptoms of people with major depressive disorder. Methods: In the sham-controlled randomized trial, twenty people with major depressive disorder referred to a private psychiatric clinic in Tehran City, Iran. They were selected by convenience sampling and divided into the intervention and control groups by randomized block design. tDCS was administered 2 mA, 20 minutes per session, for 10 sessions, 3 days per week. Immediately after, and one month after the intervention, the scores of the two groups were assessed in the Hamilton Depression Rating Scale and Beck Depression Inventory. The data were analyzed using SPSS version 16 software and using statistical methods of repeated analysis of variance and independent and dependent t-test. Results: The results of repeated analysis of variance for Hamilton (F = 43.5 and P = 0.017) and Beck (F = 125.12 and P = 0.022) depression scores showed the significance of the interaction effect of time (four stages of measurement) and group membership (experiment and control) (P < 0.05). In depression scores in both Hamilton and Beck scales in the experimental group in the intervention stages (Hamilton scale, P = 0.019, Beck scale = P = 0.017) and follow-up (Hamilton scale, P = 0.01, Beck scale = P = 0.03) was significantly reduced compared to the control group. Conclusion: The results of this study confirmed the effectiveness of tDCS in reducing symptoms of major depressive disorder. More clinical trials are needed to prove the effectiveness of tDCS compared to a variety of treatments.