Major depressive disorder (MDD) is a deliberating mental disorder with a high prevalence, and it produces heavy burden and suicide. It is one of the most common psychiatric disorders, but pharmacological treatments are ineffective in a substantial fraction of patients and are accompanied by unwanted and very serious side effects. Therefore, in addition to antidepressants treating MDD, non-pharmacological interventions have been proposed to treat MDD.

Personalized interventions for people suffering from psychiatric conditions at all stages of illness have seen an evolution in the past few years, from genomic-based subtyping and imaging-based subtyping for the optimization of first-line treatment selection to new methods for individualized image-guided targeting in patients via invasive brain stimulation or non-invasive brain stimulation. Recent literature provides exciting new proof-of-concept strategies for the correction of patient-specific dysfunctions in emotional–cognitive brain circuits for depression by non-invasive neuromodulation strategies like transcranial direct current stimulation (tDCS). Transcranial Direct Current stimulation (tDCS) has been shown to be an effective treatment for depression that can be made portable and used safely, in the privacy of people homes. It could act as the first line of defense treatment for depression. In this study, we seek further validation on the efficacy of tDCS for depression.

This proof-of-concept study intends to recruit 20 individuals suffering from MDD fulfilling the inclusion and exclusion criterion randomly dividing them to receive either active or sham tDCS. 10 patients would be recruited for active tDCS arm and 10 will be included in sham tDCS arm. The outcome parameters would be standard questionnaire-based evaluation method for depression - Montgomery and Asberg Depression Rating Scale (MADRS), Hamilton Depression Rating Scale (HDRS-17) and Clinical Global Impressions (CGI) scale. In addition, electroencephalography (EEG) and functional near infra-red spectroscopy (fNIRS) and Magnetic resonance imaging (MRI) based markers will also be evaluated to analyze if there could be any putative quantitative biomarker for treatment related progress in depression.  Depression questionnaires and cognitive batteries will be performed before the 1st session, after the 10th session and after the 20th session of tDCS as well as 4 weeks after the last tDCS session. Sessions will be conducted twice daily over 10 working days.  Stimulation will begin for 20 min in a single session, two sessions in a day separated by an inter-session interval of at least 3 hours. Participants in active group will receive stimulation during the entire 20 min session while those in sham group will receive stimulation only during the ramp up and ramp down period of about 30 sec so that the participant remain blind to the stimulation delivery. The brain imaging (fNIRS, qEEG & MRI) will be done at baseline before beginning the first tDCS session, repeated after completion of last tDCS session and after 24 weeks (about 6 months) of last tDCS session. Pre- and post-stimulation session EEG will be recorded at resting state daily, and for select event related potential (ERP) before the 1st session, and after the 20th session of tDCS. Analysis will be done using SPSS with p value significant at 0.05.