Neuromodulator approaches to depression: The potential of transcranial electric stimulation

Depression, a widespread mental health disorder, presents significant challenges in diagnosis and treatment. Amidst the myriad treatments, non-invasive Transcranial Electric Stimulation (tES), encompassing Transcranial Alternating Current Stimulation (tACS) and Transcranial Direct Current Stimulation (tDCS), has emerged as a promising intervention for Major Depressive Disorder (MDD). This review delineates the mechanisms of these modalities, their distinctions, and their potential to modulate neural oscillations and influence cognitive functions. Studies showcased the efficacy of these techniques in ameliorating depressive symptoms, with EEG and fNIRS employed to gauge their neurological impact. Observations suggest the potential in modulating for specific brain rhythms to enhance memory functions in older adults and influence working memory processes. The dynamic interplay between tDCS and tACS in altering cortical activities and their interaction with neurotransmitters like GABA further underscores their potential. However, the need for extensive research, particularly double-blind randomized control trials, remains paramount to ascertain their safety and efficacy. This review provides a comprehensive insight into the prospective role of tES in the clinical landscape of MDD treatment.