efficacy and safety of transcranial direct current stimulation (tdcs) in the treatment of bipolar depression: a systematic review

Since standard treatments often show limited efficacy in the treatment of bipolar depressive disorder, the use of non-invasive stimulation techniques such as transcranial direct current stimulation (tdcs) (tdcs) can be promising. the aim of the present study is to systematically review studies on the effectiveness of tdcs on bipolar depression. this research was conducted to investigate the effectiveness of this method in the treatment of bipolar depression. 154 articles were retrieved from google scholar, pubmed, scopus, and web of science databases, among which 19 articles were relevant to the topic. finally, 13 studies were excluded and 6 studies were included for investigation. in all these studies, the anode electrode in the left dorsolateral prefrontal cortex (dlpfc-f3) and the cathode electrode in the right dorsolateral prefrontal cortex (dlpfc-f4) were selected as stimulation areas. the results of the extracted articles indicated the tdcs is a safe method.  in summary, the results of the present study indicate that tdcs is a promising approach to treating symptoms of bipolar depression. the findings of the present study are significant from two aspects: firstly, they demonstrate the effectiveness of tdcs in reducing depressive symptoms in these patients; secondly, the lack of a long follow-up period to assess the durability of the treatment effects and the use of small sample sizes in experimental groups were the main limitations of the reviewed studies. therefore, future research is encouraged to take this issue into consideration when designing interventions.