tDCS(Transcranial Direct Current Stimulation) Efficacy in Bipolar Depression : RCT Study

Inclusion Criteria: * Type I or Type II of bipolar disorder meets the current major depression diagnostic criteria in DSM-5 * CGI Severity of lightness score ≥ 4 points * Taking mood stabilizers for at least four weeks before the day of screening Exclusion Criteria: * A history of clinically significant internal neurological disorders or head injury * mental retardation or cognitive impairment that will affect to make a consent form. * Patients at risk of suicide that may require hospitalization as determined by clinicians * A person who is determined to be excluded for using tDCS medical device for other reason (e.g. metal plate is inserted on head, etc.) * A person who is determined to have problems with scalp deformation, inflammatory response or brain wave and attachment of direct current because of other dermatological problem * A woman who disagree with medically allowed contraception\* until 24 weeks after the application of investigational device among woman subject who is possible to get pregnant \* Medically allowed contraception: condom, oral contraception for at least 3 month, injection or insert contraception, Intrauterine Device, etc. * pregnant woman or lactating woman * A person who is not suitable for this clinical trial based on principal investigator's determination other than above reasons