Inclusion criteria:  Men and woman 18-65 years of age. Primary Diagnostic and Statistical Manual (DSM-5) diagnosis of Major Depressive Disorder (MDD), with a single or recurrent episode with the additional requirement of a current episode with a duration of ≥4 weeks. Current depressive episode lasts less than 5 years (the current and previous depressive episodes are demarcated by a period of ≥2 months in which the patient did not meet full criteria for the DSM-5 definition of MDD). Total Hamilton-21 score ≥ 13 at screening visit. Capable and willing to provide informed consent. Patients without antidepressant medication or patients on an adequate (i.e., at least lowest effective) and stable (i.e., for ≥ 6 weeks) dosage of SSRI (Escitalopram, Citalopram, Sertralin, Paroxetin, Fluvoxamin, Fluoxetin), SSNRI (Duloxetin, Venlafaxin) or Others (Mirtazapin, Agomelatin, Vortioxetine) Concomitant psychotherapy is allowed if ongoing for at least 3 months prior to baseline.  Exclusion Criteria:  Investigators, site personnel directly affiliated with this study, and their immediate families (immediate family is defined as a spouse, parent, child or sibling, whether by birth or legal adoption). Addiction to gaming as assessed by the Gaming Disorder Test (GDT).  Individuals diagnosed with the following psychiatric conditions (current unless otherwise stated):  Depression assessed as secondary to a general medical condition or substance-induced Substance abuse or substance dependence (except nicotine, caffeine) in the last 6 months Psychotic disorder (lifetime) Bipolar disorder (I and II; lifetime) Eating disorder if stated as primary diagnosis Obsessive compulsive disorder if stated as primary diagnosis Post-traumatic stress disorder if stated as primary diagnosis Generalized anxiety disorder if stated as primary diagnosis Panic disorder/ social anxiety if stated as primary diagnosis Personality disorder if stated as primary diagnosis  Individuals diagnosed with a significant neurological disorder or insult including, but not limited to:  Increased intracranial pressure Space occupying brain lesion History of cerebrovascular accident Transient ischemic attack within two years Cerebral aneurysm, dementia Parkinson's disease Huntington's chorea Multiple sclerosis Epilepsy Electroconvulsive therapy (ECT) treatment in current episode History of tDCS, except for single tDCS sessions in experimental studies Use of any investigational drug within 6 weeks from baseline Suicidal risk based on MADRS item 10 score of 4-6 or attempted suicide in current episode Acute, unstable cardiac disease Intracranial implant or any other metal object within or near the head (excluding the mouth) that cannot be safely removed; implanted neuro-stimulators Known or suspected pregnancy (according to pregnancy test), and women of childbearing potential not using effective contraception History of seizures Treatment with deep brain stimulation or vagus nerve stimulation and/or any other intracranial implants (clips, cochlear implants) Any relevant unstable medical condition (e.g. acute, unstable cardiac disease)