Inclusion Criteria:  Major Depressive Disorder or Bipolar Depression in accordance to the Diagnostic and Statistical Manual (DSM) criteria Score equal to or great than 17 points on the Hamilton Depression Rating Scale Treatment-resistant depression, defined as insufficient relief of symptoms after two different first line treatments using therapeutic doses and for four to six weeks Adequate health and clinical conditions, as assessed by an anaesthesiologist and a psychiatrist  Exclusion Criteria:  Pregnancy Other psychiatric conditions such as Schizophrenia, Schizoaffective Disorder, Substance Abuse, Borderline Personality Disorder, PTSD, or Intellectual Deficiency Depressive symptoms due to a clinical condition Any clinical or neurological conditions without proper management ECT or any other neuromodulation treatment on the last six months Inability to consent