Candesartan as an Adjunctive Treatment for Bipolar Depression

A diagnosis of BD type I or II, and currently in a depressive episode, based on DSM-5 criteria. Inclusion criteria: 1. Age 18 to 65 years. 2. A diagnosis of BD type I or II according to DSM-5 criteria, established through the administration of the MINI. 3. Currently in a depressive episode, based on DSM-5 criteria. 4. MADRS \>20 at entry in the study. 5. No history of hypertension, diabetes, stroke, liver, kidney, heart disease, bleeding disorders, cancer, hypothyroidism, auto-immune diseases, and any brain disorder (seizure disorder, stroke, dementia, or neurodegenerative diseases), as well as other conditions that could impact patient's safety associated with participation in the study. 6. On therapeutic doses of a mood stabilizing drug (anticonvulsants or atypical antipsychotics, but not lithium) or combinations of medications (including antidepressants, as long as receiving at least one mood stabilizing agent) for at least two weeks. 7. Allowed psychiatric comorbid conditions, such as anxiety disorders, PTSD and past history of substance use (as long as do NOT meet abuse or dependence criteria according to the SCID-I in the past 2 months). Exclusion criteria: 1. Current use of angiotensin receptor antagonists, angiotensin converting enzyme inhibitors. (ACE inhibitors), or a history of allergies or poor tolerability to those medications 2. Current use of lithium or any other medications that could implicate in potentially dangerous. interactions with candesartan, based on available literature and the investigator's judgement. 3. Pregnancy or current breastfeeding. 4. Acute systemic infections or other acute medical conditions at the time of study entry. 5. Acute suicidal or homicidal ideation or other imminent concerns about safety, based on the investigator's judgement and/or on a score equal or higher than 4 in the item 10 of the MADRS. 6. Family history of hereditary neurologic disorder. 7. Unable to give informed consent for any reason. 8. Floating metallic objects in the body. 9. Positive urine drug screening at the time of study entry. 10. Current or previous diagnosis of intellectual disability, learning disability, or other severe neurodevelopmental disorders. 11. History of traumatic brain injury or head trauma with loss of consciousness for more than 30 minutes.