patients suffering from unipolar major depressive disorder

first depressive episode onset before 40 years old

right-handedness

english as first language

intention to commence a course of cognitive behavioural therapy

antidepressant or other psychotropic medication at any time during the study or within previous 4 weeks (8 for fluoxetine)

recent illicit drug use

prior mixed, manic, or psychotic symptoms or other psychiatric or neurological illness

standard exclusion criteria for mri scanning: pregnancy, breast feeding, any immovable metal in the body, weight above 250 lbs, claustrophobia

tdcs safety criteria: skin disease or skin treatment that could potentially cause irritation with electrical stimulation