Change in depression severity (left axis) and function (right axis) over time for the entire sample (A) and by diagnosis (B–D). Error bars represent standard error. *Twenty-four weeks was the primary end point, as this was the time point up to which medications and psychotherapy were maintained. After 24 weeks of active deep brain stimulation, medication changes and psychotherapy were allowed, as described in the text. BDI-II indicates Beck Depression Inventory II; BP, bipolar II disorder; GAF, Global Assessment of Functioning; HDRS, Hamilton Depression Rating Scale; MDD, major depressive disorder; and Pre-ran, at least 1 week after surgery before the 4-week sham stimulation phase.