The aim of this prospective, multi-centered, double-blind, randomized, delayed-stimulation/ Sham-stimulation controlled 12-month study is to evaluate the effectiveness and safety of bilateral stimulation of the subcallosal cingulate white matter (SCCwm) using the Infinity™ Deep Brain Stimulation (DBS) system as an adjunctive treatment of non-psychotic unipolar Major Depressive Disorder (MDD) for adults who are experiencing a Major Depressive Episode (MDE) with inadequate response to 4 or more antidepressant treatments.
In a double-blind fashion, half the subjects will receive active DBS therapy, while half will receive sham stimulation. After the 12-month endpoint, all subjects will be unblinded to their treatment group, and subjects in the control arm will receive active DBS therapy.