Efficacy Study of Deep Brain Stimulation in Patients With Treatment Resistant Major Depression

The main objective of this clinical trial is to assess the putative antidepressant efficacy of a therapeutic method called Deep Brain Stimulation (DBS) in patients suffering from severe, treatment-resistant depression, i.e. in patients who have not sufficiently improved under established antidepressant therapies (such as psychotherapy, antidepressant drug therapy, and electroconvulsive therapy). DBS, also known as "brain pacemaker" therapy, is a neurosurgical therapeutic method that is widely established for the treatment of other conditions such as Parkinson's disease. However, DBS is not yet approved for the treatment of patients with depression. In order to initiate DBS treatment, a neurosurgical procedure is performed in which electrodes are placed in a brain region termed 'medial forebrain bundle' (MFB). The electrodes are then used to stimulate this region with electric pulses. From previous investigations and studies with small numbers of patients, it is believed that DBS might have a positive effect on depressive symptoms in patients treated with the method.