Yes. Deep brain stimulation has been studied in patients with very severe, treat resistant depression (trd). The number of people treated has been small but results are very promising. Dbs can be in the form of an implantable device or via a new type of transcranial magnetic stimulation (tms) that can non-invasively reach deeper into the brain. Studies are ongoing but it's not mainstream.
Deep Brain Stim? If your dbs acronym means "deep brain stimulation, " there have been some small studies of this in severely treatment-resistant depressed patients. Results have been promising. http://psychcentral.com/news/2012/01/05/deep-brain-stimulation-appears-effective-for-depression-bipolar-disorder/33261.html however, it comes with neurosurgical risks, and all other treatments need to be tried first.
Yes. In intractable depression DBS can improve the symptoms by about 50%