Deep brain stimulation has been used for decades in neurology to treat movement disorders. More recent work has focused on developing applications for deep brain stimulation in psychiatric illness. Initial studies have demonstrated positive results for treatment-refractory obsessive-compulsive disorder. Initial open-label studies of deep brain stimulation at targets for treatment-resistant depression have been encouraging. However, the only 2 published controlled trials that were conducted for potential FDA approval for treatment-resistant depression were both negative. Future directions include potential use of alternate clinical trial designs, using tractography for more refined deep brain stimulation electrode targeting, and closed-loop deep brain stimulation approaches.