Background Deep brain stimulation (DBS) has been used for neuropsychiatric disorders in clinical and research settings for almost 50 years now. Recent evidence demonstrates some efficacy in treating obsessive-compulsive disorder and major depression in patients refractory to other treatment modalities beyond single case reports. This has led to a considerable surge of clinical and commercial interest in DBS for psychiatric indications. Because of the high vulnerability of psychiatric patients, the lack of extensive short- and long-term data about effectiveness and the rapid spread of questionable indications this new field in psychiatry requires ethical criteria that can be applied to both research and clinical decision-making. Objective and Methods We here present an evidence-based systematic ethical analysis of psychiatric DBS using the criteria of beneficence, nonmaleficence, and autonomy. Results and Conclusions The proposed criteria are helpful in analyzing empirical evidence, informing research investigations and guiding clinical decision-making. This will prepare the ground for ethically justified, empirically comprehensive DBS in this highly vulnerable population and allow stringent future societal discussions about its legitimation.