Deep brain stimulation (DBS) has been recognized as an effective therapy for involuntary movements. As DBS has become more widely used, it has sometimes been observed that psychiatric symptoms and personality changes are induced by DBS. Such phenomena are associated with the close cooperative function of motor, associative and limbic circuits in the cortico-basal ganglia-thalamic-cortical (CBTC) circuit, which is often selected as a target for DBS. On the other hand, clinical studies of DBS by stimulating the CBTC circuit for depression and obsessive compulsive disorder are being conducted in Western countries. The reversibility of DBS allows it to be used as a new therapeutic method for psychiatric disorders, epilepsy, aggressiveness, obesity, and cluster headache, among others. However, apprehension due to the history of abuse of psychosurgery delays the development of this field. The neurologist Egas Moniz is regarded as the founder of psychosurgery. He performed the first prefrontal leukotomy in 1935. His interventions on the brain substance caught great attention worldwide and led to the Nobel Prize in 1949; an award that remains highly controversial today. However, DBS for psychiatric diseases differs greatly from previous psychosurgery because of the reversibility of the process. The prospects and ethical and social issues of DBS for psychiatric diseases should be discussed.