[Safety and neuroethical consideration of deep brain stimulation as a psychiatric treatment]

Deep brain stimulation (DBS) is a surgical treatment involving the implantation of a medical device, which sends electrical impulses to specific parts of the brain. DBS in select brain regions has provided remarkable therapeutic benefits for treatment-resistant movement and affective disorders such as Parkinson's disease. DBS directly alters brain activity in a controlled manner, and its effects are reversible. Lately, DBS treatment has been used for the treatment of various psychiatric disorders, such as obsessive compulsive disorder, Tourette syndrome, and severe depression. However, DBS therapies for affective disorders are still at their experimental stage, and some scientists point out that there may be a risk involved, because the device implanted in a person's brain may alter his/her brain function and hence his personal identity. With support from the New Energy and Industrial Technology Development Organization (NEDO), Japanese government, we conducted international research on the effects of DBS therapies for psychiatric disorders, examined the safety of such therapies, and clarified the conditions for proper application of the DBS technique. The research items were as follows: (1) safety issues concerning the deterioration of DBS electrodes and the possibilities of developing new and better materials, (2) the role of coordinators who mediate between patients and DBS devices, (3) social concerns regarding personality changes/brain plasticity, (4) re-examination of ethical debates on prefrontal lobotomy (lessons from the past), (5) possible use of DBS for the purpose of brain enhancement, and (6) end users' expectations and fears toward DBS.