In Deep brain stimulation (DBS) psychosurgery, electrodes are implanted into the patient, delivering continual, high-frequency electrical impulses that help modulate functional neuron circuits. The method has been licensed as a therapeutic treatment for Parkinson's disease and essential tremor for a number of years.
Researchers from the University of Cologne and the Max Planck Institute analyzed DBS' efficacy by evaluating therapeutic studies from 1980 to 2009. They found improvement rates between 35 percent and 70 percent in treatment-resistant Depression, Tourette syndrome and obsessive-compulsive disorder. Side effects were generally mild and mostly reversible, according to the authors.
A separate study from Harvard Medical School and Tufts University however, suggests DBS in Parkinson's patients results in diminished ability to recognize expressions of emotions in others.
Further research into DBS treatment of psychiatric disorders is needed in order to determine a more complete side-effect profile, mechanisms of action and efficacy, however, especially those that stem form long-term treatment.