Deep brain stimulation (DBS) may hold promise for patients with treatment-resistant and severe major depression and obsessive-compulsive disorder (OCD). However, it may not be the best choice for patients with Parkinson (PD) disease who display certain compulsive behaviors, reported researchers from the Cleveland Clinic and from Brown Medical School (Providence, Rhode Island) at the annual meeting of the American Academy of Neurological Surgeons, which took place April 22-27 in San Francisco. DBS FOR INTRACTABLE DEPRESSION In the study that looked at DBS for intractable major depression, a DBS system (Soletra), which included customized leads designed by Medtronic, was implanted in the anterior limb of the internal capsule and the ventral striatum in 9 patients (7 women; average age, 27 years) who had failed trials of at least 3 classes of antidepressant drugs and were repeatedly unresponsive to psychotherapy and electroconvulsive therapy. Neurologic, psychiatric, and neuropsychologic assessments were designed to be performed preoperatively, at baseline, and at 1, 2, 3, 4, 5, 6, 9, 12, 18, and 24 months. Six of the study participants had completed at least a year of follow-up by the time the findings were reported. So far, an average 50% reduction from baseline on the Montgomery-Asberg Depression Scale score has been achieved, and significant improvements have been achieved in quality of life, reported study presenter Ali R. Rezai, MD, chairman of the Center for Neurological Restoration at the Cleveland Clinic. "Patients demonstrated progressive improvement in mood over time as well as discernible improvement in social and occupational functioning," he added. DBS FOR EXTREME OCD The study that looked at DBS for intractable OCD included 10 patients (6 men; age range, 21-58 years) in whom extreme OCD was diagnosed according to clinical criteria and standardized measures such as the Yale-Brown Obsessive Compulsive Scale (YBOCS) score. Study inclusion criteria consisted of having had behavioral therapy and having failed trials of at least 3 selective serotonin reuptake inhibitors (SSRIs) as well as trials of SSRIs in combination with neuroleptics and in combination with benzodiazepines. Eight of the 10 patients had comorbid major depression. A Soletra-based DBS system was implanted in the internal capsule and the ventral striatum. Assessments were made at baseline, at 3 to 4 weeks after surgery, and at 1, 3, 6, 16, 18, 24, 30, and 36 months in the course of receiving continuous DBS. At 3 years follow-up, YBOCS scores improved by 12.3 points-from a very severe score of 34.6 plus/minus 0.6 at baseline to 22.3 plus/minus 2.1. These scores improved over time. The scores related to depression and anxiety symptoms also significantly improved, with improvements typically occurring within the first 3 months of continuous DBS and then remaining unchanged. Significant improvements in function also were seen. Whereas none of the patients were living independently at baseline, 6 became independent during DBS therapy. DBS AND HAIR-PULLING IN PD Although DBS may prove beneficial for persons with epilepsy and intractable psychiatric illnesses, it may cause rare complications in patients with PD who exhibit particular compulsive behaviors. Cleveland Clinic researchers identified 2 patients in a large series of more than 500 patients in whom trichotillomania, hair-pulling or head-picking, or similar behavior was present, having developed either before or after DBS implantation. Head-picking in one patient who had pre-implantation history of such behavior took the form of manipulating the electrode connector. The practice "was intense enough to damage the electrode on 2 separate occasions." Another patient, who did not have a previous history of hair-pulling or head-picking behavior, experienced significant confusion during the DBS postoperative period and went on to compulsively pick at the stitches and incision site "despite constant surveillance by family members." The team noted that compulsive hair-pulling or head-picking is rarely observed in patients with PD. Nevertheless, signs of such a habit should be looked for in those patients who may be candidates for DBS.