SAN DIEGO – Parkinson's disease patients who have undergone subthalamic nucleus deep brain stimulation have higher rates of completed and attempted suicide than do others with the disease, Dr. Valerie Voon reported at the annual meeting of the American Academy of Neurology.
The rate of completed suicides following deep brain stimulation (DBS) for Parkinson's disease was found to be 0.4% and the rate of attempted suicides 0.9% in the largest multicenter study of its kind, said Dr. Voon, a psychiatrist with the National Institute of Neurological Disorders and Stroke, Bethesda, Md.
The researchers noted that the suicide rate among Parkinson's patients within the first year after undergoing subthalamic DBS was 11- 37 times higher than the suicide rate in the general population, based on World Health Organization data. The rate was 4–13 times higher in postoperative year 2 and dropped to baseline in postoperative years 3 and 4.
The rate of suicide is 10 times lower in Parkinson's disease patients who have not undergone DBS, when compared with the World Health Organization's general population data, she said.
Dr. Voon and her associates surveyed 75 movement disorders centers in North America and Europe to locate Parkinson's patients who underwent subthalamic nucleus DBS and subsequently attempted or completed suicide. Participating centers had published medical literature on DBS and had operated on more than 100 DBS patients.
Of the 75 centers, 55 responded and provided data on 5,255 Parkinson's disease patients who underwent subthalamic nucleus DBS. After DBS, 22 of the patients completed suicide (0.4%) between 1 month and 4 years.
The researchers also found that 47 patients attempted suicide (0.9%). The attempted suicides took place between approximately 1 week and 8 years following DBS.
Preoperatively, three completed and three attempted suicides were reported. These patients were on DBS wait lists. “The highest risk period is in the first 10 months to 1.5 years” after DBS, she said. “At 10 months time, 50% of the events had already occurred. At 17 months, 75% of the events had occurred.”
Logistic regression analysis based on a study of 70 controls showed that these factors were independently associated with an increased risk of suicide: past history of impulse control disorder or substance abuse, being single, or having postoperative depression.
Suicide is potentially preventable, so patients and families should be aware of this risk, Dr. Voon said.