RESUMEN
No previous reports have described a case in which deep brain stimulation elicited an acute mood swing from a depressive to manic state simply by switching one side of the bilateral deep brain stimulation electrode on and off. The patient was a 68-year-old woman with a 10-year history of Parkinson's disease. She underwent bilateral subthalamic deep brain stimulation surgery. After undergoing surgery, the patient exhibited hyperthymia. She was scheduled for admission. On the first day of admission, it was clear that resting tremors in the right limbs had relapsed and her hyperthymia had reverted to depression. It was discovered that the left-side electrode of the deep brain stimulation device was found to be accidentally turned off. As soon as the electrode was turned on, motor impairment improved and her mood switched from depression to mania. The authors speculate that the lateral balance of stimulation plays an important role in mood regulation. The current report provides an intriguing insight into possible mechanisms of mood swing in mood disorders.