Influence of bilateral Stn-stimulation on psychiatric symptoms and psychosocial functioning in patients with Parkinson's disease.

Deep brain stimulation of the subthalamic nucleus is an effective treatment for advanced Parkinson's disease. There is some evidence that subthalamic stimulation not only affects motor function, but also mood, behaviour and cognition. In the present study we investigated the effects of subthalamic stimulation on psychiatric symptoms and psychosocial functioning in a consecutive series of patients with Parkinson's disease. 33 patients were assessed three times prior to surgery and at three, nine weeks as well as three, six and twelve months after surgery. We found significant improvements in depression, anxiety, psychological symptoms and distress after surgery. In most cases the amelioration followed surgery and was stable in the course of time. Individual analysis indicated deterioration in three patients despite motor improvement. The results suggest that stimulation of the subthalamic nucleus has a positive influence on psychiatric symptoms, psychosocial functioning and distress. We observed a decline in a minority of patients.