Behavioral effects of deep brain stimulation in the subthalamic nucleus in obsessive compulsive disorder

Abstract: Obsessive compulsive disorder (OCD) is one of the most disabling psychiatric disorder. About 10% of patients with OCD do not respond to pharmacological treatment. However, deep brain stimulation (DBS) has advanced as an alternative treatment. In 2002, two patients who suffered from co-morbidity of Parkinson’s disease (PD) and OCD were treated with DBS for their PD, with DBS-electrodes placed in the subthalamic nucleus (STN). Surprisingly, not only PD symptoms but also OCD symptoms were improved. This was the first time that patients with OCD were treated with DBS in STN and it was found to markedly improve their symptoms. When performing DBS in patients with OCD, as well as for treating PD, several side-effectshave been observed. The side-effects can be both physical and psychological. In this project,the aim is to investigate the efficiency and side-effects of DBS in OCD, correlated with the position of the electrode in, or near, the STN. To address the aim, 10 published reports were analysed. It was found that all electrode positions reported resulted in great improvement of OCD symptoms. In fact, 88% of patients had significant improvement. There was no clear correlation between position of the electrode and number or type of side-effect. However, there was a trend that patients with the electrode placed in associative/limbic STN suffered from more side-effects. In conclusion, this project demonstrates that there might be a correlation between target for electrode stimulation and side-effects. It would be interesting analyse this closer, including additional electrode target areas, but also consider other possible explanations for the variety of side-effects caused by DBS for OCD.