OCD is a major cause of disability and impairment of quality of life. 10% of patients are reported approximately with severe OCD symptoms a DBS. Among possible targets, the non-motor STN is a key node of the basal ganglia circuitry, strongly connected to limbic cortical areas known to be involved in OCD.
The study was done to check the effect of chronic non-motor STN-DBS in 19 patients with treatment-resistant OCD consecutively operated in a single centre. Severity of OCD was evaluated using the YBOCS. YBOCS scores at half year, one year and 2 years postoperatively were compared with baseline. Responders were defined by >35% improvement of YBOCS scores. GAF scale was used to evaluate the impact of improvement.
After 2 years follow-up, the mean YBOCS score improved by 53.4% from 33.3±3.5 to 15.8±9.1. Fourteen out of 19 patients were considered as responders, 5 out of 19 being improved over 75% and 10 out of 19 over 50%. GAF scale improved by 92%. The most frequent adverse events consisted of transient DBS-induced hypomania and anxiety.
Chronic DBS of the non-motor STN is an effective and relatively safe procedure to treat severe OCD resistant to conventional management.