Objective: To evaluate the effectiveness of deep brain stimulation (DBS) of the globus pallidus internus (GPi) on tic severity and common comorbidities in patients with severe Tourette syndrome that is refractory to pharmacological treatment and psychotherapy. Patients and Methods: We retrospectively assessed the long-term clinical outcomes of 13 patients with treatment-refractory Tourette syndrome who underwent DBS targeting the GPi at the Beijing Tiantan Hospital from January 1, 2006, through May 31, 2013. The primary outcome was a change in tic severity as measured by the Yale Global Tic Severity Scale, and the secondary outcome was a change in associated behavioral disorders and mood as measured by the Gilles de la Tourette Syndrome-Quality of Life Scale assessment. Results: Compared with baseline, the mean reduction in the total Yale Global Tic Severity Scale scores at last follow-up (mean, 41.9 months; range, 13-80 months) was 52.1% (range, 4.3%-83.6%), and the mean improvement rates at 1 month, 6 months, 12 months, 18 months, 24 months, 30 months, and 36 or more months were 11.8%, 20.0%, 26.8%, 36.7%, 44.7%, 49.0%, and 56.7%, respectively. A paired-sample t test revealed significant improvement of tic symptoms after 6 months of DBS programming (P<.05). The Gilles de la Tourette Syndrome-Quality of Life Scale score improved by a mean of 45.7% (range, 11.0%-77.2%). Conclusion: This study is currently the largest reported GPi DBS case series of patients with treatment-refractory TS with the longest follow-up. Our results support the potential beneficial effect of GPi DBS on disabling tic reduction and improvement of quality of life. (C) 2014 Mayo Foundation for Medical Education and Research