BACKGROUND: The aim of this study was to assess psychiatric and social outcome 12 months after bilateral deep brain stimulation (DBS) of the globus pallidus pars interna (GPi) and subthalamic nucleus (STN) for advanced Parkinson's disease (PD). METHODS: We randomly assigned patients to receive GPi DBS (n = 65) or STN DBS (n = 63). Standardized psychiatric and social questionnaires were assessed at baseline and after 12 months. RESULTS: No differences were found between GPi DBS and STN DBS on psychiatric evaluation. Within-group comparisons showed small but statistically significant changes on several measures in both groups. Descriptive statistics indicated slight changes in social functioning. Marital satisfaction of patients and partners remained relatively stable after GPi and STN DBS. CONCLUSIONS: We found neither differences in psychiatric and social outcome between GPi DBS and STN DBS nor any relevant within-group differences. The decision for GPi DBS or STN DBS cannot be based on expected psychiatric or social effects. © 2015 International Parkinson and Movement Disorder Society.