Introduction: It is aimed to report the effects of bilateral subthalamic nucleus deep brain stimulation (STN-DBS) on motor symptoms, neuropsychiatric symptoms, and quality of life in Parkinson’s Disease (PD) patients. Methods: The results of 22 patients with PD, who had undergone bilateral STN-DBS, were analyzed. The Unified Parkinson’s Disease Rating Scale (UPDRS) was applied to assess the patients’ clinical characteristics before surgery and 6-, and 12-month follow-up after surgery. The quality of life of the patients was evaluated with the Parkinson’s Disease Questionnaire (PDQ-39). Neuropsychological tests including Minnesota Impulse Control Disorders Interview (MIDI), Beck Depression Inventory-II (BDI), Hospital Anxiety and Depression Scale (HADS), Lille Apathy Rating Scale (LARS), and Mini-Mental State Examination (MMSE) were also routinely performed at baseline and 6 months and 12 months after surgery. Results: The mean age of patients was 57.3±8.8 years. Fourteen patients (63.6%) were male. Significant improvements were seen in UPDRS-part- II, UPDRS-part-III UPDRS-part-IV, and PDQ-39 in the follow-ups after the surgery. No significant change was observed in 6- and 12-month follow- up visits for BDI, HADS, MMSE, and LARS, compared to baseline. A depressive episode, requiring antidepressant treatment was recorded in four (18.1%) patients. Before DBS surgery, eight patients had at least one current impulse control behaviors (ICBs). Among these eight patients; ICBs disappeared in one patient, did not change in two patients, and worsened in five patients after STN-DBS treatment. Conclusion: In patients with a history of psychiatric disease, bilateral STN-DBS treatment may aggravate psychiatric symptoms such as depression, and ICBs.