- Background: Subacromial impingement is common and frequently treated with arthroscopic subacromial decompression (ASD); however, its efficacy has recently been questioned. Poor surgical outcomes have been associated with anxiety and depression within other orthopedic subspecialties but not within this group of patients. We hypothesized that anxiety and depression are associated with worse outcomes after ASD. Methods: A retrospective review of prospectively collected data was carried out of patients undergoing ASD. Inclusion criteria were short-term relief with injection therapy and presence of Hawkins sign. Rotator cuff tears were excluded. Patients completed the Oxford Shoulder Score (OSS), Hospital Anxiety and Depression Scale (HADS), and visual analog scale for pain before and after surgery in outpatient clinic followup at 6 weeks and by postal questionnaire at 6 months. Results: The 86 patients who participated in the study were analyzed in 2 groups defined by HADS scores, group A being depressed and group B nondepressed. Both groups had less pain and improved OSS at 6 months; however, group B improved faster with improved scores at 6 weeks, which were maintained to 6 months. Group B had less pain and higher OSS at 6 months than group A. There was strong negative correlation (P < .01) between preoperative HADS score and 6-week and 6-month OSS and HADS scores. There was strong positive correlation (P < .01) between HADS score and 6-week and 6-month pain scores. High preoperative HADS score was negatively correlated to 6-month satisfaction (P < .05). Conclusion: Patients with HADS score > 11 before ASD have worse outcomes. This should be taken into account when counseling patients for surgery. (C) 2016 Journal of Shoulder and Elbow Surgery Board of Trustees.