https://www.selleckchem.com/products/ABT-263.html Treatment resistant depression (TRD; failure to respond to ≥2 treatments) affects ~20% of patients with major depressive disorder (MDD). Real-world data could help describe patient characteristics and TRD disease burden, to assess the unmet needs of TRD patients in Europe. This observational study collected data from adults with moderate to severe TRD initiating a new treatment for depression, according to local standards of care. At baseline, socio-demographic characteristics, medical history, prior and current treatments were recorded. Disease severity, health-related quality of life (HRQoL), functionality and productivity were assessed. Overall, 411 eligible patients were enrolled across seven European countries. Mean (standard deviation [SD]) patient age was 51.0 (10.8) years; 62.3% were female. Long-term sick leave was reported by 19.0% of patients; 30.2% were unemployed. The mean (SD) duration of the current episode was 2.6 (3.9) years. At baseline, mean (SD) HRQoL scores for EuroQoL 5-dimension 5-level (UK tariff) and EQ-Visual Analog Scale were 0.41 (0.25) and 41.1 (18.7), respectively. The Work Productivity and Activity Impairment questionnaire demonstrated mean (SD) absenteeism of 57.0% (44.9%) and presenteeism of 54.7% (29.5%); mean (SD) overall work impairment was 60.5% (29.9%). Key limitations are small cohort size, absence of a control group and generalizability to countries with different healthcare models. TRD patients had a high disease burden, low HRQoL and reduced function and productivity, with a substantial proportion unable to work. This demonstrates an unmet treatment need in TRD patients that, if addressed, could reduce the heavy personal and societal burden. TRD patients had a high disease burden, low HRQoL and reduced function and productivity, with a substantial proportion unable to work. This demonstrates an unmet treatment need in TRD patients that, if addressed, could reduce the heavy pe