According to past analyses of prescription and treatment patterns for major depressive disorder (MDD), the majority of MDD patients in Japan have not been treated according to the recommended guidelines. 1 In this context, the Japanese Society of Mood Disorders published the 'Treatment Guidelines for Major Depressive Disorders' (GL) in 2012, and the 'Effectiveness of Guidelines for Dissemination and Education in Psychiatric Treatment (EGUIDE)' project was launched in 2016, which aimed to standardize medical practice using quality indicators (QI) as indices for the quality of medical practice. 2, 3 The present study was a cross-sectional, retrospective study conducted in a total of 84 institutions (36 university hospitals, 23 national/