The study was led by senior health economist Edward Cox from the Nottingham Clinical Trials Unit at the University of Nottingham and Professor Richard Morriss from the Institute of Mental Health, National Institute for Health and Care Research (NIHR) Nottingham Biomedical Research Center, and the NIHR HealthTech Research Center in Mental Health (MindTech).

Major depression is the leading cause of disability lost years worldwide (WHO, 2017), and suicide from depression is one of the biggest killers of people aged between 15–49. Antidepressants and therapy delivered as first- or second-line treatments help two thirds of people with depression, but the remaining third have treatment resistant depression (TRD). This is defined as a lack of response to two courses of antidepressants.