Two problems arise when assessing treatments for depression. The first is specific to depression and the second is inherent in using randomised controlled trials as the sole evidence for deciding questions about treatment. Moncrieff and Kirsch focus on drug treatments, yet most of these issues also apply to non-drug interventions.1

Parker has described the problems of a “one size fits all” approach to trials of treatment for depression in which people with different severities of illness and symptoms are all included under the same heading of depression.2 Ensuring participants remain blind to treatment is …