1. Hierarchy of reasons for exclusion.

Reason for Exclusion	No of articles excluded (%)
Not an RCT	106 (18.5)
Not a standard pharmacological treatment	131 (22.9)
No control group/not a comparison of interest	100 (17.5)
Not TRD/at point of randomisation	112 (19.5)
Not unipolar depression	27 (4.7)
Diagnostic criteria not applied at point of randomisation	59 (10.3)
Age	6 (1.0)
Trial terminated	1 (0.2)
Review article ‐ refs checked	31 (5.4)
Total	573 (100)

^{RCT: randomised controlled trial
 TRD: Treatment‐resistant depression}