Listening to the elephant in the room: response-shift effects in clinical trials research

Abstract Background While a substantial body of work postulates that adaptation (response-shift effects) may serve to hide intervention benefits, much of the research was conducted in observational studies, not randomized-controlled trials. This scoping review identified all clinical trials that addressed response shift phenomena, and characterized how response-shift effects impacted trial findings. Methods A scoping review was done of the medical literature from 1968 to 2021 using as keywords “response shift” and “clinical trial.” Articles were included if they were a clinical trial that explicitly examined response-shift effects; and excluded if they were not a clinical trial, a full repo…