A fundamental change is needed for appraising placebo responses in psychiatry - author's reply
Abstract
Matthew Burke makes an important argument that a better biopsychosocial understanding of placebo responses in randomised controlled trials is required. More detailed design and reporting requirements for placebos in randomised controlled trials might also be informative. In addition to an assessment of the adequacy of blinding, measurement of expectancy and hope associated with the intervention, and effects on core or target symptoms as well as total score on symptom and function measures throughout the randomised controlled trials might aid interpretation.1 The distinction between active placebo (some common factors with the active treatment) and passive placebo (no common factors)2 could be useful. A discussion might be included of the nature of the placebo, its functionality, context, and how the efforts to ensure blinding might have compromised the trial in terms of demonstrating efficacy or effectiveness. These effects might be better understood with quantitative and qualitative data collection alongside the trial.
In neuromodulation studies of depression, hope and expectancy might be high since access to novel forms of neuromodulation might be restricted. All neuromodulation interventions require participants to start a regular routine of use at home or attendance outside the home. Setting a daily goal and structuring the day are components of some effective psychological treatments for depression such as behavioural activation and cognitive behaviour therapy.3 Therefore, sham neuromodulation might be considered an active placebo with a potentially larger, more variable effect on depression than the additional therapeutic effect from neuromodulation. Furthermore, the design of the study to ensure blinding might compromise both the efficacy of an intervention and the generalisability of the findings. For instance, a fixed low dose of cranial electrostimulation that was subsensory, was employed in the Alpha-Stim trial to ensure double blinding.4 However, in clinical practice, the ability to personalise the dose and use higher currents might improve its effectiveness.
RM was chief investigator on a grant from the UK National Institute for Health and Care Research (NIHR) Applied Research Collaboration (ARC) East Midlands. RM has received other NIHR funding for research on interventions for depression and has received funding from Novartis to serve on a data management and ethics committee for two trials on the treatment of depression.
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Morriss, R. K. (2023). A fundamental change is needed for appraising placebo responses in psychiatry - Author's reply. The Lancet Psychiatry, 10 (5), pp.317.