Jeremy Howick
Senior Researcher & Director, Oxford Empathetic Care Programme, Nuffield Department of Primary Care Health Sciences, University of Oxford

Effects of placebos without deception compared with no treatment: A systematic review and meta-analysis

Aim: Our aim was to address the clinical efficacy of open-label placebos compared with no treatment by systematic review, and meta-analysis where possible.
Methods: We searched the Cochrane Injuries Group’s Specialised Register, The Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations (OvidSP), EMBASE (OvidSP), and clinical trials registers and screened reference lists. We ran the most recent search on April 27 2015. All randomised controlled trials of any medical condition, which had both open-label placebo and no-treatment or treatment as usual groups were included. Two authors independently applied the selection criteria and extracted data. The risk of bias of included studies was assessed using theCochrane criteria. We used random-effects model for meta-analysis.
Results: After removing duplicates we screened 348 publications, assessed 24 articles for eligibility and identified 5 trials (260 participants) that met our inclusion criteria. The clinical conditions were: irritable bowel syndrome (IBS), depression, allergic rhinitis, back pain and attention deficit hyperactivity disorder (ADHD). The overall risk of bias was moderate. All 5 trials were eligible for meta-analysis. We found a positive effect for non-deceptive placebos (standardized mean difference (SMD) 0.88, 95% CI 0.62 to 1.14, P<0.00001, I2= 1%).
Conclusions: Open-label placebos appear to have favorable clinical outcomes, compared to no treatment or no additional treatment. Caution is warranted when interpreting the results due to the limitations including the small number of trials and lack of blinding. Larger definitive trials are now warranted to explore the potential patient benefit of open-label placebos.
Registration number: This protocol has been registered on PROSPERO (2015:CRD42015023347).


I investigate medical questions that require input from philosophy and clinical epidemiology. These include: the ontology, effects, and ethics of placebo treatments in clinical trials and clinical practice, the benefits and harms of informed consent, the extent to which basic science and mechanism research is required for clinical advancements, and the problem of too much medicine. With over 60 academic publications (including two books), I have been funded by the Medical Research Council and the National Institutes of Health Research (both in the United Kingdom) and my research has been used to shape policy. I am also a dedicated teacher who has won four teaching awards. More recently I have expanded my public engagement activities and give regular talks to lay audiences, my social media platform has over 5000 followers, and I have a forthcoming popular science book (April 2017) called Doctor You, which explains the science behind the problem of too much medicine for a lay audience.