An intriguing meta-analysis published this year warrants our attention as we consider the mechanisms behind our therapeutic interventions:
This 2025 study examines the role of the placebo effect in treatment outcomes within clinical trials. The authors selected five medical conditions
- Osteoarthritis
- Irritable Bowel Syndrome (IBS)
- Depression
- Sleep disorders
- Migraines
They analyzed a total of 150 randomized controlled trials, 30 for each condition, and examined both treatment and placebo responses.
Key findings reveal that improvements in the placebo and treatment groups are closely related. This study challenges traditional assumptions by demonstrating that the majority of treatment effects in these trials arise from context effects, for example, patient expectations, doctor-patient interactions, or of being included into a trial. Only a maximum of 28% of the variance can be attributed to pharmacological effects and this figure may still include error and unexplained variance.
This means that pharmacological effects account for a much smaller proportion of improvements than is usually assumed. The authors highlight that many treatment benefits attributed to drugs may actually stem from placebo effects.
Clinical Implications
These findings should prompt us to reconsider how we evaluate treatment efficacy in our practices. While pharmacological interventions remain significant, this research suggests we might be underestimating the therapeutic value of the clinical encounter itself. Perhaps the art of medicine—our communication skills, empathy, and the therapeutic alliance—deserves as much attention in our professional development as our knowledge of pharmacology. How might we intentionally harness these context effects to improve patient outcomes?
Treatment effects in pharmacological clinical randomized controlled trials are mainly due to placebo. Schmidt, Stefan et al. Journal of Clinical Epidemiology 2025; 179, 111658
