Research is inconclusive as to whether placebo interventions can result in clinical improvement. A number of methodological concepts must be taken into consideration when estimating differential effects of placebo interventions. Using network meta-analysis, researchers can move beyond the lack of direct comparisons available between different placebo interventions by making multiple pairwise comparisons. This design allows us to account for several components of the placebo effect. The additive effects of placebos may be beneficial in clinical practice if physicians can utilize them in a non-deceptive manner to optimize patient care. Researchers and clinicians should be aware of the existence of differential placebo responses when considering selecting appropriate placebo controls in the design of future clinical trials and when formulating treatment regimens.
Keywords: efficacy paradox; network meta-analysis; placebo.