The effect of open-label placebo on anxiety, cortisol, and pain levels in children with procedural pain.

Purpose: Needle-related procedures are painful experiences for hospitalized children and are associated with anxiety, pain and stress. Open-label placebos (i.e., placebos administered honestly as an inert substance) have recently been shown to be as effective as deceptive placebos in inducing placebo analgesia. This study systematically investigated the impact of an open-label placebo intervention on anxiety, pain and stress during venipuncture in children. Patients and methods: Forty-seven children and adolescents aged 8-14 years participated in this randomized controlled trial. Prior to venipuncture, patients in the intervention group watched a video introducing the placebo juice, and drank it. The control group received standard care. Saliva cortisol levels as well as anxiety and pain were assessed using validated questionnaires before the venipuncture, shortly afterwards and one hour later. Results: The placebo intervention did not result in significant changes in pain perception, anxiety or saliva cortisol levels. However, we observed positive correlations between anxiety and pain, as well as between baseline cortisol levels and post-venipuncture anxiety and pain. Conclusion: In this pilot-study setting, an open-label placebo intervention did not reduce pain, anxiety or saliva cortisol concentrations. The discrepancy between these initial pilot data and those of experimental studies suggests that numerous real-world factors may influence the placebo effect. Further research should identify these factors to develop strategies that maximize the therapeutic potential of the placebo effect for this patient population in clinical practice.