Placebo and Nocebo Effects in Clinical Practice

Placebo and nocebo effects arise from patients’ expectations, prior learning and the therapeutic context rather than from the specific pharmacological action of an intervention. In clinical practice these phenomena can modulate outcomes across pain management, surgery recovery, mental health and chronic conditions. Placebo effects often manifest as genuine physiological changes, engaging endogenous analgesic pathways, motivational circuits and neuroimmune mediators. Conversely, nocebo effects—negative outcomes triggered by expectations of harm or side-effects—can exacerbate symptoms and undermine treatment adherence. Clinicians encounter these responses in every consultation, whether prescribing active medications, administering inert controls or simply framing treatment narratives. Harnessing placebo mechanisms through optimised communication, ritual and setting can enhance benefit, while identifying and countering nocebo drivers is essential to minimise unwarranted adverse effects. Global research has advanced understanding of underlying neural circuits, the role of conditioning and suggestion, and the ethical use of open-label placebos, offering practical strategies to integrate expectation management into routine care.

Research from Nature Portfolio

Large-scale neuroimaging work in healthy volunteers underlines that placebo analgesia predominantly influences higher-order evaluative circuits rather than core nociceptive pathways. Functional MRI showed that expectation-induced pain relief reduced activity in neuromarkers linked to affective appraisal and value processing, while leaving primary nociceptive signatures unchanged. Such findings support the development of biomarkers that distinguish cognitive modulation from genuine sensory attenuation, with potential to refine analgesic trials. A systematic review and meta-analysis of open-label placebo trials across diverse conditions reported moderate to large symptom improvements compared with no-treatment controls. Effects were robust in pain, fatigue and mood disorders, highlighting that transparent placebo administration—when coupled with positive framing—can yield clinically meaningful change without deception. Complementing these findings, a randomised study in cancer survivors demonstrated that open-label placebo pills reduced fatigue severity and improved quality of life by nearly 30–40 %, emphasising the feasibility of integrating ethical placebo interventions into supportive care.

Placebo and Nocebo Effects in Clinical Practice publication trend

The graph below shows the total number of articles in placebo and nocebo effects in clinical practice across all publications each year (not limited to Nature Index journals).

Technical terms

Placebo Analgesia: Pain relief arising from expectation or conditioning rather than active pharmacology.

Nocebo Effect: Symptom exacerbation or adverse events triggered by negative expectations or suggestion.

Open-Label Placebo: Administration of an inert treatment with full disclosure, leveraging expectation while avoiding deception.

Contextual Factors: Elements of the therapeutic environment (verbal, behavioural, ritualistic) that modulate placebo and nocebo responses.

Expectation: A patient’s anticipatory belief about treatment benefit or harm, which can shape physiological and subjective outcomes.

References

1. How Instructions, Learning, and Expectations Shape Pain and Neurobiological Responses. Annual Review of Neuroscience (2023).
2. Placebo treatment affects brain systems related to affective and cognitive processes, but not nociceptive pain. Nature Communications (2024).
3. Effects of open-label placebos in clinical trials: a systematic review and meta-analysis. Scientific Reports (2021).
4. Open-Label Placebo Treatment for Cancer-Related Fatigue: A Randomized-Controlled Clinical Trial. Scientific Reports (2018).
5. Clinical relevance of contextual factors as triggers of placebo and nocebo effects in musculoskeletal pain. BMC Musculoskeletal Disorders (2018).
6. Placebo Effect in the Treatment of Depression and Anxiety. Frontiers in Psychiatry (2019).