DOI: 10.11648/j.ijpr.20260202.15 ISSN: 3070-1562

The Placebo Effect in Pain: Mechanisms, Applications, and Ethical Considerations

Jiaoli Sun, Xianwei Zhang
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The placebo effect — long misunderstood as mere "imagination" or self-deception— is an important and increasingly studied phenomenon in medicine. It is no longer considered a simple psychological effect, but a real mind-body connection of mobilizing the body's internal "pharmacy" for self-healing through expectations and beliefs. By integrating expectations, conditioned reflexes, and social learning, the placebo effect can reduce pain, anxiety, and fatigue by activating endogenous opioid, endocannabinoid, and dopaminergic systems. Pain is one of the great scenarios for the placebo effect, and its potential healing power is emerging. Traditional deceptive placebos (administering inert substances without the patient’s knowledge) have gradually been replaced by open-label placebos, which are more ethically acceptable because they emphasize transparency, informed consent, and avoidance of harm, while still producing meaningful clinical benefits. As deceptive placebos are replaced by open-label placebos, the placebo effect in the modern sense may subvert our understanding of "medicine" or "therapy", or it may mean a reshaping of medical processes and doctor-patient relationships. This review summarizes the neurobiological mechanisms, types, clinical applications, ethical challenges, and limitations of placebo analgesia. It emphasizes that placebos should be used only as a complementary or adjunctive therapy and must never replace specific treatments for clearly identifiable organic pathologies.

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