Working with patients' treatment expectations – what we can learn from homeopathy

Homeopathy, a form of complementary and alternative medicine, enjoys widespread use despite lacking convincing scientific evidence of effectiveness beyond the placebo effect. Numerous systematic reviews and meta-analyses have consistently failed to demonstrate superiority of homeopathic remedies over placebo treatments. This lack of evidence stems from the highly diluted nature of homeopathic remedies, rendering them essentially inert from a pharmacological perspective. The "law of infinitesimals," central to homeopathic theory, posits that dilution increases potency, a claim contradictory to basic physiological principles. However, the significant placebo response observed in homeopathic patients presents a crucial research opportunity. This discrepancy highlights the importance of understanding and harnessing placebo mechanisms, rather than focusing solely on the pharmacological properties of treatments. The review aims to explore how homeopathy systematically leverages placebo mechanisms, particularly treatment expectations, and how evidence-based medicine can ethically integrate these strategies to enhance treatment efficacy.

The review draws on extensive literature on placebo effects, examining their prevalence in diverse medical conditions (psoriatic arthritis, functional gastrointestinal disorders, cancer-related fatigue, etc.) and the neurobiological mechanisms underlying placebo responses. Research indicates that positive treatment expectation is a major driver of placebo effects, particularly pronounced in pain and depression. Placebo effects are not limited to subjective patient reports but manifest in measurable physiological changes. While the placebo response includes factors like the natural course of symptoms and regression toward the mean, the placebo effect specifically refers to changes attributable to psychological and neurobiological placebo mechanisms. A model of treatment expectation is presented, highlighting the interplay of prior information, context factors, and communication in shaping expectations and, ultimately, treatment outcomes. The authors also address nocebo effects, demonstrating how negative expectations can contribute to adverse events and symptom exacerbation. The rise of modern evidence-based medicine, with its focus on specific disease pathologies, has inadvertently downplayed the importance of these nonspecific factors, which ancient medicine relied upon heavily. This review aims to redress this imbalance by systematically integrating beneficial aspects of homeopathic practice into the framework of evidence-based medicine.

This is a narrative literature review. The authors systematically analyzed existing literature on placebo research and homeopathic practices to identify factors influencing treatment expectations. The review is structured around the framework of Bingel’s model of treatment expectation, which posits that prior information, context factors, and communication interact to shape treatment expectations and outcomes. For each factor, the review details how homeopathy systematically incorporates it and then discusses the implications of these practices for evidence-based medicine. The review also addresses the ethical considerations regarding placebo use, including the use of open-label placebos (OLPs), which openly inform patients they are receiving a placebo, contrasted with traditional deceptive placebo administration. The review compares the rationales underlying OLPs and homeopathic treatments, highlighting similarities and differences. Finally, it analyzes how conventional medicine can address the patient expectations and needs that often drive individuals towards alternative practices such as homeopathy.

The review identifies several factors determining treatment expectation: prior information, context factors, and communication. Homeopathy effectively leverages each of these: **Prior Information:** Homeopathic practitioners use positive patient testimonials, advertising, and online forums to cultivate positive expectations. The "like cures like" principle and the notion of homeopathic aggravation (temporary worsening of symptoms) are also framed to reinforce positive expectations. The iterative trial-and-error approach to finding the optimal remedy contributes to the sense of a personalized, effective treatment. **Context Factors:** Homeopathic settings utilize specific rituals (e.g., using special spoons for globules), medical instrumentation (even if scientifically invalid), and ambient factors to create an atmosphere associated with healing and efficacy. The high cost and perceived exclusivity of some homeopathic treatments further enhance their perceived value and potential effectiveness. **Communication:** Homeopathic consultations are characterized by extended, empathetic, patient-centered communication, allowing patients to fully express their concerns and fostering a strong therapeutic alliance. This contrasts sharply with the often rushed and less personal interactions in conventional medical practice. The review compares the rationales in OLPs and homeopathy. Both involve an empathetic patient-provider relationship and the explicit or implicit communication of information about treatment mechanisms and the importance of belief or expectation. However, OLP rationales are scientifically grounded, unlike those in homeopathy. The review suggests that even unconscious expectations and classically conditioned responses may contribute to the OLP effect, potentially explaining homeopathy's efficacy in some patients even without conscious belief in its mechanisms. The authors identify six key patient expectations in homeopathy: influence on the natural course of conditions, illness prevention, fewer side effects, greater control, symptom relief, and immune system boost. They discuss how evidence-based medicine can better meet these needs.

The findings demonstrate that homeopathy's effectiveness, where it exists, largely stems from its successful exploitation of well-known placebo mechanisms. While the active ingredients of homeopathic remedies are scientifically implausible, the way in which the treatments are administered, communicated, and framed powerfully influences patients’ expectations and their subsequent responses. This underscores the importance of reintegrating attention to these nonspecific factors into evidence-based medicine. The evidence for OLPs suggests that even without deception, the combination of inert treatments, strong therapeutic alliance, and positive messaging can yield significant therapeutic benefits. The six patient expectations identified highlight gaps in conventional medical practice that might be addressed by adapting aspects of homeopathic practice, such as increased consultation time, empathetic communication, and a more patient-centered approach.

This review demonstrates that while the specific modalities of homeopathy lack scientific support, the contextual and communicative aspects of its practice offer valuable insights for evidence-based medicine. By integrating evidence-based strategies to enhance placebo effects—including increased consultation time, empathetic communication, and attention to contextual factors—clinicians can better meet patients' needs and optimize treatment outcomes while adhering to rigorous ethical and scientific standards. Future research should focus on further elucidating the neurobiological mechanisms underlying the placebo effect and developing strategies for systematically harnessing these mechanisms in clinical practice. Research on optimized placebo interventions within evidence-based medicine should ensure ethical application and avoid the pitfalls of unsubstantiated claims.

As a narrative review, this study is inherently limited by the subjective interpretation of the existing literature. It does not present original empirical data and relies on the synthesis of findings from diverse studies. The focus on homeopathy as a case study might not be fully generalizable to other complementary and alternative medicine practices. Further research utilizing rigorous quantitative methodologies is necessary to validate the findings and develop evidence-based guidelines for incorporating these strategies into clinical practice.