What is the role of the placebo effect in healing? Researchers continue to explore this territory, as a new study shows that a person’s visit to a health-care provider may produce placebo effects that can bring about significant symptom improvement.

The part of the encounter that plays the greatest role in the placebo effect appears to be the provider-patient relationship, according to a press release form the National Center for Complementary and Alternative Medicine (NCCAM), which co-funded the study. In theory, the placebo effect of a medical encounter can be divided into the response to three main components: 1) the assessment and observation, 2) placebo treatment, and 3) patient-physician relationship. The new study verified this theory and examined these components of the placebo effect.

The researchers followed 262 adults with irritable bowel syndrome (IBS), age 18 or older, over the course of six weeks. The single-blind, randomized, controlled trial separated participants into three groups: assessment and observation, placebo acupuncture alone, or placebo acupuncture with a patient-practitioner relationship enhanced by warmth, attention and confidence. The researchers found that the placebo acupuncture combined with an enhanced relationship with the practitioner provided significant improvement in IBS symptoms. Simply providing placebo acupuncture yielded modest improvement of IBS symptoms over assessment and observation alone. Thus, the three components of a medical encounter can be progressively added to produce incremental symptom improvement.

The authors conclude that this study has important implications for routine clinical care and raises questions about measures that reduce interactions between patients and practitioners.

The National Institute of Diabetes and Digestive and Kidney Diseases, and the National Institutes of Health’s Office of Behavioral and Social Sciences Research also funded the study, which was led by Harvard researcher Ted Kaptchuk and colleagues