Person:

Conboy, Lisa

Objective: To determine whether placebo responses can be explained by characteristics of the patient, the practitioner, or their interpersonal interaction. Methods: We performed an analysis of videotape and psychometric data from a clinical trial of IBS patients treated with placebo acupuncture in either a warm empathic interaction (Augmented, n=96), a neutral interaction (Limited, n=97), or a waitlist control (Waitlist, n=96). We examined the relations between placebo response and: (1) patient personality and demographics; (2) treating practitioner; and (3) the patient-practitioner interaction as captured on videotape and rated by the Psychotherapy Process Q-Set (PQS). Results: Patient extraversion, agreeableness, openness to experience, and female gender were associated with placebo response, but these effects held only in the augmented group. Regression analyses controlling for all other independent variables suggest that only extraversion is an independent predictor of placebo response. There were significant differences between practitioners in outcomes, and this effect was twice as large as the effect attributable to treatment group assignment. Videotape analysis indicated that the augmented group fostered a treatment relationship similar to a prototype of an ideal healthcare interaction. Conclusions: Gender and personality influenced placebo response, but only in the warm, empathic, augmented group. This suggests that to the degree a placebo effect is evoked by the patient-practitioner relationship, personality characteristics of the patient will be associated with placebo response. This finding may explain why consistent predictors of the placebo response have been difficult to detect. In addition, practitioners differed markedly in effectiveness, despite standardized interactions. We propose that the quality of the patient-practitioner interaction accounts for the significant difference between the groups in placebo response.

Objective: To compare the effects of true and sham acupuncture in relieving symptoms of IBS. Methods: A total of 230 adult IBS patients (75% females, average age 38.4 yrs) were randomly assigned to 3 weeks of true or sham acupuncture (6 treatments) following a 3 week ‘run-in’ with sham acupuncture in an ‘augmented’ or ‘limited’ patient-practitioner interaction. A third arm of the study included a waitlist control group. The primary outcome was the IBS Global Improvement Scale (IBS-GIS) (range 1–7); secondary outcomes included IBS Symptom Severity Scale (IBS-SSS), Adequate Relief (IBS-AR) and IBS-Quality of life (IBS-QOL). Results: Though there was no statistically significant difference between acupuncture and sham acupuncture on the IBS-GIS (41% vs. 32%, p=0.25), both groups improved significantly compared to the wait list control group (37% vs. 4%, p=0.001). Similarly, small differences that were not statistically significant favored acupuncture on the other three outcomes: IBS-AR (59% vs 57%, p=0.83), IBS-SSS (31% vs 21%, p=0.18) and IBS-QOL (17% vs 13%, p=0.56). Eliminating responders during the run-in period did not substantively change the results. Side effects were generally mild and only slightly greater in the acupuncture group. Conclusion: This study did not find evidence to support the superiority of acupuncture compared to sham acupuncture in the treatment of IBS.