Patient and Practitioner Influences on the Placebo Effect in Irritable Bowel Syndrome

Abstract

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.

Personality Trait Predictors of Placebo Analgesia and Neurobiological Correlates

“…Furthermore, personality traits such as extraversion have been linked with placebo responses in patients diagnosed with irritable bowel syndrome, but only in the context of warm empathic interactions with the care provider (Kelley et al, 2009). These data suggest that personality variables interact with environmental (ie, social) cues to modulate behavioral and biological placebo responses.…”

“…In our data, this was reflected by positive correlations between agreeableness and m-opioid system activation in several midline regions (subgenual ACC, dorsal ACC and OFC) as well as the anterior and posterior insular cortex, NAc, amygdala and PAG. In this respect, agreeableness has also been linked to greater effectiveness of placebo acupuncture (Kelley et al, 2009) and empathic traits to placebo analgesia mediated through social learning (Colloca and Benedetti, 2009). Moreover, reciprocal altruism has been related to resilience (Charney, 2004) and the activation of brain areas linked to reward processing (Rilling et al, 2002).…”

Expectancy-Induced Placebo Analgesia in Children and the Role of Magical Thinking

“…The placebo, a cool-blue tinted hand disinfectant with no anesthetic properties, was then applied on both volar forearms. In order to facilitate acceptance of the analgesia suggestion, the placebo treatment administration was delivered in a warm, trustful, encouraging and caring manner since it has been shown that a good relationship between health provider and patient plays an important role in shaping the placebo response (39,40).…”

Placebo effects in children: a review

“…Although age appears to be a relevant moderator of the placebo response (as discussed above), gender differences in adults were occasionally investigated, but results are generally not consistent (5,50,51). However, experimental studies on placebo analgesia usually reveal higher placebo response rates in male adults (52).…”

“…One of the rare experimental studies in children and adolescents also revealed effects of verbal instructions on needle pain from venipuncture (76). Furthermore, warm empathic interactions between practitioners and patients have been shown to evoke significant placebo effects in adult patients with irritable bowel syndrome (50). Therefore, the effects of expectations and of patient-practitioner interactions on symptoms in children and adolescents, as well as their mediation by parents, should be further investigated.…”