The Role of Social and Interpersonal Factors in Placebo Analgesia.

Placebo effects are beneficial clinical outcomes that emerge as a result of nonspecific contextual factors, transmitted primarily by the treating physician and the social, physical, and behavioral cues he or she displays. The patient-provider therapeutic alliance is critical for determining placebo effects and health outcomes. In this chapter, we review the recent literature, suggesting that provider social characteristics modulate placebo and clinical outcomes. We highlight the importance of studying not only the provider but also the patient's perception of the provider, which is subject to the influence of the patient's psychosocial orientation, such as their psychosocial motivations and perceptions of their interpersonal relationships broadly. We argue that psychosocial orientation can exaggerate the influence of the patient-provider relationship on placebo effects and can directly affect the likelihood of placebo effects emerging by modulating the underlying biological systems that support them. Here, we examine patient loneliness, or perceived social isolation, as a case example for understanding how patients' psychosocial orientation may affect placebo effects across diseases. We propose psychosocial mechanisms by which loneliness might modulate placebo effects across medical outcomes, and focus in particular on how loneliness might specifically alter behaviorally conditioned immune responses and placebo analgesia. Future studies should directly measure social factors to formally test the effects of social isolation on placebo effects and better elucidate the role of psychosocial and interpersonal factors in placebo effects and clinical outcomes.