Placebo effects and emotion regulation: conceptual and neural similarities and differences

Placebo effects are a family of diverse effects that tap into the brain and body's latent endogenous therapeutic potential. Unlike placebo responses, which can reflect statistical artifacts and natural history, placebo effects are driven by multiple types of psychological and brain responses to the treatment context. These include memories and learned associations from past experiences, expectations about future outcomes, cognitive appraisals of the self and context, and emotional states arising from these. Likewise, these psychological and brain responses to placebo arise from multiple aspects of the therapeutic encounter, including the relationship with the care provider, specific treatment cues like procedures and setting, and suggestions. Thus, many forms of placebo effect depend on the thoughts and imagination of the patient, and their interaction with the social and physical elements of the treatment context. In this way, placebo effects may overlap with cognitive self-regulation, a family of techniques that involve using attention, appraisal, and imagination to influence one's emotions, pain, and motivation based on regulatory goals. In this chapter, we focus on the relationship between placebo effects and self-regulation of emotion. We review research on placebo effects, focusing on the idea that changes in brain processes related to affect and motivation are central and consistently identified across disorders. We then describe studies of the cognitive regulation of emotion and pain, highlighting several commonalities shared by self-regulation and placebo. The picture that is emerging is one in which appraisals of the treatment context - influenced by both placebo treatments and self-regulatory goals - shape brain systems involved in the construction of value, feelings, and motivation. These systems are central to clinical outcomes that depend on feelings and function, and interact with learning processes to alter therapeutic trajectories across disorders.