Placebo response in pain, fatigue, and performance: Possible implications for neuromuscular disorders.

The placebo response in neuromuscular disorders is not well understood. The only available data regarding its underlying mechanisms are related to neuropathic pain. In this review, we describe the factors that contribute to improved outcomes in the placebo arm, with specific attention to pain and fatigue, as well as some of the most important psychobiological mechanisms that may explain such a response. This approach may also improve our insight into the symptomatology and therapeutic responses of other neuromuscular disorders. The fact that >90% of tested analgesics for neuropathic pain have failed in advanced phases of clinical trials should prompt a greater investment of effort and resources into understanding the mechanisms and impact of placebos in clinical research. Such an endeavor will help improve the design of clinical trials and will provide information that informs clinical neuromuscular practice. Muscle Nerve 56: 358-367, 2017.