A number of studies have demonstrated substantial individual differences in placebo effects. We aimed to identify individual psychological factors that potentially predicted the magnitude of placebo hypoalgesia and individual responsiveness. The Research Domain Criteria framework and a classical conditioning with suggestions paradigm were adopted as experimental models to study placebo phenotypes in a cohort of 397 chronic pain participants with a primary diagnosis of temporomandibular disorder (TMD) and 397 healthy control (HC) participants. The magnitude of placebo hypoalgesia was operationalized as the average difference in pain ratings between the placebo and control conditions. The individual placebo responsiveness was identified as the status of placebo responders and nonresponders based on a permutation test. We observed significant placebo effects in both TMD and HC participants. A greater level of emotional distress was a significant predictor of smaller magnitude (slope b = −0.07) and slower extinction rate (slope b = 0.51) of placebo effects in both TMD and HC participants. Greater reward seeking was linked to greater postconditioning expectations (ie, reinforced expectations) in TMD (slope b = 0.16), but there was no such a prediction in HC participants. These findings highlight that negative valence systems might play a role in impairing placebo effects, with a larger impact in chronic pain participants than in healthy participants, suggesting that individuals reporting emotional distress and maladaptive cognitive appraisals of pain may benefit less from placebo effects.

许多研究表明安慰剂效应存在显着的个体差异。我们的目的是确定可能预测安慰剂痛觉减退程度和个体反应性的个体心理因素。采用研究领域标准框架和经典条件反射与建议范式作为实验模型，研究 397 名初步诊断为颞下颌疾病 (TMD) 的慢性疼痛参与者和 397 名健康对照 (HC) 参与者的安慰剂表型。安慰剂痛觉减退的程度被操作为安慰剂和对照条件之间疼痛评级的平均差异。根据排列测试，个体安慰剂反应性被确定为安慰剂反应者和无反应者的状态。我们在 TMD 和 HC 参与者中观察到显着的安慰剂效应。在 TMD 和 HC 参与者中，较高水平的情绪困扰是安慰剂效应较小程度（斜率b = -0.07）和较慢消退速度（斜率b = 0.51）的显着预测因素。TMD 中更大的奖励寻求与更大的后适应期望（即强化期望）相关（斜率b = 0.16），但 HC 参与者没有这样的预测。这些发现强调，负价系统可能在削弱安慰剂效应方面发挥作用，对慢性疼痛参与者的影响比对健康参与者的影响更大，这表明报告情绪困扰和对疼痛的适应不良认知评估的个体可能从安慰剂效应中获益较少。