Hoffmann Verena, Lanz Marina, Mackert Jennifer, Müller Timo, Tschöp Matthias, Meissner Karin
Institute of Medical Psychology, Faculty of Medicine, LMU Munich, Munich, Germany.
Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Munich, Germany.
Front Psychiatry. 2018 Dec 18;9:706. doi: 10.3389/fpsyt.2018.00706. eCollection 2018.
Patients' expectations about the benefit of an intervention are important determinants of the placebo effect. Little is known about the extent to which expectations influence outcomes of treatments in the field of appetite regulation. This study aimed to investigate the effects of treatment-related expectations on subjective and objective markers of appetite. 90 healthy participants of normal weight were randomly allocated to either an appetite-enhancing placebo group, a satiety-enhancing placebo group, or a control group. All participants received a placebo capsule along with group-specific verbal suggestions to either be appetite-promoting, or satiety-enhancing, or to have no effect on appetite. Before and during the 2 h following randomization, participants were repeatedly asked to rate feelings of hunger and satiety on visual analog scales (VAS), and blood samples were taken repeatedly to assess plasma ghrelin levels as a physiological marker of hunger. In comparison to the control group, the satiety-enhancing placebo intervention significantly reduced appetite and increased satiety. The appetite-enhancing placebo intervention did not alter subjective levels of hunger, but increased plasma ghrelin levels in females. Results provide the first experimental evidence that appetite-regulating placebo interventions can elicit a psychobiological response. Expectations are important factors to consider when evaluating the effects of interventions in the field of appetite regulation.
患者对干预措施益处的期望是安慰剂效应的重要决定因素。在食欲调节领域，期望对治疗结果的影响程度鲜为人知。本研究旨在调查与治疗相关的期望对食欲主观和客观指标的影响。90名体重正常的健康参与者被随机分配到增强食欲安慰剂组、增强饱腹感安慰剂组或对照组。所有参与者都服用了一粒安慰剂胶囊，并收到了特定组别的口头建议，分别是促进食欲、增强饱腹感或对食欲无影响。在随机分组前及分组后的2小时内，参与者被反复要求在视觉模拟量表（VAS）上对饥饿感和饱腹感进行评分，并多次采集血样以评估血浆胃饥饿素水平，作为饥饿的生理指标。与对照组相比，增强饱腹感的安慰剂干预显著降低了食欲并增加了饱腹感。增强食欲的安慰剂干预并未改变主观饥饿水平，但增加了女性的血浆胃饥饿素水平。研究结果提供了首个实验证据，表明调节食欲的安慰剂干预可引发心理生物学反应。在评估食欲调节领域干预措施的效果时，期望是需要考虑的重要因素。
