Pollo Antonella, Benedetti Fabrizio
Department of Neuroscience, Faculty of Pharmacy, University of Turin, Turin, Italy.
Prog Brain Res. 2009;175:283-94. doi: 10.1016/S0079-6123(09)17520-9.
The recent upsurge in placebo research has demonstrated the sound neurobiological substrate of a phenomenon once believed to be only patient mystification, or at best a variable to control in clinical trials, bringing about a new awareness of its potential exploitation to the patient's benefit and framing it as a positive context effect, with the power to influence the therapy outcome. Placebo effects have been described both in the experimental setting and in different clinical conditions, many of which are of neurological interest. Multiple mechanisms have been described, namely conditioning and cognitive factors like expectation, desire, and reward. A body of evidence from neurochemical, pharmacological, and neuroimaging studies points to the involvement of neural pathways specific to single conditions, such as the activation of the endogenous antinociceptive system during placebo analgesia or the release of dopamine in the striatum of parkinsonian patients experiencing placebo reduction of motor impairment. The possible clinical applications of placebo studies range from the design of clinical trials incorporating specific recommendations and minimizing the use of placebo arms to the optimization of the context surrounding the patient, in order to maximize the placebo component present in any treatment.
最近安慰剂研究的热潮表明，这一曾被认为只是患者的迷惑行为，或者至多是临床试验中需要控制的一个变量的现象，有着可靠的神经生物学基础，这使得人们开始重新认识到它可能被利用来造福患者，并将其视为一种积极的情境效应，具有影响治疗结果的力量。安慰剂效应在实验环境和不同临床状况中均有描述，其中许多状况都与神经学相关。人们已经描述了多种机制，即条件作用以及诸如期望、欲望和奖励等认知因素。来自神经化学、药理学和神经影像学研究的大量证据表明，特定状况有其特定的神经通路参与其中，比如在安慰剂镇痛过程中内源性抗伤害感受系统的激活，或者帕金森病患者在经历安慰剂效应使运动障碍减轻时纹状体中多巴胺的释放。安慰剂研究的可能临床应用范围广泛，从纳入特定建议并尽量减少安慰剂组使用的临床试验设计，到优化患者周围的环境，以便在任何治疗中最大化安慰剂成分。
