安慰针刺对照设计的研究进展与相关问题探讨

安慰对照已普遍用于临床研究,目的在于使心理因素降低到最小。然而,还没有见到最理想的安慰/假针刺设计用于针刺研究。因此,许多针灸临床研究并不符合设计常规临床试验的标准。弄清针灸安慰效应和药物学研究的差异是回答此种具有挑战问题的关键。在临床设计中为了避免失败,应当恰当地考虑安慰剂及假穴位的概念、穴位及经脉作用的特异性等。在以往的针灸研究中,对假穴位对照的设计常常拘泥于安慰剂定义。与化学药物作用于特异性受体不同,针刺可对机体多系统、多脏器、多种细胞、多种神经递质及调质、激素、多种受体产生影响。也正因为如此,针刺治疗如疼痛、紧张情绪等症状的临床效果常被斥之为是安慰效应。功能性核磁共振和其它许多研究提供的证据强烈提示:针刺对脑内多个心理和情感控制中枢,如边缘系统、前额叶皮层等有明显影响,从而导致一系列的功能调节,也可产生一定的安慰效果,但这种安慰效果对病人来说也是有益的。所以,针刺可能是治疗身心疾病的一种独特的疗法,安慰对照在针灸临床研究中需要重新评价。

Placebo Control in the Design of Acupuncture Clinical Trials

Placebo controls have often been used in standard clinical studies in order to minimize the effects of psychological interference.However,no ideal placebo(including false needle technique)has been designed for the purpose of acupuncture research.As a result,many of the clinical studies of acupuncture do not follow proper criteria for designing a conventional clinical trial.Understanding the differences of the placebo effect in acupuncture and pharmaceutical drug research is the key to answering this challenge.To do this,the concept of placebo,sham point,acupuncture point specificity and meridian all need to be properly considered in order to avoid a failure in clinical design.The sham points control in the previous acupuncture studies often obeyed the definition of the placebo.Being different from drugs which act upon pre-designed specific receptors,acupuncture may have various effects on multiple systems,organs and a lot of cells and receptors,multiple transmitters,hormones,etc..For this reason,the results of acupuncture treatment,such as pain relief and relaxation,have been criticized as a "placebo" effect.However,evidence from fMRI and other studies strongly suggest that acupuncture affects multiple psychological and emotional control centers of the brain,such as the limbic system and the prefrontal cortex.This may result in a series of functional modulations,which involves pain and stress management.The results suggest that the placebo effect could be induced by non-specific physical stimulation of acupuncture and may favor the patient's health recovery to a certain degree.From this point of view,acupuncture may be a unique remedy for "mind-body" disorders.The current placebo control design in clinical trials of acupuncture needs to be reevaluated.