Correspondence The terms ‘acupuncture’ and ‘placebo’ should be adequately defined in clinical trials Dear Editor, The December 2002 issue of CTIM contained an interesting article on the placebo response in a trial of acupuncture. 1 I would like to question the interpretation, or expression, of the results and the conclusion. The main issues affecting methodology in acu- puncture trials are the masking of interventions and the use of controls. 2,3 Concentration on these issues often diverts attention from the critical first step involved in developing a research question around acupuncture, i.e. what exactly do you mean by the term ‘acupuncture’? What individual researchers mean by ‘acupuncture’ can be inferred from their methods, but it is seldom clearly stated. This paper, for example, was based on a trial that had used off-point penetrating sham acupuncture as a control intervention, as well as a no treatment control. I infer from this that the researchers who designed the orig- inal trial considered ‘real’ acupuncture to involve needle penetration of tissues in precise anatomical locations. Whilst they are quite entitled to this im- plied opinion, a medical acupuncturist such as I would consider that the precise position of needle penetration is not always critical in ‘acupuncture’ treatment. The term ‘placebo response’ is often used rather loosely. The word ‘placebo’ derives from the Latin verb placeo meaningtoplease,soa‘placeboresponse’ might be interpreted as resulting from the effect of ‘pleasing’ the patient, i.e. the specific effect of the therapeutic interaction combined with patient expec- tation regarding the perceived intervention. Some- times the ‘placebo response’ is used to refer to all the non-specific effects in an efficacy trial, i.e. chance, natural history (or time effect), therapeu- tic interaction (including practitioner intention) and expectation. Smith and Crowther attribute an effect size of 7 to 17% to the ‘placebo response’ in their origi- nal trial. This appears to have been calculated from the difference between (off-point penetrating) ‘sham acupuncture’ and no treatment, and thus includes the specific effects of therapeutic interaction, ex- pectation and the effects of needling tissue close to classical acupuncture points. The authors refer to the latter effect at the end of their discussion as ‘the non-specific physiological effect of needling’, thus reinforcing the inference that, to them, the specific effects of acupuncture derive from needling at pre- cise anatomical locations. However, no matter how you define ‘acupuncture’, the physiological effect of needling at non-classical sites should not be con- sidered an inactive placebo, and systematic reviews of acupuncture have been criticised for making this assumption in the past. 4 Unfortunately, the majority of readers will only access the summary of this paper, which defines nei- ther ‘acupuncture’ nor ‘placebo response’, and states in the conclusion: ‘Sham acupuncture is a credible control and allows assessment of the size of the placebo response’. I do not believe that this conclu- sion is strictly accurate, since, in the context of this trial, ‘sham acupuncture’ involved a high-threshold mechanical stimulus with a measurable physiologi- cal effect (at least in terms of experimental, if not clinical, research). Mike Cummings Medical Director British Medical Acupuncture Society RLHH, Greenwell St, London WC1W 5BP, UK REFERENCES 1. Smith C, Crowther C. The placebo response and effect of time in a trial of acupuncture to treat nausea and vomiting in early pregnancy. Complement Ther Med 2002; 10(4): 210–216. 2. White AR, Filshie J, Cummings TM. Clinical trials of acupuncture: consensus recommendations for optimal treatment. Complement Ther Med 2001; 9(4): 237–245. 3. Cummings M. Commentary: Controls for acupuncture— can we finally see the light? BMJ 2001; 322(7302): 1578. 4. Cummings TM. Teasing apart the quality and validity in systematic reviews of acupuncture. Acupunct Med 2000; 18(2): 104–107. doi: 10.1016/S0965-2299(03)00075-X Authors reply on: The terms ‘acupuncture’ and ‘placebo’ should be adequately defined in clinical trials  Cummings raises several relevant questions with the design of acupuncture randomised controlled trials concerning our definition of acupuncture, sham acupuncture group and our conclusion that sham acupuncture was a credible control and al- lowed an assessment of the size of the placebo response. Cummings is correct in his interpretation from our methods section that acupuncture involved nee- dle penetration of tissues in precise anatomical loca- tions. As described in the original paper acupuncture needles were inserted in accordance within the tra- ditional framework of traditional Chinese medicine (TCM). 1 The location of acupuncture points was considered to be important and careful attention was given to correctly identifying the acupuncture points, as well as the type of needle stimulation, depth of needle insertion and achieving the de qi  doi of original article 10.1016/S0965-2299(03)00075-X. 123 Complementary Therapies in Medicine (2003), 11, 123–124 © 2003 Published by Elsevier Science Ltd.