Trials comparing real acupuncture with acupuncture involving the Streitberger needle [a common sham control used in acupuncture trials] typically only show small benefits of real acupuncture (Furlan et al. 2005). At the same time, evidence suggests that treatment involving the Streitberger needle is more effective than placebo pills (Linde et al. 2010), while both real and sham acupuncture is more effective than conventional treatment for back pain (Furlan et al. 2005). The larger effects of the Streitberger needle compared with conventional pill placebos can be interpreted in two ways: either treatment with the Streitberger needle produces an especially large placebo effect (Ernst 2006 ), or it is not a ‘real’ placebo (Paterson and Dieppe 2005). If we accept a therapeutic theory stipulating that needle penetration is the only characteristic feature of acupuncture, then the Stretiberger needle is little more than a placebo. … However it is also possible that … the Streitberger needle might include some features that are best described as characteristic. To see how, [consider] another example[:] co-amilofruse is the generic name for a drug that contains two agents that are known to have positive effects on hypertension and oedema, namely amiloride and frusemide. If the ‘placebo’ control were identical to ‘real’ co-amilofruse apart from the fact that it was missing amiloride (but contained frusemide), then a trial involving a placebo control that contained frusemide might be successful at controlling for expectations, and measuring the effects of amiloride. Yet it would not be an adequate placebo control for co-amilofruse, because it contains a feature (frusemide) that is positively effective not via some expectational route. To test whether co-amilofruse was more effective than a placebo, a control treatment could contain neither amiloride nor frusemide.

… the Streitberger needle may not be a ‘true’ placebo control. This is because there is independent evidence that acupressure is effective for treating pain independently of the expectational effects of acupressure (Lee and Done 2004). Given that the Streitberger Needle (as well of course as real acupuncture) exerts pressure, this suggests that a sensible therapeutic theory—one that applies the criteria for classifying characteristic features as features that are effective and not due to expectation effects … would classify the exerted pressure as characteristic rather than incidental. To be sure the pressure exerted by real or Streitberger acupuncture needles could be less intense than the pressure exerted as part of real acupressure therapy. However we cannot rule out that even the less intense pressure is effective for treating pain in advance of further empirical studies. Moreover, it is argued that the acupuncture consultation (which is often much longer than a conventional consultation) should be classified as characteristic (Paterson and Dieppe 2005 p. 1203). There is certainly a robust body of evidence supporting the view that longer more empathetic consultations can have relevant positive

effects when compared with other (‘placebo’) consultations (Hojat et al. 2011).

The debate about how to classify features of acupuncture could be decided more easily if there were an accepted therapeutic theory for acupuncture. But in fact there is no accepted (from a conventional point of view) therapeutic theory…