Table 2.

Summary of included studies' results.

Study	Expectancy	Summary of resultsa
Berk et al. [48]	Manipulated	There were no significant differences between real and placebo acupuncture. There were also no significant differences on shoulder mobility for those given positive versus negative information about acupuncture. Those given positive information reported lower shoulder pain than those given negative information, but this did not reach statistical significance (P = 0.053). Interaction between acupuncture and expectancy not reported.
Knox et al. (1979) [52]	Manipulated	There were no significant main effects of acupuncture or expectancy. However, posttreatment experimentally-induced pain reduced significantly from baseline in participants given real acupuncture with positive information but not in participants given real acupuncture with variable or negative information, nor in participants given placebo acupuncture with positive, variable, or negative information.
Norton et al. (1984) [53]	Assessed (dichotomised)	There was a significant interaction between acupuncture and expectancy. Simple effects revealed participants receiving real acupuncture reported significantly less experimentally-induced pain if they had “high expectancy” compared with “low expectancy”. Participants with “high expectancy” who received real acupuncture also reported significantly less pain than those also with “high expectancy” but who received placebo acupuncture. Main effects of acupuncture and expectancy not reported.
Ballegaard et al. (1995) [55]	Assessed (dichotomised)	There were no significant differences on any angina outcome between participants categorised as having “maximal expectancy” and “submaximal expectancy”. Main effect of acupuncture and its interaction with expectancy not reported.
Linde et al. (2007) [49]	Assessed (dichotomised)	Those receiving real acupuncture were more likely to respond to treatment than those receiving placebo acupuncture. Higher expectancies for acupuncture's efficacy in general and specifically for the patients' presenting condition were associated with a higher likelihood of experiencing a 50% improvement in the studies' main outcome and a reduction in pain disability index both immediately posttreatment and at follow up. Significant interaction on “some” outcomes indicating the improved outcomes for those with “high expectancy” compared with “low expectancy” were more marked for patients receiving real acupuncture than those receiving placebo acupuncture.
Bertisch et al. (2009) [50]	Assessed	No significant relationship was found between expectancies and upper arm pain following placebo acupuncture in both unadjusted and multivariate analysis.
Kong et al. (2009) [35, 54]	Manipulated	No main effect of acupuncture. Participants allocated to receive pre-conditioning consistent with acupuncture having an analgesic effect reported significantly less experimentally-induced pain following acupuncture than those allocated to receive pre-conditioning of acupuncture having no effect. There was no interaction between acupuncture and expectancy.
Sherman et al. (2010) [51]	Assessed (trichotomised)	Individualised, standardised, and placebo acupuncture were more effective at reducing chronic low back pain than usual care, but there were no significant differences among these three treatments. There were also no significant differences between those with “high”, “medium”, and “low” expectancies. Interaction between treatment and expectancy not reported.
Suarez-Almazor et al. (2010) [33]	Manipulated	No differences were found between real and placebo acupuncture, but both led to better outcomes compared with the waitlist control group. Participants allocated to receive positive information had significantly lower pain and higher satisfaction than those allocated to receive neutral information and this was independent of whether real or placebo acupuncture was administered.

^aAll results are main effects unless stated otherwise.