Effects of placebos without deception compared with no treatment: A systematic review and meta-analysis.

Objective To investigate the clinical efficacy of open-label placebos compared with no treatment in a systematic review and meta-analysis Methods We searched the Cochrane Injuries Group’s Specialised Register, The Cochrane Central Register of Controlled Trials (CENTRAL),OvidMEDLINE(R) In-Process &amp; Other Non-Indexed Citations (OvidSP), EMBASE (OvidSP), and clinical trials registers and screened reference lists. The search was run on 27th April 2015.We included all randomized controlled trials of any medical condition with open-label placebo and no-treatment groups. Authors independently assessed records and extracted data.We excluded nonrandomized trials and nonclinical studies. Risk of bias was assessed using Cochrane criteria.We used random-effects model for meta-analysis. Results We screened 348 publications, assessed 24 articles for eligibility and identified five trials (260 participants) thatmet inclusion criteria. The clinical conditions were: irritable bowel syndrome, depression, allergic rhinitis, back pain, and attention deficit hyperactivity disorder. The risk of bias was moderate.We found a positive effect for nondeceptive placebos (standardized mean difference 0.88, 95% CI 0.62 to 1.14, P &lt; 0.00001, I2 = 1%). Conclusions Open-label placebos appear to have positive clinical effects compared to no treatment. Caution is warranted when interpreting these results due to the limited number of trials identified, lack of blinding, and the fact that positive messageswere included alongside open-label placebos. Larger definitive trials are now warranted to explore the potential patient benefit of open-label placebos, to investigate the relative contributions of positive suggestions, and ethical implications.</p

Effects of placebos without deception compared with no treatment: A systematic review and meta-analysis.

Objective To investigate the clinical efficacy of open-label placebos compared with no treatment in a systematic review and meta-analysis Methods We searched the Cochrane Injuries Group’s Specialised Register, The Cochrane Central Register of Controlled Trials (CENTRAL),OvidMEDLINE(R) In-Process and Other Non-Indexed Citations (OvidSP), EMBASE (OvidSP), and clinical trials registers and screened reference lists. The search was run on 27th April 2015.We included all randomized controlled trials of any medical condition with open-label placebo and no-treatment groups. Authors independently assessed records and extracted data.We excluded nonrandomized trials and nonclinical studies. Risk of bias was assessed using Cochrane criteria.We used random-effects model for meta-analysis. Results We screened 348 publications, assessed 24 articles for eligibility and identified five trials (260 participants) thatmet inclusion criteria. The clinical conditions were: irritable bowel syndrome, depression, allergic rhinitis, back pain, and attention deficit hyperactivity disorder. The risk of bias was moderate.We found a positive effect for nondeceptive placebos (standardized mean difference 0.88, 95% CI 0.62 to 1.14, P Conclusions Open-label placebos appear to have positive clinical effects compared to no treatment. Caution is warranted when interpreting these results due to the limited number of trials identified, lack of blinding, and the fact that positive messageswere included alongside open-label placebos. Larger definitive trials are now warranted to explore the potential patient benefit of open-label placebos, to investigate the relative contributions of positive suggestions, and ethical implications.</p

Precision Electroweak Measurements on the Z resonance.

We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron–positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLD experiment using a polarised beam at SLC. The measurements include cross-sections, forward–backward asymmetries and polarised asymmetries. The mass and width of the Z boson, mZ and ΓZ, and its couplings to fermions, for example the ρ parameter and the effective electroweak mixing angle for leptons, are precisely measured: The number of light neutrino species is determined to be 2.9840±0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward–backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, , and the mass of the W boson, . These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of mt and mW, the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than at 95% confidence level