Do randomized clinical trials with inadequate blinding report enhanced placebo effects for intervention groups and nocebo effects for placebo groups?

Do randomized clinical trials with inadequate blinding report enhanced placebo effects for intervention groups and nocebo effects for placebo groups?

BACKGROUND Studies suggest that expectations powerfully shape clinical outcomes. For subjective outcomes in adequately blinded trials, health improvements are substantial and largely explained by non-specific factors.The objective of this study was to investigate if unblinding in randomized controlled trials (RCTs) is associated with enhanced placebo effects for intervention groups and nocebo e...

Do randomized clinical trials with inadequate blinding report enhanced placebo effects for intervention groups and nocebo effects for placebo groups? A protocol for a meta-epidemiological study of PDE-5 inhibitors

UNLABELLED BACKGROUND Patients' expectations of treatment effects may contribute to positive (placebo) and negative (nocebo) outcomes. The effect of patient expectations may be pronounced in subjectively assessed conditions, such as male erectile dysfunction. The aim of this project is to examine the magnitude of expectancy in trials of phosphodiesterase-5 inhibitors. We hypothesize that ran...

Psychobiological mechanisms of placebo and nocebo effects in antidepressant trials

The placebo is powerful: estimating placebo effects in medicine and psychotherapy from randomized clinical trials.

The logic of the randomized double-blind placebo control group design is presented, and problems with using the design in psychotherapy are discussed. Placebo effects are estimated by examining clinical trials in medicine and psychotherapy. In medicine, a recent meta-analysis of clinical trials with treatment, placebo, and no treatment arms was conducted (Hróbjartsson & Gøtzsche, 2001), and it ...

Neuro-Bio-Behavioral Mechanisms of Placebo and Nocebo Responses: Implications for Clinical Trials and Clinical Practice.

The placebo effect has often been considered a nuisance in basic and particularly clinical research. This view has gradually changed in recent years due to deeper insight into the neuro-bio-behavioral mechanisms steering both the placebo and nocebo responses, the evil twin of placebo. For the neuroscientist, placebo and nocebo responses have evolved as indispensable tools to understand brain me...