A modern view of placebo and placebo-related effects

2020 ◽  
pp. 193-243
Author(s):  
Fabrizio Benedetti
Keyword(s):  
Placebo Effect ◽  
Placebo Response ◽  
Spontaneous Remission ◽  
Point Of View ◽  
Therapeutic Interventions ◽  
Statistical Regression ◽  
Related Effect ◽  
Regression To The Mean ◽  
Nocebo Effect ◽  
The Mean

This chapter approaches the placebo effect from a modern point of view, namely, as a psychobiological phenomenon worthy of scientific inquiry. By definition, the placebo effect is the effect that follows the administration of an inert treatment (the placebo), whereas in a placebo-related effect no placebo is given but similar mechanisms are at work. Today, the placebo effect, or placebo response, is considered a psychobiological phenomenon that must not be confounded with other phenomena such as spontaneous remission and statistical regression to the mean. The nocebo effect, or nocebo response, is a negative placebo effect which goes in the opposite direction. There is not a single but many placebo effects across different medical conditions and therapeutic interventions, and different biological mechanisms are involved. Expectation of a future outcome plays a central role but learning is important as well.

Is there a genuine placebo effect in acute depression treatments? A reassessment of regression to the mean and spontaneous remission

2019 ◽  
Vol 25 (2) ◽  
pp. 46-48 ◽  
Author(s):  
Michael P Hengartner
Keyword(s):  
Treatment Outcome ◽  
Major Depression ◽  
Placebo Effect ◽  
Acute Treatment ◽  
Placebo Response ◽  
Spontaneous Remission ◽  
Regression To The Mean ◽  
Treatment Trials ◽  
The Mean ◽  
Antidepressant Pharmacotherapy

Regression to the mean and spontaneous improvements are rarely considered in interpretations of treatment trials for acute major depression. Here I suggest that regression to the mean and spontaneous remission may account for most improvements seen in placebo groups and also for a large proportion of variance in the acute treatment outcome of both antidepressant pharmacotherapy and psychotherapy. These findings have important implications for the interpretation of active treatments and placebo response in depression trials.

scholarly journals A longitudinal study of dehydroepiandrosterone sulphate (DHEAS) change in older men and women: the Rancho Bernardo Study

2004 ◽  
pp. 717-725 ◽  
Author(s):  
C Tannenbaum ◽  
E Barrett-Connor ◽  
GA Laughlin ◽  
RW Platt
Keyword(s):  
Smoking Status ◽  
Community Dwelling ◽  
Statistical Regression ◽  
Dehydroepiandrosterone Sulphate ◽  
Regression To The Mean ◽  
Age Related ◽  
Baseline Weight ◽  
The Mean ◽  
Underlying Mechanisms ◽  
Definition Of

OBJECTIVE: To examine the age-related and sex-specific rates and determinants of change in endogenous dehydroepiandrosterone sulphate (DHEAS) levels in older community-dwelling adults, taking into account regression to the mean. DESIGN: Prospective cohort study from Rancho Bernardo, California, USA. METHODS: Plasma for DHEAS was collected at baseline and 10-14 years later from 242 men and 207 postmenopausal women (age range, 60-77 years), who were not taking hormone therapy or corticosteroids. Age-related and sex-specific changes in DHEAS were calculated according to four different definitions of change: absolute change, annual percentage change, change exceeding 10% of baseline and change exceeding that expected from statistical regression to the mean. Determinants of DHEAS change were assessed using regression analyses. RESULTS: Baseline DHEAS levels were higher for men than women (age-adjusted means, 1.37+/-0.73 mug/ml (3.72+/-1.98 mumol/l) vs 0.73+/-0.48 mug/ml (1.98+/-1.30 mumol/l) respectively, P<0.0001), with more pronounced declines observed in men (-4.0%/year) compared with women (-2.1%/year; P<0.001). Some 28% of women and 5% of men had DHEAS levels that increased or stayed the same according to a 10% definition of change. When regression to the mean artifact was accounted for, only 15% of women and 5% of men showed true increases in DHEAS. In both sexes, baseline DHEAS levels accounted for three-quarters of the variability in absolute DHEAS change over time, with higher baseline levels resulting in greater loss. Sex, baseline weight, age and smoking status were significantly associated with DHEAS change in univariate models; only sex remained independently associated with DHEAS change in multivariate analyses, with men showing greater annual declines than women (estimated coefficient=0.006, P=0.008). CONCLUSION: In this sample, over 30% of the observed changes in DHEAS could be attributed to regression to the mean. Potential underlying mechanisms of change in DHEAS levels, and sex differences, are discussed.

The so-called “placebo effect” in benign prostatic hyperplasia treatment trials represents partially a conditional regression to the mean induced by censoring

Urology ◽  
1998 ◽  
Vol 51 (2) ◽  
pp. 242-250 ◽  
Author(s):  
Scott M. Sech ◽  
Juan D. Montoya ◽  
Pablo A. Bernier ◽  
Emma Barnboym ◽  
Sherril Brown ◽  
...  
Keyword(s):  
Benign Prostatic Hyperplasia ◽  
Placebo Effect ◽  
Prostatic Hyperplasia ◽  
Regression To The Mean ◽  
Treatment Trials ◽  
The Mean

EXPRESS: The Influence of Three-Dimensional Cues on Body Size Judgements

2022 ◽  
pp. 174702182210768
Author(s):  
Georgia Turnbull ◽  
Joanna Alexi ◽  
Georgina Mann ◽  
Yanqi Li ◽  
Manja Engel ◽  
...  
Keyword(s):  
Body Size ◽  
Analogue Scale ◽  
Three Dimensional ◽  
Point Of View ◽  
Body Volume ◽  
Serial Dependence ◽  
Regression To The Mean ◽  
Third Person ◽  
Feature Information ◽  
The Mean

Research has shown that body size judgements are frequently biased, or inaccurate. Critically, judgement biases are further exaggerated for individuals with eating disorders, a finding that has been attributed to difficulties integrating body features into a perceptual whole. However, current understanding of which body features are integrated when judging body size is lacking. In this study, we examine whether individuals integrate three-dimensional (3D) cues to body volume when making body size judgements. Computer-generated body stimuli were presented in a 3D Virtual Reality (VR) environment. Participants (N = 412) were randomly assigned to one of two conditions: in one condition the to-be-judged body was displayed binocularly (containing 3D cues to body volume), in the other, bodies were presented monocularly (2D cues only). Across 150 trials, participants were required to make a body size judgement of a target female body from a third-person point of view using an unmarked visual analogue scale (VAS). It was found that 3D cues significantly influenced body size judgements. Namely, thin 3D bodies were judged smaller, and overweight 3D bodies were judged larger, than their 2D counterpart. Furthermore, to reconcile these effects, we present evidence that the two perceptual biases, regression to the mean and serial dependence, were reduced by the additional 3D feature information. Our findings increase our understanding of how body size is perceptually encoded and creates testable predictions for clinical populations exhibiting integration difficulties.

Regression to the Mean in Pretreatment Measures of Stuttering

1981 ◽  
Vol 46 (2) ◽  
pp. 204-207 ◽  
Author(s):  
Gavin Andrews ◽  
Robin Harvey
Keyword(s):  
Spontaneous Remission ◽  
Treatment Evaluation ◽  
Post Treatment ◽  
Regression To The Mean ◽  
Spontaneous Improvement ◽  
The Mean ◽  
The Difference

Pre-post treatment evaluation designs are common in stuttering research. Their propriety depends on the assumption that spontaneous remission is not likely. There are six studies to the literature in which stutterers have been measured on two occasions some months apart. In all studies there was a trend to less stuttering on the second assessment, but in no study was the difference between scores significant. One hundred and thirty-two stutterers awaiting treatment were assessed when they were first seen and then at the beginning of treatment 1–23 months later. There was a small but significant improvement between the two assessments. The size of the improvement was comparable to those reported in the six published studies. This spontaneous improvement occurs mainly in the three months following the first assessment, and there is little change thereafter. It is concluded that pre-post studies of subjects who waited more than three months for treatment are valid and that the observed improvement can be due solely to the effects of treatment. Studies that assess improvement from the time subjects are first seen should allow for spontaneous remission to determine the improvement due to treatment.

Der Sommer und Herbst 2003 aus phänologischer Sicht | Summer and autumn 2003 from a phenological point of view

2004 ◽  
Vol 155 (5) ◽  
pp. 142-145 ◽  
Author(s):  
Claudio Defila
Keyword(s):  
Time Series ◽  
New Record ◽  
Point Of View ◽  
Late Spring ◽  
Mean Deviation ◽  
Leaf Shedding ◽  
The Mean ◽  
Very High ◽  
Selection Of

The record-breaking heatwave of 2003 also had an impact on the vegetation in Switzerland. To examine its influences seven phenological late spring and summer phases were evaluated together with six phases in the autumn from a selection of stations. 30% of the 122 chosen phenological time series in late spring and summer phases set a new record (earliest arrival). The proportion of very early arrivals is very high and the mean deviation from the norm is between 10 and 20 days. The situation was less extreme in autumn, where 20% of the 103 time series chosen set a new record. The majority of the phenological arrivals were found in the class «normal» but the class«very early» is still well represented. The mean precocity lies between five and twenty days. As far as the leaf shedding of the beech is concerned, there was even a slight delay of around six days. The evaluation serves to show that the heatwave of 2003 strongly influenced the phenological events of summer and spring.

Mines in the End Zone: Are there Downsides to Team Performance?

2020 ◽  
Vol 23 ◽  
Author(s):  
Troy V. Mumford ◽  
M. Travis Maynard
Keyword(s):  
Team Performance ◽  
Role Overload ◽  
Future Research ◽  
Negative Consequences ◽  
Regression To The Mean ◽  
Occupational Psychology ◽  
Team Success ◽  
The Mean ◽  
Overconfidence Bias

Abstract Research on teams in organizations tends to focus on understanding the causes of team performance with a focus on how to enjoy the benefits of team success and avoid the negative consequences of team failure. This paper instead asks the question, ‘what are some of the negative consequences of team success?’ A review of the literature on teams is augmented with research from cognitive science, sociology, occupational psychology, and psychology to explore the potential negative long-term consequences of teamwork success. The general topics of groupthink, overconfidence bias, regression to the mean, role overload, and strategy calcification are reviewed while discussing the implications for future research streams and practical team management.

scholarly journals Are the Effects of Homeopathy Attributable to a Statistical Artefact? A Reanalysis of an Observational Study

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Rainer Lüdtke ◽  
Stefan N. Willich ◽  
Thomas Ostermann
Keyword(s):  
Quality Of Life ◽  
Cohort Studies ◽  
Summary Score ◽  
Regression To The Mean ◽  
Sf 36 ◽  
The Mean ◽  
Component Scores ◽  
True Population ◽  
Respective Standard Deviation

Background. Cohort studies have reported that patients improve considerably after individualised homeopathic treatment. However, these results may be biased by regression to the mean (RTM).Objective. To evaluate whether the observed changes in previous cohort studies are due to RTM and to estimate RTM adjusted effects.Methods. SF-36 quality-of-life (QoL) data from a German cohort of 2827 chronically diseased adults treated by a homeopath were reanalysed by Mee and Chua’s modifiedt-test.Results. RTM adjusted effects, standardized by the respective standard deviation at baseline, were 0.12 (95% CI: 0.06–0.19,P<0.001) in the mental and 0.25 (0.22–0.28,P<0.001) in the physical summary score. Small-to-moderate effects were confirmed for the most individual diagnoses in physical, but not in mental component scores. Under the assumption that the true population mean equals the mean of all actually diseased patients, RTM adjusted effects were confirmed for both scores in most diagnoses.Conclusions. Changes in QoL after treatment by a homeopath are small but cannot be explained by RTM alone. As all analyses made conservative assumptions, true RTM adjusted effects are probably larger than presented.

Sign in / Sign up

Export Citation Format

Share Document