Choice and the Placebo Effect: A Meta-analysis

2022 ◽  
Author(s):  
Biya Tang ◽  
Kirsten Barnes ◽  
Andrew Geers ◽  
Evan Livesey ◽  
Ben Colagiuri
Keyword(s):  
Placebo Effect ◽  
Effect Size ◽  
Meta Analysis ◽  
Placebo Treatment ◽  
Placebo Effects ◽  
Sleep Difficulty ◽  
Clinical Scenarios ◽  
Health Related ◽  
Choice Frequency ◽  
Improve Patient

Abstract Background Choice has been proposed as a method of enhancing placebo effects. However, there have been no attempts to systematically evaluate the magnitude, reliability, and moderators of the influence of choice on the placebo effect. Purpose To estimate the effect size of choice on the placebo effect and identify any moderators of this effect. Methods Web of Science, PsycINFO, EMBASE, and PubMed were systematically searched from inception to May 2021 for studies comparing placebo treatment with any form of choice over its administration (e.g., type, timing) to placebo treatment without choice, on any health-related outcome. Random-effects meta-analysis was then used to estimate the effect size associated with the influence of choice on the placebo effect. Meta-regression was subsequently employed to determine the moderating effect of factors such as type of choice, frequency of choice, and size of the placebo effect without choice. Results Fifteen independent studies (N = 1,506) assessing a range of conditions, including pain, discomfort, sleep difficulty, and anxiety, met inclusion criteria. Meta-analysis revealed that choice did significantly enhance the placebo effect (Hedges’ g = 0.298). Size of the placebo effect without choice was the only reliable moderator of this effect, whereby a greater effect of choice was associated with smaller placebo effects without choice. Conclusions Treatment choice can effectively facilitate the placebo effect, but this effect appears more pronounced in contexts where the placebo effect without choice is weaker. Because most evidence to date is experimental, translational studies are needed to test whether providing choice in clinical scenarios where placebo effects are weaker may help boost the placebo effect and thereby improve patient outcomes.

scholarly journals Choice, Expectations, and the Placebo Effect for Sleep Difficulty

2019 ◽  
Author(s):  
Valerie Yeung ◽  
Louise Sharpe ◽  
Andrew Geers ◽  
Ben Colagiuri
Keyword(s):  
Placebo Effect ◽  
Sleep Onset ◽  
Sleep Time ◽  
Placebo Treatment ◽  
Sleep Onset Latency ◽  
Placebo Effects ◽  
Single Session ◽  
Sleep Difficulty ◽  
Insomnia Severity ◽  
Perceived Sleep Quality

Abstract Background Choice has been found to facilitate placebo effects for single-session treatments where standard placebo treatment without choice failed to elicit a placebo effect. However, it is unknown whether choice can enhance the placebo effect for treatments occurring over a period of days and where placebo effects are readily established without choice. Purpose We tested whether single or daily choice between two (placebo) treatments enhanced the placebo effect for sleep difficulty relative to no choice and no treatment over a 1 week period. Methods One-hundred and seventeen volunteers self-identifying with sleep difficulty were recruited under the guise of a hypnotic trial and randomized to one of the four groups. Self-reported outcomes included insomnia severity, fatigue, total sleep time (TST), sleep onset latency (SOL), perceived sleep quality (PSQ), and treatment satisfaction. Objective TST and SOL were assessed in a subsample via actigraphy. Results Overall, placebo treatment significantly improved insomnia severity, fatigue, and PSQ, confirming a placebo effect on these outcomes. However, both traditional and Bayesian analysis indicated no benefit of choice on the placebo effect on any sleep outcome. Mediation analysis of the overall placebo effect indicated that expectancy completely mediated the placebo effects for insomnia severity and PSQ and partially mediated the placebo effect for fatigue. Conclusion These findings suggest that choice does not enhance the placebo effect over longer treatment periods (up to 7 days) when placebo effects are readily established without choice. As such, any benefit of choice on placebo effects may be confined to quite specific circumstances. Clinical Trials Registration ACTRN12618001199202.

Systematic review and meta-analysis of the placebo effect in panic disorder: Implications for research and clinical practice

2022 ◽  
pp. 000486742110687
Author(s):  
Masoud Ahmadzad-Asl ◽  
Farnoush Davoudi ◽  
Safoura Mohamadi ◽  
Fatemeh Hadi ◽  
Seyed Aria Nejadghaderi ◽  
...  
Keyword(s):  
Systematic Review ◽  
Clinical Practice ◽  
Panic Disorder ◽  
Placebo Effect ◽  
Effect Size ◽  
Rating Scales ◽  
Data Extraction ◽  
Meta Analysis ◽  
Placebo Response ◽  
Patient Reports

Objective: This review aimed to measure the degree of placebo response in panic disorder. Data Sources: We searched major databases up to 31 January 2021, for randomized pharmacotherapy trials published in English. Study Selection: A total of 43 studies met inclusion criteria to be in the analysis (with 174 separate outcome measurements). Data Extraction: Changes in outcome measures from baseline in the placebo group were used to estimate modified Cohen’s d effect size. Results: A total of 43 trials (2392 subjects, 174 outcomes using 27 rating scales) were included in the meta-analysis. Overall placebo effect size was 0.57 (95% confidence interval = [0.50, 0.64]), heterogeneity ( I2: 96.3%). Higher placebo effect size was observed among clinician-rated scales compared to patient reports (0.75 vs 0.35) and among general symptom and anxiety scales compared to panic symptoms and depression scales (0.92 and 0.64 vs 0.56 and 0.54, respectively). There was an upward trend in effect size over the publication period ( r = 0.02, p = 0.002) that was only significant among clinician-rated scales ( r = 0.02, p = 0.011). There was no significant publication bias, Egger’s test ( p = 0.08). Conclusion: We observed a substantial placebo effect size in panic disorder. This effect was more prominent for some aspects of panic disorder psychopathology than for others and was correlated with the source of the assessment and publication year. This finding has implications both for research design, to address the heterogeneity and diversity in placebo responses, and for clinical practice to ensure optimal quality of care. Systematic review registration number: PROSPERO, CRD42019125979.

scholarly journals The efficacy of n-3 fatty acids DHA and EPA (fish oil) for perinatal depression

2010 ◽  
Vol 104 (11) ◽  
pp. 1577-1585 ◽  
Author(s):  
Linda A. W. Jans ◽  
Erik J. Giltay ◽  
A. J. Willem Van der Does
Keyword(s):  
Effect Size ◽  
Fixed Effects ◽  
Perinatal Depression ◽  
Post Partum ◽  
Meta Analysis ◽  
Placebo Treatment ◽  
Small Sample ◽  
Future Research ◽  
Fixed Effects Model ◽  
Beneficial Effects

Depressive symptoms are common during pregnancy and the post-partum period. Although essential n-3 PUFA may have beneficial effects on depression, it remains unclear whether they are also effective for perinatal depression. The purpose of the present study was to assess the efficacy of n-3 supplementation for perinatal depression, by performing a meta-analysis on currently available data. After a thorough literature search, we included seven randomised controlled trials in the meta-analysis, all with EPA and/or DHA supplementation. Most studies were judged to be of low-to-moderate quality, mainly due to small sample sizes and failure to adhere to Consolidated Standards of Reporting Trials guidelines. Some studies were not primarily designed to address perinatal depression. A total of 309 women on n-3 fatty acid supplementation were compared with 303 women on placebo treatment. n-3 Supplementation was not found to be significantly more effective than placebo at post-treatment with a pooled effect size (Hedges's g) of − 0·03 (95 % CI − 0·18, 0·13; P = 0·76) using a fixed-effects model. Heterogeneity was low-to-moderate (I2 = 30 %). In a subgroup analysis of three small studies of pregnant women with major depression, there was some indication of effectiveness (effect size 0·17; 95 % CI − 0·21, 0·55). In conclusion, the question of whether EPA and DHA administration is effective in the prevention or treatment of perinatal depression cannot be answered yet. Future research should focus on women who are clinically depressed (or at risk). The quality of research in this area needs to improve.

scholarly journals Molecular classification of the placebo effect in nausea

2020 ◽  
Author(s):  
Karin Meissner ◽  
Dominik Lutter ◽  
Christine von Toerne ◽  
Anja Haile ◽  
Stephen C. Woods ◽  
...  
Keyword(s):  
Placebo Effect ◽  
Plasma Proteins ◽  
Acute Phase Proteins ◽  
Molecular Classification ◽  
Placebo Treatment ◽  
Placebo Effects ◽  
Promising Tool ◽  
Go Enrichment ◽  
Organ Systems ◽  
Adjusted Scores

ABSTRACTNumerous studies have shown that the mere expectation improvement can alleviate symptoms in various conditions. These ‘placebo effects’ often include reliable changes in central and peripheral organ systems. Here, we tested for the first time whether placebo effects can be monitored and predicted by plasma proteins. In a randomized controlled design, 90 healthy participants were exposed to a 20-min vection stimulus on two separate days and were randomly allocated to placebo treatment or no treatment on the second day. Significant placebo effects on nausea, motion sickness, and gastric activity could be verified. Using state-of-the-art proteomics, 74 differentially regulated proteins were identified in placebo-treated participants as compared to no-treatment controls. Gene ontology (GO) enrichment analyses of these proteins revealed acute-phase proteins as well as microinflammatory proteins to be reliable plasma correlates of the placebo effect. Regression analyses showed that day-adjusted scores of nausea indices in the placebo group were predictable by the identified GO protein signatures. We next identified specific plasma proteins, for which a significant amount of variance could be explained by the experimental factors ‘sex’, ‘group’, ‘nausea’, or their interactions. GO enrichment analyses of these proteins identified ‘grooming behavior’ as a prominent hit, based on ‘neurexin-1’ (NRXN1) and ‘contactin-associated protein-like 4’ (CNTNAP4). Finally, Receiver Operator Characteristics (ROC) allowed to identify specific plasma proteins differentiating placebo responders from non-responders. These comprised immunoglobulins (IGHM, IGKV1D-16, IGHV3-23, IGHG1) and MASP2, related to regulation of complement activation, as well as proteins involved in oxidation reduction processes (QSOX1, CP TXN). This proof-of-concept study indicates that plasma proteomics are a promising tool to identify molecular correlates and predictors of the placebo effect in humans.

scholarly journals The Effects of Physical Education on Motor Competence in Children and Adolescents: A Systematic Review and Meta-Analysis

Sports ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 88 ◽  
Author(s):  
Håvard Lorås
Keyword(s):  
Physical Education ◽  
Children And Adolescents ◽  
Motor Skills ◽  
Effect Size ◽  
Meta Analysis ◽  
Control Groups ◽  
Motor Competence ◽  
Random Effects Models ◽  
Health Related ◽  
Meta Analyses

Appropriate levels of motor competence are an integrated part of individuals’ health-related fitness, and physical education is proposed as an important context for developing a broad range of motor skills. The aim of the current study was to apply meta-analyses to assess the effectiveness of curriculum-based physical education on the development of the overall motor competence of children and adolescents. Studies were located by searching seven databases and included according to predefined criteria. Random effects models using the standardized effect size (Hedges’ g) were used to aggregate results, including an examination of heterogeneity and inconsistency. The meta-analysis included 20 studies, and a total of 38 effect sizes were calculated. A statistically significant improvement in motor competence following curriculum-based physical education compared to active control groups was observed in children and adolescents (g = −0.69, 95% CI −0.91 to −0.46, n = 23). Participants’ ages, total time for physical education intervention, and type of motor competence assessment did not appear to be statistically significant moderators of effect size. Physical education with various curricula can, therefore, increase overall motor competence in children and adolescents.

scholarly journals Health-related quality-of-life among patients with premature ovarian insufficiency: a systematic review and meta-analysis

2019 ◽  
Vol 29 (1) ◽  
pp. 19-36 ◽  
Author(s):  
X. T. Li ◽  
P. Y. Li ◽  
Y. Liu ◽  
H. S. Yang ◽  
L. Y. He ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Effect Size ◽  
Meta Analysis ◽  
Effect Sizes ◽  
Medium Effect ◽  
Health Related Quality ◽  
Ovarian Insufficiency ◽  
Related Quality ◽  
Health Related

Abstract Purpose To systematically review studies investigating health-related quality-of-life (HrQoL) in patients with premature ovarian insufficiency (POI), to examine questionnaires used and to conduct a meta-analysis of control studies with normal ovarian function. Methods Data sources: PubMed, Embase, Web of science, CNKI, and CQVIP, searched from inception until June 2018. The search strategy was a combination of medical (e.g. POI), subjective (e.g. well-being) and methodological (e.g. questionnaires) keywords. PRISMA guidelines were used to assess outcome data quality/validity by one reviewer, verified by a second reviewer. Risk of bias within studies was evaluated. A meta-analysis compared HrQoL in patients and non-patients. Due to measurement differences in the studies, the effect size was calculated as standard mean difference. Results We identified 6869 HrQoL studies. Nineteen geographically diverse studies met inclusion criteria, dated from 2006, using 23 questionnaires. The meta-analysis included six studies with 645 POI participants (age 33.3 ± 5.47) and 492 normal-ovarian control subjects (age 32.87 ± 5.61). Medium effect sizes were found for lower overall HrQoL (pooled SMD = − 0.73, 95% CI − 0.94, − 0.51; I2 = 54%) and physical function (pooled SMD = − 0.54, 95% CI − 0.69, − 0.39; I2 = 55%). Heterogeneity was investigated. Effect sizes varied for sexual function depending on the measure (SMD = − 0.27 to − 0.74), overall HrQoL (SF-36) had the largest effect size (− 0.93) in one study. The effect sizes for psychological and social HrQoL were small. Conclusion POI is associated with low-to-medium effect size on HrQoL compared to normal ovarian controls. The greatest effects are found in general HrQoL and most sexual function areas. Condition-specific questionnaires and RCTs are recommended for further investigation.

scholarly journals Placebo treatment facilitates social trust and approach behavior

2018 ◽  
Vol 115 (22) ◽  
pp. 5732-5737 ◽  
Author(s):  
Xinyuan Yan ◽  
Xue Yong ◽  
Wenhao Huang ◽  
Yina Ma
Keyword(s):  
Placebo Effect ◽  
Social Trust ◽  
Real Life ◽  
Well Being ◽  
Placebo Treatment ◽  
Placebo Effects ◽  
Approach Behavior ◽  
Social Species ◽  
Show Evidence ◽  
And Behavior

Placebo effect refers to beneficial changes induced by the use of inert treatment, such as placebo-induced relief of physical pain and attenuation of negative affect. To date, we know little about whether placebo treatment could facilitate social functioning, a crucial aspect for well-being of a social species. In the present study, we develop and validate a paradigm to induce placebo effects on social trust and approach behavior (social placebo effect), and show robust evidence that placebo treatment promotes trust in others and increases preference for a closer interpersonal distance. We further examine placebo effects in real-life social interaction and show that placebo treatment makes single, but not pair-bonded, males keep closer to an attractive first-met female and perceive less social anxiety in the female. Finally, we show evidence that the effects of placebo treatment on social trust and approach behavior can be as strong as the effect of intranasal administration of oxytocin, a neuropeptide known for its function in facilitating social cognition and behavior. The finding of the social placebo effect extends our understanding of placebo effects on improvement of physical, mental, and social well-being and suggests clinical potentials in the treatment of social dysfunction.

scholarly journals Differential power of placebo across major psychiatric disorders: a preliminary meta-analysis and machine learning study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bo Cao ◽  
Yang S. Liu ◽  
Alessandro Selvitella ◽  
Diego Librenza-Garcia ◽  
Ives Cavalcante Passos ◽  
...  
Keyword(s):  
Machine Learning ◽  
Psychiatric Disorders ◽  
Mood Disorders ◽  
Placebo Effect ◽  
Rating Scales ◽  
Meta Analysis ◽  
Placebo Response ◽  
Pharmacological Intervention ◽  
Placebo Effects ◽  
Meta Regression

AbstractThe placebo effect across psychiatric disorders is still not well understood. In the present study, we conducted meta-analyses including meta-regression, and machine learning analyses to investigate whether the power of placebo effect depends on the types of psychiatric disorders. We included 108 clinical trials (32,035 participants) investigating pharmacological intervention effects on major depressive disorder (MDD), bipolar disorder (BD) and schizophrenia (SCZ). We developed measures based on clinical rating scales and Clinical Global Impression scores to compare placebo effects across these disorders. We performed meta-analysis including meta-regression using sample-size weighted bootstrapping techniques, and machine learning analysis to identify the disorder type included in a trial based on the placebo response. Consistently through multiple measures and analyses, we found differential placebo effects across the three disorders, and found lower placebo effect in SCZ compared to mood disorders. The differential placebo effects could also distinguish the condition involved in each trial between SCZ and mood disorders with machine learning. Our study indicates differential placebo effect across MDD, BD, and SCZ, which is important for future neurobiological studies of placebo effects across psychiatric disorders and may lead to potential therapeutic applications of placebo on disorders more responsive to placebo compared to other conditions.

The Relationship Between Immorality and Cleansing

2018 ◽  
Vol 49 (5) ◽  
pp. 303-309 ◽  
Author(s):  
Jedidiah Siev ◽  
Shelby E. Zuckerman ◽  
Joseph J. Siev
Keyword(s):  
Effect Size ◽  
Meta Analysis ◽  
Weighted Mean ◽  
The Relationship

Abstract. In a widely publicized set of studies, participants who were primed to consider unethical events preferred cleansing products more than did those primed with ethical events ( Zhong & Liljenquist, 2006 ). This tendency to respond to moral threat with physical cleansing is known as the Macbeth Effect. Several subsequent efforts, however, did not replicate this relationship. The present manuscript reports the results of a meta-analysis of 15 studies testing this relationship. The weighted mean effect size was small across all studies (g = 0.17, 95% CI [0.04, 0.31]), and nonsignificant across studies conducted in independent laboratories (g = 0.07, 95% CI [−0.04, 0.19]). We conclude that there is little evidence for an overall Macbeth Effect; however, there may be a Macbeth Effect under certain conditions.

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