Hidden Assumptions and the Placebo Effect

2009 ◽  
Vol 27 (2) ◽  
pp. 68-69 ◽  
Author(s):  
Anthony Campbell
Keyword(s):  
Placebo Effect ◽  
Folk Psychology ◽  
Placebo Response ◽  
Placebo Effects ◽  
Cartesian Dualism ◽  
Reading Research ◽  
Philosophical Assumption ◽  
Acupuncture Effects ◽  
The Brain

Whether, or how far, acupuncture effects can be explained as due to the placebo response is clearly an important issue, but there is an underlying philosophical assumption implicit in much of the debate, which is often ignored. Much of the argument is cast in terms which suggest that there is an immaterial mind hovering above the brain and giving rise to spurious effects. This model derives from Cartesian dualism which would probably be rejected by nearly all those involved, but it is characteristic of “folk psychology” and seems to have an unconscious influence on much of the terminology that is used. The majority of philosophers today reject dualism and this is also the dominant trend in science. Placebo effects, on this view, must be brain effects. It is important for modern acupuncture practitioners to keep this in mind when reading research on the placebo question.

scholarly journals Behavioural conditioning as the mediator of placebo responses in the immune system

2011 ◽  
Vol 366 (1572) ◽  
pp. 1799-1807 ◽  
Author(s):  
Sabine Vits ◽  
Elvir Cesko ◽  
Paul Enck ◽  
Uwe Hillen ◽  
Dirk Schadendorf ◽  
...  
Keyword(s):  
Immune System ◽  
Placebo Response ◽  
Clinical Settings ◽  
Immune Functions ◽  
Placebo Effects ◽  
Allograft Survival ◽  
Physiological Mechanisms ◽  
Potential Clinical Benefit ◽  
Efferent Pathways ◽  
The Brain

Current placebo research postulates that conditioning processes are one of the major mechanisms of the placebo response. Behaviourally conditioned changes in peripheral immune functions have been demonstrated in experimental animals, healthy subjects and patients. The physiological mechanisms responsible for this ‘learned immune response’ are not yet fully understood, but some relevant afferent and efferent pathways in the communication between the brain and the peripheral immune system have been identified. In addition, possible benefits and applicability in clinical settings have been demonstrated where behaviourally conditioned immunosuppression attenuated the exacerbation of autoimmune diseases, prolonged allograft survival and affected allergic responses. Here, we summarize data describing the mechanisms and the potential clinical benefit of behaviourally conditioned immune functions, with particular focus on learned placebo effects on allergic reactions.

scholarly journals 3523 Innovative Approaches to Clinical Research on Placebo Effects: A Regulatory Science Perspective

2019 ◽  
Vol 3 (s1) ◽  
pp. 118-118
Author(s):  
Kimberly Uweh
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Placebo Effect ◽  
Controlled Trial ◽  
Placebo Response ◽  
Current Treatment ◽  
Low Back ◽  
Placebo Effects ◽  
Open Label ◽  
Double Blind

OBJECTIVES/SPECIFIC AIMS: To analyze contemporary study design methods and clinical trial approaches in placebo research. METHODS/STUDY POPULATION: An analysis was conducted on the following studies: I. “Managing” the Placebo Effect: The Single-Blind Placebo Lead-in Response in Two Pain Models by RN Haden, et al. The objective of the study was to consider elements of the placebo response in the context of two pain models using a “single-blind placebo lead-in” design (SBPLI) by engaging the “placebo response” prior to randomization to active drug and placebo-controlled conditions. The methods of the study included two pilot drug trials using knee osteoarthritis (KOA) and non-radicular low back pain (LBP) subjects, SBPLI protocols were conducted. In the first study, 36 subjects with non-radicular CLBP were enrolled in a double-blind, randomized, placebo-controlled trial of hydromorphone ER. In the second study, a total of 42 subjects with chronic KOA pain were enrolled in a double-blind, randomized, placebo-controlled study of milnacipran. Gender and/or diagnosis affected placebo responses as observed in changes in patient self-reported pain, depressive and pain anxiety symptoms were examined. Additionally, the placebo response on performance-based tests (stair climbing, range of motion (ROM), sit to stand repetitions, and 6-minute treadmill distance) was evaluated. II. Randomized Placebo-Controlled Placebo Trial to Determine the Placebo Effect Size by L. Gerdesmeyer, et al. The objective of the study was to analyze the pure placebo effect on clinical, chronic pain through a blinded RCT. The methods of the study included 182 patients suffering from chronic plantar heel pain for over 6 months, who failed to respond to conservative treatments, were screened and 106 of these patients were enrolled into this study. The patients were randomly assigned to receive either a blinded placebo shockwave treatment or an unblinded placebo shockwave treatment. The primary outcome measure was the differences in percentage change of visual analogue scale (VAS) scores 6 weeks after the intervention. The secondary outcome measure was the differences in Roles and Maudsley pain score (RMS) 6 weeks after intervention. III. Open-label placebo treatment in chronic low back pain: a randomized controlled trial by C. Carvalho, et al. The objective of the study was to investigate whether placebo effects in chronic low back pain could be harnessed ethically by adding open-label placebo (OLP) treatment to treatment as usual (TAU) for 3 weeks. The methods of the study included 97 randomized participants in a 3-week randomized control trial comparing current treatment plus OLP to current treatment alone (TAU). RESULTS/ANTICIPATED RESULTS: N/a DISCUSSION/SIGNIFICANCE OF IMPACT: The aforementioned studies provide placebo researchers with contemporary and reliable methodologies to examine placebo effects on participants. These methodologies provide scientists with clinical translational research methodology styles based on the foundation of regulatory science.

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.

Learned Placebo Effects in the Immune System

2014 ◽  
Vol 222 (3) ◽  
pp. 148-153 ◽  
Author(s):  
Sabine Vits ◽  
Manfred Schedlowski
Keyword(s):  
Nervous System ◽  
Immune System ◽  
Associative Learning ◽  
Placebo Response ◽  
Immunosuppressive Drug ◽  
Immune Functions ◽  
Placebo Effects ◽  
New Therapeutic Approaches ◽  
Biological Variables ◽  
Experimental Approaches

Associative learning processes are one of the major neuropsychological mechanisms steering the placebo response in different physiological systems and end organ functions. Learned placebo effects on immune functions are based on the bidirectional communication between the central nervous system (CNS) and the peripheral immune system. Based on this “hardware,” experimental evidence in animals and humans showed that humoral and cellular immune functions can be affected by behavioral conditioning processes. We will first highlight and summarize data documenting the variety of experimental approaches conditioning protocols employed, affecting different immunological functions by associative learning. Taking a well-established paradigm employing a conditioned taste aversion model in rats with the immunosuppressive drug cyclosporine A (CsA) as an unconditioned stimulus (US) as an example, we will then summarize the efferent and afferent communication pathways as well as central processes activated during a learned immunosuppression. In addition, the potential clinical relevance of learned placebo effects on the outcome of immune-related diseases has been demonstrated in a number of different clinical conditions in rodents. More importantly, the learned immunosuppression is not restricted to experimental animals but can be also induced in humans. These data so far show that (i) behavioral conditioned immunosuppression is not limited to a single event but can be reproduced over time, (ii) immunosuppression cannot be induced by mere expectation, (iii) psychological and biological variables can be identified as predictors for this learned immunosuppression. Together with experimental approaches employing a placebo-controlled dose reduction these data provide a basis for new therapeutic approaches to the treatment of diseases where a suppression of immune functions is required via modulation of nervous system-immune system communication by learned placebo effects.

Placebos and Movies: What Do They Have in Common?

2021 ◽  
pp. 096372142110038
Author(s):  
Fabrizio Benedetti
Keyword(s):  
Everyday Life ◽  
Common Sense ◽  
Placebo Effect ◽  
Psychological Factors ◽  
General Framework ◽  
Physiological Responses ◽  
Therapeutic Effects ◽  
Physiological Effects ◽  
Placebo Effects ◽  
What Matters

Placebos are fake therapies that can induce real therapeutic effects, called placebo effects. It goes without saying that what matters for inducing a placebo effect is not so much the fake treatment itself, but rather the therapeutic ritual that is carried out, which is capable of triggering psychobiological mechanisms in the patient’s brain. Both laypersons and scientists often accept the phenomenon of the placebo effect with reluctance, as fiction-induced clinical improvements are at odds with common sense. However, it should be emphasized that placebo effects are not surprising after all if one considers that fiction-induced physiological effects occur in everyday life. Movies provide one of the best examples of how fictitious reality can induce psychological and physiological responses, such as fear, love, and tears. In the same way that a horror movie induces fear-related physiological responses, even though the viewer knows everything is fake, so the sight of a syringe may trigger the release of pain-relieving chemicals in the patient’s brain, even if the patient knows there is a fake painkiller inside. From this perspective, placebos can be better conceptualized as rituals, actions, and fictions within a more general framework that emphasizes the power of psychological factors in everyday life, including the healing context.

scholarly journals Reactivity in social scientific experiments: what is it and how is it different (and worse) than a Placebo effect?

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
María Jiménez-Buedo
Keyword(s):  
Experimental Data ◽  
Conceptual Framework ◽  
Placebo Effect ◽  
Placebo Effects ◽  
Causal Inferences ◽  
Scientific Experiments ◽  
Social Scientific ◽  
The Many ◽  
Definition Of ◽  
In Virtue Of

AbstractReactivity, or the phenomenon by which subjects tend to modify their behavior in virtue of their being studied upon, is often cited as one of the most important difficulties involved in social scientific experiments, and yet, there is to date a persistent conceptual muddle when dealing with the many dimensions of reactivity. This paper offers a conceptual framework for reactivity that draws on an interventionist approach to causality. The framework allows us to offer an unambiguous definition of reactivity and distinguishes it from placebo effects. Further, it allows us to distinguish between benign and malignant forms of the phenomenon, depending on whether reactivity constitutes a danger to the validity of the causal inferences drawn from experimental data.

scholarly journals Placebo response in treatment resistant depression: a systematic review and meta-analysis of multiple treatment modalities

BJPsych Open ◽  
2021 ◽  
Vol 7 (S1) ◽  
pp. S261-S262
Author(s):  
Brett D M Jones ◽  
Cory R. Weissman ◽  
Jewel Karbi ◽  
Tya Vine ◽  
Louise S. Mulsant ◽  
...  
Keyword(s):  
Systematic Review ◽  
Brain Stimulation ◽  
Placebo Effect ◽  
Meta Analysis ◽  
Specific Treatment ◽  
Placebo Response ◽  
Treatment Modalities ◽  
Treatment Resistant Depression ◽  
Treatment Resistant ◽  
Resistant Depression

AimsThe placebo response in depression clinical trials is a major contributing factor for failure to establish the efficacy of novel and repurposed treatments. However, it is not clear as to what the placebo response in treatment-resistant depression (TRD) patients is or whether it differs across treatment modalities. Our objective was to conduct a systematic review and meta-analysis of the magnitude of the placebo response in TRD patients across different treatment modalities and its possible moderators.MethodSearches were conducted on MEDLINE and PsychInfo from inception to January 24, 2020. Only studies that recruited TRD patients and randomization to a placebo (or sham) arm in a pharmacotherapy, brain stimulation, or psychotherapy study were included (PROSPERO 2020 CRD42020190465). The primary outcome was the Hedges’ g for the reported depression scale using a random-effects model. Secondary outcomes included moderators assessed via meta-regression and response and remission rate. Heterogeneity was evaluated using the Egger's Test and a funnel plot. Cochrane Risk of Bias Tool was used to estimate risks.Result46 studies met our inclusion criteria involving a total of 3083 participants (mean (SD) age: 45.7 (6.2); female: 52.4%). The pooled placebo effect for all modalities was large (N = 3083, g = 1.08 ,95% CI [0.95-1.20)I 2 = 0.1). The placebo effect in studies of specific treatment modalities did not significantly differ: oral medications g = 1.14 (95%CI:0.99-1.29); parenteral medications g = 1.32 (95%CI:0.59-2.04); ayahuasca g = 0.47 (95%CI:-0.28-1.17); rTMS g = 0.93 (95%CI:0.63-1.23); tDCS g = 1.32 (95%CI:0.52-2.11); invasive brain stimulation g = 1.06 (95%CI:0.64-1.47). There were no psychotherapy trials that met our eligibility criteria. Similarly, response and remission rates were comparable across modalities. Heterogeneity was large. Two variables predicted a lager placebo effect: open-label prospective design (B:0.32, 95%CI: 0.05-0.58; p:0.02) and sponsoring by a pharmaceutical or medical device company (B:0.39, 95%CI:0.13-0.65, p:0.004)). No risk of publication bias was found.ConclusionThe overall placebo effect in TRD studies was large (g = 1.08) and did not differ among treatment modalities. A better understanding of the placebo response in TRD will require: standardizing the definition of TRD, head-to-head comparisons of treatment modalities, an assessment of patient expectations and experiences, and standardized reporting of outcomes.

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.

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.

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