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Psychosomatic Medicine Jan 2021Expectations are known to be key determinants of placebo and nocebo phenomena. In previous studies, verbal suggestions to induce such expectations have mainly focused on...
OBJECTIVE
Expectations are known to be key determinants of placebo and nocebo phenomena. In previous studies, verbal suggestions to induce such expectations have mainly focused on the direction and magnitude of the effect, whereas little is known about the influence of temporal information.
METHODS
Using an experimental placebo and nocebo design, we investigated whether information about the expected onset of a treatment effect modulates the start and time course of analgesic and hyperalgesic responses. Healthy volunteers (n = 166) in three placebo and three nocebo groups were informed that the application of an (inert) cream would reduce (placebo groups) or amplify pain (nocebo groups) after 5, 15, or 30 minutes. Two control groups were also included (natural history and no expectations). Participants' pain intensity rating of electrical stimuli administered before and 10, 20, and 35 minutes after cream application was obtained.
RESULTS
Mixed-method analysis of variance showed a significant interaction between group and time (F(12,262) = 18.172, p < .001, pη2 = 0.454), suggesting that pain variations differed across time points and between groups. Post hoc comparisons revealed that the placebo and nocebo groups began to show a significantly larger change in perceived pain intensity than the no-expectancy control group at the expected time point (p < .05) but not earlier (p > .05). Once triggered, the analgesic effect remained constant over the course of the experiment, whereas the hyperalgesic effect increased over time.
CONCLUSIONS
Our results indicate that temporal suggestions can shape expectancy-related treatment effects, which, if used systematically, could open up new ways to optimize treatment outcome.
Topics: Analgesia; Humans; Hyperalgesia; Nocebo Effect; Pain; Pain Management; Placebo Effect
PubMed: 33109926
DOI: 10.1097/PSY.0000000000000882 -
Revista Medica de Chile Jun 2017
Review
Topics: Neurotransmitter Agents; Nocebo Effect; Pain; Placebo Effect; Prefrontal Cortex
PubMed: 29171627
DOI: 10.4067/s0034-98872017000600775 -
Alternative Therapies in Health and... Nov 1996Since 1955, when HK Beecher published his classic "The Powerful Placebo," it generally has been accepted that 35% of patients with any of a wide variety of disorders can... (Review)
Review
Since 1955, when HK Beecher published his classic "The Powerful Placebo," it generally has been accepted that 35% of patients with any of a wide variety of disorders can be treated with placebos alone. In recent years, average cure rates of 70%, and up to 100%, also have been quoted. Like pharmacological preparations, placebos are credited with possessing time-effect curves; cumulation and carry-over effects; differentiated actions depending on color, size, or packaging; even toxic effects. It has been postulated that placebos can prolong life, that their effects occur in surgery as well as in medicine, and that they are mediated by endorphins. In this article source material that forms the scientific basis for such claims is examined. Analysis shows that the studies on which such ideas are based, except perhaps in bronchial asthma, do not in any way justify the conclusions drawn from them. The truth is that the placebo effect is counterfeited by a variety of factors including the natural history of the disease, regression to the mean, concomitant treatments, obliging reports, experimental subordination, severe methodological defects in the studies, misquotations, etc; even, on occasion, by the fact that the supposed placebo is actually not a placebo, but has to be acknowledged as having a specific action on the condition for which it is being given. A further reason for misjudgment is the lack of clarity of the placebo concept itself. Experimental subordination and conditioning are other areas of insufficient conceptual differentiation. The authors conclude that the literature relating to the magnitude and frequency of the placebo effect is unfounded and grossly overrated, if not entirely false. They pose the question whether the existence of the so-called placebo effect is itself not largely-or indeed totally-illusory.
Topics: Asthma; General Surgery; Humans; Placebo Effect; Placebos
PubMed: 8942043
DOI: No ID Found -
Perspectives in Biology and Medicine 2018The placebo effect can be defined as a bodily change due to the symbolic effects of a treatment or treatment situation. It is further explained by the meaning model: a...
The placebo effect can be defined as a bodily change due to the symbolic effects of a treatment or treatment situation. It is further explained by the meaning model: a positive placebo response is most likely to occur when the meaning of the illness is altered for the patient in a positive direction. Moerman's suggestion that "placebo effect" be replaced by "meaning response" is based in part on dissatisfaction with the characterization of placebo, which is avoided when one focuses instead more comprehensively on placebo effect. The placebo effect can then be explained by the mental processes of expectancy or conditioning and their effect on specific neuro-chemical processes that bring about end-organ changes.
Topics: Conditioning, Psychological; Humans; Mental Processes; Models, Psychological; Placebo Effect
PubMed: 30293974
DOI: 10.1353/pbm.2018.0048 -
Pain Nov 2022Placebos and their beneficial clinical and psychological effects are well-researched, but nocebo effects receive far less attention, despite being highly undesirable.... (Review)
Review
Placebos and their beneficial clinical and psychological effects are well-researched, but nocebo effects receive far less attention, despite being highly undesirable. The aim of this restricted scoping review was to examine how nocebo effects are represented in the biomedical literature and to identify the trends and gaps in existing knowledge. After searching 5 biomedical databases and 2 clinical trials registries (from their inception to December 23, 2020) for articles on nocebo effects or negative placebo effects, 1161 eligible publications were identified. The 2 main publication types were nonsystematic reviews (37.7%) and primary research studies (35.6%); only 85 publications (7.3%) were systematic reviews and meta-analyses. The nonsystematic reviews, many of them heavily opinion-based, may contribute to the amplification of narratives, attitudes, and beliefs about nocebo effects that do not objectively reflect the primary research. The primary research articles often used nocebo effects to explain results, rather than as the primary phenomenon under investigation. Most publications were concerned with both positive and negative placebo effects, rather than just nocebo effects. Over half of the abstracts were in the field of neurology, psychiatry, psychology, or neuroscience (52.8%). The nocebo effect was most frequently investigated in the context of pain. Studies were almost exclusively in adults and more often in healthy participants than in patients. In conclusion, in the biomedical literature, there is an overabundance of nonsystematic reviews and expert opinions and a lack of primary research and high-quality systematic reviews and meta-analyses specifically dealing with nocebo effects.
Topics: Adult; Humans; Healthy Volunteers; Nocebo Effect; Pain; Placebo Effect
PubMed: 35297813
DOI: 10.1097/j.pain.0000000000002629 -
The American Journal of Clinical... Oct 2013
Topics: Biomedical Research; Humans; Hypnosis; Placebo Effect
PubMed: 24665813
DOI: 10.1080/00029157.2014.827922 -
Nature Reviews. Urology Mar 2022A placebo is an inert substance normally used in clinical trials for comparison with an active substance. However, a placebo has been shown to have an effect on its own;... (Review)
Review
A placebo is an inert substance normally used in clinical trials for comparison with an active substance. However, a placebo has been shown to have an effect on its own; commonly known as the placebo effect. A placebo is an essential component in the design of conclusive clinical trials but has itself become the focus of intense research. The placebo effect is partly the result of positive expectations of the recipient on the state of health. Conversely, a nocebo effect is when negative expectations from a substance lead to poor treatment outcomes and/or adverse events. Randomized controlled trials in functional urology have demonstrated the importance of the placebo and nocebo effects across different diseases such as overactive bladder, urinary incontinence, lower urinary tract symptoms and interstitial cystitis/painful bladder syndrome, as well as male and female sexual dysfunction. Understanding the true nature of the placebo-nocebo complex and the scope of its effect in functional urology could help urologists to maximize the positive effects of this phenomenon while minimizing its potentially negative effects.
Topics: Female; Humans; Lower Urinary Tract Symptoms; Male; Nocebo Effect; Placebo Effect; Treatment Outcome; Urology
PubMed: 34949831
DOI: 10.1038/s41585-021-00545-2 -
The Primary Care Companion For CNS... Mar 2021
Topics: Humans; Placebo Effect; Transcranial Magnetic Stimulation
PubMed: 34000176
DOI: 10.4088/PCC.20lr02874 -
Cognitive Processing Aug 2021Superstitions and the placebo effect have each been found to influence human behaviour. The present study aimed to determine whether there is a relationship between...
Superstitions and the placebo effect have each been found to influence human behaviour. The present study aimed to determine whether there is a relationship between superstition and the placebo effect, and whether this relationship affects human cognition and behaviour. We hypothesized that more superstitious people would be more prone to the placebo effect and that it would improve their performance on cognitive tasks. Results showed that in the placebo condition, more superstitious people memorized more words than less superstitious people. However, in the control condition, less superstitious people memorized more words than more superstitious people. Overall, the findings supported our hypothesis. The findings of the study are important, as they draw a link between the placebo effect and superstition, and further show that these two elements impact human performance in cognitive ability tasks.
Topics: Cognition; Humans; Placebo Effect; Superstitions
PubMed: 34231087
DOI: 10.1007/s10339-021-01025-6 -
Developmental Medicine and Child... Oct 2023Placebo responses are frequently observed in research studies and clinical contexts, yet there is limited knowledge about the placebo effect among children with... (Review)
Review
Placebo responses are frequently observed in research studies and clinical contexts, yet there is limited knowledge about the placebo effect among children with neurodevelopmental disorders. Here, we review the placebo effect in autism spectrum disorder (ASD). Placebo responses are widely evident in ASD clinical trials and could partly operate via so-called placebo-by-proxy, whereby caregivers or clinicians indirectly shape patient outcomes. Understanding the role of placebo effects in ASD may help discern genuine treatment effects from contextual factors in clinical trials. The much less studied nocebo effect, or negative placebo, might contribute to the experience of side effects in ASD treatments but empirical data is missing. Better knowledge about placebo and nocebo mechanisms may contribute to the development of more effective research designs, such as three-armed designs that account for natural history, and improved treatments for ASD symptoms. At a clinical level, deeper knowledge about placebo and nocebo effects may optimize the delivery of care for individuals with ASD in the future. WHAT THIS PAPER ADDS: Placebo responses are evident in autism spectrum disorder (ASD) clinical trials. Placebo responses in ASD are likely dependent on a placebo-by-proxy mechanism.
Topics: Humans; Child; Placebo Effect; Autism Spectrum Disorder; Nocebo Effect
PubMed: 36917698
DOI: 10.1111/dmcn.15574