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Psychiatria Danubina Jun 2014It is well-known that placebo is a substance without medical effects, which benefits the health status because of the patient's belief that the substance is effective... (Review)
Review
It is well-known that placebo is a substance without medical effects, which benefits the health status because of the patient's belief that the substance is effective and that the nocebo is defined as a substance without medical effects but which worsenes the health status of the person taking it by the negative beliefs and expectations of the patient. Starting with the history of the placebo effect and giving a review of the most significant studies reporting about the placebo effect from 1939-2013 it was our intention to give the all-around look on this phenomena discussing the neurobiological and other theories of its origin and concentrating especially on the field of psychiatry and finally coming to conclusions regarding the conductance of clinical trials and ethics. Regarding psychiatry, the placebo effect has a substantial role in most of psychiatric conditions including depression, anxiety, addictions, and contrary to what may have been expected, schizophrenia. Likewise, the nocebo effect is not to be neglected as the studies are being conducted to identify the factors causing it so it could be prevented.
Topics: History, 18th Century; History, 19th Century; History, 20th Century; History, 21st Century; Humans; Mental Disorders; Nocebo Effect; Placebo Effect; Placebos
PubMed: 24909245
DOI: No ID Found -
Drugs of Today (Barcelona, Spain : 1998) Jul 2019The placebo effect is a phenomenon of great scientific interest that affects the response in both inactive and active treatments. It is broadly understood as the product... (Review)
Review
The placebo effect is a phenomenon of great scientific interest that affects the response in both inactive and active treatments. It is broadly understood as the product of a central integration of positive expectations, reward learning and continuous conditioning inducing physiological changes in the brain. The placebo effect is accepted as a phenomenon which can be harnessed in clinical practice. It has emerged that there is not a single neurobiological mechanism involved in placebo responses, but many depending on the underlying disease. Molecular neuroimaging techniques with positron emission tomography and selective radiotracers have been significant in the understanding of the neurobiological systems involved in the placebo effect. The aim of this review was to summarize the key findings relating to the neurobiology behind the placebo effect.
Topics: Brain; Humans; Neurobiology; Placebo Effect; Positron-Emission Tomography
PubMed: 31347615
DOI: 10.1358/dot.2019.55.7.3010575 -
Handbook of Experimental Pharmacology 2019In this review, we explored different ways of controlling the placebo effects in clinical trials and described various factors that may increase/decrease the placebo... (Review)
Review
In this review, we explored different ways of controlling the placebo effects in clinical trials and described various factors that may increase/decrease the placebo effect in randomized placebo-controlled trials. These factors can be subdivided into four groups, and while not all factors are effective in every study and under all clinical conditions, they show on the whole that - even under the ideal condition of drug therapy, where blinded placebo provision is much easier and warranted than in, e.g., psychotherapy - many factors need to be controlled to ascertain that the goal of the clinical trials, fair assessment of superiority of the drug over placebo in placebo-controlled trials and fair assessment of non-inferiority of the drug compared to another drug in comparator trials, is reached. Ignorance towards the placebo effect, which was common in the past, is no longer acceptable; instead, it should be the goal of all therapeutic trials to minimize the placebo effect in clinical trials, while utilizing and maximizing it in clinical routine.
Topics: Placebo Effect; Placebos; Randomized Controlled Trials as Topic
PubMed: 31463606
DOI: 10.1007/164_2019_269 -
Archivos Argentinos de Pediatria Dec 2020
Topics: Ethics, Medical; Humans; Placebo Effect
PubMed: 33231040
DOI: 10.5546/aap.2020.eng.370 -
Trials Jul 2021Contextual effects (i.e., placebo response) refer to all health changes resulting from administering an apparently inactive treatment. In a randomized clinical trial... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Contextual effects (i.e., placebo response) refer to all health changes resulting from administering an apparently inactive treatment. In a randomized clinical trial (RCT), the overall treatment effect (i.e., the post-treatment effect in the intervention group) can be regarded as the true effect of the intervention plus the impact of contextual effects. This meta-research was conducted to examine the average proportion of the overall treatment effect attributable to contextual effects in RCTs across clinical conditions and treatments and explore whether it varies with trial contextual factors.
METHODS
Data was extracted from trials included in the main meta-analysis from the latest update of the Cochrane review on "Placebo interventions for all clinical conditions" (searched from 1966 to March 2008). Only RCTs reported in English having an experimental intervention group, a placebo comparator group, and a no-treatment control group were eligible.
RESULTS
In total, 186 trials (16,655 patients) were included. On average, 54% (0.54, 95%CI 0.46 to 0.64) of the overall treatment effect was attributable to contextual effects. The contextual effects were higher for trials with blinded outcome assessor and concealed allocation. The contextual effects appeared to increase proportional to the placebo effect, lower mean age, and proportion of females.
CONCLUSION
Approximately half of the overall treatment effect in RCTs seems attributable to contextual effects rather than to the specific effect of treatments. As the study did not include all important contextual factors (e.g., patient-provider interaction), the true proportion of contextual effects could differ from the study's results. However, contextual effects should be considered when assessing treatment effects in clinical practice.
TRIAL REGISTRATION
PROSPERO CRD42019130257 . Registered on April 19, 2019.
Topics: Female; Humans; Placebo Effect; Randomized Controlled Trials as Topic
PubMed: 34311793
DOI: 10.1186/s13063-021-05454-8 -
Acta Orthopaedica Oct 2021
Topics: Humans; Placebo Effect
PubMed: 34431744
DOI: 10.1080/17453674.2021.1969155 -
European Journal of Nuclear Medicine Nov 1997The placebo effect will have a growing importance in the field of nuclear medicine as the potentials for palliative therapy with internal sources are realized. It is... (Review)
Review
The placebo effect will have a growing importance in the field of nuclear medicine as the potentials for palliative therapy with internal sources are realized. It is important for nuclear medicine physicians and their colleagues to be familiar with the role of placebo responses in clinical trials, especially when such trials involve the subjective assessment of pain. A summary of the literature on the placebo effect in pain studies is presented in which traditional values for placebo responses are contrasted with more current thinking in the field. The few published double-blind studies of pain relief after treatment with radiotherapeutic agents are summarized specifically with respect to their cited placebo response.
Topics: Humans; Placebo Effect; Radiopharmaceuticals
PubMed: 9371880
DOI: 10.1007/s002590050173 -
American Journal of Epidemiology Jan 2021
Topics: Humans; Causality; Placebo Effect; Research Design
PubMed: 32719871
DOI: 10.1093/aje/kwaa162 -
The Canadian Journal of Cardiology Dec 2017The placebo effect is the clinical benefit caused by interaction with a caregiver and health care system in the absence of a biologically active intervention and has... (Review)
Review
The placebo effect is the clinical benefit caused by interaction with a caregiver and health care system in the absence of a biologically active intervention and has been used successfully for millennia. The placebo response results from the interaction of psychosocial mechanisms, human relationships, and preconceptions functioning in specific neuroanatomic locations with known genes and neurotransmitters. It occurs with or without the administration of an inactive substance to deliberately deceive patients. Our purpose is to review the history, benefits, and mechanisms of the placebo effect. The placebo response results from classic conditioning and positive expectations about outcome expressed by the caregiver. The outcomes are usually symptoms such as pain rather than biological outcomes such as death, and the powerful placebo may account for more than half the effect of treatment in many situations. The placebo effect results from activation of opioid, cannabinoid, and dopaminergic pathways involved in reward, expectancy, conditioning, and pain modulation. Eleven specific anatomic features in the brain identified by positron emission tomography and magnetic resonance imaging are involved. Polymorphisms in the structural genes for catecholamine O-methyltransferase and fatty acid amide oxidase significantly influence the placebo response. The placebo effect may be important in symptom suppression in angina, paroxysmal atrial fibrillation, and congestive heart failure. In the absence of deliberate deception, there are no ethical issues and given its potency, the time has come to consider how best to use the placebo in clinical practice.
Topics: Cardiology; Cardiovascular Diseases; Clinical Trials as Topic; Humans; Placebo Effect
PubMed: 29173596
DOI: 10.1016/j.cjca.2017.09.017 -
Medicina Clinica Jul 2017When we apply a physical or pharmacological treatment, there are many things that may explain the clinical improvement experienced by a patient. The drugs or physical... (Review)
Review
When we apply a physical or pharmacological treatment, there are many things that may explain the clinical improvement experienced by a patient. The drugs or physical agents applied are important, but we must also add other elements in the context of the patient-therapist relationship. Scientific evidence has proven that the placebo effect exists. This is a true biopsychosocial phenomenon produced by the context in which an intervention is carried out. Biases aside, placebo and nocebo responses are changes in patients' symptoms, due to their participation at the therapeutic meeting, with its rituals, symbols and interactions. This multitude of signals inherent in any intervention, is perceived and interpreted by patients and can create positive or negative expectations.
Topics: Attitude to Health; Ceremonial Behavior; Humans; Nocebo Effect; Placebo Effect; Professional-Patient Relations; Symbolism
PubMed: 28521961
DOI: 10.1016/j.medcli.2017.03.034