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Moral L, Mori F. Drug provocation tests in children: All that glitters is not gold. Pediatr Allergy Immunol 2023; 34:e14002. [PMID: 37622259 DOI: 10.1111/pai.14002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/21/2023] [Accepted: 07/11/2023] [Indexed: 08/26/2023]
Abstract
A proper allergy work-up, based on the gold standard drug provocation test (DPT), usually rules out suspected drug hypersensitivity in children. These tests are generally open, given their high efficiency compared with double-blind placebo-controlled DPTs. Although their negative predictive value is excellent, no studies have calculated their positive predictive value, highly dependent on the prevalence of the disease. Most studies have found a rate of <5%-10% of true beta-lactam hypersensitivity in children. Given this low prevalence (pre-test probability), a few false-positive results can significantly reduce the estimated positive predictive value. False positives may arise from the nocebo effect during the test, including nocebo by proxy, or from observer bias, which depends on professional expertise and organizational circumstances. Some studies have found a high rate of tolerance on a second DPT in children who failed the first, but these results may be affected by the interval between the two tests, of a year or more in most cases, reflecting a loss of hypersensitivity over time. Taking into account the low rate of positive DPTs, with commonly mild reactions, we suggest confirming nonsevere positive DPTs with a second provocation performed soon after the first, especially in the case of beta-lactam antibiotics, in order to improve the diagnostic accuracy, de-label more patients, and achieve a better estimation of true drug hypersensitivity prevalence. In case of mild immediate reactions, the potential benefits of a second DPT should be carefully weighed against the risk of anaphylaxis.
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Affiliation(s)
- Luis Moral
- Pediatric Allergy and Respiratory Unit, Dr. Balmis General University Hospital, Alicante Institute for Health and Biomedical Research (ISABIAL), Alicante, Spain
| | - Francesca Mori
- Allergy Unit, Meyer Children's Hospital, IRCCS Florence, Florence, Italy
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2
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Meeuwis SH, Skvortsova A, van Laarhoven AIM, Holle H, Evers AWM. Can contagious itch be affected by positive and negative suggestions? Exp Dermatol 2022; 31:1853-1862. [PMID: 36048562 PMCID: PMC10087404 DOI: 10.1111/exd.14663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/20/2022] [Accepted: 08/10/2022] [Indexed: 12/14/2022]
Abstract
Contagious itch can be evoked by observing people scratching. Verbal suggestions about to-be-received itch can influence itch intensity, as shown by placebo research, but it is unknown whether this extends to contagious itch. The current study aimed to replicate prior findings that listening to scratching and rubbing sounds elicits contagious itch, and to investigate whether suggestions can modulate this process. Healthy participants (n = 140) received positive or negative suggestions about itch in response to the sounds (aimed to decrease or increase expected itch, respectively), or no specific suggestions as a control. Participants listened to a number of audio fragments with scratching and rubbing sounds. The amount of expected itch as well as itch sensation after each audio fragment were measured by self-report. Suggestions had no effect on the expected itch. Both rubbing and scratching sounds significantly elicited itch in all groups. Scratching sounds induced more itch than rubbing sounds exclusively in the control group. These findings indicate that short suggestions might be not effective enough to modify the expectations of people regarding contagious itch. Furthermore, suggestions modulate contagious itch to some degree, but not in the hypothesized direction. Potential similarities and differences in the neurobiological mechanisms of contagious itch and nocebo effects are discussed.
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Affiliation(s)
- Stefanie H Meeuwis
- Health, Medical and Neuropsychology Unit, Institute of Psychology, Leiden University, the Netherlands.,Pain Research Group, Institute of Psychology, Jagiellonian University, Kraków, Poland
| | - Aleksandrina Skvortsova
- Health, Medical and Neuropsychology Unit, Institute of Psychology, Leiden University, the Netherlands.,Department of Psychology, McGill University, Montreal, Quebec, Canada
| | - Antoinette I M van Laarhoven
- Health, Medical and Neuropsychology Unit, Institute of Psychology, Leiden University, the Netherlands.,Leiden Institute for Brain and Cognition, Leiden University Medical Center, Leiden, the Netherlands
| | - Henning Holle
- Department of Psychology, University of Hull, Hull, UK
| | - Andrea W M Evers
- Health, Medical and Neuropsychology Unit, Institute of Psychology, Leiden University, the Netherlands.,Leiden Institute for Brain and Cognition, Leiden University Medical Center, Leiden, the Netherlands.,Medical Delta Healthy Society, Leiden University, Technical University Delft & Erasmus University Rotterdam, Rotterdam, the Netherlands
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Sölle A, Worm M, Benedetti F, Sabine Bartholomäus T, Schwender-Groen L, Klinger R. Targeted Use of Placebo Effects Decreases Experimental Itch in Atopic Dermatitis Patients: A Randomized Controlled Trial. Clin Pharmacol Ther 2021; 110:486-497. [PMID: 33894061 DOI: 10.1002/cpt.2276] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/23/2021] [Indexed: 01/05/2023]
Abstract
Evidence from pain research shows that the effectiveness of active pharmacological treatments can be enhanced by placebo effects. The "open drug administration" is superior to "hidden drug administration." In a randomized controlled trial, we aimed to show that the targeted use of placebo effects increases the efficacy of an antihistamine (dimetindene) infusion in participants with atopic dermatitis. We openly infused dimetindene (drug) in full sight with information (intervention group 1: OPEN-DRUG+INST), openly infused drug with an additional classical conditioning learning experience (intervention group 2: OPEN-DRUG+INST+COND) or infused drug without any information or sight (i.e., hidden administration (control group 1: HIDDEN-DRUG)). Control group 2 received a placebo infusion (saline) declared as dimetindene and also experienced the conditioning experience (PLAC+INST+COND). Itch was experimentally induced with histamine via a skin prick test. Outcome was assessed at the subjective (primary end point: experimental itch intensity, numeric rating scale), and objective level (secondary end point: wheal size, mm2 ). Experimental-induced itch intensity decreased in all groups but at different rates (P < 0.001). The groups with the open administration, whether it was dimetindene or placebo, had significantly stronger reductions in itch compared to the HIDDEN-DRUG group (OPEN-DRUG+INST+COND: P < 0.001; OPEN-DRUG+INST: P = 0.009; and PLAC+INST+COND: P < 0.001). Additional drug conditioning mediated via expectation led to a stronger reduction of itching (P = 0.001). Results on wheal size were similar (P = 0.048), however, no significant difference between the HIDDEN-DRUG group and the PLAC+INST+COND group (P = 0.967) was found. We conclude that specifically generated targeted placebo effects can significantly increase the action of a drug (dimetindene) and should be used in clinical practice.
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Affiliation(s)
- Ariane Sölle
- Department of Anesthesiology, Pain Medicine and Pain Psychology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Margitta Worm
- Department of Dermatology and Allergology, Allergy-Center-Charité, Charité University Medical Center Berlin, Berlin, Germany
| | - Fabrizio Benedetti
- Neuroscience Dept, University of Turin Medical School, Turin, Italy.,Plateau Rosa Labs, Zermatt, Switzerland
| | - Theresa Sabine Bartholomäus
- Department of Dermatology and Allergology, Allergy-Center-Charité, Charité University Medical Center Berlin, Berlin, Germany
| | - Lena Schwender-Groen
- Department of Anesthesiology, Pain Medicine and Pain Psychology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Regine Klinger
- Department of Anesthesiology, Pain Medicine and Pain Psychology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Meeuwis SH, van Middendorp H, Lavrijsen APM, Veldhuijzen DS, Evers AWM. Open- and Closed-Label Placebo and Nocebo Suggestions About a Sham Transdermal Patch. Psychosom Med 2021; 83:33-42. [PMID: 32969962 PMCID: PMC7748039 DOI: 10.1097/psy.0000000000000862] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 07/21/2020] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Placebo effects may occur when it is known that an inert substance is given (i.e., open-label placebo). It is not yet clear whether these effects are similar to concealed (i.e., closed-label) placebo effects for itch or whether nocebo effects can be induced under open-label conditions. METHODS Healthy volunteers (n = 112) were randomized to an open-label (I) or closed-label (II) positive suggestions group, or an open-label (III) or closed-label (IV) negative suggestions group. Participants were told, as cover story, that a transdermal caffeine patch would be applied that positively influences cognitive abilities and, as a side effect, positively or negatively (depending on group allocation) influences itch. Participants in the open-label groups were given a rationale explaining placebo and nocebo effect mechanisms. Itch (the primary outcome) was induced at baseline and postsuggestions by histamine iontophoresis. RESULTS Analyses of variance revealed significantly lower itch in the positive compared with the negative suggestions groups for both open- and closed-label contexts (all, p ≤ .008, Cohen d ≥ 0.47). Self-rated skin response was less severe after positive versus negative suggestions (all, p ≤ .017, Cohen d ≥ 0.33), but no effects on physical skin response were found (all, p ≥ .23, Cohen d ≤ 0.30). CONCLUSIONS Itch can be reduced by positive compared with negative suggestions under both open- and closed-label conditions. These findings indicate that open-label suggestions may potentially be a tool to use placebo effects for self-reported outcomes in clinical practice, for example, by explaining the role of expectancy in treatment. It needs to be investigated further under which circumstances an open-label rationale may impact placebo and nocebo effects.Trial Registration:www.trialregister.nl; NTR7174.
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Placebos without deception reduce self-report and neural measures of emotional distress. Nat Commun 2020; 11:3785. [PMID: 32728026 PMCID: PMC7391658 DOI: 10.1038/s41467-020-17654-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 07/09/2020] [Indexed: 12/19/2022] Open
Abstract
Several recent studies suggest that placebos administered without deception (i.e., non-deceptive placebos) can help people manage a variety of highly distressing clinical disorders and nonclinical impairments. However, whether non-deceptive placebos represent genuine psychobiological effects is unknown. Here we address this issue by demonstrating across two experiments that during a highly arousing negative picture viewing task, non-deceptive placebos reduce both a self-report and neural measure of emotional distress, the late positive potential. These results show that non-deceptive placebo effects are not merely a product of response bias. Additionally, they provide insight into the neural time course of non-deceptive placebo effects on emotional distress and the psychological mechanisms that explain how they function. There is controversy about whether placebos without deception cause real psychobiological benefits. Here, the authors show that the positive effects of placebos without deception are more than response bias by providing evidence they can reduce self-report and neural measures of emotional distress.
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Meeuwis SH, van Middendorp H, van Laarhoven AIM, van Leijenhorst C, Pacheco-Lopez G, Lavrijsen APM, Veldhuijzen DS, Evers AWM. Placebo and nocebo effects for itch and itch-related immune outcomes: A systematic review of animal and human studies. Neurosci Biobehav Rev 2020; 113:325-337. [PMID: 32240668 DOI: 10.1016/j.neubiorev.2020.03.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 03/24/2020] [Indexed: 12/19/2022]
Abstract
Placebo and nocebo effects can influence somatic symptoms such as pain. For itch and other dermatological symptoms these effects have been far less investigated. This review systematically integrates evidence from both animal (mainly rodents) and human trials on placebo and nocebo effects in itch, itch-related symptoms and conditions of the skin and mucous membranes, and related immune outcomes (e.g., histamine). Thirty-one animal studies, and fifty-five human studies (k = 21 healthy participants, k = 34 patients) were included. Overall, studies consistently show that placebo and nocebo effects can be induced by various methods (e.g., suggestions, conditioning and social cues), despite high heterogeneity across studies. Effects of suggestions were found consistently across subjective and behavioral parameters (e.g., itch and scratching in humans), whereas conditioning was likely to impact physiological parameters under certain conditions (e.g., conditioning of histamine levels in stressed rodents). Brain areas responsible for itch processing were associated with nocebo effects. Future research may investigate how variations in methods impact placebo and nocebo effects, and whether all symptoms and conditions can be influenced equally.
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Affiliation(s)
- Stefanie H Meeuwis
- Health, Medical and Neuropsychology Unit, Institute of Psychology, Faculty of Social and Behavioral Sciences, Leiden University, P.O. Box 9555, 2300RB, Leiden, the Netherlands; Leiden Institute for Brain and Cognition, P.O. Box 9600, 2300RC, Leiden University Medical Center, Leiden, the Netherlands.
| | - Henriët van Middendorp
- Health, Medical and Neuropsychology Unit, Institute of Psychology, Faculty of Social and Behavioral Sciences, Leiden University, P.O. Box 9555, 2300RB, Leiden, the Netherlands; Leiden Institute for Brain and Cognition, P.O. Box 9600, 2300RC, Leiden University Medical Center, Leiden, the Netherlands
| | - Antoinette I M van Laarhoven
- Health, Medical and Neuropsychology Unit, Institute of Psychology, Faculty of Social and Behavioral Sciences, Leiden University, P.O. Box 9555, 2300RB, Leiden, the Netherlands; Leiden Institute for Brain and Cognition, P.O. Box 9600, 2300RC, Leiden University Medical Center, Leiden, the Netherlands; Department of Psychiatry, Leiden University Medical Center, P.O. Box 9600, 2300RC, Leiden, the Netherlands
| | - Cora van Leijenhorst
- Health, Medical and Neuropsychology Unit, Institute of Psychology, Faculty of Social and Behavioral Sciences, Leiden University, P.O. Box 9555, 2300RB, Leiden, the Netherlands
| | - Gustavo Pacheco-Lopez
- Health, Medical and Neuropsychology Unit, Institute of Psychology, Faculty of Social and Behavioral Sciences, Leiden University, P.O. Box 9555, 2300RB, Leiden, the Netherlands; Metropolitan Autonomous University (UAM), Campus Lerma, Health Sciences Department, Lerma, 52005, Edo Mex, Mexico
| | - Adriana P M Lavrijsen
- Department of Dermatology, Leiden University Medical Center, P.O. Box 9600, 2300RC, Leiden, the Netherlands
| | - Dieuwke S Veldhuijzen
- Health, Medical and Neuropsychology Unit, Institute of Psychology, Faculty of Social and Behavioral Sciences, Leiden University, P.O. Box 9555, 2300RB, Leiden, the Netherlands; Leiden Institute for Brain and Cognition, P.O. Box 9600, 2300RC, Leiden University Medical Center, Leiden, the Netherlands
| | - Andrea W M Evers
- Health, Medical and Neuropsychology Unit, Institute of Psychology, Faculty of Social and Behavioral Sciences, Leiden University, P.O. Box 9555, 2300RB, Leiden, the Netherlands; Leiden Institute for Brain and Cognition, P.O. Box 9600, 2300RC, Leiden University Medical Center, Leiden, the Netherlands; Department of Psychiatry, Leiden University Medical Center, P.O. Box 9600, 2300RC, Leiden, the Netherlands
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7
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Evers AWM, Peerdeman KJ, van Laarhoven AIM. What is new in the psychology of chronic itch? Exp Dermatol 2019; 28:1442-1447. [PMID: 31246320 PMCID: PMC6973117 DOI: 10.1111/exd.13992] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 05/30/2019] [Accepted: 06/13/2019] [Indexed: 12/25/2022]
Abstract
Itch is often regarded as unpleasant or bothersome and is accompanied by symptoms of distress and impairments in daily life. The biopsychosocial model of chronic itch describes how psychological factors can contribute to the improvement or exacerbation of chronic itch and related scratching behaviour. Recent research underlines the important role of cognitive-affective information processing, such as attention, affect and expectancies. This may not only play a role for acute itch states, but may particularly apply to the process of itch chronification, for example, due to the vicious cycle in which these factors shape the experience of itch. The present paper focuses on new insights into the relation between itch and the cognitive-affective factors of attention, affect and expectancies. These factors are thought to play a possible aggravating role in itch in the long term and have received increasing attention in the recent empirical literature on maintaining and exacerbating factors for chronic physical symptoms. Possible psychophysiological and neurobiological pathways regarding these factors are discussed, as well as possible intervention methods.
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Affiliation(s)
- Andrea W. M. Evers
- Health, Medical and Neuropsychology UnitLeiden UniversityLeidenThe Netherlands
- Department of PsychiatryLeiden University Medical CenterLeidenThe Netherlands
- Leiden Institute for Brain and CognitionLeidenThe Netherlands
| | - Kaya J. Peerdeman
- Health, Medical and Neuropsychology UnitLeiden UniversityLeidenThe Netherlands
- Leiden Institute for Brain and CognitionLeidenThe Netherlands
| | - Antoinette I. M. van Laarhoven
- Health, Medical and Neuropsychology UnitLeiden UniversityLeidenThe Netherlands
- Department of PsychiatryLeiden University Medical CenterLeidenThe Netherlands
- Leiden Institute for Brain and CognitionLeidenThe Netherlands
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8
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9
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Meeuwis SH, van Middendorp H, van Laarhoven AIM, Veldhuijzen DS, Lavrijsen APM, Evers AWM. Effects of Open- and Closed-Label Nocebo and Placebo Suggestions on Itch and Itch Expectations. Front Psychiatry 2019; 10:436. [PMID: 31293458 PMCID: PMC6598628 DOI: 10.3389/fpsyt.2019.00436] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 06/03/2019] [Indexed: 12/12/2022] Open
Abstract
Placebo and nocebo effects have been shown to influence subjective symptoms such as itch. These effects can be induced by influencing outcome expectations through, for example, combining the application of an inert substance (e.g., a cream) with verbal suggestions on the anticipated effects of this substance. Interestingly, placebo effects also occur when it is known that a treatment is inert (i.e., open-label placebo). However, no study to date has examined the efficacy of negative and positive verbal suggestions under similar open-label and closed-label (i.e., concealed placebo/nocebo) conditions in itch. A randomized controlled between-subjects study design was applied in which healthy volunteers (n = 92) were randomized to 1) an open-label positive verbal suggestion group, 2) a closed-label positive verbal suggestion group, 3) an open-label negative verbal suggestion group, or 4) a closed-label negative verbal suggestion group. Verbal suggestions were made regarding the topical application of an inert substance. Itch was evoked experimentally by histamine iontophoresis at baseline and again following suggestions. Itch expectations, self-reported itch during and following iontophoresis, and skin response parameters were measured. Positive suggestions were found to result in significantly lower expected itch than were negative suggestions in both open- and closed-label conditions. No effects of the suggestions on itch during iontophoresis were found, but significantly lower itch was reported in the 4 min following iontophoresis in the (combined open- and closed-label) positive compared with negative verbal suggestion groups. In addition, a smaller increase in skin temperature was found in the positive compared with negative suggestion groups. The findings illustrate a potential role of (open- and closed-label) placebo for optimizing expectations and treatment effects for itch in clinical practice. Clinical Trial Registration: Netherlands Trial Register, trial number: NTR6530.
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Affiliation(s)
- Stefanie H Meeuwis
- Health, Medical and Neuropsychology Unit, Faculty of Social and Behavioural Sciences, Institute of Psychology, Leiden University, Leiden, Netherlands.,Leiden Institute for Brain and Cognition, Leiden University Medical Center, Leiden, Netherlands
| | - Henriët van Middendorp
- Health, Medical and Neuropsychology Unit, Faculty of Social and Behavioural Sciences, Institute of Psychology, Leiden University, Leiden, Netherlands.,Leiden Institute for Brain and Cognition, Leiden University Medical Center, Leiden, Netherlands
| | - Antoinette I M van Laarhoven
- Health, Medical and Neuropsychology Unit, Faculty of Social and Behavioural Sciences, Institute of Psychology, Leiden University, Leiden, Netherlands.,Leiden Institute for Brain and Cognition, Leiden University Medical Center, Leiden, Netherlands.,Department of Psychiatry, Leiden University Medical Center, Leiden, Netherlands
| | - Dieuwke S Veldhuijzen
- Health, Medical and Neuropsychology Unit, Faculty of Social and Behavioural Sciences, Institute of Psychology, Leiden University, Leiden, Netherlands.,Leiden Institute for Brain and Cognition, Leiden University Medical Center, Leiden, Netherlands
| | | | - Andrea W M Evers
- Health, Medical and Neuropsychology Unit, Faculty of Social and Behavioural Sciences, Institute of Psychology, Leiden University, Leiden, Netherlands.,Leiden Institute for Brain and Cognition, Leiden University Medical Center, Leiden, Netherlands.,Department of Psychiatry, Leiden University Medical Center, Leiden, Netherlands
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11
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[Psychological aspects of pruritus and therapy options]. Hautarzt 2016; 67:622-6. [PMID: 27341824 DOI: 10.1007/s00105-016-3825-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Besides biological factors, which cause or influence chronic pruritus, more and more attention has recently also been paid to psychological and psychoneuroimmunological factors which uphold the symptom. OBJECTIVES This review article gives an overview of the state of research regarding psychological and psychoneuroimmunological factors and the resulting therapeutic options. MATERIALS AND METHODS The article is based on a literature search in the PubMed database. RESULTS Under experimental conditions, pruritus can be induced by verbal instructions and modulated by placebo and nocebo effects. Stressful life events can also induce pruritus or its exacerbation. This can also be demonstrated on a cellular level. CONCLUSION The knowledge that pruritus intensity is modulated by cognitions, behavioral factors, and stress is important for the development and application of psychological interventions. More research should be done regarding psychological interventions in the treatment of chronic itch and they should be applied clinically more often.
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Bartels DJP, van Laarhoven AIM, van de Kerkhof PCM, Evers AWM. Placebo and nocebo effects on itch: effects, mechanisms, and predictors. Eur J Pain 2015; 20:8-13. [PMID: 26417885 DOI: 10.1002/ejp.750] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2015] [Indexed: 12/17/2022]
Abstract
Placebo and nocebo effects have been extensively studied in the field of pain and more recently also on itch. In accordance with placebo research on pain, expectancy learning via verbal suggestion or conditioning has shown to induce placebo and nocebo effects on itch, in which the combination of both procedures seems most promising. Moreover, itch can also be transferred 'contagiously' in which suggestion and social behavioural learning seem to play a role. With regard to predictors of placebo and nocebo responding on itch and contagious itch, preliminary evidence suggests a role for individual psychological characteristics and personality traits regarding negative outcome expectancies. Although findings on placebo and nocebo effects on itch seem comparable to pain, we have only just begun to understand the underlying mechanisms and predictors of placebo and nocebo effects on itch.
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Affiliation(s)
- Danielle J P Bartels
- Unit Health, Medical and Neuropsychology, Institute of Psychology, Leiden University, Leiden, the Netherlands.,Leiden Institute for Brain and Cognition (LIBC), Leiden University, Leiden, the Netherlands
| | - Antoinette I M van Laarhoven
- Unit Health, Medical and Neuropsychology, Institute of Psychology, Leiden University, Leiden, the Netherlands.,Leiden Institute for Brain and Cognition (LIBC), Leiden University, Leiden, the Netherlands
| | | | - Andrea W M Evers
- Unit Health, Medical and Neuropsychology, Institute of Psychology, Leiden University, Leiden, the Netherlands.,Leiden Institute for Brain and Cognition (LIBC), Leiden University, Leiden, the Netherlands.,Department of Medical Psychology, Radboud University Medical Center, Nijmegen, the Netherlands
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13
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Darragh M, Chang JWH, Booth RJ, Consedine NS. The placebo effect in inflammatory skin reactions: the influence of verbal suggestion on itch and weal size. J Psychosom Res 2015; 78:489-494. [PMID: 25649275 DOI: 10.1016/j.jpsychores.2015.01.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 01/19/2015] [Accepted: 01/21/2015] [Indexed: 11/25/2022]
Abstract
PURPOSE To investigate suggestion-induced placebo effects in inflammatory skin reactions. METHODS A healthy sample of volunteers (N = 48) attended two laboratory sessions. In each, a local short term inflammatory skin reaction was induced with histamine. Participants were told that one session was a control session and the other was a treatment session in which an antihistamine cream would be applied to the arm to reduce the size of the weal and the experience of itch. Inert aqueous cream was applied in both sessions. Participants were randomly allocated to undergo either the control or the treatment session first. RESULTS The placebo manipulation successfully reduced self-reported itch from the control to the placebo treatment session, but no placebo effect was demonstrated in weal size. Order effects were observed such that only those who underwent control procedures first had a smaller weal in the placebo treatment session as compared to the control session. The same order effect was seen for reported itch at one minute post histamine administration, but this disappeared at the three and five minute measures. CONCLUSION Findings suggest that explicit verbal suggestion can reduce the experience of itch. In addition to conscious awareness, a concrete representation of the suggested changes gained from prior experience to the stimulus may be an important component of placebo effects on inflammatory skin reactions.
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Darragh M, Vanderboor T, Booth RJ, Sollers JJ, Consedine NS. Placebo 'serotonin' increases heart rate variability in recovery from psychosocial stress. Physiol Behav 2015; 145:45-9. [PMID: 25840004 DOI: 10.1016/j.physbeh.2015.03.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 02/10/2015] [Accepted: 03/30/2015] [Indexed: 12/23/2022]
Abstract
OBJECTIVE To investigate placebo effects on heart rate (HR) and heart rate variability (HRV) in recovery from a psychosocial stressor. METHODS A healthy sample underwent two mental arithmetic stress tests in one experimental session. After undergoing the baseline test, participants were randomized into control or placebo groups. Prior to the second stress test, the placebo group received an intranasal dose of 'serotonin' (placebo) with the suggestion that it would enhance recovery. HR and HRV were assessed throughout procedures. RESULTS There was an increase in vagally-mediated HRV in the placebo group. The change in HR did not differ between groups. CONCLUSIONS Placebo suggestion can enhance autonomic recovery after psychosocial stress. Findings are consistent with the notion of top-down mechanisms of placebo effects, but further research would need to specifically examine the role of top-down regulatory pathways as possible mediators of placebo-induced changes in autonomic function.
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15
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Vits S, Dissemond J, Schadendorf D, Kriegler L, Körber A, Schedlowski M, Cesko E. Expectation-induced placebo responses fail to accelerate wound healing in healthy volunteers: results from a prospective controlled experimental trial. Int Wound J 2013; 12:664-8. [PMID: 24373522 DOI: 10.1111/iwj.12193] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 10/21/2013] [Accepted: 11/04/2013] [Indexed: 12/19/2022] Open
Abstract
Placebo responses have been shown to affect the symptomatology of skin diseases. However, expectation-induced placebo effects on wound healing processes have not been investigated yet. We analysed whether subjects' expectation of receiving an active drug accelerates the healing process of experimentally induced wounds. In 22 healthy men (experimental group, n = 11; control group, n = 11) wounds were induced by ablative laser on both thighs. Using a deceptive paradigm, participants in the experimental group were informed that an innovative 'wound gel' was applied on one of the two wounds, whereas a 'non-active gel' was applied on the wound of the other thigh. In fact, both gels were identical hydrogels without any active components. A control group was informed to receive a non-active gel on both wounds. Progress in wound healing was documented via planimetry on days 1, 4 and 7 after wound induction. From day 9 onwards wound inspections were performed daily accompanied by a change of the dressing and a new application of the gel. No significant differences could be observed with regard to duration or process of wound healing, either by intraindividual or by interindividual comparisons. These data document no expectation-induced placebo effect on the healing process of experimentally induced wounds in healthy volunteers.
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Affiliation(s)
- Sabine Vits
- Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, Essen, Germany
| | - Joachim Dissemond
- Department of Dermatology, Venereology and Allergology, University Hospital Essen, Essen, Germany
| | - Dirk Schadendorf
- Department of Dermatology, Venereology and Allergology, University Hospital Essen, Essen, Germany
| | - Lisa Kriegler
- Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, Essen, Germany
| | - Andreas Körber
- Department of Dermatology, Venereology and Allergology, University Hospital Essen, Essen, Germany
| | - Manfred Schedlowski
- Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, Essen, Germany
| | - Elvir Cesko
- Department of Dermatology, Venereology and Allergology, University Hospital Essen, Essen, Germany
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