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Chhabra B, Szabo A. Placebo and Nocebo Effects on Sports and Exercise Performance: A Systematic Literature Review Update. Nutrients 2024; 16:1975. [PMID: 38999724 PMCID: PMC11243088 DOI: 10.3390/nu16131975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2024] [Revised: 06/17/2024] [Accepted: 06/19/2024] [Indexed: 07/14/2024] Open
Abstract
Sports performance could be affected by placebo and nocebo effects. The last literature review on placebo and nocebo effects on sports and exercise performance was published in 2019. In the past five years, several new studies have been published. This review aimed to update the previous synthesis and evaluate the results of new studies focusing on placebo or nocebo interventions in sports and exercise by determining the form and magnitude of their effect. Hence, we searched for empirical studies published from 2019 until the end of May 2024 indexed in PubMed, Medline, Web of Science, EBSCO, and Google Scholar databases. The search yielded 20 eligible studies with control or baseline-control conditions, focusing on nutritional, mechanical, and other mixed ergogenic aids. They yielded small to large placebo effects (Cohen's d) for nutritional (d = 0.86), mechanical (d = 0.38), cream and gel (d = 0.05), and open-label placebo (d = 0.16) interventions. The pooled effect size for placebo effects was moderate to large (d = 0.67), larger than in the earlier review, suggesting that placebo effects can improve motor performance even more than previously reported. However, based on five measures from three studies, the nocebo effects were almost twice as large (d = 1.20). Accordingly, the current findings support and expand the last review in the field by yielding additional support for placebo and nocebo effects in sports and exercise.
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Affiliation(s)
- Bhavya Chhabra
- Institute of Health Promotion and Sport Sciences, Faculty of Psychology and Education, ELTE Eötvös Loránd University, 1075 Budapest, Hungary
- Doctoral School of Education, Faculty of Psychology and Education, ELTE Eötvös Loránd University, 1075 Budapest, Hungary
| | - Attila Szabo
- Faculty of Sport and Health Sciences, Széchenyi István University, 9025 Győr, Hungary
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Schaefer M, Enge S. Open-label placebos enhance test performance and reduce anxiety in learner drivers: a randomized controlled trial. Sci Rep 2024; 14:6684. [PMID: 38509101 PMCID: PMC10954622 DOI: 10.1038/s41598-024-56600-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 03/08/2024] [Indexed: 03/22/2024] Open
Abstract
Passing the driving school test can be very challenging, especially in big cities, where up to 52% of all students fail this test. Consequently, many learner drivers experience stress and anxiety. For some learner drivers these feelings can be extreme and negatively affect the performance in the driving test. Different strategies to face anxiety and stress are known, including, for example, psychological or pharmacological approaches and even placebo pills. Recent intriguing findings have also demonstrated that placebos without deception, so-called open-label placebos, successfully reduce anxiety. Here we aimed to test effects of this novel treatment for learner drivers. We investigated whether open-label placebos affect test performance and feelings of anxiety in learner drivers. Sixty-eight healthy participants (mean age 21.94 years, 26 females) were randomized into two groups. The open-label placebo group received placebo pills two weeks before the driving test (two pills each day). The control group received no treatment. Results revealed that the open-label placebo group experienced significantly less anxiety than the control group before the test (measured with the State-Trait-Anxiety-Inventory, STAI-S, and the German Test Anxiety Inventory, PAF). Moreover, in the open-label placebo group less learner drivers failed the driving test (29.41% vs. 52.95%). The results suggest that open-label placebos may provide an ethical unproblematic way to experience less anxiety and might also enhance the probability to pass the driving test. We discuss possible mechanisms of open-label placebos and limitations of our findings.
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Affiliation(s)
| | - Sören Enge
- Medical School Berlin, 12247, Berlin, Germany
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3
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Gavel EH, Barreto G, Hawke KV, Stellingwerff T, James LJ, Saunders B, Logan-Sprenger HM. How Cool is That? The Effects of Menthol Mouth Rinsing on Exercise Capacity and Performance: A Systematic Review and Meta-analysis. SPORTS MEDICINE - OPEN 2024; 10:18. [PMID: 38381237 PMCID: PMC10881929 DOI: 10.1186/s40798-024-00679-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 01/10/2024] [Indexed: 02/22/2024]
Abstract
BACKGROUND Menthol (MEN) mouth rinsing (MR) has gained considerable interest in the athletic population for exercise performance; however, the overall magnitude of effect is unknown. OBJECTIVE The aim of this systematic review and meta-analysis was to determine the efficacy of menthol MEN MR and the impact it has on exercise capacity and performance. METHODS Three databases were searched with articles screened according to the inclusion/exclusion criteria. Three-level meta-analyses were used to investigate the overall efficacy of MEN MR and the impact it has on exercise capacity and performance. Meta-regressions were then performed with 1) mean VO2peak, 2) MEN swilling duration; 3) the MEN concentration of MR solution, 4) the number of executed swills throughout a single experiment, 5) the use of flavoured sweetened, non-caloric, or non-flavoured neutral solutions as controls, 6) mean environmental temperature at the time of exercise tests, and 7) exercise type as fixed factors to evaluate their influence on the effects of MEN MR. RESULTS Ten MEN MR studies included sufficient information pertaining to MEN MR and exercise performance and capacity. MR with MEN resulted in no significant change in capacity and performance (SMD = 0.12; 95% CI - 0.08, 0.31; p = 0.23, n = 1, tau21 < 0.0001, tau22 = < 0.0001, I2 = 0%). No significant influence was detected in meta-regressions for VO2peak, (estimate: 0.03; df = 8; 95% CI - 0.03, 0.09; p = 0.27), swilling duration (5 vs. 10 s: 0.00; df = 16; 95% CI - 0.41, 0.41; p = 1.0), MEN concentration (low [0.01%] vs. high [0.1%]: - 0.08; df = 15; 95% CI - 0.49, 0.32; p = 0.67), number of swills (estimate: 0.02; df = 13; 95% CI - 0.05, 0.09; p = 0.56), the use of flavoured sweetener or non-caloric as control (non-flavoured vs. flavoured: 0.12; df = 16; 95% CI - 0.30, 0.55; p = 0.55) or mean room temperature during exercise tests (estimate: 0.01; df = 16; 95% CI - 0.02, 0.04; p = 0.62). CONCLUSION MEN MR did not significantly improve overall exercise capacity and performance, though those involved in endurance exercise may see benefits.
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Affiliation(s)
- Erica H Gavel
- Faculty of Science, Ontario Tech University, Oshawa, ON, Canada.
| | - Gabriel Barreto
- Applied Physiology and Nutrition Research Group, Center of Lifestyle Medicine, Faculdade de Medicina FMUSP, Universidade de São Paulo, São Paulo, Brazil
| | - Kierstyn V Hawke
- Faculty of Health Science, Ontario Tech University, Oshawa, ON, Canada
| | - Trent Stellingwerff
- Canadian Sport Institute - Pacific, Victoria, BC, Canada
- Exercise Science, Physical and Health Education, University of Victoria, Victoria, BC, Canada
| | - Lewis J James
- National Centre for Sport and Exercise Medicine, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Bryan Saunders
- Applied Physiology and Nutrition Research Group, Center of Lifestyle Medicine, Faculdade de Medicina FMUSP, Universidade de São Paulo, São Paulo, Brazil
- Institute of Orthopaedics and Traumatology, Faculty of Medicine FMUSP, University of São Paulo, São Paulo, Brazil
| | - Heather M Logan-Sprenger
- Faculty of Science, Ontario Tech University, Oshawa, ON, Canada
- Faculty of Health Science, Ontario Tech University, Oshawa, ON, Canada
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de Leeuw M, Laager M, Gaab J, Ruppen W, Schneider T. Boosting open-label placebo effects in acute induced pain in healthy adults (BOLPAP-study): study protocol of a randomized controlled trial. Front Med (Lausanne) 2024; 11:1238878. [PMID: 38420356 PMCID: PMC10900763 DOI: 10.3389/fmed.2024.1238878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 01/22/2024] [Indexed: 03/02/2024] Open
Abstract
Introduction Pain is a highly prevalent symptom in the hospital setting, but treatment options remain limited. Harnessing the placebo effect in an ethical manner could provide a new possibility to reduce pain in clinical practice. So called open-label placebos (OLP) have been shown to elicit significant effects in reducing acute pain. But, before implementation, more knowledge concerning the properties of OLPs is needed. This study aims to assess the duration of analgesic effects from OLP and to determine the possibility of boosting such effects. Methods and analysis This is the protocol of an ongoing (first patient enrolled in March 2023) single-site randomized trial investigating OLPs in two parts (i.e., substudies). In both parts, pain will be induced in healthy adults using an intradermal electrical stimulation model. Participants in Part 1 will have two study visits: An interventional visit with one OLP injection accompanied by an evidence-based treatment rationale and a control visit with no treatment. For Part 2, participants will be randomized into three groups: (1) A fixed-time "Booster" group including one single repetition of the OLP injection at a fixed time point, (2) an on-demand "Booster" group including one single repetition of the OLP injection on-demand, and (3) a control group who will receive just one OLP injection. Differences in pain ratings over time (using the Numeric Rating Scale) will be analyzed with several two-sample t-tests. The time point for a fixed-time "Booster" in Part 2 will be derived from Part 1 with additional statistical tools such as a broken-stick mixed-effect model. Discussion This study aims to further characterize the analgesic effects of OLPs. In doing so, it will provide valuable information needed for later implementation of OLPs in clinical practice, where they could play a role in multimodal analgesic concepts. Ethics and dissemination The "Ethikkommission Nordwest- und Zentralschweiz" (BASEC 2023-00296) approved the study protocol. Results of the analysis will be submitted for publication in a peer-reviewed journal. Clinical Trial Registration This study is registered at ClinicalTrials.gov (NCT05819476) and is listed in the Swiss National Registry at kofam.ch (SNCTP000005470).
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Affiliation(s)
- Matthijs de Leeuw
- Pain Unit, Clinic for Anesthesia, Intermediate Care, Prehospital Emergency Medicine and Pain Therapy, University Hospital Basel, Basel, Switzerland
| | - Mirjam Laager
- Department of Clinical Research, University of Basel, Basel, Switzerland
| | - Jens Gaab
- Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland
| | - Wilhelm Ruppen
- Pain Unit, Clinic for Anesthesia, Intermediate Care, Prehospital Emergency Medicine and Pain Therapy, University Hospital Basel, Basel, Switzerland
| | - Tobias Schneider
- Pain Unit, Clinic for Anesthesia, Intermediate Care, Prehospital Emergency Medicine and Pain Therapy, University Hospital Basel, Basel, Switzerland
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Buergler S, Sezer D, Gaab J, Locher C. The roles of expectation, comparator, administration route, and population in open-label placebo effects: a network meta-analysis. Sci Rep 2023; 13:11827. [PMID: 37481686 PMCID: PMC10363169 DOI: 10.1038/s41598-023-39123-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 07/20/2023] [Indexed: 07/24/2023] Open
Abstract
Three meta-analyses have demonstrated the clinical potential of open-label placebos (OLPs). However, there is a need to synthesize the existing evidence through more complex analyses that would make it possible to answer questions beyond mere efficacy. Such analyses would serve to improve the understanding of why and under what circumstances OLPs work (e.g., depending on induced expectations or across different control groups). To answer these questions, we conducted the first network meta-analyses in the field of OLPs. Our analyses revealed that OLPs could be beneficial in comparison to no treatment in nonclinical (12 trials; 1015 participants) and clinical populations (25 trials; 2006 participants). Positive treatment expectations were found to be important for OLPs to work. Also, OLP effects can vary depending on the comparator used. While the kind of administration route had no substantial impact on the OLP effects, effects were found to be larger in clinical populations than in nonclinical populations. These results suggest that the expectation, comparator, administration route, and population should be considered when designing and interpreting OLP studies.
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Affiliation(s)
- Sarah Buergler
- Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland.
| | - Dilan Sezer
- Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland
| | - Jens Gaab
- Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland
| | - Cosima Locher
- Department of Consultation-Liaison Psychiatry and Psychosomatic Medicine, University Hospital Zurich, University of Zurich, Zurich, Switzerland
- Faculty of Health, University of Plymouth, Plymouth, UK
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Nabuco LL, Mendes GF, Barreto G, Saunders B, Reis CEG. Spit It Out: Is Caffeine Mouth Rinse an Effective Ergogenic Aid? A Systematic Review and Meta-Analysis. Strength Cond J 2023. [DOI: 10.1519/ssc.0000000000000777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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Spille L, Fendel JC, Seuling PD, Göritz AS, Schmidt S. Open-label placebos-a systematic review and meta-analysis of experimental studies with non-clinical samples. Sci Rep 2023; 13:3640. [PMID: 36871028 PMCID: PMC9985604 DOI: 10.1038/s41598-023-30362-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 02/21/2023] [Indexed: 03/06/2023] Open
Abstract
The use of open-label placebos (OLPs) has shown to be effective in clinical trials. We conducted a systematic review and meta-analysis to examine whether OLPs are effective in experimental studies with non-clinical populations. We searched five databases on April 15, 2021. We conducted separate analyses for self-reported and objective outcomes and examined whether the level of suggestiveness of the instructions influenced the efficacy of OLPs. Of the 3573 identified records, 20 studies comprising 1201 participants were included, of which 17 studies were eligible for meta-analysis. The studies investigated the effect of OLPs on well-being, pain, stress, arousal, wound healing, sadness, itchiness, test anxiety, and physiological recovery. We found a significant effect of OLPs for self-reported outcomes (k = 13; standardized mean difference (SMD) = 0.43; 95% CI = 0.28, 0.58; I2 = 7.2%), but not for objective outcomes (k = 8; SMD = - 0.02; 95% CI = - 0.25, 0.21; I2 = 43.6%). The level of suggestiveness of the instructions influenced the efficacy of OLPs for objective outcomes (p = 0.02), but not for self-reported outcomes. The risk of bias was moderate for most studies, and the overall quality of the evidence was rated low to very low. In conclusion, OLPs appear to be effective when examined in experimental studies. However, further research is needed to better understand the mechanisms underlying OLPs.
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Affiliation(s)
- Lukas Spille
- Department of Psychology, Occupational Psychology, University of Freiburg, Freiburg, Germany
| | - Johannes C Fendel
- Department of Psychosomatic Medicine and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Patrik D Seuling
- Department of Psychology, Occupational Psychology, University of Freiburg, Freiburg, Germany
| | - Anja S Göritz
- Department of Psychology, Occupational Psychology, University of Freiburg, Freiburg, Germany
| | - Stefan Schmidt
- Department of Psychosomatic Medicine and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
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Kang H, Miksche MS, Ellingsen DM. Association between personality traits and placebo effects: a preregistered systematic review and meta-analysis. Pain 2023; 164:494-508. [PMID: 35947877 DOI: 10.1097/j.pain.0000000000002753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 08/02/2022] [Indexed: 11/26/2022]
Abstract
ABSTRACT Placebo effects are ubiquitous yet highly variable between individuals and therefore strongly affect clinical trial outcomes such as pain relief. It is unclear whether dispositional psychological traits influence responsiveness to placebo. This preregistered meta-analysis and systematic review synthesized the literature investigating the association between personality traits and placebo effects. Based on 21 studies with 798 participants, we performed formal meta-analyses for 10 different personality traits, including behavioral inhibition, fun seeking, goal-drive persistence, reward responsiveness, empathic concern, empathic fantasy, perspective-taking, personal distress, optimism, and anxiety. We did not find evidence of associations between any of these traits and magnitude of placebo effects, which was supported by equivalence tests. Furthermore, we did not find evidence for moderating factors such as placebo manipulation type (conditioning or nonconditioning) or condition (pain or nonpain). These findings challenge the notion that personality influences responsiveness to placebos and contradict its utility for identifying placebo "responders" and "nonresponders."
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Affiliation(s)
- Heemin Kang
- Department of Psychology, University of Oslo, Norway
- Norwegian Centre for Mental Disorders Research, Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | | | - Dan-Mikael Ellingsen
- Department of Psychology, University of Oslo, Norway
- Division of Radiology and Nuclear Medicine, Department of Physics and Computational Radiology, Oslo University Hospital, Oslo, Norway
- School of Health Sciences, Kristiania University College, Oslo, Norway
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Schaefer M, Kühnel A, Schweitzer F, Enge S, Gärtner M. Neural underpinnings of open-label placebo effects in emotional distress. Neuropsychopharmacology 2023; 48:560-566. [PMID: 36456814 PMCID: PMC9852452 DOI: 10.1038/s41386-022-01501-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/12/2022] [Accepted: 11/01/2022] [Indexed: 12/05/2022]
Abstract
While placebo effects are well-known, research in the last decade revealed intriguing effects that placebos may have beneficial effects even when given without deception. At first glance, this seems paradoxical, but several studies have reported improvements in pain, depression, or anxiety. However, it still remains unclear whether these results represent objective biological effects or simply a bias in response and what neural underpinnings are associated with the open-label placebo effects. In two studies, we address this gap by demonstrating that open-label placebos reduce self-reported emotional distress when viewing highly arousing negative pictures. This reduced emotional distress was associated with an activation of brain areas known to modulate affective states such as the periaqueductal gray, the bilateral anterior hippocampi, and the anterior cingulate cortex. We did not find any prefrontal brain activation. Furthermore, brain activation was not associated with expectation of effects. In contrast, we found that brain responses were linked to general belief in placebos. The results demonstrate that the neural mechanisms of open-label placebo effects are partly identical to the neurobiological underpinnings of conventional placebos, but our study also highlights important differences with respect to a missing engagement of prefrontal brain regions, suggesting that expectation of effects may play a less prominent role in open-label placebos.
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Affiliation(s)
| | - Anja Kühnel
- grid.466457.20000 0004 1794 7698Medical School Berlin, Berlin, Germany
| | - Felix Schweitzer
- grid.466457.20000 0004 1794 7698Medical School Berlin, Berlin, Germany
| | - Sören Enge
- grid.466457.20000 0004 1794 7698Medical School Berlin, Berlin, Germany
| | - Matti Gärtner
- grid.466457.20000 0004 1794 7698Medical School Berlin, Berlin, Germany
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Haas JW, Winkler A, Rheker J, Doering BK, Rief W. No open-label placebo effect in insomnia? Lessons learned from an experimental trial. J Psychosom Res 2022; 158:110923. [PMID: 35487141 DOI: 10.1016/j.jpsychores.2022.110923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 04/15/2022] [Accepted: 04/16/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND Open-label placebo (OLP) treatment seems to be effective in several medical conditions but has not yet been investigated in insomnia. Furthermore, it needs to be evaluated whether providing a plausible treatment rationale is essential to obtain OLP effects. METHODS In two consecutive nights, the sleep of patients with primary insomnia (n = 45) was assessed via subjective and objective measures. Before the second night, they received a single OLP pill that was randomly provided either with a treatment rationale (OLP+) or without (OLP-). When (M)ANOVAs did not reveal differential effects between the two OLP groups, the OLP+ group was compared post-hoc to a formerly assessed no pill control sample (NPC; n = 23). RESULTS Neither the MANOVAs nor the ANOVAs revealed significant interaction effects of treatment group and assessment night. The OLP+ condition was superior neither to OLP- nor to NPC in improving the patients' sleep. DISCUSSION Our findings do neither confirm the general efficacy of OLP in primary insomnia nor differential effects depending on the treatment rationale. Possible explanations lie in the dosing scheme (i.e., single OLP application), the provision of the OLP rationale by video and the experimental instead of therapeutic character of our investigation. Trials with larger samples and longer-term OLP treatment in insomnia are needed. Providing the rationale face-to-face and in a clinical setting might be additionally beneficial.
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Affiliation(s)
- Julia W Haas
- Philipps-University of Marburg, Department of Clinical Psychology and Psychotherapy, Marburg, Germany
| | - Alexander Winkler
- Justus-Liebig-University Giessen, Department of Clinical Psychology and Psychotherapy, Giessen, Germany
| | - Julia Rheker
- Philipps-University of Marburg, Department of Clinical Psychology and Psychotherapy, Marburg, Germany
| | - Bettina K Doering
- Medizinische Hochschule Brandenburg Theodor Fontane, Campus Neuruppin, Neuruppin, Germany.
| | - Winfried Rief
- Philipps-University of Marburg, Department of Clinical Psychology and Psychotherapy, Marburg, Germany
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Sezer D, de Leeuw M, Netzer C, Dieterle M, Meyer A, Buergler S, Locher C, Ruppen W, Gaab J, Schneider T. Open-Label Placebo Treatment for Acute Postoperative Pain (OLP-POP Study): Study Protocol of a Randomized Controlled Trial. Front Med (Lausanne) 2021; 8:687398. [PMID: 34805194 PMCID: PMC8602681 DOI: 10.3389/fmed.2021.687398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 10/07/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction: Open-label placebos have been proposed as way of using long recognized analgesic placebo effects in an ethical manner. Recent evidence shows efficacy of open-label placebos for clinical conditions, but there is need for more research on open-label placebos in acute pain. In the treatment of acute postoperative pain, minimization of opioid related side effects remains one of the key challenges. Therefore, this study aims at investigating the potential of adding unconditioned open-label placebos to treatment as usual as a means of reducing opioid consumption and its related side effects in patients with acute postoperative pain. Methods and Analysis: This is the protocol of an ongoing single site randomized controlled trial. The first patient was enrolled in May 2020. In total, 70 patients suffering from acute postoperative pain following dorsal lumbar interbody fusion are randomized to either a treatment as usual group or an experimental intervention group. The treatment as usual group consists of participants receiving a patient-controlled morphine pump. On day 1 and 2 post-surgery, patients in the intervention group receive, in addition to treatment as usual, two open-label placebo injections per day along with an evidence-based treatment rationale explaining the mechanisms of placebos. The primary outcome is measured by means of self-administered morphine during day 1 and 2 post-surgery. Several other outcome measures including pain intensity and adverse events as well as potential predictors of placebo response are assessed. Analysis of covariance will be used to answer the primary research question and additional statistical techniques such as generalized linear mixed models will be applied to model the temporal course of morphine consumption. Discussion: This study will provide valuable insights into the efficacy of open-label placebos in acute pain and will potentially constitute an important step toward the implementation of open-label placebos in the clinical management of acute postoperative pain. In addition, it will shed light on a cost-efficient and patient-centered strategy to reduce opioid consumption and its related side effects, without any loss in pain management efficacy. Ethics and Dissemination: The "Ethikkommission Nordwest- und Zentralschweiz" (BASEC2020-00099) approved the study protocol. Results of the analysis will be submitted for publication in a peer-reviewed journal. Clinical Trial Registration: The study is registered at ClinicalTrials.gov (NCT04339023) and is listed in the Swiss national registry at kofam.ch (SNCTP000003720).
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Affiliation(s)
- Dilan Sezer
- Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland
| | - Matthijs de Leeuw
- Pain Unit, Department of Anesthesiology, University Hospital of Basel, Basel, Switzerland
| | - Cordula Netzer
- Department of Spine Surgery, University Hospital of Basel, Basel, Switzerland
| | - Markus Dieterle
- Pain Unit, Department of Anesthesiology, University Hospital of Basel, Basel, Switzerland
| | - Andrea Meyer
- Division of Clinical Psychology and Epidemiology, Faculty of Psychology, University of Basel, Basel, Switzerland
| | - Sarah Buergler
- Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland
| | - Cosima Locher
- Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland.,Department of Consultation-Liaison Psychiatry and Psychosomatic Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Wilhelm Ruppen
- Pain Unit, Department of Anesthesiology, University Hospital of Basel, Basel, Switzerland
| | - Jens Gaab
- Division of Clinical Psychology and Psychotherapy, Faculty of Psychology, University of Basel, Basel, Switzerland
| | - Tobias Schneider
- Pain Unit, Department of Anesthesiology, University Hospital of Basel, Basel, Switzerland
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Marticorena FM, Carvalho A, Oliveira LFDE, Dolan E, Gualano B, Swinton P, Saunders B. Nonplacebo Controls to Determine the Magnitude of Ergogenic Interventions: A Systematic Review and Meta-analysis. Med Sci Sports Exerc 2021; 53:1766-1777. [PMID: 33587551 DOI: 10.1249/mss.0000000000002635] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Placebos are used as a control treatment that is meant to be indistinguishable from the active intervention. However, where substantive placebo effects may occur, studies that do not include a nonplacebo control arm may underestimate the overall effect of the intervention (active plus placebo components). This study aimed to determine the relative magnitude of the placebo effect associated with nutritional supplements (caffeine and extracellular buffers) by meta-analyzing data from studies containing both placebo and nonplacebo control sessions. METHODS Bayesian multilevel meta-analysis models were used to estimate pooled effects and express the placebo effect as a percentage of the overall intervention effect. RESULTS Thirty-four studies were included, with the median pooled effect size (ES0.5) indicating a very small (ES0.5 = 0.09 (95% credible interval (CrI), 0.01-0.17)) improvement in the performance of placebo compared with control. There was no moderating effect of exercise type (capacity or performance), exercise duration, or training status. The comparison between active intervention and control indicated a small to medium effect (ES0.5 = 0.37 (95% CrI, 0.20-0.56)). Expressed in relative terms, the placebo effect was equivalent to 25% (75% CrI, 16%-35%) and 59% (75% CrI, 34%-94%) of the total intervention effect for buffers and caffeine. CONCLUSIONS These results demonstrate a very small but potentially important placebo effect with nutritional supplementation studies. A substantive proportion of supplement effects may be due to placebo effects, with the relative proportion influenced by the magnitude of the overall ergogenic effect. Where feasible, intervention studies should use nonplacebo control-arm comparators to identify the proportion of the effect estimated to come from placebo effects and avoid underestimating the overall benefits that the physiological plus psychobiological aspects associated with an intervention provide in the real world.
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Affiliation(s)
- Felipe Miguel Marticorena
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de Sao Paulo (University of São Paulo), São Paulo, BRAZIL
| | - Arthur Carvalho
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de Sao Paulo (University of São Paulo), São Paulo, BRAZIL
| | - Luana Farias DE Oliveira
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de Sao Paulo (University of São Paulo), São Paulo, BRAZIL
| | - Eimear Dolan
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport, Rheumatology Division, Faculdade de Medicina FMUSP, Universidade de Sao Paulo (University of São Paulo), São Paulo, BRAZIL
| | | | - Paul Swinton
- School of Health Sciences, Robert Gordon University, Aberdeen, UNITED KINGDOM
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13
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Caffeine Mouth Rinse Does Not Improve Time to Exhaustion in Male Trained Cyclists. Int J Sport Nutr Exerc Metab 2021; 31:412-419. [PMID: 34311440 DOI: 10.1123/ijsnem.2020-0360] [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: 11/30/2020] [Revised: 05/10/2021] [Accepted: 05/20/2021] [Indexed: 11/18/2022]
Abstract
This study investigated the effects of caffeine mouth rinse on cycling time to exhaustion (TTE) and physiological responses in trained cyclists. In a double-blinded randomized counterbalanced cross-over design, 10 recreationally trained male cyclists (mean ± SD: 32 ± 3 years, 72.8 ± 5.3 kg, 1.78 ± 0.06 m, 13.9% ± 3.3% body fat, peak power output = 289.4 ± 24.7 W) completed two TTE tests cycling at 75% of peak aerobic power following 24 hr of dietary and exercise standardization. Cyclists were administered 25-ml mouth rinses for 5 s containing either 85 mg of caffeine or control (water) every 5 min throughout the exercise tests. No significant improvement in TTE was shown with caffeine mouth rinse compared with control (33:24 ± 12:47 vs. 28:08 ± 10:18 min; Cohen's dz effect size: 0.51, p = .14). Caffeine mouth rinse had no significant effect on ratings of perceived exertion (p = .31) or heart rate (p = .35) throughout the cycling TTE protocol. These data indicate that a repeated dose of caffeinated mouth rinse for 5 s does not improve cycling TTE in recreationally trained male cyclists. However, these findings should be taken with caution due to the small sample size and blinding ineffectiveness, while further well-design studies with larger samples are warranted.
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14
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Mendes GF, Reis CEG, Nakano EY, Zandonadi RP. Brief Version of Caffeine Expectancy Questionnaire in Brazil. Front Nutr 2021; 8:695385. [PMID: 34277689 PMCID: PMC8277974 DOI: 10.3389/fnut.2021.695385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/08/2021] [Indexed: 12/24/2022] Open
Abstract
The use of extensive questionnaires has the limitation of filling time bias, related to the ability to focus and accurately respond to many items, justifying the necessity for a brief version. This study aimed to build a brief version of the Caffeine Expectancy Questionnaire in Brazil (B-CaffEQ-BR) composed of 21 items divided into seven factors, with as adequate consistency and reproducibility as the full version. Quantitative procedures using statistical modeling were applied using the CaffEQ-BR (full version) database keeping the Mean Absolute Error (MAE) (based on the full version) <0.5 and Cronbach's α and Intraclass Correlation Coefficient (ICC) ≥0.7. The expert panel (n = 3), in a blind design, evaluated the semantic structuring within the options indicated by previous statistical modeling until the agreement of the expert panel. The participants (n = 62), Brazilian adults who were regular caffeine consumers (175.8 ± 94.4 mg/day), of whom 62.9% were women, 33.1 ± 9.7 years, 24.5 ± 3.8 kg/m2, and 62.9% of whom self-identified as white, were asked to respond twice to the online questionnaire in 48-72 h. The first sample (n = 40) tested interobserver reproducibility with the double application of B-CaffEQ-BR. Another sample (n = 22) answered the CaffEQ-BR (full version) and B-CaffEQ-BR, and the last sample (n = 18) performed the reverse process. The B-CaffEQ-BR presented excellent internal consistency (Cronbach's α ≥ 0.729) and overall reproducibility (ICC ≥ 0.915) for the entire questionnaire and its seven factors. The B-CaffEQ-BR can be a valuable tool in caffeine research with the Brazilian adult population.
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Affiliation(s)
- Guilherme Falcão Mendes
- Department of Nutrition, School of Health Sciences, University of Brasilia (UnB), Brasilia, Brazil
| | | | - Eduardo Yoshio Nakano
- Department of Statistics, Central Institute of Sciences, University of Brasilia (UnB), Brasilia, Brazil
| | - Renata Puppin Zandonadi
- Department of Nutrition, School of Health Sciences, University of Brasilia (UnB), Brasilia, Brazil
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15
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Open-label placebo treatment to improve relaxation training effects in healthy psychology students: a randomized controlled trial. Sci Rep 2021; 11:13073. [PMID: 34158569 PMCID: PMC8219834 DOI: 10.1038/s41598-021-92579-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/03/2021] [Indexed: 12/16/2022] Open
Abstract
Placebos, that are administered with deception, can reduce stress and increase relaxation. The present study investigated an open-label placebo (OLP) to improve the effects of Progressive Muscle Relaxation (PMR) training. A total of 160 psychology students were randomly assigned to a 14-day PMR course with or without daily OLP treatment. The placebo was administered along with an explanation of placebo effects and the verbal suggestion that the OLP activates the body’s natural relaxation response. The relaxation instructions for home practice were delivered via a smartphone app, which was also used for the evaluation of the exercises. The participants of the OLP group completed more PMR exercises (M = 9.75) than the group without a placebo (M = 8.15). The two groups did not differ in reported exercise-related changes in relaxation level. On average, the OLP group rated the effects of the placebo as very low and was characterized by a higher drop-out rate compared to the group without OLP. Some participants experienced the OLP as negative. In conclusion, factors that influence the acceptance of OLP treatment require further investigation.
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16
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Gentilin A, Tam E, Tarperi C, Beccarello F, Cevese A, Schena F. Post-exercise upside-down recovery does accelerate the heart rate recovery but does not improve subsequent sprint performance. J Sports Med Phys Fitness 2021; 62:1045-1052. [PMID: 33885257 DOI: 10.23736/s0022-4707.21.12321-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Many recreational cyclists believe that lying upside-down after intense physical exertion speeds up physical recovery, enhancing subsequent exercise performance. However, the effectiveness of this technique has not yet been investigated. METHODS 25 active cyclists (10 females/15 males; age 23.3±3.8 years old) performed a supramaximal 45-sec Wingate test before and after a 7-min recovery period at +45° or -20° of inclination, randomly, in a two-day cross-over protocol. The percentage decline of post- compared to pre-recovery Wingate performance was used to assess the recovery effectiveness. Kinetics of lactate, heart rate (HR), and mean blood pressure (MBP) during recovery were considered as physiological indices of recovery. RESULTS 7 subjects (5 males) did not complete the +45° protocol due to pre-syncopal symptoms. The upside-down compared to the standing recovery did not change the subsequent Wingate performance, despite faster HR decline and cyclists' perception of better recovery. The upside-down recovery did not change the kinetics of lactate clearance but prevented the MBP fall. CONCLUSIONS Among subjects who fully completed the protocol, our data reveal the ineffectiveness of the upside-down recovery to enhance subsequent exercise performance, despite the faster HR decline and personal feeling of greater recovery may suggest that assumption. Such a better psychophysical feeling when upside-down compared to standing recovery may be associated with attenuation of post-exercise hypotension symptoms. This data suggest being cautious in basing the assessment of the athlete's recovery exclusively on the post-exercise kinetics of the HR.
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Affiliation(s)
- Alessandro Gentilin
- Department of Neurosciences, Biomedicine, and Movement Science, University of Verona, Verona, Italy
| | - Enrico Tam
- Department of Neurosciences, Biomedicine, and Movement Science, University of Verona, Verona, Italy
| | - Cantor Tarperi
- Department of Neurosciences, Biomedicine, and Movement Science, University of Verona, Verona, Italy - .,Department of Clinical and Biological Sciences, University of Turin, Turin, Italy
| | - Fabio Beccarello
- Department of Neurosciences, Biomedicine, and Movement Science, University of Verona, Verona, Italy
| | - Antonio Cevese
- Department of Neurosciences, Biomedicine, and Movement Science, University of Verona, Verona, Italy
| | - Federico Schena
- Department of Neurosciences, Biomedicine, and Movement Science, University of Verona, Verona, Italy
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Effects of Open-Label Placebos on State Anxiety and Glucocorticoid Stress Responses. Brain Sci 2021; 11:brainsci11040508. [PMID: 33923694 PMCID: PMC8072693 DOI: 10.3390/brainsci11040508] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/09/2021] [Accepted: 04/11/2021] [Indexed: 12/12/2022] Open
Abstract
Stress belongs to the most frequent negative feelings people are confronted with in daily life. Strategies against acute stress include, e.g., relaxation techniques or medications, but it is also known that placebos can successfully reduce negative emotional stress. While it is widely held that placebos require deception to provoke a response, recent studies demonstrate intriguing evidence that placebos may work even without concealment (e.g., against anxiety or pain). Most of these studies are based on self-report questionnaires and do not include physiological measures. Here we report results of a study examining whether placebos without deception reduce acute stress. A total of 53 healthy individuals received either placebos without deception or no pills before participating in a laboratory stress test (Maastricht Acute Stress Test, MAST). We recorded self-report stress measures and cortisol responses before and after the MAST. Results showed no significant differences between the placebo and the control group, but when comparing participants with high relative to low beliefs in the power of placebos we found significant lower anxiety and cortisol responses for the placebo believers. These results show that non-deceptive placebos may successfully reduce acute anxiety and stress, but only in participants who had a strong belief in placebos. We discuss the results by suggesting that open-label placebos might be a possible treatment to reduce stress at least for some individuals.
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18
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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: 33] [Impact Index Per Article: 8.3] [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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Mendes GF, Reis CEG, Nakano EY, da Costa THM, Saunders B, Zandonadi RP. Translation and Validation of the Caffeine Expectancy Questionnaire in Brazil (CaffEQ-BR). Nutrients 2020; 12:E2248. [PMID: 32731330 PMCID: PMC7468745 DOI: 10.3390/nu12082248] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/18/2020] [Accepted: 07/22/2020] [Indexed: 12/30/2022] Open
Abstract
Caffeine is the world's most commonly used stimulant of the central nervous system. Caffeine is present in coffee and other beverages such as tea, soft drinks, and cocoa-based foods. The caffeine expectancy questionnaire was developed to investigate the effects of caffeine expectations and thus contribute to knowledge about its usage and subjective effects (response expectancies). This study aimed to evaluate caffeine expectation psychometrically in a sample of the Brazilian population. The original version of the "Caffeine Expectancy Questionnaire (CaffEQ)" was translated and validated into Brazilian-Portuguese and adapted to Brazilian culture to be used in the Brazilian adult (19-59 y) population. After the translation and back-translation processes of the original CaffEQ questionnaire, the content and semantic validation were performed by a group of experts. The Brazilian-Portuguese version of the questionnaire consists of 47 items, in seven factors, which assess subjective perceptions about the effects of caffeine. Interobserver reproducibility and internal consistency of the questionnaire were tested with a convenience sample (n = 50) of Brazilian adult consumers of caffeine sources, who completed the Brazilian CaffEQ (CaffEQ-BR) on two occasions separated by 24 h. All of the 47 questions were adequate regarding reliability, clarity, and comprehension. Psychometric properties could be replicated consistently. Appropriate internal consistency and validation were confirmed by Cronbach's alpha (α) 0.948, and an intraclass correlation coefficient of 0.976 was observed. The CaffEQ-BR was applied using a web-based platform to a convenience sample of Brazilian adults from all 27 Brazilian states (n = 4202 participants), along with measures of sociodemographic and caffeine consumption data. Factor validity was verified by confirmatory factor analysis. The seven factors presented a good fit for Root Mean Square Error of Approximation-RMSEA = 0.0332 (95% CI: 0.0290-0.0375). By confirming the validity and reliability of CaffEQ-BR, a useful tool is now available to assess caffeine expectations in the Brazilian adult population.
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Affiliation(s)
- Guilherme Falcão Mendes
- Department of Nutrition, School of Health Sciences, University of Brasilia (UnB), Campus Darcy Ribeiro, Asa Norte, Brasilia DF 70910-900, Brazil; (C.E.G.R.); (T.H.M.d.C.)
| | - Caio Eduardo Gonçalves Reis
- Department of Nutrition, School of Health Sciences, University of Brasilia (UnB), Campus Darcy Ribeiro, Asa Norte, Brasilia DF 70910-900, Brazil; (C.E.G.R.); (T.H.M.d.C.)
| | - Eduardo Yoshio Nakano
- Department of Statistics, Central Institute of Sciences, University of Brasilia (UnB), Campus Darcy Ribeiro, Asa Norte, Brasilia DF 70910-900, Brazil;
| | - Teresa Helena Macedo da Costa
- Department of Nutrition, School of Health Sciences, University of Brasilia (UnB), Campus Darcy Ribeiro, Asa Norte, Brasilia DF 70910-900, Brazil; (C.E.G.R.); (T.H.M.d.C.)
| | - Bryan Saunders
- Applied Physiology and Nutrition Research Group, School of Physical Education and Sport; Rheumatology Division; Faculdade de Medicina FMUSP, University of São Paulo, Sao Paulo 01246-903, Brazil;
- Institute of Orthopaedics and Traumatology, Faculty of Medicine FMUSP, University of São Paulo, Sao Paulo 01246-903, Brazil
| | - Renata Puppin Zandonadi
- Department of Nutrition, School of Health Sciences, University of Brasilia (UnB), Campus Darcy Ribeiro, Asa Norte, Brasilia DF 70910-900, Brazil; (C.E.G.R.); (T.H.M.d.C.)
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Is Open-Label Placebo a New Ergogenic Aid? A Commentary on Existing Studies and Guidelines for Future Research. Sports Med 2020; 50:1225-1229. [DOI: 10.1007/s40279-020-01285-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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