Placebo effect in children: the role of expectation and learning

Nocebo Effect on Pain Perception and Attention with Children With and Without Attention Deficit And/Or Hyperactivity Disorder

OBJECTIVE

Attention deficit disorder with or without hyperactivity (ADHD) has negative consequences for children. The effectiveness of medical interventions and educational outcomes are strongly influenced by expectations, which can be modulated by nocebo effects. The aims of this study were to compare the nocebo effect on pain perception and attention in children with and without ADHD as well as to characterize the associations of the nocebo effect with personal variables, such as anxiety, sleep, and pain catastrophizing.

METHODS

Data were collected from 30 children with and without ADHD. The nocebo effect was induced using an inactive pill, "increasing" pain perception and attention deficits. Experimental thermal pain was evoked using a thermode and recorded using a computerized visual analog scale. Attention abilities were measured with the Stop-Signal Task. We also used questionnaires to measure personal variables.

RESULTS

When combining groups, the nocebo treatment led to comparable nocebo effects for pain (increased pain perception) and attention (increased time needed for inhibition). When comparing groups, the nocebo effect on pain perception was similar for children with and without ADHD. Inattention, learning problems, anxiety, and sleep problems were associated with the nocebo response for pain and attention.

CONCLUSION

This exploratory study conducted in an experimental setting emphasizes the importance of managing children's expectations for pain perception and attention as well as the potentially deleterious impact of negative suggestions on elementary school children.

Irritable bowel syndrome in children: the placebo response rate and influencing factors a meta-analysis

BACKGROUND

Irritable bowel syndrome is common in children and exhibits a high placebo response. This study was to explore the placebo response rate and its influencing factors in children with irritable bowel syndrome.

METHODS

A systematic search was performed on Pubmed, Embase, MEDLINE, Cochrane Library, CNKI, Wanfang, and CBM from database inception to March 2022. Randomized controlled trials of irritable bowel syndrome in children were included in the study. The primary outcome was the placebo response rate of improvement.

RESULTS

Thirteen studies were included, with 445 patients in the placebo group. The rate of improvement and abdominal pain disappearance were 28.2% (95% CI, 16.6-39.9%) and 5% (95% CI, 0-18.4%). The placebo response based on the abdominal pain score was 0.675 (95% CI, 0.203-1.147). The mode of administration (P < 0.01), dosing schedule (P < 0.01), and clinical outcome assessor (P = 0.04) have a significant impact on the magnitude of placebo effect.

CONCLUSIONS

The placebo response rate for pediatric irritable bowel syndrome was 28.2%. In clinical trials, reducing dosing frequency, selecting appropriate dosage forms, and using patient-reported outcomes can help mitigate the placebo effect.

IMPACT

This is the first meta-analysis to assess the placebo response rates for improvement and disappearance in children with IBS. The finding suggested that the mode of administration, dosing schedule, and clinical outcome assessor could potentially influence the magnitude of the placebo effect in children with IBS. This study would provide a basis for estimating sample size in clinical trial design with a placebo control.

Acoustic stimulation for relieving pain during venipuncture: a systematic review and network meta-analysis

OBJECTIVES

To assess whether acoustic stimulations relieve venipuncture pain and determine which stimulation is the most effective type.

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

PubMed, Cochrane Central Register of Controlled Trials, Excerpta Medica dataBASE, Cumulative Index to Nursing and Allied Health Literature, ClinicalTrials.gov and the International Clinical Trials Registry Platform databases were systematically searched in September 2023.

STUDY SELECTION

Randomised controlled trials evaluating the efficacy of acoustic stimulations on patients undergoing venipuncture were eligible. Acoustic stimulations were classified into seven categories: five types of acoustic stimulations (music medicine (researcher selected), music medicine (patient selected), music therapy, sounds with linguistic meaning and sounds without linguistic meaning) and two controls (only wearing headphones and no treatment).

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcomes included self-reported pain intensity assessed during venipuncture and treatment cost, and secondary outcomes were self-reported mental distress and adverse events.

RESULTS

Of 6406 citations, this network meta-analysis included 27 studies including 3416 participants; the mean age was 31.5 years, and 57% were men. Among the five types of acoustic stimulations, only musical interventions, such as music medicine (patient selected) (standardised mean difference (SMD) -0.44 (95% CI: -0.84 to -0.03); low confidence), music medicine (researcher selected) (SMD -0.76 (95% CI: -1.10 to -0.42); low confidence) and music therapy (SMD -0.79 (95% CI: -1.44 to -0.14); low confidence), were associated with improved pain relief during venipuncture compared with no treatment. No significant differences existed between the types of acoustic stimulations. Free-of-charge acoustic stimulations were provided to patients, and no specific adverse events were reported. In many studies, the risk of bias was rated high because of the difficulty of blinding the intervention to the participants and the self-reported pain outcome.

CONCLUSIONS

Music interventions were associated with reduced venipuncture pain. Comparisons between types of acoustic stimulations revealed no significant differences. Therefore, music intervention could be a safe and inexpensive pain relief method for venipuncture.

PROSPERO REGISTRATION NUMBER

CRD42022303852.

Conditioning induced placebo-like and nocebo-like effects of thermal discomfort in adults but not in youth

Introduction

Conditioning can be used to modulate the perception of pain, in the form of placebo and nocebo effects. Previous studies show inconsistent results as to whether adolescents show similar, weaker, or non-significant conditioned placebo and nocebo effects compared to effects found in adults. There are suggestions that such differences (if any) may dependent on the cues used in the thermal conditioning paradigms. Therefore, in this current study, we utilized novel, neutral 3D-shaped visual cues to implicitly induce conditioned placebo-like and nocebo-like effects in adolescents and adults.

Methods

During the conditioning paradigm, distinct cues (Fribbles) were paired with low and high temperatures in 24 adults and 20 adolescents (mean age = 25.5 years). In the testing phase, these conditioned cues as well as a neutral (unconditioned) cue were presented with moderate temperatures.

Results

Thermal discomfort of moderate temperatures was lower when presented with the conditioned low heat cue (placebo-like effect) and higher when thermal stimuli were presented with the high heat cue (nocebo-like effect) compared to the neutral cue. The effects were driven by adults, as neither the placebo-like nor the nocebo-like effect was significant in adolescents. The difference between adolescents and adults was not explained by differences in temperature or discomfort levels, as adults and adolescents had comparable calibrated temperatures and levels of discomfort during heat stimuli.

Conclusion

Our findings suggest that thermal perception in adolescents is less influenced by conditioning to an engaging novel visual cue, compared to adults. Our work may have implications for better understanding the scope and limitations of conditioning as a key mechanism of placebo and nocebo effects in youth.

Placebo effects on cutaneous pain and itch: a systematic review and meta-analysis of experimental results and methodology

ABSTRACT

Placebo effects, positive treatment outcomes that go beyond treatment processes, can alter sensations through learning mechanisms. Understanding how methodological factors contribute to the magnitude of placebo effects will help define the mechanisms by which these effects occur. We conducted a systematic review and meta-analysis of experimental placebo studies in cutaneous pain and itch in healthy samples, focused on how differences in methodology contribute to the resulting placebo effect magnitude. We conducted meta-analyses by learning mechanism and sensation, namely, for classical conditioning with verbal suggestion, verbal suggestion alone, and observational learning, separately for pain and itch. We conducted subgroup analyses and meta-regression on the type of sensory stimuli, placebo treatment, number of acquisition and evocation trials, differences in calibrated intensities for placebo and control stimuli during acquisition, age, and sex. We replicated findings showing that a combination of classical conditioning with verbal suggestion induced larger placebo effects on pain ( k = 68, g = 0 . 59) than verbal suggestion alone ( k = 39, g = 0.38) and found a smaller effect for itch with verbal suggestion alone ( k = 7, g = 0.14). Using sham electrodes as placebo treatments corresponded with larger placebo effects on pain than when topical gels were used. Other methodological and demographic factors did not significantly affect placebo magnitudes. Placebo effects on pain and itch reliably occur in experimental settings with varied methods, and conditioning with verbal suggestion produced the strongest effects. Although methods may shape the placebo effect to some extent, these effects appear robust overall, and their underlying learning mechanisms may be harnessed for applications outside the laboratory.

XyloFUNS: Xylocaine to freeze during unpleasant nasopharyngeal swabs in children-a randomized controlled trial

Objectives

To evaluate the efficacy of intranasal vaporized lidocaine in reducing pain for children undergoing a nasopharyngeal (NP) swab in the Emergency Department (ED).

Study Design

A randomized blinded clinical trial was conducted in a paediatric ED. Both participants and the researcher evaluating the primary outcome were blinded. Children aged 6 to 17 years old requiring a NP swab were eligible. Participants were randomly allocated to receive intranasal lidocaine or a sham treatment prior to their NP swab. The primary outcome measure was pain during the swab as assessed by the visual analog scale. Secondary outcome measures were pain using the verbal numeric rating scale, fear using the children fear scale, and adverse effects of the intervention.

Results

Eighty-eight participants were enrolled-45 in the lidocaine group and 43 controls. The mean visual analog scale scores for pain were 46 mm in the lidocaine group and 53 mm in the control group (mean difference 7 mm; 95% CI: -5 to 19 mm). No serious adverse events were observed.

Conclusions

Intranasal lidocaine administered prior to NP swabs in the ED failed to show an improvement in pain scores for school-aged children and youth.

Improving treatment outcomes for adolescents with borderline personality disorder through a socioecological approach

BACKGROUND

There is a dearth of studies evaluating treatment efficacy for adolescents diagnosed with borderline personality disorder. The few available randomized controlled trials that have been conducted show modest results and treatments appear to have equivalent effects. The current paper draws on (a) the lessons learnt from the last 50 years of psychotherapy research in general and (b) recent advances in mentalization-based understanding of why treatment works, which together point to the importance of following a socioecological approach in the treatment of personality problems in adolescence - a developmental period that insists on a treatment approach that goes beyond the therapist-client dyad.

CASE PRESENTATION

Here, we describe such an approach, and offer a clinical case example with a young 16-year old girl diagnosed with borderline personality disorder, to illustrate what a shift toward a more socioecological approach would entail.

CONCLUSIONS

The clinical impact of the socioecological approach and the potential benefits as illustrated in the current case illustration, offers a framework that justifies and allows for the expansion of service delivery for youth with borderline personality disorder beyond dyadic therapist-client work.

Non-invasive brain stimulation and neuroenhancement

Attempts to enhance human memory and learning ability have a long tradition in science. This topic has recently gained substantial attention because of the increasing percentage of older individuals worldwide and the predicted rise of age-associated cognitive decline in brain functions. Transcranial brain stimulation methods, such as transcranial magnetic (TMS) and transcranial electric (tES) stimulation, have been extensively used in an effort to improve cognitive functions in humans. Here we summarize the available data on low-intensity tES for this purpose, in comparison to repetitive TMS and some pharmacological agents, such as caffeine and nicotine. There is no single area in the brain stimulation field in which only positive outcomes have been reported. For self-directed tES devices, how to restrict variability with regard to efficacy is an essential aspect of device design and function. As with any technique, reproducible outcomes depend on the equipment and how well this is matched to the experience and skill of the operator. For self-administered non-invasive brain stimulation, this requires device designs that rigorously incorporate human operator factors. The wide parameter space of non-invasive brain stimulation, including dose (e.g., duration, intensity (current density), number of repetitions), inclusion/exclusion (e.g., subject's age), and homeostatic effects, administration of tasks before and during stimulation, and, most importantly, placebo or nocebo effects, have to be taken into account. The outcomes of stimulation are expected to depend on these parameters and should be strictly controlled. The consensus among experts is that low-intensity tES is safe as long as tested and accepted protocols (including, for example, dose, inclusion/exclusion) are followed and devices are used which follow established engineering risk-management procedures. Devices and protocols that allow stimulation outside these parameters cannot claim to be "safe" where they are applying stimulation beyond that examined in published studies that also investigated potential side effects. Brain stimulation devices marketed for consumer use are distinct from medical devices because they do not make medical claims and are therefore not necessarily subject to the same level of regulation as medical devices (i.e., by government agencies tasked with regulating medical devices). Manufacturers must follow ethical and best practices in marketing tES stimulators, including not misleading users by referencing effects from human trials using devices and protocols not similar to theirs.

Sustained, Multifaceted Improvements in Mental Well-Being Following Psychedelic Experiences in a Prospective Opportunity Sample

In the last 15 years, psychedelic substances, such as LSD and psilocybin, have regained legitimacy in clinical research. In the general population as well as across various psychiatric populations, mental well-being has been found to significantly improve after a psychedelic experience. Mental well-being has large socioeconomic relevance, but it is a complex, multifaceted construct. In this naturalistic observational study, a comprehensive approach was taken to assessing well-being before and after a taking a psychedelic compound to induce a "psychedelic experience." Fourteen measures of well-being related constructs were included in order to examine the breadth and specificity of change in well-being. This change was then analysed to examine clusters of measures changing together. Survey data was collected from volunteers that intended to take a psychedelic. Four key time points were analysed: 1 week before and 2 weeks, 4 weeks, and 2 years after the experience (N = 654, N = 315, N = 212, and N = 64, respectively). Change on the included measures was found to cluster into three factors which we labelled: 1) "Being well", 2) "Staying well," and 3) "Spirituality." Repeated Measures Multivariate Analysis of Variance revealed all but the spirituality factor to be improved in the weeks following the psychedelic experience. Additional Mixed model analyses revealed selective increases in Being Well and Staying Well (but not Spirituality) that remained statistically significant up to 2 years post-experience, albeit with high attrition rates. Post-hoc examination suggested that attrition was not due to differential acute experiences or mental-health changes in those who dropped out vs. those who did not. These findings suggest that psychedelics can have a broad, robust and sustained positive impact on mental well-being in those that have a prior intention to use a psychedelic compound. Public policy implications are discussed.

Placebo and nocebo effects in youth: subjective thermal discomfort can be modulated by a conditioning paradigm utilizing mental states of low and high self-efficacy

Introduction:

Conditioning is a key mechanism of placebo and nocebo effects in adults, but little is known about these effects in youth. This study investigated whether personalized verbal cues evoking a sense of high or low self-efficacy can induce conditioned placebo and nocebo effects on subjective discomfort of noxious heat in youth.

Methods:

In a structured interview, 26 adolescents (13–18 years) described personal situations in which they experienced a sense of high, low or neutral self-efficacy. Participants were then asked to recall these memories during a conditioning paradigm, in which a high thermal stimulus applied to the forearm was repeatedly paired with a low self-efficacy cue and a low thermal stimulus with a high self-efficacy cue. In a testing phase, high, low and neutral self-efficacy cues were paired with the same moderate temperature. We hypothesized that conditioned high and low self-efficacy cues would induce conditioned placebo and nocebo responses to moderate temperatures.

Results:

Moderate temperatures were rated as more uncomfortable when paired with the conditioned low compared with the neutral self-efficacy cue (nocebo effect). While in the whole-group analysis, there was no significant difference between ratings of moderate thermal stimuli paired with high compared with neutral self-efficacy cues (placebo effect), a sub-group of participants with a greater range of emotional valence between high and neutral self-efficacy cues revealed a significant placebo effect. The strength of the nocebo effect was associated with higher anxiety and lower hope.

Conclusion:

Conditioned associations using internal self-efficacy states can change subjective discomfort of thermal sensations.

Conditioned Placebo- and Nocebo-Like Effects in Adolescents: The Role of Conscious Awareness, Sensory Discrimination, and Executive Function

Background: Conditioning is a key mechanism of placebo and nocebo effects in adults. Little is known about the underlying mechanisms of placebo and nocebo effects in youth and how they might be influenced by conscious awareness and cognitive abilities. In this study, the role of conditioning on thermal perception in youth was investigated. Methods: Differences in thermal ratings were assessed in response to consciously and non-consciously perceived cues that were conditioned to either low or high heat. Furthermore, we tested whether executive function mediates the effect of conditioning on thermal perception. Thirty-five high-school students (14-17 years) completed an executive function task and underwent a sensory perception paradigm. In a conditioning phase, two distinct neutral faces (conditioned cues) were coupled to either a low or a high temperature stimulus delivered to participants' forearms. In a testing phase, the conditioned cues, and novel faces (non-conditioned control cues), were paired with identical moderate thermal stimuli. In this testing phase, for half of the participants cues were presented consciously (supraliminally) and for the other half non-consciously (subliminally). Results: We found a significant main effect of cue type on thermal ratings (p = 0.003) in spite of identical heat being administered following all cues. Post-hoc analyses indicated that the nocebo-like effect (conditioned high cue compared to control) was significant (p = 0.027); the placebo-like effect (conditioned low cue compared to control) was non-significant. No difference between cues presented supra- vs. subliminally and no significant interaction effects were found. The association between sensory discrimination and the magnitude of the nocebo-like effect was mediated by executive function. Conclusions: To our best knowledge, this is the first study establishing a relationship between thermal perception, nocebo effects, and executive function in youth. Our results may have important implications for understanding cognitive/ learning processes involved in nocebo effects.