Learning by observing: a systematic exploration of modulatory factors and the impact of observationally induced placebo and nocebo effects on treatment outcomes

Introduction

Observational learning (OL) refers to learning through observing other people's behavior. OL has been suggested as an effective and simple tool to evoke treatment expectations and corresponding placebo and nocebo effects. However, the exact mechanisms by which OL shapes treatment outcomes, its moderating factors and possible areas of application remain unclear. We thus reviewed the existing literature with two different literature searches to answer the following questions: Which influencing factors contribute to OL-induced placebo and nocebo effects (in healthy volunteers and patients) and how large are these effects (search 1)? In which medical fields has OL been used so far to modulate treatment expectancy and treatment outcomes in patients, their caregivers, and at-risk groups (search 2)? We also aimed to explore whether and how the assessment of treatment expectations has been incorporated.

Methods

We conducted two independent and comprehensive systematic literature searches, both carried out on September 20, 2022.

Results

We identified 21 studies that investigated OL-mediated placebo and nocebo effects for pain and itch, the (placebo) efficacy of sham treatment on anxiety, and the (nocebo) induction of medication side effects (search 1). Studies showed that OL can efficiently induce placebo and nocebo effects across different presentation modes, with medium effect sizes on average: placebo effects, d = 0.79 (range: d = -0.36-1.58), nocebo effects, d = 0.61 (range: d = 0.04-1.5). Although several moderating factors have been investigated, their contribution to OL-induced effects remains unclear because of inconsistent results. Treatment expectation was assessed in only four studies. Regarding medical applications of OL (search 2), we found 12 studies. They showed that OL was effectively applied in preventive, therapeutic and rehabilitative interventions and that it was mainly used in the field of psychosomatics.

Discussion

OL effects on treatment outcomes can be both positive and negative. Future research should investigate which individuals would benefit most from OL and how OL can be implemented most effectively to induce placebo and avoid nocebo effects in clinical settings.

Systematic review registration

This work was preregistered at the Center for Open Science as open-ended registration (doi: 10.17605/OSF.IO/FVHKE). The protocol can be found here: https://archive.org/details/osf-registrations-fvhke-v1.

Negative expectations (nocebo phenomenon) in clinical interventions: A scoping review

Unpredictable, undesirable, and confusing reactions in the face of psychological or medical interventions make the clinical presentation more complicated and may represent clinically unexplained symptoms and also disturbed the doctor-patients relationship and decrease patients' benefits of treatment. It seems that negative expectations from the treatment (nocebo phenomenon) can explain such reactions. The aim of the current study is a scoping review and investigate different aspects of the nocebo phenomenon (negative expectations) in clinical interventions. This paper follows a scoping review of the existence, importance, and multidimensions of the nocebo phenomenon in medical and psychological interventions. Data sources include literature databases (ProQuest, PubMed, Google Scholar, and Scopus) reviewed from inception dates to 2023, and the terms negative expectations, nocebo effect, placebo effect, negative placebo, and clinical interventions were searched. The review of the available articles showed that negative expectations play an important role in the process and effectiveness of clinical interventions. Negative expectations (here named nocebo effect) can significantly interfere with rapport and treatment processes. Some underlying components of the nocebo effect include negative expectancies, conditioning, social learning, memory, cognitive distortions, meaning, motivation, somatic focus, negative reinforcements, personality, anxiety, and neurophysiological factors such as CCK, dopamine, and cortisol are proposed for development and presence of nocebo phenomenon in clinical practice. Negative expectations with its biopsychosocial aspects play an important and amazing role in disorganizing medical and psychological interventions. Using appropriate methods to reduce nocebo effects in therapeutic interventions may increase treatment compliance and adherence and increase the effectiveness of interventions.

Health Scares: Tracing Their Nature, Growth and Spread

Background

Health scares are highly publicised threats to health that increase public concern and protective behaviours but are later shown to be unfounded. Although health scares have become more common in recent times, they have received very little research attention. This is despite the fact that health scares often have negative outcomes for individuals and community by affecting health behaviours and causing high levels of often unnecessary anxiety.

Method

In this paper we undertook a review and analysis of the major types of health scares as well as the background factors associated with health scares and their spread.

Results

We found most health scares fell into seven main categories; environmental contaminants, food, malicious incidents, medical treatments, public health interventions, radiation from technology and exotic diseases. For most health scares there are important background factors and incident characteristics that affect how they develop. Background factors include conspiracy theories, trust in governmental agencies, anxiety, modern health worries and wariness of chemicals. Incident characteristic include being newly developed, not understood or unseen, man-made rather than natural and whether the incident is out of personal control. We also identified the aspects of traditional and social media that exacerbate the rapid spread of health scares.

Conclusion

More research is needed to identify the characteristics of media stories that intensify the levels of public concern. Guidelines around the media's reporting of health incidents and potential health threats may be necessary in order to reduce levels of public anxiety and the negative public health impact of health scares.

Peer-to-peer: The Social Transmission of Symptoms Online

BACKGROUND

Social learning can be highly adaptive-for example, avoiding a hotplate your friend just burnt themselves on-but it has also been implicated in symptom transmission. Social learning is particularly pertinent given the rapid increase in the use of online mediums for social interaction. Yet, little is known about the social transmission of symptoms online or social chains extending further than a single model-observer interaction.

PURPOSE

To explore whether socially induced symptoms could be propagated through a three-generation social transmission chain in an online setting.

METHODS

We explored the social transmission of cybersickness following a virtual reality (VR) experience through online webcam interactions. One hundred and seventy-seven adults viewed a VR video in one of four links along a social transmission chain, after: viewing an actor model cybersickness to the VR video (First-Generation); viewing the First-Generation participant undergo VR (Second-Generation); viewing the Second-Generation participant undergo VR (Third-Generation); or naïve (Control).

RESULTS

Cybersickness was strongest in First-Generation participants, indicating social transmission from the model. This was mediated by expectancy and anxiety. Whether or not subsequent generations experienced cybersickness depended on what the observed participant verbally reported, which is consistent with social transmission.

CONCLUSIONS

Results demonstrate that symptoms can be readily transmitted online, and that expectancy and anxiety are involved. Although it is inconclusive as to whether symptoms can propagate along a social transmission chain, there is some evidence of protection from symptoms when a model who does not report any symptoms is observed. As such, this research highlights the role of social transmission in the modulation of symptoms through virtual mediums.

The influence of video-based social modelling on the nocebo effect

OBJECTIVE

Seeing someone else experience side effects (i.e., social modelling) can increase negative expectations and subsequent nocebo effects. In face-to-face contexts, this effect appears stronger in female participants. Less is known about the influence of gender on negative expectations and nocebo effects generated via video-based social modelling.

METHODS

One hundred and seven undergraduate participants recruited from a participant pool at an Australian university took part in a study ostensibly investigating the influence of beta-blocker medications (actually a sham treatment) on physiological and psychological aspects of anxiety. Participants were randomly assigned to either a no-treatment control group, a standard treatment group, or a video modelling group, in which participants viewed video-recorded confederates (one male, one female) report experiencing four side effects (two each) after taking the study treatment. Symptoms were assessed 15-min following pill ingestion, and at follow-up 24 h later.

RESULTS

Video modelling of side effects, compared to standard treatment, interacted with gender and was associated with increased reporting of modelled symptoms in female compared to male participants, p = .01, η_p²=0.06. Video modelling also increased negative expectations in female compared to male participants, p = .03, η_p²=0.07, and expectations mediated the influence of modelling on modelled symptoms in female participants.

CONCLUSIONS

Social modelling of side effects via video increased negative expectations, and nocebo symptoms, to a greater extent in female participants. These findings suggest that males and females are differentially impacted by video-based side effect modelling. Results have implications for social modelling of side effects via social media and patient-support websites.

Impact of media coverage on side effect reports from the COVID-19 vaccine

OBJECTIVE

Past research shows that media coverage of medicine side effects can produce a nocebo response. New Zealand news media discussed myocarditis following the Pfizer COVID-19 vaccine. This study examined whether side effects mentioned in the media increased compared to control symptoms not mentioned.

METHODS

The study analysed 64,086 vaccine adverse reaction reports, retrieved from the medicine safety authority. Generalised linear regressions compared the side effect rate during three discrete periods of media reporting (August 2021, December 2021, April 2022) with the pre-media baseline rate. The outcomes were weekly reports of chest discomfort, monthly reports of chest, heart and breathing symptoms, and myocarditis, pericarditis, and anxiety. Control symptoms were fever, numbness, and musculoskeletal pain. Logistic regressions investigated factors associated with side effect reporting.

RESULTS

The reporting rate of chest discomfort was 190% greater in the five weeks after the first media item (p < .001). The monthly reporting rates of the symptoms mentioned in the media were significantly greater after the news coverage (ps ≤ 0.001). There was no effect of media on the control side effect fever (p = .06). There was an effect of media on myocarditis, pericarditis and anxiety (ps < 0.001). Anxiety, male gender, and younger age were significantly associated with side effects.

CONCLUSION

The results indicate that a media-induced nocebo response occurred. This is most likely due to increased expectations and awareness of COVID-19 vaccine side effects, elevated symptom experience from anxiety, and consequently greater reporting of the symptoms in line with the media coverage.

Changing attitudes towards psychotherapy via social observations: are similarities more important than discrepancies?

OBJECTIVES

Therapy expectations and attitudes towards psychotherapy contribute substantially to the outcome, process and duration of psychotherapy. The a priori use of role model videos seems to be promising for changing expectations and attitudes towards psychotherapy. In contrast, underlying mechanisms, like identifying with the role model, have been sparsely investigated in studies so far. For instance, the effects of similarities and differences between the role model and the observer are not clear yet.

METHODS

A total of 158 persons were recruited and randomly assigned to four groups. In one of three experimental groups, participants watched an expectation-optimised video with patients giving information about their mostly positive therapy outcomes (positive model). Two further experimental groups saw the same video, but either received instructions to focus on similarities (similarity group) or on differences (discrepancy group) between the patients and themselves. A further control group watched a video with patients who gave information about their symptoms. As the primary outcome variable, we assessed attitudes towards psychotherapy using the Questionnaire on Attitudes towards Psychotherapy (QAPT). It was filled in before and after watching the video and after a two-week follow-up period.

RESULTS

Contrary to the hypotheses, the discrepancy group and the experimental group without further intervention (positive model) showed significant improvements in their attitudes towards psychotherapy after watching the video, while such an effect was not found in the similarity group or control group.

CONCLUSION

Focusing on similarities between patient examples and the observer does not support a change in therapy expectations or attitudes through observation, while a positive video model without instructions, or with the instruction to focus on differences does. Attentional interference and depth of cognitive evaluation are discussed as possible reasons.

TRIAL REGISTRATION

Ethical approval (2018-19k) was obtained from the ethics committee of the Psychological Department, University of Marburg, and the trial was registered at Aspredicted.org (#22,205; 16.04.2019).

The mode of delivery and content of communication strategies used in mandatory and non-mandatory biosimilar transitions: a systematic review with meta-analysis

Effective patient-provider communication is crucial to promote shared decision-making. However, it is unclear how to explain treatment changes to ensure patient acceptance, such as when transitioning from a bio-originator to a biosimilar. This review investigates communication strategies used to educate patients on transitioning to biosimilars and explores whether the willingness to transition and treatment persistence differs for the delivery (verbal or written) and the amount of information provided. MEDLINE, Embase, Scopus, and relevant conference databases were systematically searched. Communication strategies from 33 studies (88% observational cohort studies) published from 2012 to 2020 were synthesized and willingness to transition, persistence, and subjective adverse events explored. Patients only received information verbally in 11 studies. The remaining 22 studies also provided written information. Cost-saving was the main reason provided for the transition. Patients were most willing to transition when receiving written and verbal information (χ² = 5.83, p = .02) or written information that only addressed a few (3-5) concerns (χ² = 16.08, p < .001). There was no significant difference for persistence or subjective adverse events (p's > .05). Few randomized controlled trials have been conducted. Available data shows more willingness to transition when patients received written and verbal information. Initial documents should contain basic information and consultations or telephone calls used to address concerns.

When one suffers less, all suffer less: Individual pain ratings are more effective than group ratings in producing placebo hypoalgesia

Background

Placebo hypoalgesia can be induced by observing a person (model) whose pain relief is the result of the use of an inert substance or procedure. This study examined whether verbal modelling, that is, showing pain ratings provided by other people, is sufficient to induce placebo hypoalgesia.

Methods

Participants from the experimental groups were acquainted with pain ratings (presented on VASs) derived from a single person (groups 1 and 3) or a group of people (groups 2 and 4) that were allegedly subjected to the same painful procedure. The ratings of pain stimuli that were allegedly applied with placebo were lower than the ratings of stimuli applied without placebo. In two of the experimental groups (group 3 and 4), participants also watched a video recording showing individuals who allegedly provided pain ratings; however, they did not observe them undergoing pain stimulation. The control group did not undergo any manipulation. Then, the participants received a series of the same thermal pain stimuli that were applied either with or without placebo and rated their intensity.

Results

Placebo hypoalgesia was induced only in participants presented with pain ratings provided by a single person, regardless of whether this person was previously seen. However, the pain ratings presented to the participants generally decreased individual pain sensations, regardless of whether they came from a group of people or a single person.

Conclusions

Verbal modelling can produce placebo hypoalgesia and reduce pain sensations. It may be effectively used in clinical practice to modify patients' responses to pain treatment.

Significance

This study shows that knowledge about pain ratings provided by another person is sufficient to induce placebo hypoalgesia; thus, neither direct nor indirect observation of a person experiencing pain is necessary to induce this effect. Pain ratings derived from a group of people can decrease pain sensations but they do not produce placebo hypoalgesia.

One of us or one of them? The effects of the model's and observer's characteristics on placebo analgesia induced by observational learning

Previous studies have proved that observational learning can induce placebo analgesia, but the factors that influence observationally induced placebo analgesia have not yet been extensively examined. The primary goal of this study was to investigate the effect of information about the role that the observed person (model) plays in the experiment on the magnitude of the observationally induced placebo effect. This study also examined the contribution of the observer’s empathy, conformity and fear of pain to the placebo analgesia induced by observational learning. The effects induced in two experimental groups and one control group were compared. Participants in the experimental groups observed a model introduced as either another participant taking part in the study or a coworker of the experimenter. The model rated the intensity of pain induced by electrocutaneous stimuli preceded by color stimuli. One-half of all participants watched a model rating pain stimuli preceded by the color orange as higher than stimuli preceded by the color blue; for the other half, the ratings were the opposite. There was no observation in the control group. Subsequently, all participants received pain stimuli of the same intensity preceded by orange and blue stimuli and rated the intensity of the experienced pain. Placebo analgesia was found in both experimental groups. However, the way the observed model was introduced to participants did not affect the magnitude of placebo analgesia. Thus, the study showed that the role played by the model is not crucial for observationally induced placebo analgesia. The examined observer’s individual characteristics did not predict the magnitude of placebo effect.

The effect of television and print news stories on the nocebo responding following a generic medication switch

Background

Following a nationwide switch to a generic antidepressant, a series of negative media stories publicised the experiences of some patients having side effects following the switch. This occurred first in print media and five months later it occurred again in television news. In this study we examined the effect of television news stories compared to print stories on adverse drug reaction reporting. We also examined the change in reporting rate of specific side effects mentioned in the TV news bulletins.

Method

Using an interrupted time series analysis of data from a national adverse reactions database, we compared the number of adverse reaction reports after the print and television coverage and the changes in reporting rate of side effects mentioned and not mentioned in TV news stories.

Results

We found a significant increase in adverse reaction reports following TV news items that discussed patients’ reports of side effects following the medication switch (interruption effect = 73.25, p = .046). The reporting rate of symptoms mentioned in the TV news bulletins also increased, in particular suicidal thoughts (interruption effect = 23.60, p = .031). The effect of TV stories on adverse reaction reports was 211% greater than the print articles.

Conclusions

Television stories have a much stronger effect than print media on nocebo responding and specific symptoms mentioned in the bulletins have a direct influence on the type of side effects subsequently reported. Media guidelines should be developed to reduce the negative public health effects of media coverage following medication switches.

[Biosimilars and the nocebo effect]

Biosimilars have been approved for use in Germany for many years and in the meantime also in rheumatology but only a few years ago. Biosimilars, which are biotechnologically manufactured products the same as reference biologicals, have actually now achieved a substantial proportion of the market in some regions but there are still doubters among patients and physicians who fear a loss of quality even if there is no evidence for this. A part of this problem can be explained by the nocebo effect but which furthermore also has a substantial medical importance. This effect is described and explained in this article. Psychosocial and context-related factors, such as the relationship between patient and physician, previous experience with treatment and treatment expectations can either improve or impair the efficacy of treatment interventions. These phenomena are commonly known as placebo and nocebo effects. As placebo and nocebo effects can influence the development of symptoms, the frequency of undesired events and the efficacy of treatment, it is decisive to know these effects and to develop strategies for prevention in order to optimize the treatment results. Although in recent years experimental studies have achieved substantial progress in the clarification of the psychosocial and neurobiological mechanisms of placebo effects, detailed mechanisms of nocebo effects are still widely unexplored. An improved understanding of these mechanisms promises the development of user-friendly strategies for the clinical care to improve treatment results and patient satisfaction.

It is not just the drugs that matter: the nocebo effect

The role of psychological mechanisms in the treatment process cannot be underestimated, the well-known placebo effect unquestionably being a factor in treatment. However, there is also a dark side to the impact of mental processes on health/illness as exemplified by the nocebo effect. This phenomenon includes the emergence or exacerbation of negative symptoms associated with the therapy, but arising as a result of the patient's expectations, rather than being an actual complication of treatment. The exact biological mechanisms of this process are not known, but cholecystokinergic and dopaminergic systems, changes in the HPA axis, and the endogenous secretion of opioids are thought to be involved. The nocebo effect can affect a significant proportion of people undergoing treatment, including cancer patients, leading in some cases to the cessation of potentially effective therapy, because of adverse effects that are not actually part of the biological effect of treatment. In extreme cases, as a result of suggestions and expectations, a paradoxical effect, biologically opposite to the mechanism of the action of the drug, may occur. In addition, the nocebo effect may significantly interfere with the results of clinical trials, being the cause of a significant proportion of complications reported. Knowledge of the phenomenon is thus necessary in order to facilitate its minimalization and thus improve the quality of life of patients and the effectiveness of treatment.

Evidence of a Media-Induced Nocebo Response Following a Nationwide Antidepressant Drug Switch

In 2017, patients on a generic or branded antidepressant venlafaxine were switched to a new generic formulation (Enlafax). In February and April 2018, two major NZ media outlets ran stories about the new generic being less effective and causing specific side effects. This study aimed to examine the effect of the media coverage on drug side effects reported to the national Centre for Adverse Reactions Monitoring (CARM) and whether the specific symptoms reported in the media increased compared to side effects not reported in the media.

We analysed monthly adverse reaction reports for Enlafax to CARM from October 2017 to June 2018 and compared adverse reports, complaints of decreased therapeutic effect and specific symptom reports before and after the media coverage using an interrupted time series analysis.

We found the number of side effects and complaints of reduced therapeutic effect increased significantly following the media stories (interruption effect = 41.83, 95% CI [25.25, 58.41], p = .003; interruption effect = 15.49, 95% CI [7.01, 23.98], p = .012, respectively). The specific side effects mentioned in the media coverage, including suicidal thoughts, also increased significantly compared to other side effects not mentioned in the media.

In the context of a drug switch, media reports of side effects appear to cause a strong nocebo response by increasing both the overall rate of side effect reporting and an increase in the specific side effects mentioned in the media coverage, including reduced drug efficacy and heightened suicidal thoughts.

The study provides further evidence that media coverage of side effects can induce a nocebo effect.

This is the first study to look at media coverage of an antidepressant brand switch.

The increase in reported adverse events was higher for those symptoms mentioned in the media reports.

Decreasing the Burden of Side Effects Through Positive Message Framing: an Experimental Proof-of-Concept Study

PURPOSE

Informing patients about treatment side effects increases the occurrence and intensity of side effects. Since the obligatory informed consent procedure in drug treatments requires transparency and nocebo research suggests that the informed consent of a drug leads to an increased occurrence of the mentioned side effects, the aim of this proof of concept study was to determine the effect of two different framings of informed consent on the occurrence, intensity, and perceived threat of side effects.

METHODS

Healthy male participants (n = 80) were randomized to one of two framing groups. The positive framing group was informed that the common side effect dizziness was a sign that the drug had started to work, while the neutral framing group was told that dizziness is an unpleasant but well-known side effect. Side effects were measured after the administration of metoprolol, an antihypertensive agent. Post hoc moderator analyses investigated the effect of pre-existing negative beliefs about the general harm of medication on the framing manipulation.

RESULTS

Metoprolol-specific drug-attributed side effects were rated significantly less threatening in the positive framing group. The between-group effect size (Cohen's d) was small (d = 0.38, p = 0.049). Exploratory post hoc moderator analyses suggest that participants who believed that medication is a source of harmful effects benefited from positive framing, compared to neutral framing of drug-attributed side effects.

CONCLUSIONS

Positive framing was partially effective in decreasing specific side effect measures, particularly among participants with a tendency to believe that medicine is harmful. Informed consent procedures should therefore be personalized, focusing on patients with negative treatment beliefs.

Psychobiological Mechanisms of Placebo and Nocebo Effects: Pathways to Improve Treatments and Reduce Side Effects

Placebo effects constitute a major part of treatment success in medical interventions. The nocebo effect also has a major impact, as it accounts for a significant proportion of the reported side effects for many treatments. Historically, clinical trials have aimed to reduce placebo effects; however, currently, there is interest in optimizing placebo effects to improve existing treatments and in examining ways to minimize nocebo effects to improve clinical outcome. To achieve these aims, a better understanding of the psychological and neurobiological mechanisms of the placebo and nocebo response is required. This review discusses the impact of the placebo and nocebo response in health care. We also examine the mechanisms involved in the placebo and nocebo effects, including the central mechanism of expectations. Finally, we examine ways to enhance placebo effects and reduce the impact of the nocebo response in clinical practice and suggest areas for future research.

How Does Observational Learning Produce Placebo Effects? A Model Integrating Research Findings

There is a growing body of evidence proving that observational learning, in addition to classical conditioning and verbal suggestions, may induce both placebo analgesia and nocebo hyperalgesia. However, much less is known about the mechanisms and factors influencing placebo effects induced by observational learning. The paper critically reviews the research findings in the field in the context of Bandura’s social learning theory. We apply Bandura’s taxonomy of the sources of social learning (behavioral, symbolic, and verbal modeling) and discuss the results of previous studies. Critical points in the placebo effects induced by observational learning are identified. We discuss aspects of behavior presented by the model (both verbal and non-verbal) involved in the formation of placebo effects induced by observational learning as well as the role of expectancies in this process. As a result, we propose a model that integrates the existing research findings. The model shows the main ways of transmission of pain-related information from the model to the observer. It highlights the role of expectancies and the individual characteristics of the observer in formation of placebo analgesia and nocebo hyperalgesia induced by observational learning. Finally, we propose future research directions based on our model.

The Power of Labeling in Nocebo Effects

Nocebo effects comprise two broad types: primary nocebo effects, in which overall treatment efficacy is reduced; and nocebo side effects, which result in the increased experience of unpleasant secondary side effects. An important factor in generating nocebo effects of both types is the patient's expectations of how well a treatment will work, and how likely it is to cause side effects. One source of negative expectations is the presence of generic-as opposed to brand name-labeling. A medicine's labeling is likely to be one of the first aspects of a treatment that is encountered by a patient, and perhaps the most common labeling information on pharmaceuticals is the labeling that identifies the drug as being made by the originator brand manufacturer, or as a generic copy. Although generic medicines are pharmaceutically equivalent to their brand name counterparts, generics are often viewed with distrust and perceived to be inferior to branded medicines. Negative perceptions of generic pharmaceuticals may contribute to reduced treatment efficacy via enhanced primary nocebo effects, and increased nocebo side effects. This chapter reviews evidence for the role of brand and generic labeling in treatment outcomes across a range of contexts-most often laboratory research assessing pain outcomes, as well as the influence of related factors including price, familiarity, and treatment switches. Although increasing evidence suggests that labeling of medicines can shape nocebo effects, interventions to improve perceptions of generics do not necessarily translate into more positive treatment outcomes.

The Influence of Social Modeling, Gender, and Empathy on Treatment Side Effects

Background

Social modeling has the capacity to shape treatment outcomes, including side effects.

Purpose

This study investigated the influence of social modeling of treatment side effects, gender, and participant empathy, on side effects of a placebo treatment.

Methods

Ninety-six participants (48 females) completed a study purportedly investigating the influence of modafinil (actually placebo) on alertness and fatigue. The participants were randomly seated with a male or female confederate and saw this confederate report experiencing side effects or no side effects. Participant empathy was assessed at baseline. Changes in modeled and general symptoms, and misattribution of symptoms, were assessed during the session and at 24-hr follow-up.

Results

During the experimental session, seeing side effect modeling significantly increased modeled symptoms (p = .023, d = 0.56) but not general or misattributed symptoms. Regardless of modeling condition, female participants seated with a female model reported significantly more general symptoms during the session. However, response to social modeling did not differ significantly by model or participant gender. At follow-up, the effect of social modeling of side effects had generalized to other symptoms, resulting in significantly higher rates of modeled symptoms (p = .023, d = 0.48), general symptoms (p = .013, d = 0.49), and misattributed symptoms (p = .022, d = 0.50). The experience of modeled symptoms in response to social modeling was predicted by participants’ levels of baseline empathy.

Conclusions

Social modeling of symptoms can increase the side effects following treatment, and this effect appears to generalize to a broader range of symptoms and symptom misattribution over time. Higher baseline empathy seems to increase response to social modeling.

Bad news: The influence of news coverage and Google searches on Gardasil adverse event reporting

BACKGROUND

Human papilloma virus vaccines are a safe and effective tool for reducing HPV infections that can cause cervical cancer. However, uptake of these vaccines has been suboptimal, with many people holding negative beliefs and misconceptions. Such beliefs have been linked with the experience of unpleasant side effects following medical treatment, and media coverage may heighten such concerns.

METHODS

The present study sought to assess the influence of news coverage (number of news articles per month) on adverse event reporting in response to Gardasil vaccination in New Zealand over a 7.5-year period, and whether the influence of news coverage was mediated by internet search activity (Google search volumes). Multiple linear regression analyses and simple mediation analyses were used, controlling for year and number of vaccinations delivered.

RESULTS

News coverage in the previous month, and Google search volumes in the same month, were significant predictors of adverse event reporting, after accounting for vaccination rates and year. Concurrent Google search volumes partially mediated the effect of prior news coverage.

CONCLUSION

The results suggest that some of the adverse events reported were not related to the vaccination itself, but to news coverage and internet search volumes, which may have contributed to public concerns about potentially unpleasant or harmful outcomes. These findings have implications for the importance of psychological and social factors in adverse event reporting, and the role of the news media in disseminating health information.

Parental work absenteeism is associated with increased symptom complaints and school absence in adolescent children

Background

Previous studies have proposed that having parents out of work may influence adolescent illness behaviour and school attendance. However, prior research investigating this question has been limited by retrospective reporting and case control studies. In a large epidemiological study we investigated whether parental work absence was associated with symptom complaints and increased school absenteeism in adolescents.

Methods

We analysed data from a large epidemiological study of 10,243 Norwegian adolescents aged 16–19. Participants completed survey at school, which included demographic data, parental work absence and current health complaints. An official registry provided school attendance data.

Results

Parental work absence was significantly related to the number of adolescent symptom complaints as well as school absenteeism. Having a father out of work was associated with an increased likelihood of being in the highest quartile of symptom reporting by an odds-ratio of 2.2 and mother by 1.6 (compared to the lowest quartile). Similarly, parental work absenteeism was associated with an increased likelihood of being in the highest quartile for school absence by an odds-ratio of 1.9 for a father being out of work and 1.5 for a mother out of work. We found that the number of adolescent symptom complaints mediated the relationship between parental work absenteeism and school absenteeism.

Conclusion

We found that parental work absence was significantly associated with the number of adolescent symptom complaints and school absenteeism. The results suggest that parents may play a critical modelling role in the intergenerational transmission of illness and disability behaviour.

Can you change my preferences? Effect of social influence on intertemporal choice behavior

The present study presents a novel social observation paradigm to examine whether temporal discounting (TD) can be modulated in a specific direction. In particular, after estimating a baseline discount rate, we exposed subjects to a pattern of choice that was opposite to their baseline preferences, i.e., subjects preferring immediate over delayed rewards were exposed to a farsighted pattern of behavior and vice-versa. The results showed a significant decrease of the discount rate in the discounter group and an increase in the farsighted group. The effect was mainly guided by a modification of the subjective values at short time delays and was stronger in subjects with extreme, compared to mild, baseline preferences. Importantly, the magnitude and direction of the effect predicted the baseline preferences. These findings have potentially very relevant implications for the prevention and treatment of clinical conditions, such as addition-related disorders, characterized by severe impairments of decision-making mechanisms.