Nocebo effects in health psychology

Identifying the psychological effects of nocebo education: results from two pre-registered experiments

Providing treatment side effect information to patients increases the risk of harm due to the nocebo effect. Nocebo education, in which patients learn about nocebo effects, is a novel strategy that can be used across a variety of situations and individuals to decrease unpleasant treatment side effects. It is currently unclear which psychological changes are induced by nocebo education, which is information required to maximize this intervention. Two pre-registered studies investigated the effects of nocebo education on side effect expectations, side effect control beliefs, feelings toward treatments, intentions to avoid or seek side effect information, and perceptions of treatment efficacy. In Study 1 (N = 220), adult participants either watched or did not watch a nocebo education intervention video prior to reading vignettes about receiving a surgical treatment for pain and a medication for pain. Study 2 (N = 252) was similar to Study 1, with the inclusion of a health behavior video control group and participants only reading about a medication treatment for pain. In both experiments, nocebo education reduced global side effect expectations and increased side effect self-efficacy beliefs. Nocebo education also increased intentions to avoid side effect information and decreased intentions to seek more side effect information. Evidence was inconclusive on whether nocebo education changes affective associations with the treatments. The findings demonstrate that nocebo education has a multi-faceted influence with the potential to change patient behavior. The results can be used to improve the management of adverse treatment side effects.

Attention and nocebo hyperalgesia: Testing a novel virtual reality attention bias modification paradigm

Nocebo effects in pain (nocebo hyperalgesia) have received significant attention recently, with negative expectancies and anxiety proposed to be explanatory factors. While both expectancy and anxiety can bias attention, attention has been rarely explored as a potential mechanism involved in nocebo hyperalgesia. The present study aimed to explore whether attention bias modification (ABM) using an immersive, ecologically valid VR paradigm successfully induced attention biases (AB) and subsequently influenced nocebo hyperalgesia. One-hundred and two healthy participants were randomised in a 2 (AB training: towards vs. away from pain) x 2 (nocebo condition: nocebo vs. control) design. Pain-related AB was successfully changed by the VR paradigm as measured by reaction time and gaze, with moderate to large effects. Participants then completed either a nocebo instruction and conditioning procedure (nocebo paradigm) or a matched control procedure. The primary outcome was self-reported pain intensity. Secondary outcomes were attention bias and self-reports of expectancy, anticipatory anxiety, and state anxiety. The nocebo paradigm induced significantly greater pain expectancy, anticipatory anxiety and pain intensity during the test phase for the nocebo group compared to control. Pain expectancy also fully mediated the effect of the nocebo group on nocebo hyperalgesia and anticipatory anxiety in separate models. ABM did not, however, affect nocebo hyperalgesia or pain expectancy, casting doubt on the potential for ABM to inoculate against nocebo hyperalgesia. Unexpected effects of ABM were observed for state anxiety and anticipatory anxiety, whereby training away from pain exacerbated each, which necessitates further exploration. PERSPECTIVE: This article tests the efficacy of a novel attention bias modification paradigm, designed in virtual reality, for inducing pain-related biases, and whether these biases exacerbate or inoculate against nocebo hyperalgesia. While pain-related biases were successfully induced, there was no relationship with the strength of induced nocebo hyperalgesia.

The downside to choice: instrumental control increases conditioned nocebo hyperalgesia

ABSTRACT

Nocebo hyperalgesia is a pervasive problem in which the treatment context triggers negative expectations that exacerbate pain. Thus, developing ethical strategies to mitigate nocebo hyperalgesia is crucial. Emerging research suggests that choice has the capacity to reduce nocebo side effects, but choice effects on nocebo hyperalgesia have not been explored. This study investigated the impact of choice on conditioned nocebo hyperalgesia using a well-established electrocutaneous pain paradigm where increases in noxious stimulation were surreptitiously paired with the activation of a sham device. In study 1, healthy volunteers (N = 104) were randomised to choice over (nocebo) treatment administration, nocebo administration without choice, or a natural history control group. Nocebo hyperalgesia was greater for those with choice than no choice, suggesting that choice increased rather than diminished nocebo hyperalgesia. Study 2 tested whether providing positive information about the benefits of choice in coping with pain could counteract heightened nocebo hyperalgesia caused by choice. A different sample of healthy adults (N = 137) were randomised to receive nocebo treatment with choice and positive choice information, choice only, or no choice. The positive choice information failed to attenuate the effect of choice on nocebo hyperalgesia. The current results suggest that, rather than decreasing nocebo hyperalgesia, treatment choice may exacerbate pain outcomes when a painful procedure is repeatedly administered. As such, using choice as a strategy to mitigate nocebo outcomes should be treated with caution.

The effect of social learning on the nocebo effect: a systematic review and meta-analysis with recommendations for the future

ABSTRACTIndividuals frequently update their beliefs and behaviours based on observation of others' experience. While often adaptive, social learning can contribute to the development of negative health expectations, leading to worsened health outcomes, a phenomenon known as the nocebo effect. This systematic review and meta-analysis examined: whether social learning is sufficient to induce the nocebo effect, how it compares to other forms of induction (classical conditioning and explicit instruction), and factors that influence these effects. The meta-analysis included twenty studies (n = 1388). Social learning showed a medium-large effect size (Hedges' g = .74) relative to no treatment and a to small-medium effect (g = .42) when compared to neutral modelling. The effect of social learning was similar in magnitude to classical conditioning but greater than explicit instruction with a small-medium effect (g = .46). Face-to-face social modelling, longer exposure, higher proportions of female participants and models, and greater observer empathy led to stronger socially-induced nocebo effects. However, further research is essential as only a minority of studies measured important constructs like negative expectancies and state anxiety. Nonetheless, the study highlights social learning as a key pathway for nocebo effects, suggesting it as a target for interventions to reduce the substantial personal and societal burden caused by nocebo effects.

Pain Rating is Worth a Thousand Words: Nocebo Hyperalgesia Induced by Verbal Modeling Prevails Over the Effects of Symbolic Modeling and Verbal Suggestion

This study compares the effectiveness of verbal modeling, symbolic modeling, and verbal suggestion in inducing nocebo hyperalgesia. It is the first study to examine the contribution of stress to observationally induced nocebo hyperalgesia. This study's experimental groups represented various sources of social information: a group of people participating in the study (verbal modeling), a single participant (symbolic modeling), and an experimenter (verbal suggestion). During the experiment, participants received electrocutaneous stimuli at the same intensity, some of which were applied with a nocebo (sham device). Participants in the verbal modeling group were acquainted with pain ratings that had allegedly been provided by other participants. The ratings suggested that other participants experienced more pain in the nocebo trials than in the control trials. In the symbolic modeling group, participants observed a videotaped model experiencing more pain in the nocebo than in the control trials. In the verbal suggestion group, participants received a verbal suggestion of hyperalgesia in the nocebo trials and no suggestion in the control trials. No manipulations were used in the control group. To investigate whether nocebo hyperalgesia is stable over time, an additional extinction phase was conducted. Nocebo hyperalgesia was induced by verbal modeling only and was partially mediated by expectancy. Stress was a significant moderator of the induced effect. Nocebo hyperalgesia was extinguished during the extinction phase. The obtained results provide potential implications for minimizing nocebo hyperalgesia in clinical practice by, for instance, controlling patients' expectancies and stress levels. PERSPECTIVE: The study shows the role of pain-related information derived from other people in shaping negative treatment experiences in the individual. Because information from others has a particular impact on individuals experiencing stress, both this information and the stress level of patients should be monitored in the treatment process.

Understanding the Role of Expectancy, Anticipatory Anxiety, and Attention Bias in Nocebo Hyperalgesia: A Gaze-Contingent Attention Bias Modification Study

Nocebo effects in pain (nocebo hyperalgesia) have been thoroughly researched, and negative expectancies have been proposed as a key factor in causing nocebo hyperalgesia. However, little is known about the psychological mechanisms by which expectations exacerbate the perception of pain. A potential mechanism that has been proposed within wider pain research is pain-related attention. The aim of the present study was thus to explore whether attention bias (AB) to pain influenced nocebo hyperalgesia. One-hundred and thirty-four healthy participants were randomized in a 2 (AB training: towards vs away from pain) × 2 (nocebo condition: nocebo vs control) design. Pain-related AB was manipulated through a novel, partially gaze-contingent dot-probe task. Participants then completed either a nocebo instruction and conditioning paradigm or a matched control condition. Primary outcomes were measures of expectancy, anticipatory anxiety, and pain intensity completed during a nocebo test phase. Results showed that the AB manipulation was unsuccessful in inducing ABs either toward or away from pain. The nocebo paradigm induced significantly greater expectancy, anticipatory anxiety, and pain intensity for the nocebo groups compared to the control groups. In a posthoc analysis of participants with correctly induced ABs, AB towards pain amplified nocebo hyperalgesia, expectancy, and anticipatory anxiety relative to AB away from pain. The results are consistent with the expectancy model of nocebo effects and additionally identify anticipatory anxiety as an additional factor. Regarding AB, research is needed to develop reliable means to change attention sample-wide to corroborate the present findings. PERSPECTIVE: This article explores the role of AB, expectancy, and anticipatory anxiety in nocebo hyperalgesia. The study shows that expectancy can trigger anticipatory anxiety that exacerbates nocebo hyperalgesia. Further, successful AB training towards pain heightens nocebo hyperalgesia. These findings identify candidate psychological factors to target in minimizing nocebo hyperalgesia.

The desire for side-effect information in pain treatment: an experimental analysis of contextual and individual difference factors

ABSTRACT

Informing patients about potential side effects of pain treatment is a requirement that protects patients and aids decision making, but it increases the likelihood of unwanted nocebo side effects. If patients do not desire all side-effect information, it may be possible to ethically reduce nocebo effects through authorized concealment of side effects, whereby patients and clinicians engage in shared decision-making to regulate the disclosure of side-effect information. Currently, there is no experimental data clarifying the factors that causally influence desire for side-effect information in pain treatment. In 2 cross-sectional, between-subjects scenario experiments (experiment 1 N = 498, experiment 2 N = 501), 18 to 79-year-old community adults learned about a lower back pain treatment, and potential side-effect severity, frequency, and duration were manipulated. Individual differences in information avoidance were also recorded. In both experiments, participants reported high desire for side-effect information, but the desire was reduced when side effects were described as less severe, less frequent, and participants scored high in information avoidance. Results were not moderated by participants' level of contact with the health care system, chronic health condition, or clinical pain history. Additional analyses indicated that low side-effect severity and frequency lessen desire for side-effect information because these variables reduce belief that side-effect information will be needed in the future and lower feelings of anticipated regret. The experiments identify situational and individual-difference factors that decrease the desire for side-effect information and provide evidence on when and for whom it may be useful for physicians to engage in shared medical decision-making with the goal of reducing nocebo side effects.

The relationship between expectancy, anxiety, and the nocebo effect: a systematic review and meta-analysis with recommendations for future research

Despite the theoretical prominence of expectancy and anxiety as potential mechanisms of the nocebo effect, not all studies measure expectancy and/or anxiety, and there are inconsistent findings among those that do. The present study sought to systematically review and meta-analyse available data to evaluate the relationship between expectancy, anxiety and the nocebo effect. The two key questions were: (1) whether nocebo manipulations influence expectancy and anxiety; and (2) whether expectancy and anxiety are associated with the subsequent nocebo effect. Fifty-nine independent studies (n = 3129) were identified via database searches to 1st August 2021. Nocebo manipulations reliably increased negative expectancy with a large effect (g = .837) and state anxiety with a small effect (g = .312). Changes in expectancy and state anxiety due to the nocebo manipulation were associated with larger nocebo effects (r = .376 and .234, respectively). However, there was no significant association between dispositional anxiety and the nocebo effect. These findings support theories that rely on situationally-induced expectancy and anxiety, but not dispositional anxiety, to explain nocebo effects. Importantly, being malleable, these findings suggest that interventions that target maladaptive negative expectancies and state anxiety could be beneficial for reducing the harm nocebo effects cause across health settings. Recommendations for future research are discussed.

Socially Acquired Nocebo Effects Generalize but Are Not Attenuated by Choice

BACKGROUND

Socially observing a negative treatment-related experience has been shown to modulate our own experience with the same intervention, leading to worsened health outcomes. However, whether this social learning generalizes to similar but distinct interventions has not been explored nor what manipulations can reduce these effects.

PURPOSE

To determine whether socially acquired nocebo effects can be generated by observing a negative experience with a similar, but distinct intervention, and whether choice can reduce these effects.

METHODS

Across three experiments, a community sample of healthy adults (N = 336) either watched a confederate report cybersickness to the same Virtual Reality (VR) activity they were assigned to (Social Modeling: Consistent); a similar, but different VR activity (Social Modeling: Inconsistent); or did not view the confederate (No Social Modeling). Participants were either given choice over the VR (Choice) or assigned by the experimenter (No Choice).

RESULTS

Across the experiments, there was significantly greater cybersickness in both Social Modeling groups relative to No Social Modeling, while the two Social Modeling groups did not differ. There was no significant effect of Choice or a Choice by Social Modeling interaction. Social Modeling elicited greater anxiety and expectancies for cybersickness. Furthermore, these mechanisms mediated the association between social modeling and cybersickness.

CONCLUSIONS

Socially acquired side-effects were demonstrated to generalize to similar, but distinct interventions, highlighting the diffuse and robust effect social modeling can have on our experiences. However, choice did not attenuate the experience of cybersickness, highlighting the need for alternative methods to counteract the effect of social modeling.

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.

Social communication pathways to COVID-19 vaccine side-effect expectations and experience

OBJECTIVE

Negative beliefs about medication and vaccine side-effects can spread rapidly through social communication. This has been recently documented with the potential side-effects from the COVID-19 vaccines. We tested if pre-vaccination social communications about side-effects from personal acquaintances, news reports, and social media predict post-vaccination side-effect experiences. Further, as previous research suggests that side-effects can be exacerbated by negative expectations, we assessed if personal expectations mediate the relationships between social communication and side-effect experience.

METHOD

In a prospective longitudinal survey (N = 551), COVID-19 vaccine side-effect information from three sources-social media posts, news reports, and first-hand accounts from personal acquaintances-as well as side-effect expectations, were self-reported pre-vaccination. Vaccination side-effect experience was assessed post-vaccination.

RESULTS

In multivariate regression analyses, the number of pre-vaccination social media post views (β = 0.17) and impressions of severity conveyed from personal acquaintances (β = 0.42) significantly predicted an increase in pre-vaccination side-effect expectations, and the same variables (βs = 0.11, 0.14, respectively) predicted post-vaccination side-effect experiences. Moreover, pre-vaccination side-effect expectations mediated the relationship between both sources of social communication and experienced side-effects from a COVID-19 vaccination.

CONCLUSIONS

This study identifies links between personal acquaintance and social media communications and vaccine side-effect experiences and provides evidence that pre-vaccination expectations account for these relationships. The results suggest that modifying side-effect expectations through these channels may change the side-effects following a COVID-19 vaccination as well as other publicly discussed vaccinations and medications.

Moving forward: Implementing health psychology research to improve patient acceptance of biosimilars

As more biosimilars enter the pharmaceutical market, patient acceptance remains a significant barrier to their uptake. Psychological factors, such as negative expectations, are important causes of patient hesitancy. As a result, patients can develop nocebo responses following a transition, discontinue biosimilar treatment early, or have poor adherence. These negative outcomes may offset some of the cost-saving potential of biosimilars. Key healthcare professionals such as pharmacists, physicians, and nurses already play a noteworthy role in educating and transitioning patients. However, given the psychological aspect of biosimilar acceptance, it is logical for healthcare professionals and researchers to draw on research and theory from health psychology. This commentary outlines how a multidisciplinary approach can add to the understanding of the mechanisms behind patient resistance to biosimilars and help engage patients in the transitioning process. It also explores how health psychology strategies that have been successful in similar areas can be translated to help conduct more effective transitions. Future directions in research are discussed.

Using Positive Attribute Framing to Attenuate Nocebo Side Effects: A Cybersickness Study

BACKGROUND

Side effect warnings can contribute directly to their occurrence via the nocebo effect. This creates a challenge for clinicians and researchers, because warnings are necessary for informed consent, but can cause harm. Positive framing has been proposed as a method for reducing nocebo side effects whilst maintaining the principles of informed consent, but the limited available empirical data are mixed.

PURPOSE

To test whether positive attribute framing reduces nocebo side effects relative to negative framing, general warning, and no warning.

METHODS

Ninety-nine healthy volunteers were recruited under the guise of a study on virtual reality (VR) and spatial awareness. Participants were randomized to receive positively framed ("7 out of 10 people will not experience nausea"), negatively framed ("3 out of 10 people will experience nausea"), general ("a proportion of people will experience nausea"), or no side effect warnings prior to VR exposure.

RESULTS

Receiving a side effect warning increased VR cybersickness relative to no warning overall, confirming that warnings can induce nocebo side effects. Importantly, however, positive framing reduced cybersickness relative to both negative framing and the general warning, with no difference between the latter two. Further, there was no difference in side effects between positive framing and no warning.

CONCLUSIONS

These findings suggest that positive framing not only reduces nocebo side effects relative to negative framing and general warnings, but actually prevents nocebo side effects from occurring at all. As such, positive attribute framing may be a cheap and ethical way to reduce nocebo side effects.