Distraction and placebo: two separate routes to pain control

An explosion of recent research has studied whether placebo treatments influence health-related outcomes and their biological markers, but almost no research has examined the psychological processes required for placebo effects to occur. This study tested whether placebo treatment and cognitive distraction reduce pain through shared or independent processes. We tested the joint effects of performance of an executive working memory task and placebo treatment on thermal pain perception. An interactive effect of these two manipulations would constitute evidence for shared mechanisms, whereas additive effects would imply separate mechanisms. Participants (N = 33) reported reduced pain both when they performed the working memory task and when they received the placebo treatment, but the reductions were additive, a result indicating that the executive demands of the working memory task did not interfere with placebo analgesia. Furthermore, placebo analgesia did not impair task performance. Together, these data suggest that placebo analgesia does not depend on active redirection of attention and that expectancy and distraction can be combined to maximize pain relief.     

Placebo, belief, and health. A cognitive–emotion model

The present paper reviews empirical research on placebo effects, and presents a cognitive–emotional model of the psychological mechanisms involved. It is argued that illness often involves psychological aspects; people not only sense their signs of physical illness, but also interpret these signs, and respond emotionally to their interpretations. Cognitions of danger (e.g. fear of dying) produce anxiety, whereas cognitions of loss (e.g. loss of one's health) produce sadness or depression. It is argued that an important part of the placebo effect is due to the development of placebo beliefs (beliefs of the form "This treatment is going to cure me"), which may counteract the kind of cognitions that produce anxiety and depression; placebo beliefs produce emotional responses (hope, calm, etc.), which are antagonistic to depression and anxiety. Further, if anxiety and depression tend to affect a person's physical health negatively, placebo beliefs may be expected to have a positive influence on physical health. Placebo effects may occur not only with pure placebos (e.g. sugar pills), but with all kinds of medical and psychological treatments; even treatments that contain active ingredients of a non-placebo nature may involve important placebo components. Placebo effects may vary in strength, depending on the therapist's behaviour (verbal information to the patient, enthusiasm, optimism, interest, etc.), and on the patient's idiosyncratic meaning structures (which invest various kinds of treatment with different placebo value).     

Adherence,expectations and the placebo response: Why is good adherence to an inert treatment beneficial?

Objective: The current study sought to better understand why good adherence to a placebo treatment has been reliably associated with health benefits. We proposed a model where initial expectations shape adherence, which then influences subsequent expectations that affect placebo response. Design: Seventy-two participants were told that they were enrolling in a study of physical activity and memory, and were asked to increase their physical activity by 35% for two weeks (placebo treatment). Main outcome measures: Adherence to this physical activity target was measured by pedometer. Expectations and short-term memory (free recall) were assessed before and after physical activity. Results: Initial expectations predicted adherence to physical activity (r = .27, p < .03), but adherence did not predict subsequent expectations (r = .06, p = .60). Testing a multi-step meditational model revealed that initial expectations predicted better memory even after controlling for adherence, subsequent expectations, baseline memory and gender (c’ = 1.10, 95% CI = .46–1.74). Stronger expectations for memory improvement predicted better memory performance, but adherence and later expectations did not mediate this association. Conclusions: Good adherence to a placebo may reflect strong treatment expectations which may convey benefits by enhancing the non-specific effects of treatment.     

Choice‐making,Expectations, and Treatment Positivity: How and When Choosing Shapes Aversive Experiences

Every day we use products and treatments with unknown but expected effects, such as using medication to manage pain. In many cases, we have a choice over which products or treatments to use; however, in other cases, people choose for us or choices are unavailable. Does choosing (versus not choosing) have implications for how a product or treatment is experienced? The current experiments examined the role of choice‐making in facilitating so‐called expectation assimilation effects—or situations in which a person's experiences (e.g., discomfort and pain) are evaluated in a manner consistent with their expectations. In Experiment 1, participants were initially exposed to a baseline set of aversive stimuli (i.e., sounds). Next, some participants were given expectations for two “treatments” (i.e., changes in screen display) that could ostensibly reduce discomfort. Critically, participants were either given a choice or not about which of the two treatments they preferred. Participants in a control condition were not provided with treatment expectations. Results revealed that discomfort experiences assimilated to expectations only when participants were provided with choice. Experiment 2 replicated this finding and provided evidence against the idea that demand characteristics and choice‐making unrelated to the core task (i.e., choices without associated expectations) could account for the results. Further, Experiment 2 showed that choosing reduced discomfort because of increased positivity about the treatment. Results are discussed in the context of extant research on choice‐making and expectation effects. Copyright © 2013 John Wiley & Sons, Ltd.     

Biased Assimilation: Effects of Assumptions and Expectations on the Interpretation of New Evidence

People so readily generalize that they often 'know' in advance what they are going to like and what they are going to dislike. They develop assumptions and expectations, which in part determine their future evaluative responses. Biased assimilation occurs when perceptions of new evidence are interpreted in such a way as to be assimilated into preexisting assumptions and expectations. Because this bias may not be deliberate, people suspect the motives of others who do not share their evaluations, and the bias is difficult to overcome. Biased assimilation most likely occurs, however, because acting as though one's assumptions and expectations are correct is generally more adaptive than acting as though one's assumptions and expectations might be wrong. Therefore, overcoming a general tendency toward biased assimilation is not necessarily desirable.     

Treatment Choice and Placebo Expectation Effects

Placebo expectations can have a strong influence on physical and mental health outcomes. In prior research examining placebo expectation effects, participants have been assigned placebo treatments rather than being actively involved in selecting their treatment. In modern health care, however, individuals are often involved in health care decisions. We review relevant literature regarding choice and placebo expectation effects and conclude that exercising choice over a treatment should strengthen placebo effects. Data relevant to this hypothesis is reviewed. Next, we provide a framework for understanding the key variables involved in mediating and moderating the influence of treatment choice on placebo expectation effects. Finally, theoretical and practical issues revolving around treatment choice in the context of placebo effects are raised.     

Drug effects: Agonistic and antagonistic processes

The research presented here has shown that tolerance to drugs can be accelerated by conditioning processes. Placebo effects may be considered the opposite of tolerance, and we have shown that placebo effects may be objectively recorded by physiological measures (electromyography, skin conductance responses, and event‐related potentials), as well as by behavioral and subjective methods. The placebo response, or more precisely, the expectation of drug effects, can add to the effect of the drug. Drug antagonistic expectations can also reverse the effect of the drug. There is some evidence that placebo effects are strongest when expectations are reinforced by administration of an active drug. Expectations have graded effects and may affect symptoms to a smaller or larger degree. Although drug effects can be considered stimuli, the investigation of the role of classical conditioning in drug use and drug effects involves special issues that must be carefully considered.     

Affect and emotions in placebo and nocebo effects: What do we know so far?

Once considered nuisance variance in clinical trials, placebo effects and nocebo effects are now widely recognized as important and mutable psychobiological contributors to mental and physical health. Psychological theory explaining these effects emphasizes associative learning and conscious expectations. It has long been suggested, however, that affective states such as moods, emotions, and distress could play a significant role. In this paper, we draw together and review the empirical data linking affective states to placebo and nocebo effects. To organize this disparate literature, three questions are addressed: (1) Does pre‐existing state and trait affect modulate placebo and nocebo effects? (2) Does administering placebo and nocebo treatments change affective states, and if so, does the resulting affect causally influence placebo and nocebo effects? Finally, (3) Can placebo treatments be successfully employed as a regulation strategy to modulate different affective states? In reviewing the evidence in relation to these three questions, it is clear that affect does play a key role in placebo and nocebo effects in many circumstances, and further, there may be a reciprocal dynamic at play between a treatment event, affect, and placebo/nocebo effects. The paper concludes by discussing implications for theory and intervention and recommends future research priorities.     

Fail or flourish? Cognitive appraisal moderates the effect of solo status on performance

When everyone in a group shares a common social identity except one individual, the one who is different from the majority has solo status. Solo status increases one's visibility and performance pressure, which may result in stress. Stress has divergent effects on performance, and individuals' response to stressful situations is predicted by their cognitive appraisal (challenge or threat) of the situation. Two experiments test the hypothesis that cognitive appraisal moderates the effect of solo status on performance. Experiment 1 finds that at relatively high appraisal levels (resources exceed demands), solo status improves men's and women's performance; at relatively low appraisal levels, solo status hurts performance. Experiment 2 replicates this effect for solo status based on minimal group assignment. Results suggest that for individuals who feel challenged and not threatened by their work, it may help to be a solo.     

Context‐induced placebo effects—An investigation of contrast effects in response expectations and actual product efficacy

Recent research on the placebo effect of marketing actions has demonstrated that characteristics that are not inherent to a product's physical properties per se, such as its price, brand, or packaging can considerably shape consumers' expectations about and actual efficacy of a marketed product. However, potential contextual effects that other products may have on the construction of consumers' efficacy beliefs and objective consumption outcomes remain unexplored. Across two experimental studies, we show that people's response expectations regarding a focal product are inversely related to the alleged superiority of context options and that such context‐induced expectations can carry over to behavioural performance metrics; a phenomenon we refer to as context‐induced placebo effects.     

Hypnosis, suggestion, and placebo in the reduction of experimental pain

Two experiments compared placebo and hypnotic analgesia in high and low hypnotizable subjects. Experiment 1 demonstrated that hypnotic and placebo analgesia were equally ineffective in low hypnotizables, but that hypnotic analgesia was much more effective than placebo analgesia in high hypnotizables. Experiment 2 replicated these results, but also included low and high hypnotizables who were given a nonhypnotic suggestion for analgesia. Both the low and high hypnotizables in this group reported greater suggested than placebo analgesia and as much suggested analgesia as high hypnotizable hypnotic subjects. Both experiments found substantial discrepancies between the amount of pain reduction subjects expected from the various treatments and the amount of pain reduction they actually reported following exposure to those treatments. In Experiment 2, subjects in all treatments who reduced reported pain engaged in more cognitive coping and less catastrophizing than those who did not reduce pain. Theoretical implications are discussed.     

Predictions of dental pain: the fear of any expected evil, is worse than the evil itself

In a study of 40 subjects, who twice underwent extensive dental treatment, the relationships between expectations and experiences of pain and of anxiety were investigated. Inaccurate expectations were adjusted in the same way as observed in the laboratory. Especially anxious subjects expected more pain and anxiety than they experienced, and they appeared to need more experiences before their predictions became accurate. In the course of time, the expectations (and memories) of anxious subjects returned to their original more inaccurate level of prediction. The results suggest that the old schema is ultimately reinstated if disconfirmations are few and far between. Anxious subjects did not experience more pain, but they did experience more anxiety than fearless subjects. Detailed investigation of processes of change after disconfirmation showed that anxiety experienced during treatment is a factor that plays a part in maintaining the problem of inaccurate expectations and fear of treatment. Theoretical and clinical implications of these findings are discussed.     

The neurobiology of virtual reality pain attenuation.

During the past decade, virtual reality (VR) has gained recognition as a means of attenuating pain during medical procedures. However, while investigators have examined the effects of virtual environments on level of distraction, subjective pain intensity, and brain activity, there have been only a handful of investigations into the neurobiological mechanisms associated with VR's efficacy. In an effort to explain how VR may alter pain perception and produce analgesia, as well as to guide the development of novel and improved VR pain treatments, this review aims to link the wealth of empirical data examining the neurobiology of pain to the growing field of VR. This review is separated into three main sections: (a) a brief overview of the current literature on the use of VR for the treatment of pain; (b) a review of the basic neurobiology of how pain is detected, processed, and controlled by the brain; and (c) an exploration into how current VR pain treatments may impact the pain system to produce analgesia. In addition, the future of VR for pain treatment is discussed, including how current treatments might be improved and novel ways to use VR to treat pain might be developed. Speculation on future VR interventions is based on our current understanding of how the brain processes pain and how VR appears to alter this process and produce analgesia.     

Dispositional optimism as a predictor of men's decision-related distress after localized prostate cancer.

This study investigated prospectively the relationship between optimism, threat appraisal, seeking support and information, cognitive avoidance, physical treatment side effects, and decision-related distress in 111 men with localized prostate cancer. Men were assessed at diagnosis and 2 and 12 months after treatment. Baseline decision-related distress predicted distress 2 and 12 months after treatment. Optimism was a significant prospective and concurrent predictor of decision-related distress, with the effect mediated by proximal cancer threat appraisal. Seeking support and information and cognitive avoidance were not associated with decision-related distress at any time point. For physical treatment side effects, concurrent urinary symptoms were predictive of decision-related distress 2 months after treatment. Results suggest that decision-related distress is generated by similar processes to that of the psychological distress that follows a cancer diagnosis. Screening for men with high decision-related distress for referral to in-depth decision support is suggested. Outcome expectations may present as a therapy target to increase the effectiveness of decisional support that is utility based.     

Peer-group affiliation and adolescent self-esteem: an integration of ego-identity and symbolic-interaction theories

To evaluate expectations derived from ego-identity theory and symbolic-interaction theories about the association between self-concept and peer-group affiliations in adolescence, we examined the self-esteem of 221 7th through 12th graders associated by peers with one of five major school crowds and 106 students relatively unknown by classmates and not associated with any school crowd. Among crowd members, self-esteem was directly related to the position of one's crowd in the peer-group status hierarchy (based on both peer-rated and self-perceived crowd affiliation). Outsiders' self-esteem differed in relation to the accuracy of their reflected appraisal of and the salience they attached to crowd affiliation. Crowd members as a whole exhibited higher self-esteem than outsiders as a whole. Differences, however, were mediated by crowd status, salience of crowd affiliation, and the accuracy of reflected appraisals. An adequate interpretation of the findings required an integration of Festinger's (1954, 1957) social comparisons and cognitive-dissonance theories, Cooley's (1902) notions of reflected appraisal, and Newman and Newman's (1976) extrapolations from ego-identity theory.     

Neural circuitry of emotion regulation: Effects of appraisal,attention, and cortisol administration

Psychosocial well-being requires effective regulation of emotional responding in context of threat or stress. Neuroimaging studies have focused on instructed, volitional regulation (e.g., reappraisal or distancing), largely ignoring implicit regulation that does not involve purposeful effort to alter emotional experience. These implicit processes may or may not involve the same neural pathways as explicit regulatory strategies. We examined the neurobiology of implicit emotional regulation processes and the impact of the stress hormone cortisol on these processes. Our study task employed composite pictures of faces and places to examine neural activity during implicit emotional processing (of emotional faces), while these responses were implicitly regulated by attention shift away from the emotionally evocative stimuli, and while subjects reflectively appraised their own emotional response to them. Subjects completed the task in an fMRI scanner after random assignment to receive placebo or hydrocortisone (HCT), an orally administered version of cortisol. Implicit emotional processing activated insula/IFG, dACC/dMPFC, midbrain and amygdala. With attention shifting, we saw diminished signal in emotion generating/response regions (e.g., amygdala) and increased activations in task specific attention regions like parahippocampus. With appraisal of emotions, we observed robust activations in medial prefrontal areas, where activation is also seen in instructed reappraisal studies. We observed no main effects of HCT administration on brain, but males and females showed opposing neural effects in prefrontal areas. The data suggest that different types of emotion regulation utilize overlapping circuits, but with some strategy specific activation. Further study of the dimorphic sex response to cortisol is needed.     

Conditioned placebo responses

Following earlier animal research, we attempt to condition placebo effects in human subjects. Four groups of 8 voluntary subjects were told that the experimenters would test a powerful new analgesic cream over three sessions by assessing its ability to reduce experimentally induced pain. The analgesic cream was, in fact, a placebo. In the first session all subjects were tested with and without the cream to assess their placebo response. In the second session, to condition two groups (with differing stimulation levels) to experience pain relief in response to the placebo, we repeatedly paired a reduction in nocioceptive stimulation with placebo administration. (Subjects were unaware that stimulation levels were manipulated). To condition the other two groups (with different stimulation levels) to experience an exacerbation of the pain, we paired an increase in nocioceptive stimulation with placebo administration. In the third session, all subjects were again tested for placebo response. Results suggested that placebo responses are conditionable in the laboratory in both a positive and negative direction. The clinical implications of a learning theory of placebo behavior are discussed.     

Response expectancy theory and application: A decennial review

Response expectancy is the anticipation of automatic, subjective, and behavioral responses to particular situational cues. More than a decade of research in diverse laboratories indicates that response expectancies are important considerations in designing and administering treatments and prevention programs for such problems as anxiety disorders, depression, substance abuse, and sexual dysfunction. Response expectancy also plays a central role in the effects of antidepressive medication, psychotherapy, and hypnosis. In addition, studies of the effects of placebos reveal that response expectancies can produce lasting changes in pain, anxiety, depression, alertness, tension, sexual arousal, alcohol craving and consumption, aggression, asthma, warts, and contact dermatitis. The veracity of many self-reported placebo effects have been corroborated by changes in physiological function.     

Effects of pain acceptance and pain control strategies on physical impairment in individuals with chronic low back pain

Psychosocial treatments for chronic pain are effective. There is a need, however, to understand the processes involved in determining how these treatments contribute to behavior change. Control and acceptance strategies represent two potentially important processes involved in treatment, although they differ significantly in approach. Results from laboratory-based studies suggest that acceptance-oriented strategies significantly enhance pain tolerance and behavioral persistence, compared with control-oriented strategies. There is a need, however, to investigate processes of acceptance and control directly in clinical settings. The present study investigated the effects of three brief instructional sets (pain control, pain acceptance, continued practice) on demonstrated physical impairment in 74 individuals with chronic low back pain using an analogue experimental design. After controlling for baseline performance, the pain acceptance group demonstrated greater overall functioning on a set of 7 standardized physical tasks relative to the other two groups, which did not differ from one another. Further, the acceptance group exhibited a 16.3% improvement in impairment, whereas the pain control group worsened by 8.3% and the continued practice group improved by 2.5%. These results suggest that acceptance may be a key process involved in behavior change in individuals with chronic pain.     

Are smokers interested in genetic testing for smoking addiction? A socio-cognitive approach

Genetic advances have made genetically tailored smoking cessation treatments possible. In this study, we examined whether smokers are interested in undergoing a genetic test to identify their genetic susceptibility to nicotine addiction. In addition, we aimed to identify socio-cognitive determinants of smokers’ intention to undergo genetic testing. Following the protection motivation theory (PMT), we assessed the following constructs using an online survey among 587 smokers: threat appraisal (i.e. susceptibility and severity), fear, coping appraisal (i.e. response efficacy and self-efficacy), response costs and intention. In addition, knowledge, social norms and information-seeking behaviour were measured. Mean intention rates were 2.57 on a 5-point scale. Intention was significantly associated with threat appraisal and coping appraisal, as predicted by the PMT. Fear of the outcome was negatively associated with the intention to undergo genetic testing, but response costs, knowledge and social influence were not. Intention to undergo genetic testing in turn was positively related to seeking information about genetic testing and genetically tailored smoking cessation treatments. Smokers seem ambivalent or ‘on the fence’ with regard to undergoing a genetic test for smoking addiction. Socio-cognitive concepts such as susceptibility, severity, response efficacy and self-efficacy may be used to inform or educate smokers about the value of genetically tailored smoking cessation treatments.