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Commercial Features of Placebo and Therapeutic Efficacy

In response to Dr Browning, I did not lay the problems
of general surgery “at the feet of primary care.” Having been
involved in an effort to undo the flawed sustainable growth
rate system for the past decade, I know that the system is
broken. In a rational world, specialties would unite to cor-
rect this flawed system, which seems cynically designed to
pit specialties against each other.
The calculations for physician compensation used in
the cited study of internal medicine reimbursement
off in 2004 while the increases in evaluation and manage-
ment codes took place in 2004 through 2007. For
example, evaluation and management codes increased in
work relative value units from 2006 to 2007 (code 99213:
increase from 0.67 to 0.92 [37%]; code 99214: 1.10 to
1.42 [29%]; and code 99215: 1.77 to 2.00 [12.9%]). Fur-
thermore, this article has been rebutted.
The primary
care–specialty income gap has largely been corrected, at
an estimated cost of $4 billion.
I appreciate the enthusiasm of Dr Maa and colleagues
for the surgical hospitalist, particularly in emergency and
trauma care. However, I do not believe this is the answer
to the shortage of general surgeons, who not only do
emergency and trauma care but often perform endoscopy
and other general surgical operations in critical access
Philosophically, I have difficulty with medical or surgi-
cal hospitalists. My objection to the medical hospitalist
system is that patients may perceive that they are being
abandoned by their primary care physician at a time of
their most dire need—when they are sufficiently ill to
require hospitalization. I would hope that this sense of
abandonment is not present in a surgical hospitalist sys-
tem. When we train “physicians who operate,” we try to
instill judgment about the need for surgery. But if opera-
tion is required, the operator must be thoroughly compe-
tent. I believe that such decisions are more informed
when the physician/surgeon is familiar with the patient.
The surgical hospitalist system may aid trauma and emer-
gency care in urban centers but will not solve the access
problem in small rural hospitals.
Josef E. Fischer, MD
Department of Surgery
Harvard Medical School
Boston, Massachusetts
Financial Disclosures: None reported.
1. Zuckerman R, Doty B, Gold M, et al. General surgery programs in small rural
New York state hospitals. J Rural Health. 2006;22(4):339-342.
2. Smart DR, ed. Physician Characteristics and Distribution in the US, 2007. Chi-
cago, IL: American Medical Association; 2007.
3. Bodenheimer T, Berenson R, Rudolf P. The primary care-specialty income gap:
why it matters. Ann Intern Med. 2007;146(4):301-306.
4. Rich WL III. The primary care-specialty income gap. Ann Intern Med. 2007;
5. Centers for Medicare & Medicaid Services (CMS). Medicare program: revi-
sions to payment policies, five-year review of work relative value units, changes
to the practice expense methodology under the physician fee schedule, and other
changes to payment under part B. Fed Regist. 2006;71(231):69623-70251.
Commercial Features of Placebo
and Therapeutic Efficacy
To the Editor: It is possible that the therapeutic efficacy of
medications is affected by commercial features such as lower
prices. Because such features influence patients’ expecta-
they may play an unrecognized therapeutic role by
influencing the efficacy of medical therapies, especially in
conditions associated with strong placebo responses.
investigate this possibility, we studied the effect of price on
analgesic response to placebo pills.
Methods. In 2006 we recruited 82 healthy paid volunteers
in Boston, Massachusetts, using an online advertisement. Each
participant was informed by brochur eabout a (purported) new
opioid analgesic approved by the Food and Drug Administra-
tion; it was described as similar to codeine with faster onset time,
but it was actually a placebo pill. After randomization, half of
the participants were informed that the drug had a regularprice
of $2.50 per pill and half that the price had been discounted to
$0.10 per pill (no reason for the discount was mentioned). All
participants received identical placebo pills and were paid $30.
Participants were blinded to the study purpose, and research-
ers were blinded to groupassignment. The study was approved
by the Massachusetts Institute of Technology institutional re-
view board, and all participants providedwritten informed con-
sent and were debriefed after the study.
The protocol followed an established approach for studying
Electrical shocks to the wrist were calibrated to each par -
ticipant’s pain tolerance. After calibration, participants received
the test shocks, rating the pain on a computerized visual ana-
log scale anchored by the labels “no pain at all” and “the worst
pain imaginable.” Participants received all possible shocks in
2.5-V increments between 0 V and their calibrated tolerance.
Stimulation at each intensity level was carried out twice for each
participant (before and after taking the pill), and the change
in reaction to the stimulation was assessed. V isual analog scale
ratings were converted to a 100-point scale, the postpill score
for each voltage was subtracted from the prepill score, and the
mean of these differences was calculated for each participant.
The per centage of participants experiencing a mean score re-
duction vs increase was compared between the 2 groups using
a 2-tailed
test. Because stronger pain may be associated with
stronger placebo responses,
we also compared r esults for the
50% most painful shocks for each participant. In addition, mean
differ ences at each voltage between the 2 groupswer e compar ed
overall with a sign test and individually with F tests. A P value
of .05 was considered statistically significant. Analyses were per-
formed using SPSS version 15 (SPSS Inc, Chicago, Illinois).
Results. Patient characteristics are shown in the T
the regular-price group, 85.4% (95% confidence interval [CI],
74.6%-96.2%) of the participants experienced a mean pain re-
duction after taking the pill, vs 61.0% (95% CI, 46.1%-75.9%)
in the low-price (discounted) group (P =.02). Similar results
1016 JAMA, March 5, 2008—Vol 299, No. 9 (Reprinted) ©2008 American Medical Association. All rights reserved.
at INSEAD, on March 4, 2008 www.jama.comDownloaded from
occurredwhen analyzing only the 50% most painful shocks for
each participant (80.5% [95% CI, 68.3%-92.6%] vs 56.1% [95%
CI, 40.9%-71.3%], respectively; P =.03).
Considering all voltages tested, pain reduction was greater
for the regular-price pill (P .001). In addition, for 26 of
29 intensities (from 10 to 80 V), mean pain reduction was
greater for the regular-price pill (F
Comment. These results are consistent with described phe-
nomena of commercialvariables affectingquality expectations
and expectations influencing therapeutic efficacy.
Placebo re-
sponses to commer cial featureshavemany potential clinical im-
plications. For example, they may help explain the popularity
of high-cost medical therapies (eg, cyclooxygenase 2 inhibitors)
over inexpensive, widely available alternatives (eg, over-the-
counter nonsteroidalanti-inflammatory drugs) and why patients
switchingfr om branded medicationsmayr eportthattheir generic
equivalents are less effective. Studies of real-worldeffectiveness
may be more generalizable if they reflect how medications are
sold in addition to how they are formulated. Furthermore, cli-
nicians may be able to harness quality cues in beneficial ways,
for example, by de-emphasizing potentially deleterious com-
mercial factors (eg, low-priced, generic).
These findings need to be replicated in broader popula-
tions and clinical settings to better understand how commu-
nicating quality cues with patient populations can maximize
treatment benefits and patient satisfaction.
Rebecca L. Waber, BS
Massachusetts Institute of Technology
Cambridge, Massachusetts
Baba Shiv, PhD
Stanford University
Stanford, California
Ziv Carmon, PhD
Dan Ariely, PhD
Massachusetts Institute of Technology
Author Contributions: Dr Ariely had full access to all of the data in the study and
takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Waber, Shiv, Carmon, Ariely.
Acquisition of data: Waber.
Analysis and interpretation of data: Waber, Ariely.
Drafting of the manuscript: Waber, Shiv, Ariely.
Critical revision of the manuscript for important intellectual content: Waber, Shiv,
Carmon, Ariely.
Statistical analysis: Waber, Ariely.
Obtained funding: Ariely.
Administrative, technical, or material support: Waber.
Study supervision: Ariely.
Financial Disclosures: None reported.
Funding/Support: This study was funded by the Massachusetts Instituteof Technology.
Role of the Sponsor: The sponsor had no role in the design or conduct of the study;
the collection, management, analysis, or interpretation of data; or the preparation,
review, or approval of the manuscript.
Additional Contributions: Taya Leary, MS, Tom Pernikoff, BS, and John Keefe, BS, all
with the Massachusetts Institute of Technology at the time of this study, provided as-
sistance in datacollection. Mr Keefe receivedcompensation for thisrole. Andrew Lippman,
PhD, Massachusetts Instituteof Technology, provided logisticalsupport and MarkVangel,
PhD, Massachusetts General Hospital, provided statistical assistance. Neither received
compensation for these roles.
1. Rao AR, Monroe KB. The effect of price, brand name, and store name on buy-
ers’ perceptions of product quality. J Marketing Res. 1989;26(3):351-357.
2. Benedetti F. How the doctor’s words affect the patient’s brain. Eval Health Prof.
3. Koshi EB, Short CA. Placebo theory and its implications for research and clini-
cal practice. Pain Pract. 2007;7(1):4-20.
4. Berns GS, Chappelow MC, Zink CF, Pagnoni G, Martin-Skurski ME. Neurobio-
logical substrates of dread. Science. 2006;312(5774):754-758.
5. Price DD, Fields HL. The contribution of desire and expectation to placebo an-
algesia: implications for new research strategies. In: Harrington A, ed. The Placebo
Effect: An Interdisciplinary Exploration. Cambridge, Massachusetts: Harvard Uni-
versity Press; 1999:118-119.
6. Gracely RH, Dubner R, Deeter WR, Wolskee PJ. Clinicians’ expectations influ-
ence placebo analgesia. Lancet. 1985;1(8419):43.
Table. Comparison of Participants Assigned to Regular-Price Placebo
vs Low-Price (Discounted) Placebo
Regular Price
(n = 41)
Low Price
(n = 41)
Women, No. (%) 27 (65.9) 24 (58.5) .50
Age, mean (SD), y 30.9 (12.4) 30.0 (11.4) .74
Calibrated maximum tolerance,
mean (SD), V
51.8 (18.7) 54.9 (23.3) .50
Shocks received, No. (SD) 18.2 (7.2) 18.6 (9.1) .80
Change in pain scores
All shocks,
No. (%) [95% CI]
Pain reduction 35 (85.4)
25 (61.0)
Pain increase 6 (14.6)
16 (39.0)
Highest-intensity shocks only,
No. (%) [95% CI]
Pain reduction 33 (80.5)
23 (56.1)
Pain increase 8 (19.5)
18 (43.9)
Abbreviation: CI, confidence interval.
Comparison of participants experiencing a mean reduction in pain after vs before the
placebo pill was administered (visual analog scale point reduction between 0.01 and
48.4) and those experiencing a mean increase in pain (visual analog scale point in-
crease between 0 and 29.2).
Highest 50% of shocks by intensity.
Figure. Pain Ratings by Voltage Intensity
Regular price
Low price
Shock Intensity, V
Mean Difference
Placebo price
15 20 25 30 35 40 45 50 55 60 65 70 75 80
41 41 40 37 31 27 23 21 20 18 14 12 9 8
41 41 41 40 38 31 29 27 24 19 17 11 7 5 4
Mean difference in pain ratings, after vs before placebo, by voltage intensity. Higher
value indicates greater pain reduction. The table depicts the intensity of the shocks
and the number of observations in the regular-price and low-price conditions. P
value is less than .05 for the shock intensities 27.5 V through 30.0 V, 35.0 V through
75.0 V, and 80.0 V.
©2008 American Medical Association. All rights reserved. (Reprinted) JAMA, March 5, 2008—Vol 299, No. 9 1017
at INSEAD, on March 4, 2008 www.jama.comDownloaded from
... For example, Amar et al. (2011) demonstrated that brand names can enhance objective product efficacy because of the association of the brand name with efficacy. Likewise, Waber et al. (2008) showed that price affected the therapeutic efficacy of medications due to the association between (higher) price and product efficacy. In the food domain, research has shown that visual cues that imply larger food size (e.g., larger packaging images) increase people's judgment of the food's caloric value, because size is associated with caloric content . ...
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Can moral associations linked with food products harm hedonic consumption experience? Across four studies, we show that moral associations linked to food that clash with values (racism and animal welfare) held by today's ethical consumers can engender moral disgust, which in turn undermines both expected and actual taste experience. The studies contribute to the literature by showing that associations impact consumption experience even in the absence of concrete actions, and by revealing moral disgust as the mechanism underlying this phenomenon. Importantly, this effect was observed even when the moral associations involved racism or sustainability (e.g., animal welfare), which have no direct relationship to product quality. This reveals that mere moral associations, rather than quality associations, influence hedonic consumption experience, rather than quality associations. More broadly, the findings point to the ways in which extrinsic attributes affect product experience and evaluation, particularly in hedonic consumption. This may be particularly impactful for values clashing with those championed by ethical consumers. From a practical perspective, these studies provide a broader perspective on corporate social responsibility by showing that companies should exercise caution when exploiting the moral associations linked to their products.
... Electrical shocks to the wrist were given twice for each participant, before and after taking the pill, to assess the change in pain. Reduction in pain was reported by 85.4% of the regular-price group and by 61.0% of the discounted price group (Waber et al., 2008). The result shows that simple beliefs, or inner communication, that "expensive pills would have stronger effects" caused the difference. ...
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This paper offers theoretical explanations for why "guided touch" or manual touch with verbal communication can be an effective way of treating the body (e.g., chronic pain) and the mind (e.g., emotional disorders). The active inference theory suggests that chronic pain and emotional disorders can be attributed to distorted and exaggerated patterns of interoceptive and proprioceptive inference. We propose that the nature of active inference is abductive. As such, to rectify aberrant active inference processes, we should change the "Rule" of abduction, or the "prior beliefs" entailed by a patient's generative model. This means pre-existing generative models should be replaced with new models. To facilitate such replacement-or updating-the present treatment proposes that we should weaken prior beliefs, especially the one at the top level of hierarchical generative models, thereby altering the sense of agency, and redeploying attention. Then, a new prior belief can be installed through inner communication along with manual touch. The present paper proposes several hypotheses for possible experimental studies. If touch with verbal guidance is proven to be effective, this would demonstrate the relevance of active inference and the implicit prediction model at a behavioral level. Furthermore, it would open new possibilities of employing inner communication interventions, including self-talk training, for a wide range of psychological and physical therapies.
... It is well-established that pain should be highest during a painful-stimulus condition when no treatment is provided, reduced slightly under a placebo treatment, and reduced the most by effective analgesics. On placebo effectiveness, see for example Colloca and Barsky (19) and also demonstrations that higher-priced placebos work better than lower-priced ones (20). Using this knowledge, we test the novel three-region measure in a rigorous study with a 3-armed, placebo-controlled, randomized crossover trial design including 24 healthy adults. ...
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Background Self-reported pain levels, while easily measured, are often not reliable for quantifying pain. More objective methods are needed that supplement self-report without adding undue burden or cost to a study. Methods that integrate multiple measures, such as combining self-report with physiology in a structured and specific-to-pain protocol may improve measures.Method We propose and study a novel measure that combines the timing of the peak pain measured by an electronic visual-analog-scale (eVAS) with continuously-measured changes in electrodermal activity (EDA), a physiological measure quantifying sympathetic nervous system activity that is easily recorded with a skin-surface sensor. The new pain measure isolates and specifically quantifies three temporal regions of dynamic pain experience: I. Anticipation preceding the onset of a pain stimulus, II. Response rising to the level of peak pain, and III. Recovery from the peak pain level. We evaluate the measure across two pain models (cold pressor, capsaicin), and four types of treatments (none, A=pregabalin, B=oxycodone, C=placebo). Each of 24 patients made four visits within 8 weeks, for 96 visits total: A training visit (TV), followed by three visits double-blind presenting A, B, or C (randomized order). Within each visit, a participant experienced the cold pressor, followed by an hour of rest during which one of the four treatments was provided, followed by a repeat of the cold pressor, followed by capsaicin.ResultsThe novel method successfully discriminates the pain reduction effects of the four treatments across both pain models, confirming maximal pain for no-treatment, mild pain reduction for placebo, and the most pain reduction with analgesics. The new measure maintains significant discrimination across the test conditions both within a single-day's visit (for relative pain relief within a visit) and across repeated visits spanning weeks, reducing different-day-physiology affects, and providing better discriminability than using self-reported eVAS.Conclusion The new method combines the subjectively-identified time of peak pain with capturing continuous physiological data to quantify the sympathetic nervous system response during a dynamic pain experience. The method accurately discriminates, for both pain models, the reduction of pain with clinically effective analgesics.
... As such, anything that contributes to the belief in therapeutic efficacy will likely induce a placebo effect. For example, the optimism/enthusiasm (Shapiro, 1969), as well as the perceived authority (Kirmayer, 1994) of the physician, elaborate procedures and devices (De Craen et al., 2000;Kaptchuk et al., 2000), costliness of the intervention (Waber et al., 2008) have all been shown to enhance therapeutic efficacy through the placebo effect. In addition to the specific features of the physician and therapeutic practice themselves, observing other patients improve after taking a certain drug increases one's own recovery under the same drug treatment (Faasse & Petrie, 2016). ...
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The placebo effect, used today as the benchmark to evaluate treatment efficacy, plays a major functional role in traditional medical practices. To better understand its effect at the population level, I use a formal approach to examine the population dynamics of the placebo effect and show a reciprocal causal relationship between belief and efficacy: belief in the efficacy of treatments enhances their realized efficacy, which in turn increases people’s confidence in their therapeutic power. A unique equilibrium for subjective belief and realized efficacy always exists. Its magnitude depends on how beliefs are constructed (relative weight on observed action vs. observed outcome). I further investigate how the placebo effect affects the maintenance of existing medical technologies and the invasion of new technologies by explicitly modeling a belief construction process. Analytical and simulation results show that although the placebo effect primarily suppresses the spread of new technologies, it may occasionally enhance the adoption of superior technological variants under specific parameter combinations.
... In one study, placebos that supposedly cost $2.50 per pill relieved pain in 85% of participants, while placebos allegedly costing $0.10 only relieved pain in 61% of the sample (25). Of particular relevance to the discussion of a rationale, verbal instructions modify the placebo effect. ...
Although content sharing on the Internet used to be free of charge, increasing numbers of customers are willing to pay for shared online content. However, little is known about whether, when, and why the price of shared content affects the benefits of sharer. Using a secondary data analysis and two lab experiments, this paper examines the effect of content pricing on content sales and customer satisfaction. The results indicate that content price has a divergent impact on sales and customer satisfaction. Specifically, an increase in content price improves sales but hurts customer satisfaction for certified sharers; an increase in content price hurts sales but improves customer satisfaction for non-certified sharers. Thus, content sharers cannot use the pricing mechanism to simultaneously enjoy high sales (fortune) and high customer satisfaction (prestige), and they need the trade-off between sales and customer satisfaction. These findings have theoretical and managerial implications for content sharing.
Background: Since randomized controlled trials have indicated that adjuvant chemotherapy prolongs survival and reduces recurrence rates after surgical resection of pancreatic adenocarcinoma, a gemcitabine based chemotherapy has become part of the interdisciplinary treatment concept for pancreatic cancer in accordance to current guidelines. Objectives: The aim of this project was to analyse the validity of the CONKO -001 trial as a basis for the recommendation of adjuvant chemotherapy in many international guidelines. Methods: We analysed the validity of the CONKO - 001 trial regarding study design, recruitment period, participating institutions, patient selection, randomisation, stratification, standardization of surgical treatment and histological examination, statistical methods and interpretation of results. We additionally analysed the study regarding the risk of bias using the RoB 2 Tool. Finally we reviewed the influence of the pharmaceutical industry and potential conflicts of interest. Results: We identified several shortcomings of the study concerning the study protocol, the participating clinics, the patient recruitment, the randomization pattern, the standardization of surgical treatment and histological examination, the statistical methods, the evaluation of the results and the influence of the pharmaceutical industry. According to the Cochrane RoB 2 Tool the study was judged to raise some concerns in three of the five risk domains for the outcome "overall survival". Conclusions: Based on our review, the results of the CONKO-001-study should be revisited and critically reviewed. The recommendation to include adjuvant chemotherapy with gemcitabine deserves a critical appraisal.
Background Mandatory disclosure of the price of prescription drugs within direct-to-consumer pharmaceutical advertisements (DTCA) has been proposed as a potential means of curbing rising drug costs in the United States. While price transparency in DTCA has widespread public support, empirical evidence regarding the effects of such drug prices disclosures remains limited. Objectives This study assessed the degree to which a price disclosure was noticed, the individual characteristics associated with price disclosure recognition, and the impact on perceived drug affordability, effectiveness, and safety. Methods A randomized experiment was conducted among 2,138 members of the Amerispeak online panel. Participants were shown a television commercial for a drug treating either type II diabetes, deep vein thrombosis/pulmonary embolism (DVT/PE), or rheumatoid arthritis (RA) that disclosed the list price, disclosed the list price plus the average out-of-pocket cost, or had no price disclosure. Results Roughly forty percent of participants noticed when a price was disclosed while 20–24% noticed information about individual costs varying (the higher of these percentages occurred when the average out-of-pocket cost was provided). Attention did not vary systematically with the cost amount. Recognition of the different elements of the price disclosure were most predicted by sociodemographic variables such as race, education, and income as well as health characteristics. Price disclosure altered perceived affordability of the advertised medication in a manner consistent with the costs provided, but such consistent significant effects were not found for perceived drug effectiveness and safety. Conclusions Repeated exposure to price disclosure in television DTCA or supplementary sources of price information may be necessary to increase attention to drug price information, especially among those who are most vulnerable to the burden of drug costs. Price transparency appears useful for adjusting affordability perceptions, but additional research needs to examine how such perceptions factor into healthcare decision-making and drug pricing.
Despite the bioequivalence of brand-name and generic drugs, some patients have complained about diminished efficacy after consumption. We administered brand and generic name constructs for loxoprofen sodium hydrate to patients in a variety of forms, including tablets and powder. We used the visual analog scale (VAS) to investigate and examine whether efficacy differences were attributed to the drug action or to a placebo effect. The responses of the 5 patients that entered this study showed different results when the brand-name and generic drugs were taken in a state where they could be distinguished from each other, and the VAS change when they were indistinguishable. In particular, three patients yielded large VAS differences when they consumed the brand-name and generic drugs in the form of tablets, but the VAS change was smaller when the drug was pulverized and consumed in powder form. This study suggests that there is no difference in the actual efficacy between the brand-name and the generic drug forms, and that any noted differences are likely attributed to a placebo effect. The placebo effect has positive or negative effects owing to various factors. As healthcare professionals, we must strive to maximize the therapeutic effects.
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Although placebo effect is a common phenomenon in medicine and research, its mechanisms are not well understood. With the advent of modern medicine, placebo became a symbol for an outdated, morally questionable practice implying deceit and paternalism. However, in recent years, there has been an increasing amount of rigorous research into the mechanisms of placebo response and placebo analgesia with most studies coming from the field of pain medicine. New theories on placebo mechanisms have shown that placebo represents the psychosocial aspect of every treatment and the study of placebo is essentially the study of psychosocial context that surrounds the patient. Therefore, its understanding is essential for researchers and all medical practitioners, particularly those dealing with patients suffering from pain, depression, and motor disorders. In this article, we review the theories on placebo mechanisms and discuss their implications for clinical practice and the design of clinical trials.
The authors integrate previous research that has investigated experimentally the influence of price, brand name, and/or store name on buyers' evaluations of prod¬uct quality. The meta-analysis suggests that, for consumer products, the relation¬ships between price and perceived quality and between brand name and perceived quality are positive and statistically significant. However, the positive effect of store name on perceived quality is small and not statistically significant. Further, the type of experimental design and the strength of the price manipulation are shown to significantly influence the observed effect of price on perceived quality.
Clinicians have long known that context is important in any medical treatment and that the words and attitudes of doctors and nurses can have great impact on the patient. There is now experimental evidence indicating that the medical context influences specific neural systems. The importance of the context is shown by the lesser effectiveness of hidden administrations of analgesics compared with open ones. Because the placebo effect is a context effect, its study has been useful in clarifying this complex issue. There are now several lines of evidence that placebo analgesia is mediated by endogenous opioids and placebo motor improvement by endogenous dopamine. Moreover, a placebo treatment is capable of affecting many brain regions in depressed patients. All these studies, taken together, lead to a neurobiological understanding of the events occurring in the brain during the interaction between the therapist and his or her patient.
Given the choice of waiting for an adverse outcome or getting it over with quickly, many people choose the latter. Theoretical models of decision-making have assumed that this occurs because there is a cost to waiting—i.e., dread. Using functional magnetic resonance imaging, we measured the neural responses to waiting for a cutaneous electric shock. Some individuals dreaded the outcome so much that, when given a choice, they preferred to receive more voltage rather than wait. Even when no decision was required, these extreme dreaders were distinguishable from those who dreaded mildly by the rate of increase of neural activity in the posterior elements of the cortical pain matrix. This suggests that dread derives, in part, from the attention devoted to the expected physical response and not simply from fear or anxiety. Although these differences were observed during a passive waiting procedure, they correlated with individual behavior in a subsequent choice paradigm, providing evidence for a neurobiological link between the experienced disutility of dread and subsequent decisions about unpleasant outcomes.
Placebo theory and its implications for research and clinical practice
  • E B Koshi
  • C A Short
Koshi EB, Short CA. Placebo theory and its implications for research and clinical practice. Pain Pract. 2007;7(1):4-20.
The contribution of desire and expectation to placebo analgesia: implications for new research strategies
  • D D Price
  • H L Fields
Price DD, Fields HL. The contribution of desire and expectation to placebo analgesia: implications for new research strategies. In: Harrington A, ed. The Placebo Effect: An Interdisciplinary Exploration. Cambridge, Massachusetts: Harvard University Press; 1999:118-119.