Targeting neural correlates of placebo effects.

Harnessing the placebo effects would prompt critical ramifications for research and clinical practice. Noninvasive brain stimulation (NIBS) techniques, such as transcranial magnetic stimulation and multifocal transcranial electric stimulation, could manipulate the placebo response by modulating the activity and excitability of its neural correlates. To identify potential stimulation targets, we conducted a meta-analysis to investigate placebo-associated regions in healthy volunteers, including studies with emotional components and painful stimuli. Using biophysical modeling, we identified NIBS solutions to manipulate placebo effects by targeting either a single key region or multiple connected areas. Moving to a network-oriented approach, we then ran a quantitative network mapping analysis on the functional connectivity profile of clusters emerging from the meta-analysis. As a result, we suggest a multielectrode optimized montage engaging the connectivity patterns of placebo-associated functional brain networks. These NIBS solutions hope to provide a starting point to actively control, modulate or enhance placebo effects in future clinical studies and cognitive enhancement studies.

Genetic variation in catechol-O-methyltransferase modifies effects of clonidine treatment in chronic fatigue syndrome.

Clonidine, an α2-adrenergic receptor agonist, decreases circulating norepinephrine and epinephrine, attenuating sympathetic activity. Although catechol-O-methyltransferase (COMT) metabolizes catecholamines, main effectors of sympathetic function, COMT genetic variation effects on clonidine treatment are unknown. Chronic fatigue syndrome (CFS) is hypothesized to result in part from dysregulated sympathetic function. A candidate gene analysis of COMT rs4680 effects on clinical outcomes in the Norwegian Study of Chronic Fatigue Syndrome in Adolescents: Pathophysiology and Intervention Trial (NorCAPITAL), a randomized double-blinded clonidine versus placebo trial, was conducted (N=104). Patients homozygous for rs4680 high-activity allele randomized to clonidine took 2500 fewer steps compared with placebo (Pinteraction=0.04). There were no differences between clonidine and placebo among patients with COMT low-activity alleles. Similar gene-drug interactions were observed for sleep (Pinteraction=0.003) and quality of life (Pinteraction=0.018). Detrimental effects of clonidine in the subset of CFS patients homozygous for COMT high-activity allele warrant investigation of potential clonidine-COMT interaction effects in other conditions.

The imagined itch: brain circuitry supporting nocebo-induced itch in atopic dermatitis patients.

BACKGROUND: Psychological factors are known to significantly modulate itch in patients suffering from chronic itch. Itch is also highly susceptible to both placebo and nocebo (negative placebo) effects. Brain activity likely supports nocebo-induced itch, but is currently unknown. METHODS: We collected functional MRI (fMRI) data from atopic dermatitis (AD) patients, in a within-subject design, and contrast brain response to nocebo saline understood to be allergen vs open-label saline control. Exploratory analyses compared results to real allergen itch response and placebo responsiveness, evaluated in the same patients. RESULTS: Nocebo saline produced greater itch than open saline control (P < 0.01). Compared to open saline, nocebo saline demonstrated greater fMRI response in caudate, dorsolateral prefrontal cortex (dlPFC), and intraparietal sulcus (iPS) - brain regions important for cognitive executive and motivational processing. Exploratory analyses found that subjects with greater dlPFC and caudate activation to nocebo-induced itch also demonstrated greater dlPFC and caudate activation, respectively, for real allergen itch. Subjects reporting greater nocebo-induced itch also demonstrated greater placebo reduction of allergen-evoked itch, suggesting increased generalized modulation of itch perception. CONCLUSIONS: Our study demonstrates the capacity of nocebo saline to mimic both the sensory and neural effects of real allergens and provides an insight to the brain mechanisms supporting nocebo-induced itch in AD, thus aiding our understanding of the role that expectations and other psychological factors play in modulating itch perception in chronic itch patients.

Sharing pain and relief: neural correlates of physicians during treatment of patients.

Patient-physician interactions significantly contribute to placebo effects and clinical outcomes. While the neural correlates of placebo responses have been studied in patients, the neurobiology of the clinician during treatment is unknown. This study investigated physicians' brain activations during patient-physician interaction while the patient was experiencing pain, including a 'treatment', 'no-treatment' and 'control' condition. Here, we demonstrate that physicians activated brain regions previously implicated in expectancy for pain-relief and increased attention during treatment of patients, including the right ventrolateral and dorsolateral prefrontal cortices. The physician's ability to take the patients' perspective correlated with increased brain activations in the rostral anterior cingulate cortex, a region that has been associated with processing of reward and subjective value. We suggest that physician treatment involves neural representations of treatment expectation, reward processing and empathy, paired with increased activation in attention-related structures. Our findings further the understanding of the neural representations associated with reciprocal interactions between clinicians and patients; a hallmark for successful treatment outcomes.

Patient-Clinician Brain Response During Clinical Encounter and Pain Treatment.

The patient-clinician relationship is known to significantly affect the pain experience, as empathy, mutual trust and therapeutic alliance can significantly modulate pain perception and influence clinical therapy outcomes. The aim of the present study was to use an EEG hyperscanning setup to identify brain and behavioral mechanisms supporting the patient-clinician relationship while this clinical dyad is engaged in a therapeutic interaction. Our previous study applied fMRI hyperscanning to investigate whether brain concordance is linked with analgesia experienced by a patient while undergoing treatment by the clinician. In this current hyperscanning project we investigated similar outcomes for the patient-clinician dyad exploiting the high temporal resolution of EEG and the possibility to acquire the signals while patients and clinicians were present in the same room and engaged in a face-to-face interaction under an experimentally-controlled therapeutic context. Advanced source localization methods allowed for integration of spatial and spectral information in order to assess brain correlates of therapeutic alliance and pain perception in different clinical interaction contexts. Preliminary results showed that both behavioral and brain responses across the patient-clinician dyad were significantly affected by the interaction style.Clinical Relevance- The context of a clinical intervention can significantly impact the treatment of chronic pain. Effective therapeutic alliance, based on empathy, mutual trust, and warmth can improve treatment adherence and clinical outcomes. A deeper scientific understanding of the brain and behavioral mechanisms underlying an optimal patient-clinician interaction may lead to improved quality of clinical care and physician training, as well as better understanding of the social aspects of the biopsychosocial model mediating analgesia in chronic pain patients.

In Vitro Angiogenesis Effect of Xuefu Zhuyu Decoction () and Vascular Endothelial Growth Factor: A Comparison Study.

OBJECTIVE: To compare the angiogenesis behaviors of vascular endothelial growth factor (VEGF) and Chinese medicine Xuefu Zhuyu Decoction (, XZD) treatments. METHODS: Human microvascular endothelial cells (HMEC-1) were treated with various concentrations of either XZD-containing serum (XZD-CS) or VEGF for 24, 48, and 72 h, respectively. Cell viability, proliferation, migration, adhesion, and in vitro tube formation assays were used to assess their angiogenic effects. RESULTS: VEGF promoted all cellular phases involved in angiogenesis including cell viability, proliferation, migration, adhesion, and tube formation (<0.05 or <0.01). Unlike the continuous promotion effects of VEGF at the above stages, XZD inhibited cell viability and proliferation (<0.05 or <0.01) and only promoted tube formation in the early phase of angiogenesis (<0.01). CONCLUSIONS: These two medications promote different angiogenesis behaviors, which might be an important reason for their distinct therapeutic profile in clinical usage.

A meta-analysis of the placebo response in complementary and alternative medicine trials of irritable bowel syndrome.

Among patients with irritable bowel syndrome (IBS) enrolled in clinical trials of conventional medical therapy, the placebo response rate is high. IBS patients also frequently use complementary and alternative medicine (CAM), which may act through an 'enhanced placebo effect'. The purpose of this study was to estimate the magnitude of the placebo response rate in CAM trials for IBS and to identify factors that influence this response. We performed a systematic review and meta-analysis of randomized, placebo-controlled clinical trials of CAM therapies for IBS identified from MEDLINE/EMBASE/PsychLIT databases from 1970 to 2006. Placebo and active treatment response rates for global symptom improvement were assessed. Nineteen studies met the inclusion criteria. The pooled estimate of the placebo response rate was 42.6% (95% confidence interval, 38.0-46.5%). Significant heterogeneity existed across trials (range 15.0-72.2%, P < 0.00001). Higher placebo response rates correlated with a longer duration of treatment (r = 0.455, P = 0.05) and a greater number of office visits (r = 0.633, P = 0.03). Among IBS patients in CAM trials, the placebo response rate is high. That this rate is similar in magnitude to that seen in conventional medicine trials suggests that the placebo response is independent of the type of therapy used and that it is not particularly 'enhanced' in CAM trials.

Effects of subtle cognitive manipulations on placebo analgesia - An implicit priming study.

BACKGROUND: Expectancy is widely accepted as a key contributor to placebo effects. However, it is not known whether non-conscious expectancies achieved through semantic priming may contribute to placebo analgesia. In this study, we investigated if an implicit priming procedure, where participants were unaware of the intended priming influence, affected placebo analgesia. METHODS: In a double-blind experiment, healthy participants (n = 36) were randomized to different implicit priming types; one aimed at increasing positive expectations and one neutral control condition. First, pain calibration (thermal) and a credibility demonstration of the placebo analgesic device were performed. In a second step, an independent experimenter administered the priming task; Scrambled Sentence Test. Then, pain sensitivity was assessed while telling participants that the analgesic device was either turned on (placebo) or turned off (baseline). Pain responses were recorded on a 0-100 Numeric Response Scale. RESULTS: Overall, there was a significant placebo effect (p < 0.001), however, the priming conditions (positive/neutral) did not lead to differences in placebo outcome. Prior experience of pain relief (during initial pain testing) correlated significantly with placebo analgesia (p < 0.001) and explained 34% of placebo variance. Trait neuroticism correlated positively with placebo analgesia (p < 0.05) and explained 21% of placebo variance. CONCLUSIONS: Priming is one of many ways to influence behaviour, and non-conscious activation of positive expectations could theoretically affect placebo analgesia. Yet, we found no SST priming effect on placebo analgesia. Instead, our data point to the significance of prior experience of pain relief, trait neuroticism and social interaction with the treating clinician. SIGNIFICANCE: Our findings challenge the role of semantic priming as a behavioural modifier that may shape expectations of pain relief, and affect placebo analgesia.

The placebo effect in irritable bowel syndrome trials: a meta-analysis.

BACKGROUND: Despite the apparent high placebo response rate in randomized placebo-controlled trials (RCT) of patients with irritable bowel syndrome (IBS), little is known about the variability and predictors of this response. OBJECTIVES: To describe the magnitude of response in placebo arms of IBS clinical trials and to identify which factors predict the variability of the placebo response. METHODS: We performed a meta-analysis of published, English language, RCT with 20 or more IBS patients who were treated for at least 2 weeks. This analysis is limited to studies that assessed global response (improvement in overall symptoms). The variables considered as potential placebo modifiers were study design, study duration, use of a run-in phase, Jadad score, entry criteria, number of office visits, number of office visits/study duration, use of diagnostic testing, gender, age and type of medication studied. FINDINGS: Forty-five placebo-controlled RCTs met the inclusion criteria. The placebo response ranged from 16.0 to 71.4% with a population-weighted average of 40.2%, 95% CI (35.9-44.4). Significant associations with lower placebo response rates were fulfillment of the Rome criteria for study entry (P=0.049) and an increased number of office visits (P=0.026). CONCLUSIONS: Placebo effects in IBS clinical trials measuring a global outcome are highly variable. Entry criteria and number of office visits are significant predictors of the placebo response. More stringent entry criteria and an increased number of office visits appear to independently decrease the placebo response.

Chiropractic: origins, controversies, and contributions.

Chiropractic is an important component of the US health care system and the largest alternative medical profession. In this overview of chiropractic, we examine its history, theory, and development; its scientific evidence; and its approach to the art of medicine. Chiropractic's position in society is contradictory, and we reveal a complex dynamic of conflict and diversity. Internally, chiropractic has a dramatic legacy of strife and factionalism. Externally, it has defended itself from vigorous opposition by conventional medicine. Despite such tensions, chiropractors have maintained a unified profession with an uninterrupted commitment to clinical care. While the core chiropractic belief that the correction of spinal abnormality is a critical health care intervention is open to debate, chiropractic's most important contribution may have to do with the patient-physician relationship.

Randomized trial comparing traditional Chinese medical acupuncture, therapeutic massage, and self-care education for chronic low back pain.

BACKGROUND: Because the value of popular forms of alternative care for chronic back pain remains uncertain, we compared the effectiveness of acupuncture, therapeutic massage, and self-care education for persistent back pain. METHODS: We randomized 262 patients aged 20 to 70 years who had persistent back pain to receive Traditional Chinese Medical acupuncture (n = 94), therapeutic massage (n = 78), or self-care educational materials (n = 90). Up to 10 massage or acupuncture visits were permitted over 10 weeks. Symptoms (0-10 scale) and dysfunction (0-23 scale) were assessed by telephone interviewers masked to treatment group. Follow-up was available for 95% of patients after 4, 10, and 52 weeks, and none withdrew for adverse effects. RESULTS: Treatment groups were compared after adjustment for prerandomization covariates using an intent-to-treat analysis. At 10 weeks, massage was superior to self-care on the symptom scale (3.41 vs 4.71, respectively; P =.01) and the disability scale (5.88 vs 8.92, respectively; P<.001). Massage was also superior to acupuncture on the disability scale (5.89 vs 8.25, respectively; P =.01). After 1 year, massage was not better than self-care but was better than acupuncture (symptom scale: 3.08 vs 4.74, respectively; P =.002; dysfunction scale: 6.29 vs 8.21, respectively; P =.05). The massage group used the least medications (P<.05) and had the lowest costs of subsequent care. CONCLUSIONS: Therapeutic massage was effective for persistent low back pain, apparently providing long-lasting benefits. Traditional Chinese Medical acupuncture was relatively ineffective. Massage might be an effective alternative to conventional medical care for persistent back pain.

The double-blind, randomized, placebo-controlled trial: gold standard or golden calf?

The double-blind randomized controlled trial (RCT) is accepted by medicine as objective scientific methodology that, when ideally performed, produces knowledge untainted by bias. The validity of the RCT rests not just on theoretical arguments, but also on the discrepancy between the RCT and less rigorous evidence (the difference is sometimes considered an objective measure of bias). A brief overview of historical and recent developments in "the discrepancy argument" is presented. The article then examines the possibility that some of this "deviation from truth" may be the result of artifacts introduced by the masked RCT itself. Can an "unbiased" method produce bias? Among the experiments examined are those that augment the methodological stringency of a normal RCT in order to render the experiment less susceptible to subversion by the mind. This methodology, a hypothetical "platinum" standard, can be used to judge the "gold" standard. The concealment in a placebo-controlled RCT seems capable of generating a "masking bias." Other potential biases, such as "investigator self-selection," "preference," and "consent" are also briefly discussed. Such potential distortions indicate that the double-blind RCT may not be objective in the realist sense, but rather is objective in a "softer" disciplinary sense. Some "facts" may not exist independent of the apparatus of their production.

Do medical devices have enhanced placebo effects?

Although the placebo in a clinical trial is often considered simply a baseline against which to evaluate the efficacy of a clinical intervention, there is evidence that the magnitude of placebo effect may be a critical factor in determining the results of a trial. This article examines the question of whether devices have enhanced placebo effects and, if so, what the implications may be. While the evidence of an enhanced placebo effect remains rudimentary, it is provocative and therefore worthy of further study. Suggestions are made, therefore, for how such an effect can be investigated without violating the principles of informed consent.

Are randomized control trial outcomes influenced by the inclusion of a placebo group?: a systematic review of nonsteroidal antiinflammatory drug trials for arthritis treatment.

Placebo groups are often included in randomized control trials evaluating drug therapy, yet we know little about the placebo effect. The purpose of our study was to evaluate how the presence of a placebo group in a randomized control trial (RCT) influences the patients' ratings of the efficacy of an active drug therapy and their reporting of its adverse effects. We identified studies published between 1966 and 1994 using MEDLINE. Randomized control trials evaluating acetylsalicylic acid, diclofenac, or indomethacin for the treatment of osteo or rheumatoid arthritis were included in our sample. Two investigators independently extracted data. Fifty-eight treatment arms met our inclusion criteria and were available for analysis. Twenty-five treatment arms evaluated a nonsteroidal antiinflammatory drug (NSAID) in placebo control trials and 33 in comparative trials. Using a logistic regression model to adjust for the differences between the evaluated drugs and between the types of arthritis, we found that patients receiving an NSAID in a placebo control trial were more likely to withdraw due to inefficacy (OR=1.3; 95% CI, 1.0 to 1.6; P=0.04). Using a similar model, withdrawals due to adverse effects were found to be more common when the NSAID was given in trials that did not include a placebo group (OR=1.5; 95% CI, 1.1 to 1.9; P=0.002) as were reports of cutaneous (OR=4.2; 95% CI, 1.7 to 9.9), gastrointestinal (OR=1.6; 95% CI, 1.3 to 2.0), and other types (OR=5.3; 95% CI, 3.8 to 7.4) of adverse effects. Although reports of central nervous system adverse effects were more frequent in the comparative trials, this difference was not significant. Including a placebo group in a RCT changes how patients rate the efficacy and adverse effects of their therapy. Our results highlight the need to consider the placebo effect in the design and analyses of clinical trials.

Availability of acupuncture in the hospitals of a major academic medical center: a pilot study.

BACKGROUND: Acupuncture is widely used by the American public, but little is known about its availability and use in academic medical settings. We performed a pilot study to compare acupuncture services provided by hospitals affiliated with a major academic teaching institution, and a parallel survey of services provided through an acupuncture school in one city in New England. METHODS: Between December 2000 and July 2001, a telephone survey was conducted of the 13 hospitals affiliated with Harvard Medical School, and the clinics affiliated with the New England School of Acupuncture. RESULTS: Acupuncture was available in 8 of the 13 hospitals. Acupuncture was provided in ambulatory clinics in all eight hospitals, but was available to inpatients in only one hospital. Six hospitals delivered acupuncture through an outpatient pain treatment service, one through a women's health center, one through an HIV clinic, and one hospital delivered acupuncture through two services; a program in the anesthesia department and a multi-disciplinary holistic program in a primary care department. In contrast, the acupuncture school clinics provided services through an on-site clinic at the school, through acupuncture departments at two community-based hospitals, and through a network of 12 satellite acupuncture-dedicated clinics operating throughout the state. CONCLUSION: Acupuncture is available on a limited basis in a majority of the teaching hospitals in this city. At the acupuncture school clinics, there are few barriers to care. Future health care studies will need to examine the role of acupuncture in diverse geographic settings and to examine its impact on quality of care, teaching and its role in research in academic centers.