What is controlled for in placebo-controlled trials?

Investigating the hypoalgesic effects of spinal manipulative therapy using hidden pain conditioning and positive expectation in patients with chronic low back pain: protocol for a randomised controlled trial

INTRODUCTION

Placebo effects are responses capable of modulating pain and influencing treatment response. Two mechanisms are commonly related to placebo effects: expectations and conditioning. However, the research in this field is focused on laboratory studies with healthy participants. This study aims to identify whether a conditioning procedure with positive induced expectations about spinal manipulative therapy (SMT) will result in greater hypoalgesic effects in adults with chronic low back pain (CLBP) in a clinical trial design.

METHODS AND ANALYSIS

This trial will enrol 264 patients with non-specific CLBP, aged 18-60 years. Patients will undergo a calibration test to determine the thermal pain threshold for the hidden pain conditioning procedure. Afterward, they will be randomised to one of the three groups: hidden pain conditioning with positive induced expectations-group one (G1); positive expectations-group two (G2) and neutral expectations-group three (G3). Patients will receive instructions to manipulate the expectations. The pretreatment heat pain test will be performed before the SMT and after the intervention patients will undergo again the heat pain intensity test. However, only patients in G1 will receive hidden pain conditioning to reinforce the association between SMT and pain intensity reduction. All patients will undergo five sessions of SMT. The outcomes will be assessed immediately after the last session and at the 6 weeks and 3-month follow-ups. All statistical analyses will be conducted following intention-to-treat principles, and the treatment effects will be determined with linear mixed models.

ETHICS AND DISSEMINATION

The Federal University of São Carlos approved this research (Process n° 52359521.1.0000.5504). All participants will give written informed consent. Dissemination of the results will include publications in peer-reviewed journals and presentations at conferences. If positive expectations and classical conditioning improve outcomes, it may support the administration of such intervention.

TRIAL REGISTRATION NUMBER

NCT05202704.

Conscious connected breathing with breath retention intervention in adults with chronic low back pain: protocol for a randomized controlled pilot study

BACKGROUND

Chronic pain is a major source of human suffering, and chronic low back pain (cLBP) is among the most prevalent, costly, and disabling of pain conditions. Due to the significant personal and societal burden and the complex and recurring nature of cLBP, self-management approaches that can be practiced at home are highly relevant to develop and test. The respiratory system is one of the most integrated systems of the body, and breathing is bidirectionally related with stress, emotion, and pain. Thus, the widespread physiological and psychological impact of breathing practices and breathwork interventions hold substantial promise as possible self-management strategies for chronic pain. The primary aim of the current randomized pilot study is to test the feasibility and acceptability of a conscious connected breathing with breath retention intervention compared to a sham control condition.

METHODS

The rationale and procedures for testing a 5-day conscious connected breathing with breath retention intervention, compared to a deep breathing sham control intervention, in 24 adults (18-65 years) with cLBP is described. Both interventions will be delivered using standardized audio recordings and practiced over 5 days (two times in-person and three times at-home), and both are described as Breathing and Attention Training to reduce possible expectancy and placebo effects common in pain research. The primary outcomes for this study are feasibility and acceptability. Feasibility will be evaluated by determining rates of participant recruitment, adherence, retention, and study assessment completion, and acceptability will be evaluated by assessing participants' satisfaction and helpfulness of the intervention. We will also measure other clinical pain, psychological, behavioral, and physiological variables that are planned to be included in a follow-up randomized controlled trial.

DISCUSSION

This will be the first study to examine the effects of a conscious connected breathing with breath retention intervention for individuals with chronic pain. The successful completion of this smaller-scale pilot study will provide data regarding the feasibility and acceptability to conduct a subsequent trial testing the efficacy of this breathing self-management practice for adults with cLBP.

TRIAL REGISTRATION

Clinicaltrials.gov, identifier NCT04740710 . Registered on 5 February 2021.

Vitamin D Status, Cardiovascular Risk Profile, and miRNA-21 Levels in Hypertensive Patients: Results of the HYPODD Study

The vitamin D and microRNA (miR) systems may play a role in the pathogenesis of cardiometabolic disorders, including hypertension. The HYPODD study was a double-blind placebo-controlled trial aiming to assess the effects of cholecalciferol treatment in patients with well-controlled hypertension and hypovitaminosis D (25OHD levels < 50 nmol/L). In addition to this clinical trial, we also evaluated the effects of cholecalciferol and calcitriol treatment on miR-21 expression in vivo and in vitro, respectively. Changes in the cardiovascular risk profiles were evaluated in HYPODD patients treated with cholecalciferol (C-cohort) or with placebo (P-cohort). The miR-21circulating levels were measured in four C-cohort patients and five P-cohort patients. In vitro, the miR-21 levels were measured in HEK-293 cells treated with calcitriol or with ethanol vehicle control. Cholecalciferol treatment increased 25OHD levels and reduced parathormone, total cholesterol, and low-density lipoprotein cholesterol levels in C-cohort patients, whereas no significant changes in these parameters were observed in P-cohort patients. The miR-21 circulating levels did not change in the C- or the P-cohort patients upon treatment. Calcitriol treatment did not affect miR-21 levels in HEK-293 cells. In conclusion, hypovitaminosis D correction ameliorated the cardiovascular risk profiles in hypertensive patients treated with cholecalciferol but did not influence the miR-21 expression.

Great Expectations: recommendations for improving the methodological rigor of psychedelic clinical trials

RATIONALE

Psychedelic research continues to garner significant public and scientific interest with a growing number of clinical studies examining a wide range of conditions and disorders. However, expectancy effects and effective condition masking have been raised as critical limitations to the interpretability of the research.

OBJECTIVE

In this article, we review the many methodological challenges of conducting psychedelic clinical trials and provide recommendations for improving the rigor of future research.

RESULTS

Although some challenges are shared with psychotherapy and pharmacology trials more broadly, psychedelic clinical trials have to contend with several unique sources of potential bias. The subjective effects of a high-dose psychedelic are often so pronounced that it is difficult to mask participants to their treatment condition; the significant hype from positive media coverage on the clinical potential of psychedelics influences participants' expectations for treatment benefit; and participant unmasking and treatment expectations can interact in such a way that makes psychedelic therapy highly susceptible to large placebo and nocebo effects. Specific recommendations to increase the success of masking procedures and reduce the influence of participant expectancies are discussed in the context of study development, participant recruitment and selection, incomplete disclosure of the study design, choice of active placebo condition, as well as the measurement of participant expectations and masking efficacy.

CONCLUSION

Incorporating the recommended design elements is intended to reduce the risk of bias in psychedelic clinical trials and thereby increases the ability to discern treatment-specific effects of psychedelic therapy.

Can Patient Expectations Modulate the Short-Term Effects of Dry Needling on Sensitivity Outcomes in Patients with Mechanical Neck Pain? A Randomised Clinical Trial

OBJECTIVE

Dry needling is commonly used for the management of musculoskeletal pain patients. However, the effects of patient expectations are uncertain. Our aim was to determine the effect of patient expectations on short-term clinical outcomes after the application of a single session of dry needling in individuals with neck pain.

METHODS

We conducted a randomized, placebo controlled, clinical trial including fifty patients with mechanical neck pain. Participants received a single session of dry needling or sham needling in a blinded design. Predicted patient expectation was categorized as positive, neutral, or negative. Outcomes including neck pain intensity (visual analogue scale, 0-100), pressure pain thresholds (PPTs) and self-perceived improvement (Global Rating of Change [GROC], -7 to + 7) were assessed at baseline, one day (immediately post), and 7 days (one week) after the intervention by a blinded assessor. Repeated measures ANCOVAs were conducted to assess the effects of real/sham needling adjusted by patient expectations.

RESULTS

Individuals receiving dry needling exhibited better outcomes than those receiving sham needling immediately and one-week after (all, P < 0.01). No general effects of patient expectations, either related to pain recovery or function improvement, were observed on the clinical outcomes, except for a small association of questionable clinical relevance between positive expectations and localized PPTs in the dry needling group.

CONCLUSION

This study did not find a significant effect of predicted patient expectations on the short-term effects of dry needling on pain intensity and PPTs in people with mechanical neck pain.

Evidence versus advocacy, as related to radiofrequency denervation in the treatment of chronic low back pain and the MINT trials

In 2017, JAMA: Journal of the American Medical Association published the results of the MINT trials, prospective research involving 681 patients, all of whom received exercise therapy for low back pain. Half of the patients were randomized to additionally receive radiofrequency denervation (RFD) treatment. 88% of patients completed the 3-month follow-up, and 77% completed the 12-month follow-up. In this context, RFD provided no added benefit over the baseline of exercise therapy. In 2018, five authors, all experts in pain medicine, published a 'Daring Discourse' article in the journal Regional Anesthesia and Pain Medicine (RAPM), criticizing the findings of the MINT trials. Although 3 of the 5 authors of the RAPM 'Daring Discourse' article reported in conflict of interest statements-as is appropriate-that they were consultants to corporations that produce RFD equipment, the authors failed to disclose that 4 of 5 are on the editorial board of RAPM and all 5 are current officers in the medical organization that owns RAPM: that is, the American Society of Regional Anesthesia and Pain Medicine. Noteworthy, there was no published response from the MINT trial investigators to the Daring Discourse criticisms, either in the aforementioned example or in downstream venues where some of the same Daring Discourse authors continued their widely disseminated criticisms of the JAMA/MINT trials report. We believe that these actions taken by the Daring Discourse authors and RAPM have unfairly tipped the scales in the evaluation and application of RFD treatment of low back pain. In our commentary, we discuss: (1) the challenges associated with using clinical trials to predict clinical efficacy, (2) appropriate and inappropriate uses of postpublication commentary on original research findings, (3) the use of inappropriate commentary (and related means) to alter clinical practice in the presence of contradictory research findings, and (4) potential conflicts of interest related to the authors' and Journal's publication of the unopposed MINT trials criticism.

The Influence of Treatment Expectations on Clinical Outcomes and Cortisol Levels in Patients With Chronic Neck Pain: An Experimental Study

BACKGROUND

The role of contextual factors like pre-existing treatment expectations has been established. However, the effect of verbally delivered treatment expectations in patient-therapist communication has not been considered, nor has the role of cortisol changes within the placebo/nocebo response in people with chronic neck pain.

OBJECTIVE

To examine the effect of verbally delivered treatment expectations on clinical outcomes in physical therapy practice and to determine if changes in cortisol levels are associated with changes in neck pain and disability.

METHODS

Eighty-three patients with chronic neck pain were randomly allocated to 3 different verbally delivered expectations (positive, negative, neutral) during physical therapy interventions.

MAIN OUTCOME MEASURES

salivary cortisol, pain and disability, and cervical range of motion.

RESULTS

Pain significantly improved in the positive (P < 0.001) and neutral (P < 0.001) expectations groups. For salivary cortisol levels, a significant increase was observed in response to treatment in the neutral (P = 0.045) and negative (P < 0.001) expectations groups. No significant correlations were found between changes in salivary cortisol levels and the change in pain in the neutral and negative expectations groups.

CONCLUSIONS

Physical therapists treating people with chronic neck pain should be attentive when communicating the expected treatment effects to their patients. Whereas verbally delivered positive or neutral expectations may be beneficial for pain-related measures, giving negative expectations may result in a lack of a treatment response on pain. Cortisol levels increased in response to verbally delivered neutral and negative expectations, in the absence of a nocebo effect. This questions the presumed role of cortisol in the nocebo effect.

Lay People's Ethical Attitudes To Placebo Treatment: A Q-Methodology Study

BACKGROUND

Placebo-treatment acceptability is debated among ethicists, mostly due to conflict between respect-to-autonomy and beneficence principles. It is not clear how lay people balance these and other ethical principles.

METHODS

One hundred and eighty-seven respondents rank-ordered 42 opinion statements covering various ethical aspects of placebo-treatment, according to a 9-category symmetrical distribution. We analyzed statements' scores using averaging-analysis and by-person factor analysis (Q-methodology).

RESULTS

Respondents' mean (SD) age was 34.6 (10.6) years, 54% were women, 40% healthcare-related, 68% Muslims (31% Christians), and 39% received general education in Saudi Arabia (24% in the Philippines). On averaging-analysis, the most-agreeable statements were "Acceptable if benefit to patient large" and "Acceptable with physician intent to benefit patient". The most-disagreeable statements were "Acceptable with physician self-benefit intent" and "Acceptable with large harm to other patients". Muslims gave a higher rank to "Giving no description is acceptable", "Acceptable with small benefit to patient", and "Acceptable with physician intent to benefit patient" and a lower rank to "Acceptable to describe as inactive drug", "Acceptable with physician intent to please patient caring relative", and "Acceptable with moderate harm to other patients" (p<0.01). Q-methodology detected several ethical attitude models that were mostly multi-principled and consequentialism-dominated. The majority of Christian and Philippines-educated women loaded on a "relatively family and deception-concerned" model, whereas the majority of Muslim and Saudi Arabia-educated women loaded on a "relatively common-good-concerned" model. The majority of Christian and healthcare men loaded on a "relatively deception-concerned" model, whereas the majority of Muslim and non-healthcare men loaded on a "relatively motives-concerned" model. Of nine intent-related statements, ≥2 received extreme rank on averaging-analysis and in 100% of women and men models.

CONCLUSION

1) On averaging-analysis, patient's beneficence (consequentialism) followed by physician's intent (virtue ethics) were more important than deception (respect-to-autonomy). 2) Q-methodology identified several ethical attitude models that were mostly multi-principled and associated with respondents' demographics.

A systematic review of drug treatment of vulvodynia: evidence of a strong placebo effect

BACKGROUND

Vulvodynia is the most common type of chronic pelvic pain and dyspareunia in premenopausal women. The effect of drugs for the treatment of vulvodynia remains poorly discussed.

OBJECTIVES

To conduct a systematic review of randomised controlled studies which assess medications used to treat vulvar pain in vulvodynia.

SEARCH STRATEGY

Web of Science, Cochrane Library, EBSCO Academic, LILACS and MEDLINE were searched from 1985 to September 2016.

SELECTION CRITERIA

Randomised controlled trials comparing any kind of medication for vulvodynia treatment with placebo or with another medication in adult patients were included.

DATA COLLECTION AND ANALYSIS

The two investigators independently conducted data extraction. The synthesis was provided by the pain reduction index. Study quality assessment was performed using the Cochrane Handbook for Systematic Reviews of Intervention and analysis of publication bias was conducted.

MAIN RESULTS

Five studies were included in qualitative synthesis. Number of participants varied from 30 to 133 participants among the eligible studies, resulting in a total of 297 patients. The pain reduction rates of patients with vulvodynia assessed by Q-tipped cotton test and visual analogue scale varied between studies. Placebo was shown to be as effective as any medication.

CONCLUSIONS

There is a need for further studies evaluating topical monotherapy for the treatment of vulvodynia, as they are the main drugs used in clinical practice.

TWEETABLE ABSTRACT

No medication has shown impact on vulvar pain in vulvodynia. There is evidence of a placebo effect.

Drug*placebo interaction effect may bias clinical trials interpretation: hybrid balanced placebo and randomized placebo-controlled design

Background

Conventional randomized placebo-controlled study design assumes the absence of drug*placebo interaction. We hypothesized the presence of such an interaction and that conventionally estimated drug effect might be biased. The objectives of the study were to determine the drug*placebo interaction effect (main) and compare conventionally estimated and interaction model-estimated drug effects (secondary).

Methods

We used a hybrid of balanced placebo and randomized placebo-controlled designs. Four hundred eighty healthy volunteers were randomized to three groups. The first received hydroxyzine (25 mg) described as hydroxyzine or placebo, the second received placebo described as hydroxyzine or placebo, and the third received hydroxyzine and placebo described as unknown; each in a randomized crossover design. Seven participants failed to crossover. Group assignment was concealed from participants and study coordinators. Coordinators were blinded to group and intervention assignment. Participants and coordinators were deceived as to study objectives. Main outcomes were mean area-under-the-curve of drowsiness (therapeutic outcome) and mouth-dryness (adverse outcome), self-reported on 100 mm visual analog scale over 7 h. Drug, placebo, placebo + interaction, and total effects were estimated using analysis of covariance by comparing received hydroxyzine/told placebo to received placebo/told placebo, received placebo/told hydroxyzine to received placebo/told placebo, received hydroxyzine/told hydroxyzine to received hydroxyzine/told placebo, and received hydroxyzine/told hydroxyzine to received placebo/told placebo, respectively. Drug effect was also conventionally estimated in the third group.

Results

Mean (SD) age was 31.4 (6.6) years, 65% were males. There was significant difference between placebo + interaction effect and placebo effect for both drowsiness and mouth-dryness with a mean difference (95% confidence interval) of 35.1 (5.6 to 64.6) and 23.8 (2.4 to 45.2) mm*hr, respectively. Total effect was larger than the sum of drug and placebo effects for drowsiness (139.7 (109.8 to 169.6) vs. 99.1 (68.2 to 130.0) mm*hr) and mouth-dryness (63.6 (41.1 to 86.1) vs. 34.7 (11.1 to 58.4) mm*hr). Conventionally estimated drug effect was larger than interaction model-estimated drug effect for drowsiness (69.2 (45.5 to 92.8) vs. (58.3 (31.6 to 85.0) mm*hr) and mouth-dryness (19.9 (5.3 to 34.5) vs. 9.5 (−9.2 to 28.1) mm*hr).

Conclusions

There is significant and important drug*placebo interaction effect that may bias conventionally estimated drug effect.

Trial registration

ClinicalTrial.gov identifier: NCT01501591 (registered December 25, 2011).

Efficacy and safety of atomoxetine hydrochloride in Korean adults with attention-deficit hyperactivity disorder

INTRODUCTION

This article aims to assess the efficacy and safety of atomoxetine in Korean adults with attention-deficit hyperactivity disorder (ADHD).

METHODS

This post hoc double-blind, placebo-controlled study of atomoxetine (40-120 mg/day) over 10 weeks in adults with ADHD at 45 Japanese, Korean, and Taiwanese study sites focused on patient data from Korea (atomoxetine, n = 37; placebo, n = 37). Primary efficacy outcome was change in baseline-to-endpoint Conners' Adult ADHD Rating Scale-Investigator-rated: Screening Version (CAARS-Inv:SV) Total ADHD Symptoms score. Secondary efficacy outcomes included changes in Adult ADHD Quality of Life (AAQoL) total, Behavior Rating Inventory of Executive Function-Adult Version Self-Report (BRIEF-A:Self-Report), and Clinical Global Impression-ADHD-Severity (CGI-ADHD-S) scale scores.

RESULTS

Atomoxetine-treated patients demonstrated a mean 18.9-point reduction in CAARS-Inv:SV total ADHD Symptoms score, compared with the 7.45-point reduction in placebo-treated patients (P ≤ 0.01). Significantly greater improvement was found for atomoxetine versus placebo in CGI-ADHD-S (P ≤ 0.01), BRIEF-A:Self-Report global executive composite (P ≤ 0.05), and metacognition index (P ≤ 0.01) executive function scores. Nausea, decreased appetite, and dry mouth were reported with significantly greater frequency by atomoxetine-treated patients, and only one placebo-treated patient discontinued because of adverse event. A 2.1-kg reduction in weight and a 7.5-beat/minute increase in pulse rate were observed in atomoxetine-treated patients.

DISCUSSION

These data support a significant benefit of 80- to 120-mg once daily atomoxetine versus placebo for treatment of ADHD in adult Korean patients. A high placebo response rate was observed in this adult Korean sample; a higher discontinuation rate was also observed in atomoxetine-treated patients. These observations warrant further investigation.

Research on placebo analgesia is relevant to clinical practice

Over the decades, research into placebo responses has shed light onto several endogenous (i.e. produced from within) mechanisms underlying modulation of pain perception initiated after the administration of inert substances (i.e. placebos). Chiropractors and manual therapists should embrace analgesic-placebo-research in an attempt to maximize clinical benefit. Historical views that placebo responses are fake, passive, undesirable, and require deception and therefore should be minimized and avoided in clinical practice are outdated. Further, statements that contend the placebo response represents a single mechanism are overly simplistic. This commentary will discuss research that shows that there are several active biological processes underlying modulation of pain perception involved in placebo analgesia and its counterpart nocebo hyperalgesia. We contend that it is highly likely that, to some extent, all of these biological processes are engaged, in varying degrees, following all interventions and represent endogenous pain modulating processes. Failure, of chiropractors and manual therapists, to embrace a more contemporary view of analgesic-placebo-research serves as a barrier to transferring knowledge into clinical practice and represents a missed opportunity to improve the delivery of current treatments.

Peripheral pulsed electromagnetic fields may reduce the placebo effect in migraine patients that do not respond to the sham intervention in a randomized, placebo-controlled, double-blind, cross-over clinical trial

OBJECTIVE

The purpose of the study was to evaluate the effect of the pulsed electromagnetic fields (PEMF) and its possible modulation of the placebo effect in migraine.

DESIGN

Placebo-controlled, randomized, double-blind, cross-over clinical trial.

SETTING

Government third level hospital.

INTERVENTIONS

Patients with migraine were included. PEMF were applied to the wrist with a bracelet.

MAIN OUTCOME MEASURES

Frequency and intensity of the migraine attacks at baseline and during treatment were recorded. Also, we valuated the possible influence of gender and the presence of aura in the PEMF and placebo responses.

RESULTS

Eighteen patients (fifteen women, 30±2 years old) were included. Migraine frequency and intensity was reduced with both PEMF and placebo to a similar extent in the whole population. However, in responders to placebo, migraine intensity was reduced to a median of 100% with the placebo and to 60% with the PEMF, while in non-responders there was only a slight effect of both treatments. Our results do not suggest an influence of gender or presence of aura in the outcomes.

CONCLUSIONS

Treatment with PEMF may not alter either migraine intensity or frequency compared to baseline, but may reduce the response to placebo in migraine patients.

Interaction between drug and placebo effects: a cross-over balanced placebo design trial

Background

The total effect of a medication is the sum of its drug effect, placebo effect (meaning response), and their possible interaction. Current interpretation of clinical trials' results assumes no interaction. Demonstrating such an interaction has been difficult due to lack of an appropriate study design.

Methods

180 adults were randomized to caffeine (300 mg) or placebo groups. Each group received the assigned intervention described by the investigators as caffeine or placebo, in a randomized crossover design. 4-hour-area-under-the-curve of energy, sleepiness, nausea (on 100 mm visual analog scales), and systolic blood pressure levels as well as caffeine pharmacokinetics (in 22 volunteers nested in the caffeine group) were determined. Caffeine drug, placebo, placebo-plus-interaction, and total effects were estimated by comparing outcomes after, receiving caffeine described as placebo to receiving placebo described as placebo, receiving placebo described as caffeine or placebo, receiving caffeine described as caffeine or placebo, and receiving caffeine described as caffeine to receiving placebo described as placebo, respectively.

Results

The placebo effect on area-under-the-curve of energy (mean difference) and sleepiness (geometric mean ratio) was larger than placebo-plus-interaction effect (16.6 [95% CI, 4.1 to 29.0] vs. 8.4 [-4.2 to 21.0] mm*hr and 0.58 [0.39 to 0.86] vs. 0.69 [0.49 to 0.97], respectively), similar in size to drug effect (20.8 [3.8 to 37.8] mm*hr and 0.49 [0.30 to 0.91], respectively), and its combination with the later was larger than total caffeine effect (29.5 [11.9 to 47.1] mm*hr and 0.37 [0.22 to 0.64]). Placebo-plus-interaction effect increased caffeine terminal half-life by 0.40 [0.12 to 0.68] hr (P = 0.007).

Conclusions

Drug and placebo effects of a medication may be less than additive, which influences the interpretation of clinical trials. The placebo effect may increase active drug terminal half-life, a novel mechanism of placebo action.

Trial Registration

ClinicalTrials.gov identification number - NCT00426010.

Oral desipramine and topical lidocaine for vulvodynia: a randomized controlled trial

OBJECTIVE

To estimate the efficacy of common treatments for vulvodynia: topical lidocaine monotherapy, oral desipramine monotherapy, and lidocaine-desipramine combined therapy.

METHODS

A 12-week randomized, double-blinded, placebo-controlled trial was conducted on 133 vulvodynia-afflicted women assigned to four treatment arms: placebo tablets-placebo cream, desipramine tablets-placebo cream, placebo tablets-lidocaine cream, and desipramine tablets-lidocaine cream. The tampon test was selected as primary end point using a modified intention-to-treat analysis. Twelve secondary end points were also examined. At completion of the 12-week randomized phase, women were examined "open label" through 52 weeks postrandomization.

RESULTS

All treatment arms reported substantial tampon-test pain reduction: 33% reduction placebo cream-placebo tablet, 20% reduction lidocaine cream-placebo tablet, 24% reduction placebo cream-desipramine tablet, and 36% reduction lidocaine cream-desipramine tablet. Compared with placebo, we found no significant difference in tampon-test pain reduction with desipramine (t=0.90; P=.37) or lidocaine (t=1.27; P=.21). Of the remaining 12 outcome measures, only the Index of Sexual Satisfaction, improved with desipramine compared with placebo (t=-2.81; P=.006). During the open-label phase, women undergoing vestibulectomy surgery reported significantly improved pain as measured by cotton swab test and the McGill Pain Scale compared with nonsurgical alternatives.

CONCLUSION

Oral desipramine and topical lidocaine, as monotherapy or in combination, failed to reduce vulvodynia pain more than placebo. Placebo or placebo-independent effects are behind the substantial pain improvement seen in all treatment allocations.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT00276068.

LEVEL OF EVIDENCE

I.

Dynamic nature of the placebo response

Traditionally, placebo has been associated with using an inert substance, in part so the subsequent response could be attributed to the target treatment, controlling for the confound of a “placebo effect.” ^,, Placebo’s link with inert substances is so strong that “sham treatment” is a common synonym, and widespread placebo use is discouraged—even when there is supporting evidence for its effectiveness.^,, Recent research has helped to redefine placebo, and this editorial will highlight key information supporting a contemporary view of placebo.

The importance of placebo in headache research

The best way to appreciate the efficacy of drug and behavioural therapy in the acute and prophylactic treatment of headache is to perform placebo-controlled randomized trials. In order to plan and conduct these studies in the most appropriate way, it is desirable to know which factors influence the placebo response. This paper reviews factors which influence the placebo response in clinical trials, such as expectation, blinding, route of application of drugs and age, gender and geographical distribution. Response rates of placebo in the treatment of acute headache episodes are higher than in headache prophylaxis. Invasive procedures such as injections have a higher placebo response compared with oral drugs. Variables known to influence the placebo response have to be taken into consideration to calculate properly the power of planned randomized trials.

Open-label study of a proprietary treatment program targeting type A gamma-aminobutyric acid receptor dysregulation in methamphetamine dependence

OBJECTIVE

To evaluate the safety and efficacy of the pharmacological component of a proprietary medical treatment program targeting type A gamma-aminobutyric acid receptor dysregulation in adults who met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision criteria for methamphetamine dependence.

PARTICIPANTS AND METHODS

A prospective, open-label, single-group study of the medication portion of a proprietary treatment program for methamphetamine dependence was conducted from July 1, 2005, to May 10, 2006, at Research Across America, an outpatient private, for-profit, clinical research company in Dallas, TX. In the study, flumazenil, hydroxyzine, and gabapentin, all of which were approved by the US Food and Drug Administration for indications other than drug dependence, were used off-label for the treatment of methamphetamine dependence. Fifty persons who had used methamphetamine within 7 days of study entry were enrolled and received the treatment. Treatment lasted 4 weeks, followed by 8 weeks of weekly follow-up visits to monitor for methamphetamine use via urine drug tests and self-reporting.

RESULTS

Participant retention was higher than expected, with 85% of participants completing the program. Significant decrease in methamphetamine use (P<.001) was noted at 84 days after vs 90 days before treatment. If missing data are counted as days of methamphetamine use, a 47% reduction in use was observed for the entire sample (P<.001) and a 65% reduction for the 36 who completed the 8-week evaluation phase (P<.001). Urine test results and self-reported use were positively correlated (Pearson r=0.72, P<.001). The frequency of cravings was reduced on average by 66% (P<.001), with 30 of 31 (97%) of the 36 who completed the study reporting reduction in cravings.

CONCLUSION

Substantial reductions in methamphetamine cravings and use were observed in all phases of treatment, and the retention rate of participants was high. These findings suggest that the efficacy of the medications and of the entire program in treating methamphetamine dependence should be examined in controlled trials.