Scientific and ethical issues in the use of placebo controls in clinical trials

Negative expectations (nocebo phenomenon) in clinical interventions: A scoping review

Unpredictable, undesirable, and confusing reactions in the face of psychological or medical interventions make the clinical presentation more complicated and may represent clinically unexplained symptoms and also disturbed the doctor-patients relationship and decrease patients' benefits of treatment. It seems that negative expectations from the treatment (nocebo phenomenon) can explain such reactions. The aim of the current study is a scoping review and investigate different aspects of the nocebo phenomenon (negative expectations) in clinical interventions. This paper follows a scoping review of the existence, importance, and multidimensions of the nocebo phenomenon in medical and psychological interventions. Data sources include literature databases (ProQuest, PubMed, Google Scholar, and Scopus) reviewed from inception dates to 2023, and the terms negative expectations, nocebo effect, placebo effect, negative placebo, and clinical interventions were searched. The review of the available articles showed that negative expectations play an important role in the process and effectiveness of clinical interventions. Negative expectations (here named nocebo effect) can significantly interfere with rapport and treatment processes. Some underlying components of the nocebo effect include negative expectancies, conditioning, social learning, memory, cognitive distortions, meaning, motivation, somatic focus, negative reinforcements, personality, anxiety, and neurophysiological factors such as CCK, dopamine, and cortisol are proposed for development and presence of nocebo phenomenon in clinical practice. Negative expectations with its biopsychosocial aspects play an important and amazing role in disorganizing medical and psychological interventions. Using appropriate methods to reduce nocebo effects in therapeutic interventions may increase treatment compliance and adherence and increase the effectiveness of interventions.

A simple method for correcting for the Will Rogers phenomenon with biometrical applications

In its basic form, the Will Rogers phenomenon takes place when an increase in the average value of each of two sets is achieved by moving an element from one set to another. This leads to the conclusion that there has been an improvement, when in fact essentially nothing has changed. Extended versions of this phenomenon can occur in epidemiological studies, rendering their results unreliable. After describing epidemiological and clinical studies that have been affected by the Will Rogers phenomenon, this paper presents a simple method to correct for it. The method involves introducing a transition matrix between the two sets and taking probability weighted expectations. Two real-world biometrical examples, based on migration economics and breast cancer epidemiology, are given and improvements against a naïve analysis are demonstrated. In the cancer epidemiology example, we take account of estimation uncertainty. We also discuss briefly some limitations associated with our method.

[Biosimilars and the nocebo effect]

Biosimilars have been approved for use in Germany for many years and in the meantime also in rheumatology but only a few years ago. Biosimilars, which are biotechnologically manufactured products the same as reference biologicals, have actually now achieved a substantial proportion of the market in some regions but there are still doubters among patients and physicians who fear a loss of quality even if there is no evidence for this. A part of this problem can be explained by the nocebo effect but which furthermore also has a substantial medical importance. This effect is described and explained in this article. Psychosocial and context-related factors, such as the relationship between patient and physician, previous experience with treatment and treatment expectations can either improve or impair the efficacy of treatment interventions. These phenomena are commonly known as placebo and nocebo effects. As placebo and nocebo effects can influence the development of symptoms, the frequency of undesired events and the efficacy of treatment, it is decisive to know these effects and to develop strategies for prevention in order to optimize the treatment results. Although in recent years experimental studies have achieved substantial progress in the clarification of the psychosocial and neurobiological mechanisms of placebo effects, detailed mechanisms of nocebo effects are still widely unexplored. An improved understanding of these mechanisms promises the development of user-friendly strategies for the clinical care to improve treatment results and patient satisfaction.

Psychobiological Mechanisms of Placebo and Nocebo Effects: Pathways to Improve Treatments and Reduce Side Effects

Placebo effects constitute a major part of treatment success in medical interventions. The nocebo effect also has a major impact, as it accounts for a significant proportion of the reported side effects for many treatments. Historically, clinical trials have aimed to reduce placebo effects; however, currently, there is interest in optimizing placebo effects to improve existing treatments and in examining ways to minimize nocebo effects to improve clinical outcome. To achieve these aims, a better understanding of the psychological and neurobiological mechanisms of the placebo and nocebo response is required. This review discusses the impact of the placebo and nocebo response in health care. We also examine the mechanisms involved in the placebo and nocebo effects, including the central mechanism of expectations. Finally, we examine ways to enhance placebo effects and reduce the impact of the nocebo response in clinical practice and suggest areas for future research.

Incidence of Placebo Adverse Events in Randomized Clinical Trials of Targeted and Immunotherapy Cancer Drugs in the Adjuvant Setting: A Systematic Review and Meta-analysis

IMPORTANCE

Several reports have associated the placebo effect with objective response and improvement of a clinical condition in oncology, but only a few studies have analyzed the adverse events (AEs) in the placebo groups of the clinical trials.

OBJECTIVE

To determine the incidence of placebo AEs reported in randomized clinical trials of modern cancer drugs in the adjuvant setting.

DATA SOURCES

Based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline, a systematic literature search of English-language publications from January 1, 2000, through April 15, 2018, was performed using MEDLINE (PubMed). The following search terms were used to retrieve all trials from the PubMed library: adjuvant, maintenance, consolidation, and placebo, in addition to specific cancer type-related keywords.

STUDY SELECTION

A double-blind, randomized, placebo-controlled, phase 3 design was mandatory for study inclusion. Only studies enrolling patients who had undergone macroscopically complete resections were included. No other anticancer treatments in addition to placebo were allowed in the control group. Only trials involving a targeted therapy (tyrosine kinase, BRAF, or MEK inhibitors) or immunotherapy-related drugs were included. Trials using chemotherapy, interferon, and endocrine therapy were excluded. Two authors (D.H.E. and F.D.W.) independently reviewed the studies for inclusion.

DATA EXTRACTION AND SYNTHESIS

Data were extracted by investigators, and random-effects meta-analysis was performed to estimate the proportion of grade 3 to 4 placebo AEs in the included studies.

MAIN OUTCOMES AND MEASURES

Incidence of grade 3 to 4 placebo AEs in the placebo groups.

RESULTS

Of 731 studies screened, 10 eligible trials were found including 4 tumor types (melanoma, non-small cell lung cancer, gastrointestinal stromal tumor, and renal cell carcinoma). Overall, 11 143 patients (6270 [56.3%] in the treatment group with mean [SD] age of 55.6 [4.2] years and 4873 patients [43.7%] in the placebo group with mean [SD] age of 55.9 [4.3] years) were included. The mean incidence of any-grade placebo AEs was 85.1% (95% CI, 79.2%-91.0%). The most frequent (mean [SD]) grade 3 to 4 placebo AEs in patients were hypertension (2.8% [2.2%]), fatigue (1.0% [0.9%]), and diarrhea (0.8% [0.6%]). The overall, random-effects pooled incidence of grade 3 to 4 placebo AEs was 18% (95% CI, 15%-21%), with a high level of heterogeneity (I2 = 86%). Frequency of grade 3 to 4 placebo AEs was found to be correlated in the treatment and placebo groups (ρ = 0.7; P = .03). Mean study drug discontinuation owing to placebo AEs was 3.9% (95% CI, 2.7%-5.2%).

CONCLUSIONS AND RELEVANCE

Placebo administration was associated with a substantial incidence of grade 3 to 4 placebo AEs in modern cancer adjuvant trials. This finding should be considered by investigators, sponsors, regulatory authorities, and patient support groups.

Stellate ganglion block for treating hot flashes: a viable treatment option or sham procedure?

Stellate ganglion block (SGB) has been used for over 70 years to treat various cervical pain syndromes. Over the past 8 years, 4 different groups have reported on SGB's effects on hot flashes from unblinded, open-label trials. Review of these studies has shown markedly disparate results in terms of the magnitude of hot flash reduction from Baseline with one trial showing a 90% reduction in hot flashes and 3 other trials showing 28-44% reductions in hot flashes. The inconsistencies in these results in addition to the known potentially large (>50%) placebo effects that can occur in randomized controlled hot flash clinical trials make it difficult to render any conclusions regarding the efficacy of SGB for hot flashes at this time. A randomized controlled trial, including a sham saline treatment arm, needs to be performed to properly assess SGB's effects on hot flashes, Methodological challenges with such a study design are addressed and several suggestions are proposed to manage these challenges.

Is randomization to placebo safe? Risk in placebo-controlled angina trials: angina risk meta-analysis

OBJECTIVE

It was the aim of this study to document the risks of symptomatic patients with angina in placebo-controlled, anti-anginal drug development trials in which symptom-limited exercise testing was used as the primary endpoint.

PATIENTS AND METHODS

The original case report forms submitted to the United States Food and Drug Administration in support of approval of new or supplemental new drug applications between 1973 and 2001 were identified and subjected to a by-patient meta-analysis, utilizing both a maximum likelihood analysis and classical Mantel-Haenszel methods.

RESULTS

There were 63 placebo-controlled, clinical trials that randomized 10,865 patients, with 1,047 patient-years of observation time. The trials involved 21 different chemical entities from 4 different drug classes. The relative risk (RR) for withdrawal (placebo compared to drug-treated patients) was not increased [RR = 0.92, 95% confidence interval (CI) 0.78-1.08; p = 0.28]. Of interest, a RR of 0.54 (95% CI 0.26-1.04; p < 0.068) for irreversible harm (a combination of cerebrovascular accidents, myocardial infarction and death) and a RR of 0.89 (95% CI 0.61-1.30; p = 0.56) for serious cardiovascular events (myocardial infarction, congestive heart failure, cerebrovascular accidents) both non-statistically significantly favored being randomized to placebo.

CONCLUSIONS

For the development of current or future drugs for the treatment of angina, there is no obvious contraindication to the use of placebo controls and exercise tolerance testing.

Clinical trials of drugs used off-label in neonates: ethical issues and alternative study designs

The use of drugs for indications unapproved by the Food and Drug Administration (FDA), often called "off label use, "is widespread in children, including neonates. The widespread off-label use of drugs in neonates presents ethical and safety challenges. Since the passage of the Best Pharmaceuticals for Children Act (BPCA) in 2002, both the FDA and National Institutes of Health (NIH) have taken initiatives to facilitate and encourage research to achieve the necessary labeling for drugs routinely used in infants and children. Federal regulations provide broad rules and guidance for the protection of human subjects in research. However, there are ethical issues that a physician may face when designing clinical trials of drugs in neonates that are routinely used off-label and widely believed to be beneficial. We attempt to describe these ethical challenges and provide recommendations, including alternative study designs, to resolve them in an ethical framework that takes into account the Belmont Report, the statement of the World Medical Association (WMA), and federal regulations.

Placebo response in Parkinson's disease: comparisons among 11 trials covering medical and surgical interventions

Placebo-associated improvements have been previously documented in small series of Parkinson's disease (PD) patients. Using a strict definition of placebo-associated improvement, we examined rates and timing of placebo responses to identify patient- and study-based characteristics, predicting positive placebo response in several PD clinical trials. We collected individual patient data from the placebo groups of 11 medical and surgical treatment trials involving PD patients with differing PD severities and placebo-assignment likelihoods. We defined a positive placebo response as > or = 50% improvement in total Unified Parkinson's Disease Rating Scale motor (UPDRSm) score or a decrease by > or = 2 points on at least two UPDRSm items compared to baseline. We calculated positive placebo response rates at early (3-7 weeks), mid (8-18 weeks), and late (23-35 weeks) stages of follow-up. Odds ratios for patient- and study-based characteristics were obtained from a model fitted using generalized estimating equations. There were 858 patients on placebo who met inclusion criteria for analysis. Three studies involved patients without need of symptomatic treatment, two involved patients without motor fluctuations needing symptomatic treatment, and six (three medical and three surgical) involved patients with motor fluctuations. The overall placebo response rate was 16% (range: 0-55%). Patients with higher baseline UPDRSm scores and studies that focused on PD with motor fluctuations, surgical interventions, or those with a higher probability of placebo assignment showed increased odds of positive placebo response. Placebo responses were temporally distributed similarly during early, mid, and late phases of follow-up. Placebo-related improvements occur in most PD clinical trials and are similarly distributed across all 6 months of follow-up. Recognition of factors that impact placebo response rates should be incorporated into individual study designs for PD clinical trials.

What happened to posteroventral pallidotomy for Parkinson's disease and dystonia?

Fifteen years after its resurrection, pallidotomy for Parkinson's disease (PD) and dystonia has once again been supplanted, this time by deep brain stimulation (DBS). Did this occur because pallidotomy was not effective or safe, or because DBS was found to be more effective and safer? This review focuses on the evidence-and its quality-supporting the effectiveness and safety of pallidotomy for PD and dystonia, and the comparative effectiveness and safety of DBS of the subthalamic nucleus (STN) and globus pallidus pars interna (GPi). Discussed first are the determinants of "level 1" recommendations, including the confounding effects on interpretation of randomized clinical trials (RCTs) that fail to control for patient bias (i.e., placebo effects). Although several RCTs have been performed comparing unilateral pallidotomy to medical therapy, GPi DBS, or STN DBS for PD, none controlled for patient bias. Comparison of these trials to estimate the placebo effect, and examination of retrospective case series, suggests that the true effectiveness of unilateral pallidotomy is 20% to 30% reduction of 'off' total motor UPDRS scores, which is similar to the effects of unilateral GPi DBS or STN DBS, but less than bilateral STN DBS. At experienced centers, safety of unilateral pallidotomy appears equivalent to unilateral DBS, but bilateral DBS is likely safer than bilateral pallidotomy. Whereas there have been no RCTs of pallidotomy for dystonia, two double-blind, sham-controlled RCTs of bilateral GPi DBS were performed. Nevertheless, limited uncontrolled series suggest that bilateral pallidotomy is similar to GPi DBS in effectiveness and safety for dystonia. Thus, pallidotomy was not rejected because of lack of effectiveness or safety, and it remains a viable alternative in situations where DBS is not available or not feasible.

Clinical trial design issues: at least 10 things you should look for in clinical trials

Randomized controlled trials remain the gold standard study design and yield the highest level of scientific credence. However, recognition of the limitations of the randomized controlled trial is important. This review highlights 10 potentially problematic areas one should carefully assess when performing or reading an article reporting the results of a randomized controlled trial, problematic areas that can affect the outcome of the trial and therefore mislead the reader. These areas include ethical issues, eligibility criteria, masking (blinding), randomization, analytic methods, the selection of subjects for the interventional and comparison groups, selection of end points, and the interpretation of the results. Each of these is discussed, and examples of published articles are used to highlight the main points.

Can keeping clinical trial participants blind to their study treatment adversely affect subsequent care?

Subjects in controlled clinical trials obtain experience with study-provided treatment that could inform their further therapy by awareness of the efficacy or inefficacy of the study treatment they received. However, patients in blinded trials typically do not learn right after their participation what treatment they actually received during the study, even though it is possible to do so while maintaining the necessary blinding of investigators. Keeping investigators and subjects blind to treatment assignment throughout a trial is a key element of clinical research methodology, but the value of keeping participants and their medical providers blinded after participation is less certain and may pose risks that include delay in the receipt of efficacious care, exacerbation of symptoms, or prolonged exposure to superfluous or toxic treatment. The significance of these risks is likely to vary with the specific disease and the time course of its response to available therapies. Currently, it seems appropriate for investigators a) to evaluate the risks of keeping subjects blind after participation, b) to justify doing so in relation to serious, identifiable risks to the study's validity and apprise prospective subjects clearly that information about their response to specific treatment during the trial will not be available to guide their post-study care, and c) to consider methods for debriefing subjects before their resumption of open treatment that preserve the integrity of investigator blinding. In the long-run, research on the impact that keeping subjects uninformed about study treatment has on post-study patient outcomes and on study integrity can foster the development of procedures that optimally balance both.

Randomized controlled trials of epilepsy surgery

PURPOSE

To review the following aspects of surgical randomized controlled trials (RCTs) in epilepsy: rationale, methodological issues, and state of the art.

METHODS

An overview of the literature and author's experience with methodological issues in surgical RCTs, contrasting them with those encountered in medical trials; a general comparison of RCTs and non-RCTs (observational studies); and a literature search for and review of existing surgical RCTs in epilepsy.

RESULTS

Nonrandomized (observational) studies provide useful but potentially biased information about the effect of interventions. Because of their ability to deal with bias, RCTs are the optimum vehicle to obtain a true estimate of the effect of interventions, including surgery. Only seven surgical RCTs, encompassing 535 patients, have been performed in epilepsy, with variable adhesion to standard methodology for conducting RCTs. The major issues facing researchers undertaking surgical RCTs in epilepsy include timing of the study in relation to adoption of the intervention as standard practice, acceptance of randomization to an invasive procedure, timing of randomization in relation to the actual intervention, standardization of the surgical procedure, blinding, and patient recruitment.

CONCLUSIONS

RCTs are the gold standard for evaluating surgical treatments. Despite the large number and types of surgical interventions used to treat epilepsy, only a handful has been subjected to the scientific rigour of RCTs. The challenges faced by researchers undertaking surgical RCTs in epilepsy are substantial but not insurmountable. Possible avenues to address these methodological hurdles are suggested.

Surgical "placebo" controls

OBJECTIVE

To set ethical guidelines on the use of surgical placebo controls in the design of surgical trials.

BACKGROUND DATA

Ethical concerns recently arose from surgical trials where subjects in the control arm underwent surgical procedures that had the appearance of a therapeutic intervention, but during which the essential therapeutic maneuver was omitted. Although there are ethical guidelines on the use of a placebo in drug trials, little attention has been paid to the use of a surgical placebo control in surgical trials.

METHODS

The Council on Ethical and Judicial Affairs developed ethical guidelines based on a wide literature search and consultation with experts.

RESULTS

Surgical placebo controls should be limited to studies of new surgical procedures aimed at treating diseases that are not amenable to other surgical therapies, and are reasonably anticipated to be susceptible to substantial placebo effects. If the standard nonsurgical treatment is efficacious and acceptable to the patient, then it must be offered as part of the study design.

CONCLUSIONS

Surgical placebo controls should be used only when no other trial design will yield the requisite data and should always be accompanied by a rigorous informed consent process and a careful consideration of the related risks and benefits. The recommended ethical guidelines were adopted as AMA ethics policy and are now incorporated in the AMA's Code of Medical Ethics.

Placebo surgery for Parkinson's disease: do the benefits outweigh the risks?

In April 1999, Dr. Curt Freed of the University of Colorado in Denver and Dr. Stanley Fahn of Columbia Presbyterian Center in New York presented the results of a four-year, $5.7 million government-financed study using tissue from aborted fetuses to treat Parkinson’s disease at a conference of the American Academy of Neurology. The results of the first government-financed, placebo-controlled clinical study using fetal tissue showed that the symptoms of some Parkinson’s patients had been relieved. This research study involved forty subjects, nineteen women and twenty-one men; all suffered from Parkinson’s disease for an average of 13.5 years. In the study, each subject underwent neurosurgery: “four tiny burr holes, drilled through the wrinkle lines above the eyebrows into the skull, to clear a pathway to the brain. But only half received injections of fetal cells into the putamen, the region of the brain that controls movement; the other half received nothing. One year later, three members of the placebo group said their symptoms had improved.” In two-thirds of the transplant recipients, the fetal tissue took hold and seemed to establish a new network to produce the missing neurochemical dopamine.

Placebos, placebo effect, and the response to the healing situation: the evolution of a concept

In spite of its impressive progress, medicine has been strongly criticized for relying on its modern biomedical tradition to the neglect of the psychosocial aspects of health. This neglect may account for patients' dissatisfaction and eventual use of alternative health approaches. The concept of placebo has sustained dramatic "protean" metamorphoses through the ages. For centuries, placebos have been regarded as powerful deceptive therapies. From the middle of the twentieth century, however, conventional medicine has used placebos as methodologic tools to distinguish the specific from the nonspecific ingredients in treatments. In modern medical research, the double-blind, placebo-controlled, randomized clinical trial has been established as the gold standard for the assessment of any new treatment. Recently a new trend regarding placebos seems to have emerged. The placebo and other nonspecific effects elicited by the "healing situation" have been independently subjected to scientific study. Progress in this area may promote useful clinical applications, enabling physicians to broaden their perspectives on the healing process. We present the historical changes of the concept of placebo and the ethical issues raised by their use.

An algorithm for evaluating the ethics of a placebo-controlled trial

The purpose of this article is to clarify the decision points that are important to consider when evaluating the ethics of a placebo-controlled trial. The ethical requirements for research involving human subjects are reviewed, and the rationale for and potential problems with concomitant placebo control are explained. A series of case discussions are used to illustrate each decision point. The critical decision points in the evaluation of the ethics of a placebo-controlled trial are as follows: (i) Is placebo being used in place of standard therapy? (ii) Is standard therapy likely to be effective? (iii) Is the toxicity of standard therapy such that patients routinely refuse this treatment? (iv) Could the use of placebo result in severe suffering or irreversible harm? (v) Is the variability in the placebo response such that it is reasonable to consider other options for the control group? (vi) Would a reasonable person with an average degree of altruism and risk aversiveness agree to participate in this study? The algorithm presented in this article gives researchers and research monitors (such as Institutional Review Board members) the tools they need to evaluate the ethics of a study that uses concomitant placebo control.

The ethics of drug research in children

The obligation of society to improve the welfare of its members requires the conduct of paediatric drug trials. Nevertheless, research activities must satisfy obligations to individual participants. The obligation to protect the welfare of children requires that nontherapeutic research procedures generally involve no more than minimal risk. It also requires that randomisation occurs only when the relative merits of therapeutic procedures remain unsettled among the relevant community of experts. The duty to respect the developing autonomy of children requires that they be included in decision-making about research participation in a manner consistent with the level of their decision-making capacity. However, when children lack mature decision-making capacities, the duty of parents to protect their welfare may properly constrain their choices. Justice requires that the benefits and burdens of research be distributed in a manner that assures equal opportunity for all children. Vulnerable children should receive special protection against the burdens of nontherapeutic research procedures. The benefits of participating in clinical trials should be available to all children with serious illnesses for which current treatment is unsatisfactory. Justice also requires that initiatives be undertaken to rectify current shortcomings in the scope of paediatric drug research. Striking an appropriate balance between obligations to conduct research and to protect the interests of participants is essential to the moral integrity of paediatric drug research.

The uncertainty principle and industry-sponsored research

BACKGROUND

Reporting of pharmaceutical-industry-sponsored randomised clinical trials often result in biased findings, either due to selective reporting of studies with non-equivalent arms or publication of low-quality papers, wherein unfavourable results are incompletely described. A randomised trial should be conducted only if there is substantial uncertainty about the relative value of one treatment versus another. Studies in which intervention and control are thought to be non-equivalent violates the uncertainty principle.

METHODS

We examined the quality of 136 published randomised trials that focused on one disease category (multiple myeloma) and adherence to the uncertainty principle. To evaluate whether the uncertainty principle was upheld, we compared the number of studies favouring experimental treatments over standard ones. We analysed data according to the source of funding.

FINDINGS

Trials funded solely or in part by 35 profit-making organisations had a trend toward higher quality scores (mean 2.94 [SD 1.3]; median 3) than randomised trials supported by 95 governmental or other non-profit organisations (2.4 [0.8]; 2; p=0.06). Overall, the uncertainty principle was upheld, with 44% of randomised trials favouring standard treatments and 56% innovative treatments (p=0.17); mean and median preference evaluation scores were 3.7 (1.0) and 4. However, when the analysis was done according to the source of funding, studies funded by non-profit organisations maintained equipoise favouring new therapies over standard ones (47% vs 53%; p=0.608) to a greater extent than randomised trials supported solely or in part by profit-making organisations (74% vs 26%; p=0.004).

INTERPRETATION

The reported bias in research sponsored by the pharmaceutical industry may be a consequence of violations of the uncertainty principle. Sponsors of clinical trials should be encouraged to report all results and to choose appropriate comparative controls.

Placebo-controlled trials in psychiatric research: an ethical perspective

The placebo-controlled trial is widely regarded as the gold standard for testing the efficacy of new treatments; however, this research design is subject to ethical controversy, especially when standard treatments of proven efficacy exist. After examining regulatory standards and ethical codes relevant to placebo-controlled trials, I offer a critique of arguments against the use of placebo control groups in psychiatric research. An absolute ethical prohibition of placebo-controlled trials in psychiatric disorders for which standard, effective treatments exist is rejected because it is based on a flawed conception of research ethics, ignores important contextual factors characteristic of psychiatric research, and could lead to the approval and use of new medications that appear equivalent in efficacy to standard treatments but may be no more effective than placebos. Four standards governing the ethical use of placebos in psychiatric clinical trials are explicated: 1) placebo-controlled trials should have scientific and clinical merit; 2) risks should be minimized and justified by the anticipated benefits of generating clinically relevant scientific knowledge and the expected benefits, if any, to individual patient volunteers; 3) patient volunteers should give informed consent; and 4) investigators should offer short-term treatment optimization to patient volunteers after completion of research participation.

The placebo effect

Placebos have been traditionally regarded as deceptive therapies and have not been understood in the broader context of social symbols and of interpersonal factors that surround the healing process itself. Although the power of inert substances to heal is well recognized, the placebo effect also influences the outcome of conventional therapies. The role of the placebo in modern medicine is poorly defined because of a lack of a common understanding of what the placebo effect is and because of the negative connotions associated with its use. The response rate to placebo varies by illness. The natural course of disease and patient or physician bias can be misinterpreted as a placebo response. In research, the placebo effect is therapeutic noise to be removed by placebo-controlled trials. Few studies are designed to measure the placebo response rate directly. Placebos are a reminder of how little is known about mind-body interaction. The placebo effect may be one of the most versatile and underused therapeutic tools at the disposal of physicians.

The role of personality factors in the reporting of side effect complaints to moclobemide and placebo: a study of healthy male and female volunteers

Although there is good evidence of a relationship between certain personality factors (viz. neuroticism and hypochondriasis) in the reporting of somatic symptoms-both in clinical and in nonclinical research-the recognition of the moderating role of individual differences in the frequency and intensity of side effect reporting is virtually absent from drug trial research. This study was a double-blind moclobemide-versus-placebo trial, the purpose of which was twofold: to investigate the degree of side effect complaints in a sample of healthy nonclinical men and women and to assess the role of personality in symptom reporting. Although there was no overall difference between the groups with respect to side effect complaints, there was a highly significant neuroticism x group x time interaction. In both groups, we found the expected positive relationship between neuroticism and symptom reporting at baseline. At the end of the study, however, this relationship was close to zero in the moclobemide group and had increased to close to 0.60 in the placebo group. These results were essentially replicated when neuroticism was substituted in the regression model by a psychometric measure of hypochondriasis. Our findings provide a striking demonstration of the role of personality factors in the placebo adverse response. As well, they indicate that adverse reactions to the medication were also linked to personality differences. Taken together, our results underscore the importance of considering individual differences in all aspects of pharmacologic research that involve subjective interpretation on the part of patients and subjects.

The use of placebos in clinical trials for acute schizophrenia

This review examines the scientific and ethical justification for the use of randomized concurrent placebo-controlled trials in the treatment of acute relapse in chronic schizophrenia. A literature search was conducted, and the national regulatory authority was consulted. Many placebo-controlled studies of acute or chronic schizophrenia are being published and it is the official position of both the Canadian and US regulatory authorities that such studies are required for both scientific and ethical reasons. The specific strengths and limitations of placebo-controlled studies are reviewed. Examples, drawn from Canadian studies, are presented to illustrate their benefits. It is concluded that the use of placebos in the particular situation of acute or chronic schizophrenia is ethically and scientifically justified. It forms an essential component of a comprehensive drug evaluation for new antipsychotic medications.