Nocebo in chronic inflammatory demyelinating polyneuropathy; a systematic review and meta-analysis of placebo-controlled clinical trials

Impairment of Hypnosis by Nocebo Response and Related Neurovegetative Changes: A Case Report in Oral Surgery

This article presents the third molar removal in a highly hypnotizable patient, who had been successfully submitted to oral surgery with hypnosis as stand-alone anesthesia in previous sessions. Unexpectedly, hypnosis initially failed, as a result of a nocebo response due to a previous dentist's bad communication; two complaints made by the patient were associated with increased sympathetic activity (as defined by increased heart rate and electrodermal activity and decreased heart rate variability). After deepening of hypnosis, the patient achieved a full hypnotic analgesia allowing for a successful conclusion of the intervention, an event associated with decreased heart rate, electrodermal activity, and increased heart rate variability. Hence, the initial failure was paralleled by a decreased parasympathetic activity and increased sympathetic activity, while hypnotic analgesia was associated with the opposite pattern. The patient's postoperative report indicated that the initial failure of hypnosis depended on a strong nocebo effect because of a previous dentist distrusting hypnosis and persuading her that it was not enough to face a third molar removal.

Placebo and nocebo responses in randomized controlled trials of non-tumor necrosis factor biologics and Janus kinase inhibitors in patients with active rheumatoid arthritis showing insufficient response to tumor necrosis factor inhibitors: A meta-analysis

OBJECTIVE

This study evaluated the frequency and magnitude of placebo and nocebo responses in placebo-controlled RCTs of non-tumor necrosis factor (TNF) biologics and Janus kinase (JAK) inhibitors in rheumatoid arthritis (RA) patients with insufficient response to TNF inhibitors.

METHODS

A meta-analysis on rates of placebo response, adverse effects (AEs), severe AEs (SAEs), and withdrawal due to AEs in placebo-controlled RCTs of non-TNF biologics and JAK inhibitors in patients with RA and an insufficient response to TNF inhibitors was conducted.

RESULTS

In 9 RCTs containing 3442 patients the pooled incidence of ACR20 response rate in placebo-treated patients was 22.1 (95% CI 16.4-29.1%) and 27.9% (95% CI 24.5-31.6%) in RCTs of non-TNF and JAK inhibitors, respectively. Strong negative correlation was observed between ACR20 response and AE rates in the placebo arm, indicating that the greater the placebo response, the weaker the nocebo response (r = -0.762, P = 0.017). Strong positive correlation was observed between ACR20 response in the placebo and active comparator arms, indicating that the greater the placebo response, the greater the treatment response (r = 0.737, P = 0.003). The pooled estimate in placebo-treated patients with ≥1 AE was 71.8 (95% CI 57.4-82.7%) and 58.7% (95% CI 52.8-64.3%) in RCTs of non-TNF and JAK inhibitors, respectively. The pooled estimate in placebo-treated patients withdrawing due to an AE was 3.8 (95% CI 2.7-5.3%) and 4.0% (95% CI 2.7-6.0%) in RCTs of non-TNF and JAK inhibitors, respectively. Strong positive correlation was observed between AE rates in the placebo and active arms, indicating that the greater the nocebo response, the stronger the AE rate in the active arm (r = 0.855, P = 0.003).

CONCLUSION

There were higher placebo and less nocebo effects of JAK vs. non-TNF inhibitors in RA patients with an insufficient response to TNF inhibitors, and the greater the placebo response, the weaker the nocebo response and the greater the efficacy.

Nocebo Response in Attention Deficit Hyperactivity Disorder: Meta-Analysis and Meta-Regression of 105 Randomized Clinical Trials

OBJECTIVE

To determine nocebo response in ADHD, identify covariates modifying nocebo response, and study the relationship between nocebo response and drug safety.

METHOD

Systematic review of randomized, double-blind, placebo-controlled clinical trials (RCT) investigating the efficacy and safety of pharmacological interventions for ADHD patients. The influence of covariates was studied using meta-regression.

RESULTS

A total of 105 studies with 8,743 patients in placebo arms were included. Slightly over half (55.5%) of the patients experienced adverse events (AE) while receiving placebo. Nocebo response was associated positively with age, treatment length and method for collecting AEs. Studies with the largest nocebo response showcased the greatest drug response and the best outcome for drug safety.

CONCLUSION

Nocebo response in ADHD RCTs is remarkable, showing a positive relationship with drug response, and a negative relationship with drug safety.

Nocebo effect in multiple system atrophy: systematic review and meta-analysis of placebo-controlled clinical trials

Background

Nocebo effect is prevalent among neurological diseases, resulting in low adherence and treatment outcome. We sought to examine the nocebo effect in randomized controlled trials (RCTs) in multiple system atrophy (MSA).

Methods

We searched RCTs in MSA from Medline since September, 2021. RCTs for drug treatment conducted in adult MSA patients with more than 5 cases in each treatment arm were included. We assessed the number of dropout due to placebo intolerance. We also did a symptomatic/disease-modifying subgroup analysis based on two different treatment purposes. The STATA software was used for statistical analysis. Overall heterogeneity was assessed using the Cochran Q and I².

Results

Data were extracted from 11 RCTs fulfilling our search criteria. Of 540 placebo-treated patients, 64.2% reported at least one adverse event (AE) and 7.5% reported dropout because of AEs. The chance of dropping out because of an AE and experiencing at least one AE did not differ between placebo and active drug treatment arms. Besides, the pooled nocebo dropout rate in the symptomatic subgroup was similar to that of the disease-modifying subgroup.

Conclusion

In MSA RCTs, nocebo dropout rate was not at a low level among neurological disorders. Nocebo effect was an important reason of dropout because of AE in placebo and active drug treatment arms. Different treatment purposes may not influence nocebo effect.

Pain, the uknown: epistemological issues and related clinical implications

Despite the huge development of pain management in the past decades, pain remains elusive and many patients still remain in the middle of the ford struggling between low drug efficacy and their overuse. A reason for pain elusiveness is its nature of subjective phenomenon, escaping the meshes of the objectivist, mechanist-reductionist net prevailing in medicine. Actually, pain is not only a symptom but an essential aspect of life, consciousness and contact with the world and its noetic and autonoetic components play a key role in the development of the concepts of pleasure-unpleasure and good-evil. The intensity and tolerability of pain and suffering also depends on what the pain means to the patient. The outstanding effects of placebo and nocebo, behavioral and non-pharmacological techniques warrant the need for a shift from the traditional positivist idea of patient as passive carrier of disease to the patient as active player of recovery and move toward a patient's centered approach exploiting individual resources for recovery. Among the mentioned techniques, hypnosis has proved to increase pain threshold up to the level of surgical analgesia, improve acute and chronic pain as well as coping and resilience, helping to decrease both drug overuse and the costs of pharmacological therapy. The wealth of available data suggest the need for a holistic approach, aiming to take care of the individual as an inseparable mind-body unit in its interplay with the environment, where patient's inner world, his/her experience and cognition are taken into due account as powerful resources for recovery through a phenomenological-existential approach.

Placebo and nocebo responses in randomized controlled trials of Janus kinase inhibitor monotherapy for rheumatoid arthritis : A meta-analysis

OBJECTIVE

The goal of this meta-analysis was to assess the frequency and magnitude of placebo and nocebo responses in placebo-controlled randomized controlled trials (RCTs) of Janus kinase (JAK) inhibitor monotherapy for rheumatoid arthritis (RA) METHODS: We performed a meta-analysis on the rates of placebo response, adverse effects (AEs), severe AEs (SAEs) and withdrawal due to AEs in placebo-controlled randomized clinical trials (RCTs) of JAK inhibitor therapy for RA.

RESULTS

Five RCTs contained a total of 1422 patients (746 trial participants and 676 controls). The pooled incidence of an American College of Rheumatology 20% (ACR20) response rate was 33.0% (95% CI 19.6-44.9%) in placebo-treated patients and 68.3% (95% CI 61.4-74.1%) in active drug-treated patients. A strong negative correlation was observed between drug efficacies (ACR20 response) and AE rates in the placebo arm, indicating that the stronger the placebo response, the weaker the nocebo response (r = -0.906, P = 0.034). The pooled estimate of at least one AE was 54.1% (95% CI 44.6-63.4%) in placebo-treated patients and 54.5% (95% CI 46.2-62.6%) in active drug-treated patients. The pooled SAE rate was 3.9% (95% CI 2.7-5.7%) in placebo-treated patients and 3.8% (95% CI 2.5-5.7%) in active comparator-treated patients. The pooled estimate of withdrawal owing to an AE was 4.1% (95% CI 1.4-11.3%) in placebo-treated patients and 2.1% (95% CI 0.8-5.4%) in active drug-treated patients. However, there were no differences in the pooled risk of AE, SAEs, or withdrawal owing to AEs between the active comparator and placebo groups. A strong positive correlation was observed in AE rates between the placebo and active arms, indicating that the stronger the nocebo response, the higher the AE rate in the active arm (r = 0.957, P = 0.012).

CONCLUSION

The frequency of placebo and nocebo responses was 33.0 and 54.1%, respectively, in JAK monotherapy trials for RA. The findings indicated that the strengths of placebo and nocebo responses are inversely proportional and that clinically significant differences were absent between AE, SAE, and dropout owing to AEs.

[Nocebo, informed consent and doctor-patient communication]

Negative previous experiences (conditioning), observational learning and expectations can trigger nocebo effects. They are responsible for a substantial proportion of the side effects of medical treatment, and are induced primarily by risk information for informed consent. This has been demonstrated in studies on patient groups with or without modified medical information. Drug trials in the field of neurology and psychiatry have regularly revealed side effects and drop-out also in placebo groups. The underlying neurobiological mechanisms were experimentally investigated especially for nocebo-induced hyperalgesia, whereby the specifically involved regions of the brain could be identified by functional imaging as well as changes in the dopamine, endorphin and cholecystokinin systems. Nocebo effects are specific, i.e. they are closely related to patient information and can induce or aggravate exactly the symptoms addressed. Nevertheless, informed consent is an essential part of doctor-patient communication; however, information on risks can be markedly less damaging when unnecessary repetitions are avoided, misunderstandings are recognized or resolved and several different options are given. In addition, risks should always be named together with positive aspects, such as the advantages of the appropriate treatment, the prophylactic measures applied or the early detection and treatment of developing side effects. The best protection against harm caused by information on risks is a trustful doctor-patient relationship. Poor knowledge of nocebo effects or lack of countermeasures constitute a serious threat to patients and according to the current state of knowledge could be rated as medical malpractice.

Maximizing placebo response in neurological clinical practice

The placebo effect is a widely recognized phenomenon in clinical research, with a negative perception that it could hide the "true" drug effect. In clinical care its positive potential to increase known drug effects has been neglected for too long. The placebo and nocebo responses have been described in many neurologic disorders such as Parkinson's, Huntington's and Alzheimer's diseases, restless leg syndrome, tics, essential tremor, dystonia, functional movement disorders, neuropathic pain, headaches, migraine, amyotrophic lateral sclerosis, myasthenia gravis, chronic inflammatory demyelinating polyneuropathy, multiple sclerosis and epilepsy. Knowledge regarding placebo mechanisms and their consequences on clinical outcome have greatly improved over the last two decades. This evolution has led to reconsiderations of the importance of placebo response in the clinic and has given several clues on how to improve it in daily practice. In this chapter, we first illustrate "why," e.g. the reasons (relevance to clinical practice, help in differential diagnosis/treatment of psychogenic movements, clinical impact, proven neurobiological grounds, health economic potential), and "how," e.g. the means (increase patients' knowledge, increase learning, improve patient-doctor relationship, increase Hawthorne effect, increase positive/decrease negative expectations (the Rosenthal effect), personalize placebo response), the placebo should be maximized (and nocebo avoided) in neurological clinical practice. Future studies regarding more specific neurobiological mechanisms will allow a finer tuning of placebo response in clinical practice. The use of placebo in clinical practice raises ethical issues, and a recent expert consensus regarding placebo use in the clinic is a first step to future guidelines necessary to this field.

Nocebo and lessebo effects

The power of placebos is commonly associated with the placebo effect. In contrast, detrimental effects related to the use of a placebo are little studied and less well recognized. This chapter covers the nocebo and lessebo effects defined, respectively, as expectation of harm in the form of adverse events in a placebo arm and reduction of therapeutic benefit due to the uncertainty of being allocated to placebo. The lessebo effect is a more recent concept and has been described only in depression, schizophrenia and Parkinson's disease. The nocebo response was evaluated in many neurological diseases, including epilepsy, multiple sclerosis, Parkinson's disease, Alzheimer's disease, restless leg syndrome, among others. Meta-analyses of randomized controlled trials in these conditions reveal a significant variability of the magnitude of the nocebo response and that factors related to study design, study participants or neurological disease can be associated with a nocebo response, although with the opposing findings across conditions. The knowledge about neurobiological mechanisms of the nocebo effect is poor for neurological diseases, and most of the information has been generated in pain. Functional neuroimaging suggests the existence of a distinct network for the anticipation and the experience of a hyperalgesia nocebo response. Different types of neurotransmitters have been involved, including cholecystokinin, dopamine and opioids. Recognizing the potential impact of nocebo and lessebo effects, mitigating strategies are in development with application to clinical research and clinical practice, such as a contextualized informed consent process, alternative study designs and enhancement of patient-physician communication.

Nocebo effect in myasthenia gravis: systematic review and meta-analysis of placebo-controlled clinical trials

Nocebo refers to the adverse events (AEs) experienced when taking a placebo drug and is believed to be a centrally mediated process. We sought to examine the AEs following placebo administration in Randomised Controlled Trials (RCTs) for Myasthenia Gravis (MG) patients. A systematic literature search was performed on Medline and Web of Science for RCTs for MG pharmacological treatments. We assessed the number of placebo-treated patients reporting at least one AE and the number of dropouts because of AEs. Data were extracted from six RCTs fulfilling the search criteria. Four out of five placebo-treated participants (80.1%) reported at least one AE and one in 40 (2.4%) discontinued placebo treatment because of AE. All patients participating in the MG trials reported similar AEs independent of the study arm to which they belonged (placebo or active treatment). This meta-analysis demonstrates a low nocebo dropout rate in MG compared to central nervous system disorders.

Nocebo in cerebellar ataxia: A systematic review and meta-analysis of placebo-controlled clinical trials

INTRODUCTION

Nocebo, the negative counterpart of the placebo phenomenon results in the induction of adverse events (AEs) following the administration of an inert substance. Nocebo has been demonstrated to be associated with low treatment compliance in clinical trials, thus affecting treatment outcomes. This study sought to determine the prevalence of nocebo in cerebellar ataxia.

METHODS

A systematic literature search was conducted on Pubmed for randomized controlled trials (RCTs) for cerebellar ataxia treatments. The number of drug-related AEs and the number of withdrawals due to drug intolerance in the placebo group were statistically analysed.

RESULTS

The literature search identified 214 studies, of which 6 studies fulfilled the inclusion criteria. Approximately 1 in 20 (4.8%) placebo-treated patients withdrew treatment due to AEs and approximately 1 in 7 (13.8%) placebo-treated participants reported at least one AE. Participants in cerebellar ataxia trials reported similar AEs across both treatment groups (active and placebo).

CONCLUSION

Our results demonstrate that the nocebo effect in cerebellar ataxia is amongst the lowest in neurological diseases.

Safety, Tolerability, and Nocebo Phenomena During Transcranial Magnetic Stimulation: A Systematic Review and Meta-Analysis of Placebo-Controlled Clinical Trials

BACKGROUND

The methodology used for the application of repetitive transcranial magnetic stimulation (TMS) is such that it may induce a placebo effect. Respectively, adverse events (AEs) can occur when using a placebo, a phenomenon called nocebo. The primary aim of our meta-analysis is to establish the nocebo phenomena during TMS. Safety and tolerability of TMS were also studied.

METHODS

After a systematic Medline search for TMS randomized controlled trials (RCTs), we assessed the number of patients reporting at least one AE and the number of discontinuations because of AE in active and sham TMS groups.

RESULTS

Data were extracted from 93 RCTs. The overall pooled estimate of active TMS and placebo treated patients who discontinued treatment because of AEs was 2.5% (95% CI 1.9%-3.2%) and 2.7% (95% CI 2.0%-3.5%), respectively. The pooled estimate of active TMS and placebo treated patients experiencing at least one AE was 29.3% (95% CI 19.0%-22.6%) and 13.6% (95% CI 11.6%-15.8%), respectively, suggesting that the odds of experiencing an AE is 2.60 times higher (95% CI 1.75-3.86) in the active treatment group compared to placebo (p < 0.00001). The most common AE was headache, followed by dizziness. Secondary meta-analyses in depression and psychotic disorders showed that the odds of experiencing an AE is 3.98 times higher (95% CI 2.14-7.40) and 2.93 times higher (95% CI 1.41-6.07), respectively, in the active treatment groups compared to placebo.

CONCLUSIONS

TMS is a safe and well-tolerated intervention. Nocebo phenomena do occur during TMS treatment and should be acknowledged during clinical trial design and daily clinical practice.