A comparison of placebo and no-treatment during a hypnotic clinical trial

Control interventions in randomised trials among people with mental health disorders

BACKGROUND

Control interventions in randomised trials provide a frame of reference for the experimental interventions and enable estimations of causality. In the case of randomised trials assessing patients with mental health disorders, many different control interventions are used, and the choice of control intervention may have considerable impact on the estimated effects of the treatments being evaluated.

OBJECTIVES

To assess the benefits and harms of typical control interventions in randomised trials with patients with mental health disorders. The difference in effects between control interventions translates directly to the impact a control group has on the estimated effect of an experimental intervention. We aimed primarily to assess the difference in effects between (i) wait-list versus no-treatment, (ii) usual care versus wait-list or no-treatment, and (iii) placebo interventions (all placebo interventions combined or psychological, pharmacological, and physical placebos individually) versus wait-list or no-treatment. Wait-list patients are offered the experimental intervention by the researchers after the trial has been finalised if it offers more benefits than harms, while no-treatment participants are not offered the experimental intervention by the researchers.

SEARCH METHODS

In March 2018, we searched MEDLINE, PsycInfo, Embase, CENTRAL, and seven other databases and six trials registers.

SELECTION CRITERIA

We included randomised trials assessing patients with a mental health disorder that compared wait-list, usual care, or placebo interventions with wait-list or no-treatment .

DATA COLLECTION AND ANALYSIS

Titles, abstracts, and full texts were reviewed for eligibility. Review authors independently extracted data and assessed risk of bias using Cochrane's risk of bias tool. GRADE was used to assess the quality of the evidence. We contacted researchers working in the field to ask for data from additional published and unpublished trials. A pre-planned decision hierarchy was used to select one benefit and one harm outcome from each trial. For the assessment of benefits, we summarised continuous data as standardised mean differences (SMDs) and dichotomous data as risk ratios (RRs). We used risk differences (RDs) for the assessment of adverse events. We used random-effects models for all statistical analyses. We used subgroup analysis to explore potential causes for heterogeneity (e.g. type of placebo) and sensitivity analyses to explore the robustness of the primary analyses (e.g. fixed-effect model).

MAIN RESULTS

We included 96 randomised trials (4200 participants), ranging from 8 to 393 participants in each trial. 83 trials (3614 participants) provided usable data. The trials included 15 different mental health disorders, the most common being anxiety (25 trials), depression (16 trials), and sleep-wake disorders (11 trials). All 96 trials were assessed as high risk of bias partly because of the inability to blind participants and personnel in trials with two control interventions. The quality of evidence was rated low to very low, mostly due to risk of bias, imprecision in estimates, and heterogeneity. Only one trial compared wait-list versus no-treatment directly but the authors were not able to provide us with any usable data on the comparison. Five trials compared usual care versus wait-list or no-treatment and found a SMD -0.33 (95% CI -0.83 to 0.16, I² = 86%, 523 participants) on benefits. The difference between all placebo interventions combined versus wait-list or no-treatment was SMD -0.37 (95% CI -0.49 to -0.25, I² = 41%, 65 trials, 2446 participants) on benefits. There was evidence of some asymmetry in the funnel plot (Egger's test P value of 0.087). Almost all the trials were small. Subgroup analysis found a moderate effect in favour of psychological placebos SMD -0.49 (95% CI -0.64 to -0.30; I² = 53%, 39 trials, 1656 participants). The effect of pharmacological placebos versus wait-list or no-treatment on benefits was SMD -0.14 (95% CI -0.39 to 0.11, 9 trials, 279 participants) and the effect of physical placebos was SMD -0.21 (95% CI -0.35 to -0.08, I² = 0%, 17 trials, 896 participants). We found large variations in effect sizes in the psychological and pharmacological placebo comparisons. For specific mental health disorders, we found significant differences in favour of all placebos for sleep-wake disorders, major depressive disorder, and anxiety disorders, but the analyses were imprecise due to sparse data. We found no significant differences in harms for any of the comparisons but the analyses suffered from sparse data. When using a fixed-effect model in a sensitivity analysis on the comparison for usual care versus wait-list and no-treatment, the results were significant with an SMD of -0.46 (95 % CI -0.64 to -0.28). We reported an alternative risk of bias model where we excluded the blinding domains seeing how issues with blinding may be seen as part of the review investigation itself. However, this did not markedly change the overall risk of bias profile as most of the trials still included one or more unclear bias domains.

AUTHORS' CONCLUSIONS

We found marked variations in effects between placebo versus no-treatment and wait-list and between subtypes of placebo with the same comparisons. Almost all the trials were small with considerable methodological and clinical variability in factors such as mental health population, contents of the included control interventions, and outcome domains. All trials were assessed as high risk of bias and the evidence quality was low to very low. When researchers decide to use placebos or usual care control interventions in trials with people with mental health disorders it will often lead to lower estimated effects of the experimental intervention than when using wait-list or no-treatment controls. The choice of a control intervention therefore has considerable impact on how effective a mental health treatment appears to be. Methodological guideline development is needed to reach a consensus on future standards for the design and reporting of control interventions in mental health intervention research.

Effects of electrostatic therapy on nighttime sleep and daytime symptoms in patients with chronic insomnia: Evidences from an open label study

INTRODUCTION

Transcranial electric stimulation (TES) is a neuromodulation approach that applies low-intensity electrical current to the brain and has been proposed as a treatment for insomnia. Electrostatic therapy is a kind of TES and people do not have a feeling of electrical stimuli when the voltage of static electricity is lower than 2,000 volts. However, no studies have examined the effects of electrostatic therapy on objective sleep and daytime symptoms in patients with insomnia.

MATERIALS AND METHODS

Thirty chronic insomnia patients were included. All patients received a 6 week electrostatic therapy and three comprehensive assessments including two consecutive polysomnography (PSG) and daytime symptoms assessments, at pre-treatment, 3 week and 6 week of treatment. Insomnia Severity Index (ISI) was used to assess the severity of insomnia. Multiple sleep latency test (MSLT), Epworth Sleepiness Scale (ESS), and Flinders Fatigue Scale (FFS) were used to assess objective and self-reported daytime sleepiness and fatigue, respectively. Attention network test (ANT) was used to assess attention levels.

RESULTS

Total ISI scores decreased significantly at 3 weeks (p < 0.001) and 6 weeks (p < 0.001) after initiation of treatment. Furthermore, objective total sleep time (TST, p = 0.020) and sleep efficiency (SE, p = 0.009) increased and wake time after sleep onset (p = 0.012) decreased significantly after 6 weeks electrostatic therapy. Regarding daytime symptoms, ESS and FFS scores decreased significantly at 3 weeks (ESS, p = 0.047; FFS, p = 0.017) and 6 weeks (ESS, p = 0.008; FFS, p = 0.003) after initiation of treatment. Moreover, executive control improved significantly from pre-treatment to 3 weeks (p = 0.006) and 6 weeks (p = 0.013) and altering network improved significantly at 6 weeks (p = 0.003) after initiation of treatment. Secondary analyses showed that TST and SE improved significantly after electrostatic therapy in insomnia patients who slept < 390 min (all p-value < 0.05). However, no significant changes regarding TST and SE were observed in insomnia patients who slept ≥ 390 min.

CONCLUSION

Electrostatic therapy improves both nighttime sleep and daytime symptoms in patients with chronic insomnia. The effect on objective sleep appears to be stronger in patient with objective short sleep duration. Electrostatic therapy might be a therapeutic choice for insomnia patients with difficulty maintaining sleep and not responding to behavioral treatments.

CLINICAL TRIAL REGISTRATION

[www.clinicaltrials.gov], identifier [ChiCTR2100051590].

Neuro-Bio-Behavioral Mechanisms of Placebo and Nocebo Responses: Implications for Clinical Trials and Clinical Practice

The placebo effect has often been considered a nuisance in basic and particularly clinical research. This view has gradually changed in recent years due to deeper insight into the neuro-bio-behavioral mechanisms steering both the placebo and nocebo responses, the evil twin of placebo. For the neuroscientist, placebo and nocebo responses have evolved as indispensable tools to understand brain mechanisms that link cognitive and emotional factors with symptom perception as well as peripheral physiologic systems and end organ functioning. For the clinical investigator, better understanding of the mechanisms driving placebo and nocebo responses allow the control of these responses and thereby help to more precisely define the efficacy of a specific pharmacological intervention. Finally, in the clinical context, the systematic exploitation of these mechanisms will help to maximize placebo responses and minimize nocebo responses for the patient's benefit. In this review, we summarize and critically examine the neuro-bio-behavioral mechanisms underlying placebo and nocebo responses that are currently known in terms of different diseases and physiologic systems. We subsequently elaborate on the consequences of this knowledge for pharmacological treatments of patients and the implications for pharmacological research, the training of healthcare professionals, and for the health care system and future research strategies on placebo and nocebo responses.

Effect of Placebo Conditions on Polysomnographic Parameters in Primary Insomnia: A Meta-Analysis

STUDY OBJECTIVES

Little is known about the role of placebo response in the pharmacotherapy of primary insomnia, especially about the effect of placebo intake on objectively assessed outcome variables. Our aim was therefore to conduct an effect-size analysis of placebo conditions in randomized controlled drug trials addressing primary insomnia also including polysomnography.

DESIGN

We conducted a comprehensive literature search using PubMed, PsycINFO, PSYNDEX, PQDT OPEN, OpenGREY, ISI Web of Knowledge, Cochrane Clinical Trials, and the World Health Organization International Clinical Trials Registry Platform. The meta-analysis used a random effects model and was based on 32 studies reporting 82 treatment conditions covering a total of 3,969 participants. Special emphasis was given to the comparison of objective and subjective outcomes and the proportion of the placebo response to the drug response.

MEASUREMENTS AND RESULTS

Effect sizes estimates (Hedges g) suggest that there is a small to moderate yet significant and robust placebo response reducing the symptoms of insomnia in terms of sleep onset latency (-0.35), total sleep time (0.42), wake after sleep onset (-0.29), sleep efficiency (0.31), subjective sleep onset latency (-0.29), subjective total sleep time (0.43), subjective wake after sleep onset (-0.32), subjective sleep efficiency (0.25) and sleep quality (0.31). Thus, the placebo response was also evident in objective, physiological (polysomnographic) variables. Our results indicate that 63.56% of the drug responses are achieved even in the placebo groups.

CONCLUSIONS

In light of these strong placebo responses, future studies should investigate how to exploit placebo mechanisms in clinical practice.

The impact of eszopiclone on sleep and cognition in patients with schizophrenia and insomnia: a double-blind, randomized, placebo-controlled trial

BACKGROUND

Insomnia is frequent in schizophrenia and may contribute to cognitive impairment as well as overuse of weight inducing sedative antipsychotics. We investigated the effects of eszopiclone on sleep and cognition for patients with schizophrenia-related insomnia in a double-blind placebo controlled study, followed by a two-week, single-blind placebo phase.

METHODS

Thirty-nine clinically stable outpatients with schizophrenia or schizoaffective disorder and insomnia were randomized to either 3mg eszopiclone (n=20) or placebo (n=19). Primary outcome measure was change in Insomnia Severity Index (ISI) over 8 weeks. Secondary outcome measure was change in MATRICS Consensus Cognitive Battery (MATRICS). Sleep diaries, psychiatric symptoms, and quality of life were also monitored.

RESULTS

ISI significantly improved more in eszopiclone (mean=-10.7, 95% CI=-13.2; -8.2) than in placebo (mean=-6.9, 95% CI=-9.5; -4.3) with a between-group difference of -3.8 (95% CI=-7.5; -0.2). MATRICS score change did not differ between groups. On further analysis there was a significant improvement in the working memory test, letter-number span component of MATRICS (mean=9.8±9.2, z=-2.00, p=0.045) only for subjects with schizophrenia on eszopiclone. There were improvements in sleep diary items in both groups with no between-group differences. Psychiatric symptoms remained stable. Discontinuation rates were similar. Sleep remained improved during single-blind placebo phase after eszopiclone was stopped, but the working memory improvement in patients with schizophrenia was not durable.

CONCLUSIONS

Eszopiclone stands as a safe and effective alternative for the treatment of insomnia in patients with schizophrenia. Its effects on cognition require further study.

Dissection of the factors driving the placebo effect in hypnotic treatment of depressed insomniacs

OBJECTIVES

Our prior work has shown that there is improvement in self-reported sleep in persons receiving placebo in hypnotic clinical trials. We examined the components of the "placebo response" in a hypnotic clinical trial.

METHODS

This was an exploratory analysis of a randomized, double-blind clinical trial of eszopiclone versus placebo in the treatment of persons with depression and insomnia who were also receiving fluoxetine at a clinic of a teaching hospital. Sixty adults with both depression and insomnia symptoms, who were free of significant primary sleep disorders, received open-label fluoxetine for 9weeks. Patients were further randomized 1:1 to receive either masked eszopiclone 3mg or placebo at bedtime after the first week of fluoxetine. We examined the respective contributions of three factors associated with the "placebo effect": (1) regression to the mean, (2) expectancy, and (3) social desirability.

RESULTS

There was evidence for regression to the mean for the continuous measurement of the Insomnia Severity Index (ISI) and the Hamilton Depression Rating Scale. There was evidence for expectancy in self-reported Wake After Sleep Onset, continuous measurement of ISI, and dichotomous remission/non-remitter measurement of ISI. There was evidence of social desirability affecting self-reported Total Sleep Time.

CONCLUSIONS

Factors that have been associated with the "placebo effect" are operating in hypnotic clinical trials. However, the role of each factor differs depending upon which self-reported variable is being considered. The findings have implications for clinical trial design in insomnia.

Nightly treatment of primary insomnia with eszopiclone for six months: effect on sleep, quality of life, and work limitations

STUDY OBJECTIVES

To evaluate 6 months' eszopiclone treatment upon patient-reported sleep, fatigue and sleepiness, insomnia severity, quality of life, and work limitations.

DESIGN

Randomized, double blind, controlled clinical trial.

SETTING

54 research sites in the U.S.

PATIENTS

830 primary insomnia patients who reported mean nightly total sleep time (TST) < or = 6.5 hours/night and/or mean nightly sleep latency (SL) >30 min.

INTERVENTION

Eszopiclone 3 mg or matching placebo.

MEASUREMENTS

Patient-reported sleep measures, Insomnia Severity Index, Medical Outcomes Study Short-Form Health Survey (SF-36), Work Limitations Questionnaire, and other assessments measured during baseline, treatment Months 1-6, and 2 weeks following discontinuation of treatment.

RESULTS

Patient-reported sleep and daytime function were improved more with eszopiclone than with placebo at all months (P <0.001). Eszopiclone reduced Insomnia Severity Index scores to below clinically meaningful levels for 50% of patients (vs 19% with placebo; P <0.05) at Month 6. SF-36 domains of Physical Functioning, Vitality, and Social Functioning were improved with eszopiclone vs placebo for the Month 1-6 average (P < 0.05). Similarly, improvements were observed for all domains of the Work Limitations Questionnaire with eszopiclone vs placebo for the Month 1-6 average (P <0.05).

CONCLUSIONS

This is the first placebo-controlled investigation to demonstrate that long-term nightly pharmacologic treatment of primary insomnia with any hypnotic enhanced quality of life, reduced work limitations, and reduced global insomnia severity, in addition to improving patient-reported sleep variables.

The effect of placebo administration on the first-night effect in healthy young volunteers

The first-night effect is a well-known phenomenon that is considered to result from a subject's lack of adaptation to the unfamiliar environment of a sleep laboratory and to the technical equipment used for polysomnography. The effect has been explored as a laboratory model for transient insomnia. The main characteristics of this effect are short total sleep time (TST) and rapid eye movement (REM) sleep, a lower sleep efficiency index, and longer REM sleep latency. Previous studies have reported that personality traits (such as trait anxiety) are a potential cause of the first-night effect and that the placebo effect is closely related to the anxiety levels of the subjects. To the best of our knowledge, there are no reports regarding the effects of a placebo on first-night sleep. This omission can be explained by the fact that the polysomnographic recordings obtained during the first night of a study are generally excluded from the analysis in order to avoid the inclusion of the first-night effect. In the present study, 8 male university students were subjected to polysomnographic examinations during drug-free, placebo-administration, and benzodiazepine-administration conditions in order to clarify the placebo effect on sleep during consecutive nights, particularly on the first night. The recordings for each condition were conducted for 4 consecutive nights. A placebo or 5 mg nitrazepam was administered at 2230 h using a double-blind crossover design, while no drug was administered during the drug-free condition. There was a 10-day interval between the examination of each condition. Polysomnographic recording was started at 2300 h and continued until the natural awakening of the subjects on the next morning. Subsequently, the subjects were requested to fill in a rating scale that is used to evaluate the subjective perception of sleep. An increase in stage-2 sleep associated with the first-night effect was observed on the first night during the drug-free and placebo-administration conditions. However, REM sleep reduction associated with the first-night effect was detected on the first night during the drug-free condition; this decrease in REM sleep was counteracted by the placebo during the placebo-administration condition. The nitrazepam, but not the placebo, decreased both slow-wave sleep (SWS) and REM sleep. The values for the tendency to fall asleep, feeling refreshed upon awakening in the morning, and the tension upon awakening in the morning were improved to a greater extent by the placebo and nitrazepam administrations than when no drug was administered. These results demonstrate the possibility that placebo administration may have a hypnotic/anxiolytic effect and may improve transient insomnia without causing SWS and REM sleep reductions.

Meta-analysis of sleep changes in control groups of insomnia treatment trials

A meta-analysis assessing the magnitude of sleep changes from baseline in placebo-treated (psychological and pharmacological placebo) and untreated groups issued from independent trials was conducted. Comparisons were then performed to assess if the magnitude of sleep changes in the placebo control groups were significantly different than those of the untreated group. Medline, PsychInfo and Current Contents databases (1990-2004) were searched for primary insomnia treatment studies using a randomized controlled parallel-group design. Effect sizes were computed for each end-point variable based on subjective (patient-reported) and polysomnographic measures. Thirty-four studies (n = 1392 subjects) met inclusion criteria; twenty-three used a pharmacological placebo (n = 1163), four used a psychological placebo (n = 81), and seven used a waitlist condition (n = 148). Between-group comparisons were performed using a random effects model analysis. Significant pre-post changes were observed in the pharmacological placebo condition on several sleep parameters, both on objectively and subjectively measured outcomes [objective and subjective sleep onset latency (SOL) and total sleep time (TST) and subjective wake after sleep onset]. Although a tendency was observed for objective SOL, only the changes on subjective SOL and TST in the pharmacological placebo condition were significantly different from the corresponding changes in the untreated group. No differences were significant for the psychological placebo groups. Although the present findings suggest that sleep may significantly change in response to a pharmacological placebo, conclusions remain tentative because of possible confounds that may arise when comparing groups issued from different trials. Further research directly comparing placebo groups and untreated groups from the same randomized trials remains necessary.