Antidepressant study design affects patient expectancy: a pilot study

Inpatient's, therapist's and staff's expectations regarding treatment and their effects on placebo response in the psychiatric ward - results from an add-on oxytocin RCT

OBJECTIVES

Patient's and therapist's expectations are considered an important factor influencing placebo response in experimental and therapeutic settings. Nevertheless, the placebo effects of common neurological facilitators that promote treatment efficacy have not been explored. In the present study we examined the estimations of patients, therapists, and staff members, regarding their treatment type and assessed their influence on the facilitating effects of oxytocin.

METHODS

Patients (N = 87) were randomized and double-blindly allocated to receive either oxytocin or placebo, twice daily for a period of four weeks, as part of a larger randomized, double-blind, placebo-controlled trial. Patient's, therapist's and staff's expectations were assessed based on their estimation of treatment type (agent or placebo). Multilevel modeling and univariate and multivariate regression analysis were performed to assess the effects of patient's, therapist's, and staff's estimations on treatment outcome beyond the effects of treatment type.

RESULTS

Staff's, therapist's, and patient's estimations were significantly associated with treatment outcomes. Nevertheless, only therapist's and patient's estimations significantly predicted improvement beyond actual administration, with therapist's and patient's estimations associated with improvement in trait anxiety (STAI-T, B=-1.80, p < .05, and B=-2.02, p < .05, respectively); therapist's estimations were associated with improvement in general distress (OQ-45, B=-3.71, p < .05), and patient's estimations were associated with symptom relief (HSCL-11, B=-0.13, p < .05). Overall, patient's estimations had a higher relative contribution to treatment success, with standardized coefficients across scales ranging from - 0.06 to -0.26.

CONCLUSIONS

The neurobiological factors that promote treatment success are also influenced by patient's and therapist's expectations. Future studies should consider these effects when examining their impact in inpatient settings.

An Investigation of Further Strategies to Optimize Early Treatment Gains in Brief Therapies for Insomnia

OBJECTIVES

Identifying those who are most (and least) likely to benefit from a stepped-care approach to cognitive behavioral therapy for insomnia (CBT-I) increases access to insomnia therapies while minimizing resource consumption. The present study investigates non-targeted factors in a single-session of CBT-I that may act as barriers to early response and remission.

METHODS

Participants (N = 303) received four sessions of CBT-I and completed measures of subjective insomnia severity, fatigue, sleep-related beliefs, treatment expectations, and sleep diaries. Subjective insomnia severity and sleep diaries were completed between each treatment session. Early response was defined as a 50% reduction in Insomnia Severity Index (ISI) scores and early remission was defined by < 10 on the ISI after the first session.

RESULTS

A single-session of CBT-I significantly reduced subjective insomnia severity scores and diary total wake time. Logistic regression models indicated that lower baseline fatigue was associated with increased odds of early remission (B = -.05, p = .02), and lower subjective insomnia severity (B = -.13, p = .049). Only fatigue was a significant predictor of early treatment response (B = -.06, p = .003).

CONCLUSIONS

Fatigue appeared to be an important construct that dictates early changes in perceived insomnia severity. Beliefs about the relationship between sleep and daytime performance may hinder perceived improvements in insomnia symptoms. Incorporating fatigue management strategies and psychoeducation about the relationship between sleep and fatigue may target non-early responders. Future research would benefit from further profiling potential early insomnia responders/remitters.

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.

A randomised cross-over study assessing the "blue pyjama syndrome" in major depressive episode

This paper introduces a “blue pyjama syndrome” (whereby wearing hospital pyjamas results in an exaggerated impression of severity). We performed a 5-day, prospective, randomized, cross-over study in a French mood disorder unit for inpatients. At Day 1 (D1) and Day 5 (D5), two 5-minute video interviews were recorded with patients in pyjamas or in day clothes (the sequence was randomly allocated). Psychiatrists unaware of the study objective assessed the videos and scored their clinical global impressions (CGI, with scores ranging from 1 to 7). Of 30 participants with major depressive episode selected for inclusion, 26 participants (69% women) provided useable data for an evaluation by 10 psychiatrists. Pyjamas significantly increased the psychiatrists’ CGI ratings of disease severity by 0·65 [0·27; 1·02] points. The psychiatrists’ global impressions also rated patients as significantly less severe at D5 in comparison with D1 by −0·66 [−1·03; −0·29] points. The “blue pyjama syndrome” is in the same order of magnitude as the difference observed after a week of hospitalisation. This potentially calls into question the reliability and validity of observer ratings of depression.

Common Factors in Pediatric Psychiatry: A Review of Essential and Adjunctive Mechanisms of Treatment Outcome

OBJECTIVE

The purpose of this article is to review the literature on hypothesized behavioral correlates of pharmacotherapy treatment response. A particular focus is placed on what have been referred to as "common factors" across mental health treatments, including medication adherence, therapeutic alliance, motivation for behavior change, and expectancies for positive treatment outcomes. These understudied factors may provide unique explanations for mechanisms of symptom change, patient risk as a result of protocol deviation, and attenuated treatment outcomes.

METHOD

A literature search was conducted to evaluate the relationship between treatment processes in pediatric psychiatry and medication adherence, therapeutic alliance, motivation for behavior change, and expectancies for positive treatment outcomes.

RESULTS

Substantial variability and room for improvement was identified for each common factor. Behavioral protocols have already been developed to address many aspects of common factors in pediatric psychiatric treatment, but are not yet a part of many practice parameters.

CONCLUSION

Interventions to improve common factors can be used immediately in tandem with psychopharmacological interventions to provide increased symptom relief and reduce patient risk. Furthermore, incorporating instruction in common factors interventions can positively affect training of future providers and enhance understanding of the mechanisms of effect of medications. An increased focus on common factors, with a particular emphasis on quantifying the magnitude and mechanisms of their effects on psychopharmacological interventions stand to benefit child patients, their families, treatment providers, training facilities, and pharmaceutical manufacturers.

Different Disclosed Probabilities to Receive an Antiemetic Equally Decrease Subjective Symptoms in an Experimental Placebo Study: To Be or Not to Be Sure

PURPOSE

The purpose of this study was to examine whether the disclosed probability of receiving an antiemetic affects nausea.

METHODS

Forty-eight healthy participants (mean [SD] age, 26.8 [5.4] years; 50% female) were exposed to 5 × 2 minutes of nauseogenic body rotations on 2 days. On day 2, participants were randomized to 3 experimental groups that were given different instructions concerning the probability of receiving an antiemetic remedy (100%, 50%, or 0% probability), whereas all received an inert substance. Subjective symptoms, behavioral (rotation tolerance) measures, and physiologic (electrogastrogram) measures of nausea were assessed and mediator and moderator analyses performed for effects of expectations and psychological characteristics on outcomes.

FINDINGS

Disclosed probabilities of both 100% and 50% significantly reduced subjective symptoms of nausea in an equal manner compared with the 0% probability group from day 1 to day 2. This effect was found for neither rotation tolerance nor myoelectric gastric activity. Expectations and psychological characteristics did not affect the results found. Post hoc analyses revealed that women only seem to be susceptible to this placebo effect.

IMPLICATIONS

Nausea is susceptible to placebo effects independent of the disclosed probability of receiving a drug and of explicit expectations. In line with placebo research, this effect is probably attributable to central mechanisms, and it is speculated that it could be related to the reward circuitry and social interactions.

Therapeutic alliance in antidepressant treatment: cause or effect of symptomatic levels?

BACKGROUND

Previous studies have shown that in psychotherapy alliance is a predictor of symptomatic change, even while accounting for the temporal precedence between alliance and symptoms. However, the extent to which alliance predicts outcomes in psychopharmacology is yet to be fully investigated considering the fact that alliance can be the result, rather than the cause, of symptomatic change. The current prospective study examined whether the alliance predicts outcomes in psychopharmacology, while controlling for previous symptomatic change throughout the course of treatment.

METHODS

Data from a psychopharmacological randomized controlled trial for the treatment of adult major depression (n = 42), including the patients' rating of the alliance with the physicians, were analyzed. Multilevel models controlling for autoregressive lag of the dependent variable were used in all analyses to examine the effect of alliance on outcome.

RESULTS

The effect of alliance on outcome, while controlling for prior symptomatic levels, was significant and restricted to the middle phase of treatment (week 4, p = 0.005), when most of the reductions in symptoms were observed. Exploratory analyses of the differences between placebo and medication conditions suggest that the differences between the patients in their average alliance levels predicted a greater reduction in symptoms in the placebo compared to the medication conditions (p = 0.008). The main limitation is the small cohort size.

CONCLUSIONS

The findings suggest an effect of alliance on outcome in psychopharmacology, which is not merely the result of previous symptomatic levels. This effect may be more robust in conditions that do not include active treatment (placebo), possibly serving as a compensatory effect.

Improving study design for antidepressant effectiveness assessment

Antidepressants effectiveness in major depressive disorder (MDD) is still questioned because the extrapolation of randomized controlled trial (RCT) results to "real life" settings is problematic. The application of the RCT paradigm in a disorder of this type, where global care plays a central role, raises questions regarding the internal and external validity of this type of study. Outcome measurement, attrition rates, the ability of the double-blind design to control for expectations, placebo response, the representativeness of trial participants and publication bias are major methodological pitfalls. This review discusses these issues. It is illustrated using original data and proposes some alternatives for assessing antidepressant effectiveness via different approaches. Some are easy to implement, such as ecological measures, qualitative approaches, improvement of analytical strategy and improvement of blinding procedures. Some are sophisticated, involving temporary deception to deal with the confounding effect of expectations, and they raise ethical issues. Others resort to external validity, this being the case in observational studies. But all are necessary to explore antidepressant effectiveness.

A randomized, prospective pilot study of patient expectancy and antidepressant outcome

BACKGROUND

This study is a randomized, prospective, investigation of the relationships between clinical trial design, patient expectancy and the outcome of treatment with antidepressant medication. Method Adult out-patients with major depressive disorder (MDD) were randomized to either placebo-controlled (PC, 50% probability of receiving active medication) or comparator (COMP, 100% probability of receiving active medication) administration of antidepressant medication. Independent-samples t tests and analysis of covariance (ANCOVA) were used to determine whether the probability of receiving active medication influenced patient expectancy and to compare medication response in the PC v. COMP conditions. We also tested the correlations between baseline expectancy score and final improvement in depressive symptoms across study groups.

RESULTS

Subjects randomized to the COMP condition reported greater expectancy of improvement compared to subjects in the PC condition (t = 2.60, df = 27, p = 0.015). There were no statistically significant differences in the analyses comparing antidepressant outcomes between subjects receiving medication in the COMP condition and those receiving medication in the PC condition. Higher baseline expectancy of improvement was correlated with lower final depression severity scores (r = 0.53, p = 0.021) and greater improvement in depressive symptoms over the course of the study (r = 0.44, p = 0.058).

CONCLUSIONS

The methods described represent a promising way of subjecting patient expectancy to scientific study. Expectancy of improvement is affected by the probability of receiving active antidepressant medication and seems to influence antidepressant response.

The hidden effects of blinded, placebo-controlled randomized trials: an experimental investigation

The knowledge of having only a 50% chance of receiving an active drug can result in reduced efficacy in blinded randomized clinical trials (RCTs) compared to clinical practice (reduced external validity). Moreover, minor onset sensations associated with the drug (but not with an inert placebo) can further challenge the attribution of group differences to drug-specific efficacy (internal validity). We used a randomized experimental study with inert placebos (inert substance) vs active placebos (inducing minor sensations), and different instructions about group allocation (probability of receiving drug: 0%, 50%, 100%). One hundred forty-four healthy volunteers were informed that a new application method for a well-known painkiller would be tested. Pain thresholds were assessed before and after receiving nasal spray. Half of the nasal sprays were inert placebos (sesame oil), while the other half were active placebos inducing prickling nasal sensations (sesame oil with 0.014% capsaicin). The major outcome was pain threshold after placebo application. A substantial expectation effect was found for the inert placebo condition, with participants who believed they had received an active drug reporting the highest pain thresholds. Active placebos show substantial differences to passive placebos in the 50% chance group. Therefore, patient expectations are significantly different in placebo-controlled clinical trials (50% chance) vs clinical practice (100% chance). Moreover, minor drug onset sensations can challenge internal validity. Effect sizes for these mechanisms are medium, and can substantially compete with specific drug effects. For clinical trials, new study designs are needed that better control for these effects.

Does differential drop-out explain the influence of study design on antidepressant response? A meta-analysis

BACKGROUND

Response to antidepressants is higher in active comparator relative to placebo-controlled clinical trials. Increased patient expectancy in comparator trials has been hypothesized to explain this finding, but previous analyses have not accounted for the increased drop-out observed in placebo-controlled trials.

METHODS

A systematic literature review was conducted to identify published antidepressant clinical trials reporting data on intent-to-treat (ITT) as well as completer patient populations. The influence of participant drop-out on observed antidepressant response was investigated by comparing the ITT and completer data sets in separate multilevel meta-analyses of antidepressant response in placebo-controlled and comparator trials.

RESULTS

18 placebo-controlled and 18 active comparator studies were available for analysis. Using the intent-to-treat data, the odds of responding to medication in comparator trials were 1.9 times the odds in placebo-controlled trials (95% CI=1.3-2.7, p=0.001). The same pattern was obtained among study completers, in whom the odds of responding to antidepressant medication were 1.9 times higher in comparator as opposed to placebo-controlled study designs (95% CI=1.2-3.0, p=0.009).

LIMITATIONS

Publication bias, the use of trial-level summary data, and unreported clinical or demographic differences between the ITT and completer patient populations may have influenced the study results.

CONCLUSIONS

Increased drop-out in placebo-controlled vs. active comparator studies of antidepressant medications does not appear to explain the difference in response rates between these study types. Rather, increased patient expectancy resulting from the certainty of receiving active medication in comparator trials may lead to improved response rates.

Controlled trial of safety and efficacy of bright light therapy vs. negative air ions in patients with bipolar depression

Treatment of bipolar disorder often results in patients taking several drugs in an attempt to alleviate residual depressive symptoms, which can lead to an accumulation of side effects. New treatments for bipolar depression that do not increase the side effect burden are needed. One nonpharmacological treatment with few side effects, bright light therapy, has been shown to be an effective therapy for seasonal affective disorder, yet has not been extensively studied for other forms of depression. Forty-four adults with bipolar disorder, depressed phase were randomized to treatment with bright light therapy, low-density or high-density negative ion generator for 8 weeks. The primary measure of efficacy was the Structured Interview Guide for the Hamilton Depression Rating Scale with Atypical Depression Supplement (SIGH-ADS). Adverse events were assessed using the Young Mania Rating Scale (YMRS) and Systematic Assessment for Treatment Emergent effects (SAFTEE). All outcome variables were statistically analyzed using a mixed model repeated measure analysis of variance (ANOVA). The results showed no statistically significant differences between groups in any outcome measures at study end point; adverse events, including switches into hypomania, were rare. Further research is needed to determine the efficacy of bright light therapy in this population.

Deconstructing pediatric depression trials: an analysis of the effects of expectancy and therapeutic contact

OBJECTIVE

This study investigated how study type, mean patient age, and amount of contact with research staff affected response rates to medication and placebo in acute antidepressant trials for pediatric depression.

METHOD

Data were extracted from nine open, four active comparator, and 18 placebo-controlled studies of antidepressants for children and adolescents with depressive disorders. A multilevel meta-analysis examined how study characteristics affected response rates to antidepressants and placebo.

RESULTS

The primary finding was a main effect of study type across patient age and contact amount, such that the odds of medication response were greater in open versus placebo-controlled studies (odds ratio 1.87, 95% confidence interval 1.17-2.99, p = .012) and comparator studies (odds ratio 2.01, 95% confidence interval 1.16-3.48, p = .015) but were not significantly different between comparator and placebo-controlled studies. No significant main effects of patient age or amount of contact with research staff were found for analyses of response rates to medication and placebo. Response to placebo in placebo-controlled trials did significantly increase with the amount of therapeutic contact in older patients (age by contact; odds ratio 1.08, 95% confidence interval 1.01-1.15, p = .038).

CONCLUSIONS

Although patient expectancy strongly influences response rates to medication and placebo in depressed adults, it appears to be less important in the treatment of children and adolescents with depression. Attempts to limit placebo response and improve the efficiency of antidepressant trials for pediatric depression should focus on other causes of placebo response apart from expectancy.

Usual and unusual care: existing practice control groups in randomized controlled trials of behavioral interventions

OBJECTIVE

To evaluate the use of existing practice control groups in randomized controlled trials of behavioral interventions and the role of extrinsic health care services in the design and conduct of behavioral trials.

METHOD

Selective qualitative review.

RESULTS

Extrinsic health care services, also known as nonstudy care, have important but under-recognized effects on the design and conduct of behavioral trials. Usual care, treatment-as-usual, standard of care, and other existing practice control groups pose a variety of methodological and ethical challenges, but they play a vital role in behavioral intervention research.

CONCLUSIONS

This review highlights the need for a scientific consensus statement on control groups in behavioral trials.

Predicting individual differences in placebo analgesia: contributions of brain activity during anticipation and pain experience

Recent studies have identified brain correlates of placebo analgesia, but none have assessed how accurately patterns of brain activity can predict individual differences in placebo responses. We reanalyzed data from two fMRI studies of placebo analgesia (N = 47), using patterns of fMRI activity during the anticipation and experience of pain to predict new subjects' scores on placebo analgesia and placebo-induced changes in pain processing. We used a cross-validated regression procedure, LASSO-PCR, which provided both unbiased estimates of predictive accuracy and interpretable maps of which regions are most important for prediction. Increased anticipatory activity in a frontoparietal network and decreases in a posterior insular/temporal network predicted placebo analgesia. Patterns of anticipatory activity across the cortex predicted a moderate amount of variance in the placebo response (∼12% overall, ∼40% for study 2 alone), which is substantial considering the multiple likely contributing factors. The most predictive regions were those associated with emotional appraisal, rather than cognitive control or pain processing. During pain, decreases in limbic and paralimbic regions most strongly predicted placebo analgesia. Responses within canonical pain-processing regions explained significant variance in placebo analgesia, but the pattern of effects was inconsistent with widespread decreases in nociceptive processing. Together, the findings suggest that engagement of emotional appraisal circuits drives individual variation in placebo analgesia, rather than early suppression of nociceptive processing. This approach provides a framework that will allow prediction accuracy to increase as new studies provide more precise information for future predictive models.