Impact of antidepressant treatment history on clinical outcomes in placebo and medication treatment of major depression

Open-Label placebo for the treatment of unipolar depression: Results from a randomized controlled trial

BACKGROUND

The response to placebo is robust in studies of various antidepressant treatments. The strong placebo response, combined with the absence of side-effects, has prompted suggestions to use the ethically sound open-label placebo (OLP) as a treatment for depression. The aim of the present study was to assess the efficacy of OLP as an adjunct to treatment as usual (TAU) in the setting of a randomized controlled trial for the treatment of unipolar depression.

METHODS

Thirty-eight patients (age: 50 ± 17.1; 73.7% females) were randomized to either eight-week OLP treatment (n = 18) or four weeks of TAU followed by four weeks of OLP (n = 20). Clinical and socio-demographic measures were assessed at baseline, after four weeks, and at the end of the trial. Response to treatment was determined using the QIDS SR-16.

RESULTS

There was an overall decrease in depression levels over time, F(2,35) = 3.98, p = .028. A significant group x time interaction was found only among non-geriatric patients (<65years) with an early onset of depression (<50years), F(2,22) = 3.89, p = .036. Post-hoc tests indicated a significant decrease during the first four weeks, but only in the OLP group, t(11) = 2.29, p = .043.

LIMITATIONS

Small sample size and the use of a self-report questionnaire to assess depressive symptoms.

CONCLUSIONS

Our findings support the possibility that OLP is an effective treatment for the relatively young population of depressed patients. Additional studies are warranted to explore the use of OLP in clinical practice.

Does Sex/Gender Play a Role in Placebo and Nocebo Effects? Conflicting Evidence From Clinical Trials and Experimental Studies

Sex has been speculated to be a predictor of the placebo and nocebo effect for many years, but whether this holds true or not has rarely been investigated. We utilized a placebo literature database on various aspects of the genuine placebo/nocebo response. In 2015, we had extracted 75 systematic reviews, meta-analyses, and meta-regressions performed in major medical areas (neurology, psychiatry, internal medicine). These meta-analyses were screened for whether sex/gender differences had been noted to contribute to the placebo/nocebo effect: in only 3 such analyses female sex was associated with a higher placebo effect, indicating poor evidence for a contribution of sex to it in RCTs. This was updated with another set of meta-analyses for the current review, but did not change the overall conclusion. The same holds true for 18 meta-analyses investigating adverse event (nocebo) reporting in RCT in the placebo arm of trials. We also screened our database for papers referring to sex/gender and the placebo effect in experimental studies, and identified 28 papers reporting 29 experiments. Their results can be summarized as follows: (a) Despite higher sensitivity of pain in females, placebo analgesia is easier to elicit in males; (b) It appears that conditioning is effective specifically eliciting nocebo effects; (c) Conditioning works specifically well to elicit placebo and nocebo effects in females and with nausea; (d) Verbal suggestions are not sufficient to induce analgesia in women, but work in men. These results will be discussed with respect to the question why nausea and pain may be prone to be responsive to sex/gender differences, while other symptoms are less. Lastly, we will discuss the apparent discrepancy between RCT with low relevance of sex, and higher relevance of sex in specific experimental settings. We argue that the placebo response is predominantly the result of a conditioning (learning) response in females, while in males it predominantly may be generated via (verbal) manipulating of expectancies. In RCT therefore, the net outcome of the intervention may be the same despite different mechanisms generating the placebo effect between the sexes, while in experimental work when both pathways are separated and explicitly explored, such differences may surface.

Placebo Effects in Psychotherapy: A Framework

The issue of placebo response and the extent of its effect on psychotherapy is complex for two specific reasons: i) Current standards for drug trials, e.g., true placebo interventions, double-blinding, cannot be applied to most psychotherapy techniques, and ii) some of the "nonspecific effects" in drug therapy have very specific effects in psychotherapy, such as the frequency and intensity of patient-therapist interaction. In addition, different psychotherapy approaches share many such specific effects (the "dodo bird verdict") and lack specificity with respect to therapy outcome. Here, we discuss the placebo effect in psychotherapy under four aspects: a) nonspecific factors shared with drug therapy (context factors); b) nonspecific factors shared among all psychotherapy traditions (common factors); c) specific placebo-controlled options with different psychotherapy modalities; and d) nonspecific control options for the specific placebo effect in psychotherapy. The resulting framework proposes that the exploration and enumeration of context factors, common factors, and specific factors contributes to the placebo effects in psychotherapy.

Placebo Effect in the Treatment of Depression and Anxiety

The aim of this review is to evaluate the placebo effect in the treatment of anxiety and depression. Antidepressants are supposed to work by fixing a chemical imbalance, specifically, a lack of serotonin or norepinephrine in the brain. However, analyses of the published and the unpublished clinical trial data are consistent in showing that most (if not all) of the benefits of antidepressants in the treatment of depression and anxiety are due to the placebo response, and the difference in improvement between drug and placebo is not clinically meaningful and may be due to breaking blind by both patients and clinicians. Although this conclusion has been the subject of intense controversy, the current article indicates that the data from all of the published meta-analyses report the same results. This is also true of recent meta-analysis of all of the antidepressant data submitted to the Food and Drug Administration (FDA) in the process of seeking drug approval. Also, contrary to previously published results, the new FDA analysis reveals that the placebo response has not increased over time. Other treatments (e.g., psychotherapy and physical exercise) produce the same benefits as antidepressants and do so without the side effects and health risks of the active drugs. Psychotherapy and placebo treatments also show a lower relapse rate than that reported for antidepressant medication.

Placebo response and its determinants in children with ADHD across multiple observers and settings: A randomized clinical trial

This study aims to quantify placebo response (PR) in children with attention deficit hyperactivity disorder (ADHD) as assessed by parents and teachers and to explore some of its determinants. Five hundred and forty children with ADHD (ages 6-12) were recruited to a randomized, double-blind, placebo-controlled crossover trial with methylphenidate. The main outcome variable was Conners' Global Index (CGI), based on assessment of behaviour by parents (CGI-P) and teacher (CGI-T). PR was calculated as the difference between CGI-P/T scores at baseline and placebo week. There was a highly significant PR as assessed by the parents' and teachers' (p < 0.001). The magnitude of PR as assessed by parents was greater (10.57 points) compared to that assessed by teachers (3.93 points). The determinants of PR were different between parents and teachers. For parents, income, marital status, education, maternal smoking during pregnancy, and prior psychostimulant exposure (PPE) showed a significant effect on PR. For teachers, only ethnicity and PPE had an effect. The pattern of PR revealed two distinct profiles that may shed some light on the mechanisms involved in PR. PR in children with ADHD varies depending on the setting of the observations and the evaluator. Several psychosocial factors have been identified as modulators of PR. This is relevant for the design and interpretation of clinical trials and for clinical practice.

Age and sex as moderators of the placebo response – an evaluation of systematic reviews and meta-analyses across medicine

Predictors of the placebo response (PR) in randomized controlled trials (RCT) have been searched for ever since RCT have become the standard for testing novel therapies and age and gender are routinely documented data in all trials irrespective of the drug tested, its indication, and the primary and secondary end points chosen. To evaluate whether age and gender have been found to be reliable predictors of the PR across medical subspecialties, we extracted 75 systematic reviews, meta-analyses, and meta-regressions performed in major medical areas (neurology, psychiatry, internal medicine) known for high PR rates. The literature database used contains approximately 2,500 papers on various aspects of the genuine PR. These ‘meta-analyses’ were screened for statistical predictors of the PR across multiple RCT, including age and gender, but also other patient-based and design-based predictors of higher PR rates. Retrieved papers were sorted for areas and disease categories. Only 15 of the 75 analyses noted an effect of younger age to be associated with higher PR, and this was predominantly in psychiatric conditions but not in depression, and internal medicine but not in gastroenterology. Female gender was associated with higher PR in only 3 analyses. Among the patient-based predictors, the most frequently noted factor was lower symptom severity at baseline, and among the design- based factors, it was a randomization ratio that selected more patients to drugs than to placebo, more frequent study visits, and more recent trials that were associated with higher PR rates. While younger age may contribute to the PR in some conditions, sex does not. There is currently no evidence that the PR is different in the elderly. PR are, however, markedly influenced by the symptom severity at baseline, and by the likelihood of receiving active treatment in placebo- controlled trials.

Antidepressant treatment history and drug-placebo separation in a placebo-controlled trial in major depressive disorder

RATIONALE

A history of antidepressant treatment may predispose subjects toward placebo nonresponse in randomized controlled trials (RCTs) in major depressive disorder (MDD).

OBJECTIVE

The objective of this study is to examine self-reported prior antidepressant treatment and response in relationship to clinical outcome in an 8-week randomized trial of reuptake inhibitor antidepressant medication (MED) versus placebo (PBO) administered along with limited supportive care.

METHODS

Chi-square and MMRM analyses examined MED vs. PBO outcomes in antidepressant-naïve vs. antidepressant-experienced subjects. Linear regression models examined treatment history along with covariates as predictors of clinical improvement.

RESULTS

Among completers (n = 56), there was no significant difference in response rate between MED (53.3 %) and PBO (42.3 %) (χ (2) = 0.33, p = 0.28, 1-tailed). The antidepressant-experienced subgroup (n = 37), however, showed a significantly greater response rate to MED (52.4 %) than PBO (25.0 %) (χ (2) = 2.82, p = 0.047, 1-tailed). The full intent-to-treat (ITT) sample (n = 69) did not show a significant difference between MED and PBO group improvement over time, but in the treatment-experienced subgroup (n = 46), MED showed significantly greater improvement than PBO (coefficient = .39, SE = .23, p = .045, 1-tailed). A history of prior antidepressant treatment predicted poorer overall response independent of pretreatment symptom severity, number or length of previous episodes, subject expectations, or family history of MDD.

CONCLUSIONS

Treatment history appears to constitute a factor that is distinct from other commonly studied illness characteristics or expectancy measures, and that impacts overall response as well as drug-placebo separation in RCTs.

Placebo eff ects in psychiatry: mediators and moderators

A strong placebo response in psychiatric disorders has been noted for the past 50 years and various attempts have been made to identify predictors of it, by use of meta-analyses of randomised controlled trials and laboratory studies. We reviewed 31 meta-analyses and systematic reviews of more than 500 randomised placebo-controlled trials across psychiatry (depression, schizophrenia, mania, attention-deficit hyperactivity disorder, autism, psychosis, binge-eating disorder, and addiction) for factors identified to be associated with increased placebo response. Of 20 factors discussed, only three were often linked to high placebo responses: low baseline severity of symptoms, more recent trials, and unbalanced randomisation (more patients randomly assigned to drug than placebo). Randomised controlled trials in non-drug therapy have not added further predictors, and laboratory studies with psychological, brain, and genetic approaches have not been successful in identifying predictors of placebo responses. This comprehensive Review suggests that predictors of the placebo response are still to be discovered, the response probably has more than one mediator, and that different and distinct moderators are probably what cause the placebo response within psychiatry and beyond.

How to study placebo responses in motion sickness with a rotation chair paradigm in healthy participants

Placebo responses occur in every medical intervention when patients or participants expect to receive an effective treatment to relieve symptoms. However, underlying mechanisms of placebo responses are not fully understood. It has repeatedly been shown that placebo responses are associated with changes in neural activity but for many conditions it is unclear whether they also affect the target organ, such as the stomach in motion sickness. Therefore, we present a methodology for the multivariate assessment of placebo responses by subjective, behavioral and objective measures in motion sickness with a rotation chair paradigm. The physiological correlate of motion sickness is a shift in gastric myoelectrical activity towards tachygastria that can be recorded with electrogastrography. The presented study applied the so-called balanced placebo design (BPD) to investigate the effects of ginger compared to placebo and the effects of expectations by verbal information. However, the study revealed no significant main or interactional effects of ginger (as a drug) or information on outcome measures but showed interactions when sex of participants and experimenters are taken into considerations. We discuss limitations of the presented study and report modifications that were used in subsequent studies demonstrating placebo responses when rotation speed was lowered. In general, future placebo studies have to identify the appropriate target organ for the studied placebo responses and to apply the specific methods to assess the physiological correlates.

Do prefrontal midline electrodes provide unique neurophysiologic information in Major Depressive Disorder?

Brain oscillatory activity from the midline prefrontal region has been shown to reflect brain dysfunction in subjects with Major Depressive Disorder (MDD). It is not known, however, whether electrodes from this area provide unique information about brain function in MDD. We examined a set of midline sites and two other prefrontal locations for detecting cerebral activity differences between subjects with MDD and healthy controls. Resting awake quantitative EEG (qEEG) data were recorded from 168 subjects: 47 never-depressed adults and 121 with a current major depressive episode. Individual midline electrodes (Fpz, Fz, Cz, Pz, and Oz) and prefrontal electrodes outside the hairline (Fp1, Fp2) were examined with absolute and relative power and cordance in the theta band. We found that MDD subjects exhibited higher values of cordance (p = 0.0066) at Fpz than controls; no significant differences were found at other locations, and power measures showed trend-level differences. Depressed adults showed higher midline cordance than did never-depressed subjects at the most-anterior midline channel. Salient abnormalities in MDD may be detectable by focusing on the prefrontal midline region, and EEG metrics from focused electrode arrays may offer clinical practicality for clinical monitoring.

Lessons to be learned from placebo arms in psychopharmacology trials

Large placebo effects are typically reported in clinical drug trials and evidence suggests placebo effects have increased over time. The diminishing drug-placebo difference calls into question the effectiveness of pharmacological treatments and provides a challenge to prove the effectiveness of new medications. This chapter discusses explanations for the increasing placebo effect. It highlights the contribution of spontaneous remission to the improvement in placebo groups, but focuses particularly on the role of patient and clinician expectations. Certain characteristics of the trial design can influence the formation of patient expectations and, subsequently, true placebo responses. Side effects in clinical trials may also contribute inadvertently to placebo responses. Side effects after starting medication can inform participants about their allocation to an active treatment group. Thus, they may enhance expectations of improvement and contribute to nonspecific effects in clinical trials. It is argued that specific and nonspecific effects interact in drug groups of clinical trials. This interaction influences drug-placebo differences in clinical trials (i.e., trial sensitivity). Future research should aim to identify which patients will respond best to drugs and those who may be better treated with placebos.

Does prior antidepressant treatment of major depression impact brain function during current treatment?

The relationship between prior antidepressant treatment and prefrontal brain functional response to subsequent treatment with antidepressant medication or placebo is unknown. Eighty-nine adults with Major Depressive Disorder (MDD), characterized as antidepressant-experienced or antidepressant-naive, received one week of single-blind placebo treatment prior to eight weeks of randomized treatment with medication (fluoxetine or venlafaxine; n = 47) or placebo (n = 42) in one of three similar placebo-controlled trials. Brain function was assessed at baseline, end of placebo lead-in, and during randomized treatment using quantitative electroencephalography (qEEG). The authors assessed change in prefrontal theta-band cordance (PFC) in antidepressant-experienced vs. antidepressant-naive subjects. Treatment history groups differed significantly on PFC change during the placebo lead-in even when controlling for clinical and demographic variables (F(1,62) = 4.27, p = .04). As assessed in linear mixed models that examined treatment history (antidepressant-experienced or antidepressant-naive), treatment assignment (medication or placebo), and their interaction as predictors, treatment history also predicted PFC change during the randomized phase of treatment even when controlling for pretreatment clinical and demographic and symptom improvement during treatment (F(1,5o) = 5.20, p = .03). The interaction was not significant. Post hoc analyses showed that antidepressant-experienced subjects treated with placebo showed PFC changes that did not differ from PFC changes seen in the medication group. Results suggest that prefrontal brain functional changes during treatment for MDD may differ depending upon prior treatment with antidepressant medication.

Predictors of remission in depression to individual and combined treatments (PReDICT): study protocol for a randomized controlled trial

BACKGROUND

Limited controlled data exist to guide treatment choices for clinicians caring for patients with major depressive disorder (MDD). Although many putative predictors of treatment response have been reported, most were identified through retrospective analyses of existing datasets and very few have been replicated in a manner that can impact clinical practice. One major confound in previous studies examining predictors of treatment response is the patient's treatment history, which may affect both the predictor of interest and treatment outcomes. Moreover, prior treatment history provides an important source of selection bias, thereby limiting generalizability. Consequently, we initiated a randomized clinical trial designed to identify factors that moderate response to three treatments for MDD among patients never treated previously for the condition.

METHODS/DESIGN

Treatment-naïve adults aged 18 to 65 years with moderate-to-severe, non-psychotic MDD are randomized equally to one of three 12-week treatment arms: (1) cognitive behavior therapy (CBT, 16 sessions); (2) duloxetine (30-60 mg/d); or (3) escitalopram (10-20 mg/d). Prior to randomization, patients undergo multiple assessments, including resting state functional magnetic resonance imaging (fMRI), immune markers, DNA and gene expression products, and dexamethasone-corticotropin-releasing hormone (Dex/CRH) testing. Prior to or shortly after randomization, patients also complete a comprehensive personality assessment. Repeat assessment of the biological measures (fMRI, immune markers, and gene expression products) occurs at an early time-point in treatment, and upon completion of 12-week treatment, when a second Dex/CRH test is also conducted. Patients remitting by the end of this acute treatment phase are then eligible to enter a 21-month follow-up phase, with quarterly visits to monitor for recurrence. Non-remitters are offered augmentation treatment for a second 12-week course of treatment, during which they receive a combination of CBT and antidepressant medication. Predictors of the primary outcome, remission, will be identified for overall and treatment-specific effects, and a statistical model incorporating multiple predictors will be developed to predict outcomes.

DISCUSSION

The PReDICT study's evaluation of biological, psychological, and clinical factors that may differentially impact treatment outcomes represents a sizeable step toward developing personalized treatments for MDD. Identified predictors should help guide the selection of initial treatments, and identify those patients most vulnerable to recurrence, who thus warrant maintenance or combination treatments to achieve and maintain wellness.