Validity of clinical trials of antidepressants

Investigating Resistance to Antidepressants in Animal Models

Major depressive disorder is one of the most prevalent psychiatric diseases, and up to 30-40% of patients remain symptomatic despite treatment. Novel therapies are sorely needed, and animal models may be used to elucidate fundamental neurobiological processes that contribute to human disease states. We conducted a systematic review of current preclinical approaches to investigating treatment resistance with the goal of describing a path forward for improving our understanding of treatment resistant depression. We conducted a broad literature search to identify studies relevant to the preclinical investigation of treatment resistant depression. We followed PRISMA (Preferred Reporting Items for Systemic Reviews and Meta-Analyses) guidelines and included all relevant studies. We identified 467 studies in our initial search. Of these studies, we included 69 in our systematic review after applying our inclusion/exclusion criteria. We identified 10 broad strategies for investigating treatment resistance in animal models. Stress hormone administration was the most commonly used model, and the most common behavioral test was the forced swim test. We systematically identified and reviewed current approaches for gaining insight into the neurobiology underlying treatment resistant depression using animal models. Each approach has its advantages and disadvantages, but all require careful consideration of their potential limitations regarding therapeutic translation. An enhanced understanding of treatment resistant depression is sorely needed given the burden of disease and lack of effective therapies.

Efficacy of Cognitive Behavioral Therapy for Anxiety-Related Disorders: A Meta-Analysis of Recent Literature

PURPOSE OF REVIEW

Effective treatment of anxiety-related disorders is crucial, considering the prevalence of such disorders and their association with poor psychosocial functioning. To evaluate the most recent evidence on the efficacy of cognitive behavioral therapy (CBT) for anxiety-related disorders in adults, we conducted a meta-analysis of randomized placebo-controlled trials published since 2017.

RECENT FINDINGS

Ten studies with a total of 1250 participants met the inclusion criteria. Seven of these studies examined PTSD. The findings demonstrated small placebo-controlled effects of CBT on target disorder symptoms (Hedges' g = 0.24, p < 0.05) and depression (Hedges' g = 0.15, p = n.s). When examining only PTSD studies, effects were reduced (Hedges' g = 0.14, p < 0.05). Heterogeneity in most analyses was very low, and no publication bias was found. Effect sizes from placebo-controlled trials from the past 5 years appear to be smaller than those in prior meta-analyses. The findings are largely driven by research on PTSD, with few placebo-controlled trials of other anxiety-related disorders published since 2017.

The antidepressant standoff: why it continues and how to resolve it

BACKGROUND

Antidepressant medications (ADMs) are widely used and long-term use is increasing. Given this extensive use and recommendation of ADMs in guidelines, one would expect ADMs to be universally considered effective. Surprisingly, that is not the case; fierce debate on their benefits and harms continues. This editorial seeks to understand why the controversy continues and how consensus can be achieved.

METHODS

'Position' paper. Critical analysis and synthesis of relevant literature.

RESULTS

Advocates point at ADMs impressive effect size (number needed to treat, NNT = 6-8) in acute phase treatment and continuation/maintenance ADM treatment prevention relapse/recurrence in acute phase ADM responders (NNT = 3-4). Critics point at the limited clinically significant surplus value of ADMs relative to placebo and argue that effectiveness is overstated. We identified multiple factors that fuel the controversy: certainty of evidence is low to moderate; modest efficacy on top of strong placebo effects allows critics to focus on small net efficacy and advocates on large gross efficacy; ADM withdrawal symptoms masquerade as relapse/recurrence; lack of association between ADM treatment and long-term outcome in observational databases. Similar problems affect psychological treatments as well, but less so. We recommend four approaches to resolve the controversy: (1) placebo-controlled trials with relevant long-term outcome assessments, (2) inventive analyses of observational databases, (3) patient cohort studies including effect moderators to improve personalized treatment, and (4) psychological treatments as universal first-line treatment step.

CONCLUSIONS

Given the public health significance of depression and increased long-term ADM usage, new approaches are needed to resolve the controversy.

Withdrawal effects confounding in clinical trials: another sign of a needed paradigm shift in psychopharmacology research

Randomized controlled trials' ability to produce evidence useful for people to decide whether to take, continue taking, or stop taking psychotropic drugs has been intensely critiqued, along with the trials' commercial, ideological, and regulatory contexts. This article applies the critique to the topic of withdrawal effects confounding the outcomes of relapse-prevention trials where prescribed psychotropic drugs are discontinued. Until recently, the complexity and reach of withdrawal and post-withdrawal effects were neglected by mainstream psychiatry, but not by lay users of prescribed psychotropics. This article discusses withdrawal effects as part of the pharmacology of psychotropic drugs but shaped by psychosocial factors, and possibly shaping the presentation of psychological distress generally. It outlines biases and misconceptions in assumptions, design, and reporting of general efficacy trials and findings from a recent review of 80 discontinuation trials. In theory, relapse-prevention trials are tautological and exaggerate efficacy. In publications, they pay little attention to the central feature of their design, favor abrupt or rapid discontinuations, do not attend to environmental factors, and provide insufficient data to allow re-analyses. Thus, relapse-prevention RCTs likely confound the detection of their main outcome of interest: "relapse." Using slower tapers, active placebo controls, and specific covariates in analyses would reduce the risk of withdrawal confounding, and better reporting would reduce the opaqueness of trials. The crisis in psychopharmacology is fueled partly by the disconnect between claims of therapeutic efficacy from so-called best-evidence methods despite unchanging population-level indicators of psychiatric sickness. Only by "stacking the deck" against trial sponsors' hoped-for outcomes can psychopharmacology trials regain scientific credibility.

Efficacy of selective serotonin reuptake inhibitors in the absence of side effects: a mega-analysis of citalopram and paroxetine in adult depression

It has been suggested that the superiority of antidepressants over placebo in controlled trials is merely a consequence of side effects enhancing the expectation of improvement by making the patient realize that he/she is not on placebo. We explored this hypothesis in a patient-level post hoc-analysis including all industry-sponsored, Food and Drug Administration-registered placebo-controlled trials of citalopram or paroxetine in adult major depression that used the Hamilton Depression Rating Scale (HDRS) and included a week 6 symptom assessment (n=15). The primary analyses, which compared completers on active treatment without early adverse events to completers on placebo (with or without adverse events) with respect to reduction in the HDRS depressed mood item showed larger symptom reduction in patients given active treatment, the effect sizes being 0.48 for citalopram and 0.33 for paroxetine. In actively treated subjects reporting early adverse events, who also outperformed those given placebo, the severity of the adverse events did not predict response. Several sensitivity analyses, for example, including (i) those using change of the sum of all HDRS-17 items as effect parameter, (ii) those excluding all subjects with adverse events (that is, also those on placebo) and (iii) those based on the intention-to-treat population, were all in line with the primary analyses. The finding that both paroxetine and citalopram are clearly superior to placebo also when not producing adverse events, as well as the lack of association between adverse event severity and response, argue against the theory that antidepressants outperform placebo solely or largely because of their side effects.

Efficacy of antidepressants: bias in randomized clinical trials and related issues

INTRODUCTION

Countless antidepressant randomized trials were conducted and showed statistically significant benefits of selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) over placebo. Meanwhile, critics are increasing regarding the efficacy of antidepressants in the treatment of MDD because at least a proportion of clinical trials could be hampered by various biases. In contrast, number of failed trials is increasing in the recent years which have made developing psychiatric medications progressively more time-consuming and expensive. Areas covered: Biases and related issues in clinical trials for antidepressants can be identified as an important common contributing factor to the two paradoxical phenomenon. This review identifies possible biases that can occur before, during, and after clinical trials of antidepressant. Expert commentary: Recent studies not only may over-estimate efficacy of antidepressants, but also may exaggerate placebo response because of various biases. Sponsorship and publication biases have been one of the targets of the criticism and ethical debate. Thus, initiating new trend of research by re-organizing academic-industry partnership will be the most important task in the next five years.

Treatment and Prevention of Depression

Depression is one of the most common and debilitating psychiatric disorders and is a leading cause of suicide. Most people who become depressed will have multiple episodes, and some depressions are chronic. Persons with bipolar disorder will also have manic or hypomanic episodes. Given the recurrent nature of the disorder, it is important not just to treat the acute episode, but also to protect against its return and the onset of subsequent episodes.

Several types of interventions have been shown to be efficacious in treating depression. The antidepressant medications are relatively safe and work for many patients, but there is no evidence that they reduce risk of recurrence once their use is terminated. The different medication classes are roughly comparable in efficacy, although some are easier to tolerate than are others. About half of all patients will respond to a given medication, and many of those who do not will respond to some other agent or to a combination of medications. Electro-convulsive therapy is particularly effective for the most severe and resistant depressions, but raises concerns about possible deleterious effects on memory and cognition. It is rarely used until a number of different medications have been tried.

Although it is still unclear whether traditional psychodynamic approaches are effective in treating depression, interpersonal psychotherapy (IPT) has fared well in controlled comparisons with medications and other types of psychotherapies. It also appears to have a delayed effect that improves the quality of social relationships and interpersonal skills. It has been shown to reduce acute distress and to prevent relapse and recurrence so long as it is continued or maintained. Treatment combining IPT with medication retains the quick results of pharmacotherapy and the greater interpersonal breadth of IPT, as well as boosting response in patients who are otherwise more difficult to treat. The main problem is that IPT has only recently entered clinical practice and is not widely available to those in need.

Cognitive behavior therapy (CBT) also appears to be efficacious in treating depression, and recent studies suggest that it can work for even severe depressions in the hands of experienced therapists. Not only can CBT relieve acute distress, but it also appears to reduce risk for the return of symptoms as long as it is continued or maintained. Moreover, it appears to have an enduring effect that reduces risk for relapse or recurrence long after treatment is over. Combined treatment with medication and CBT appears to be as efficacious as treatment with medication alone and to retain the enduring effects of CBT. There also are indications that the same strategies used to reduce risk in psychiatric patients following successful treatment can be used to prevent the initial onset of depression in persons at risk. More purely behavioral interventions have been studied less than the cognitive therapies, but have performed well in recent trials and exhibit many of the benefits of cognitive therapy.

Mood stabilizers like lithium or the anticonvulsants form the core treatment for bipolar disorder, but there is a growing recognition that the outcomes produced by modern pharmacology are not sufficient. Both IPT and CBT show promise as adjuncts to medication with such patients. The same is true for family-focused therapy, which is designed to reduce interpersonal conflict in the family. Clearly, more needs to be done with respect to treatment of the bipolar disorders.

Good medical management of depression can be hard to find, and the empirically supported psychotherapies are still not widely practiced. As a consequence, many patients do not have access to adequate treatment. Moreover, not everyone responds to the existing interventions, and not enough is known about what to do for people who are not helped by treatment. Although great strides have been made over the past few decades, much remains to be done with respect to the treatment of depression and the bipolar disorders.

Active placebo control groups of pharmacological interventions were rarely used but merited serious consideration: a methodological overview

OBJECTIVES

Active placebos are control interventions that mimic the side effects of the experimental interventions in randomized trials and are sometimes used to reduce the risk of unblinding. We wanted to assess how often randomized clinical drug trials use active placebo control groups; to provide a catalog, and a characterization, of such trials; and to analyze methodological arguments for and against the use of active placebo.

STUDY DESIGN AND SETTING

An overview consisting of three thematically linked substudies. In an observational substudy, we assessed the prevalence of active placebo groups based on a random sample of 200 PubMed indexed placebo-controlled randomized drug trials published in October 2013. In a systematic review, we identified and characterized trials with active placebo control groups irrespective of publication time. In a third substudy, we reviewed publications with substantial methodological comments on active placebo groups (searches in PubMed, The Cochrane Library, Google Scholar, and HighWirePress).

RESULTS

The prevalence of trials with active placebo groups published in 2013 was 1 out of 200 (95% confidence interval: 0-2), 0.5% (0-1%). We identified and characterized 89 randomized trials (published 1961-2014) using active placebos, for example, antihistamines, anticholinergic drugs, and sedatives. Such trials typically involved a crossover design, the experimental intervention had noticeable side effects, and the outcomes were patient-reported. The use of active placebos was clustered in specific research settings and did not appear to reflect consistently the side effect profile of the experimental intervention, for example, selective serotonin reuptake inhibitors were compared with active placebos in pain trials but not in depression trials. We identified and analyzed 25 methods publications with substantial comments. The main argument for active placebo was to reduce risk of unblinding; the main argument against was the risk of unintended therapeutic effect.

CONCLUSION

Pharmacological active placebo control interventions are rarely used in randomized clinical trials, but they constitute a methodological tool which merits serious consideration. We suggest that active placebos are used more often in trials of drugs with noticeable side effects, especially in situations where the expected therapeutic effects are modest and the risk of bias due to unblinding is high.

5-HTR1A and 5-HTR2A genetic polymorphisms and SSRI antidepressant response in depressive Chinese patients

OBJECTIVE

Genetic variabilities within the serotoninergic system may predict response or remission to antidepressant drugs. Several serotonin receptor (5-HTR) gene polymorphisms have been associated with susceptibility to psychiatric diseases. In this study, we analyzed the correlation between 5-HTR1A and 5-HTR2A polymorphisms and response or remission to selective serotonin reuptake inhibitors (SSRIs) drugs.

METHODS

Two hundred and ninety patients who met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for major depressive disorder were involved in this study. SSRIs (fluoxetine, paroxetine, citalopram, or sertraline) were selected randomly for treatment. The Hamilton Rating Scale for Depression was used to evaluate the antidepressant effect. To assess 5-HTR gene variabilities, two single-nucleotide polymorphisms in 5-HTR1A (rs1364043 and rs10042486) and three in 5-HTR2A (rs6311, rs6313, and rs17289304) were genotyped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry using the Sequenom MassARRAY Analyzer 4 system.

RESULTS

There were 220 responders and 70 nonresponders (120 remissioners and 170 nonremissioners) after 6 weeks of treatment. We found no association between any of the five 5-HTR1A and 5-HTR2A gene polymorphisms and antidepressant drug response or remission (P>0.05). It is worth mentioning that TT genotype frequency of rs10042486 was significantly different from the CT genotype frequency between responders and nonresponders, although the significance was not maintained after correcting for multiple testing.

CONCLUSION

Thus, 5-HTR1A and 5-HTR2A gene polymorphisms may not play an important role in antidepressant drug response or remission.

Antidepressants and the risk of suicide in young persons--prescription trends and toxicological analyses

OBJECTIVE

To assess trends in the use of antidepressants among young suicides after the warning that these drugs might increase the risk of suicide.

METHOD

Individual data of all 845 suicides in the 10- to 19-year age group in Sweden in the time period 1992-2003 (baseline), and in 2004-2010 (after the warning). Outcome data are prescriptions of antidepressants prior to death and detections of antidepressants in post-mortem toxicology.

RESULTS

After the warning, suicide in this age group increased for five consecutive years (60.5%). The increase occurred among individuals not treated with antidepressants.

CONCLUSION

This study provides further support for the hypothesis that the warning, contrary to its intention, may have increased young suicides by leaving a number of suicidal young persons without treatment with antidepressants.

Molecular profiling of the lateral habenula in a rat model of depression

Objective

This study systematically investigated the effect of chronic mild stress and response to antidepressant treatment in the lateral habenula at the whole genome level.

Methods

Rat whole genome expression chips (Affymetrix) were used to detect gene expression regulations in the lateral habenula of rats subjected to chronic mild stress (mild stressors exchanged twice a day for 8 weeks). Some rats received antidepressant treatment during fifth to eights week of CMS. The lateral habenula gene expression profile was studied through the gene ontology and signal pathway analyses using bioinformatics. Real-time quantitative polymerase chain reaction (RT-PCR) was used to verify the microarray results and determine the expression of the Fcrla, Eif3k, Sec3l1, Ubr5, Abca8a, Ankrd49, Cyp2j10, Frs3, Syn2, and Znf503 genes in the lateral habenula tissue.

Results

In particular we found that stress and antidepressant treatment affected intracellular cascades like growth factor receptor signaling, G-protein-coupled receptor signaling, and Wnt signaling – processes involved in the neuroplastic changes observed during the progression of depression and antidepressant treatment.

Conclusion

The present study suggests an important role of the lateral habenula in the development of depression-like conditions and correlates to previous studies demonstrating a significant role of the lateral habenula in depressive-like conditions and antidepressant treatment.

The potential role of Marginal Structural Models (MSMs) in testing the effectiveness of antidepressants in the treatment of patients with major depression in everyday clinical practice

OBJECTIVES

To better evaluate the effectiveness of antidepressant drugs in the treatment of major depression in clinical practice.

METHODS

A simulation experiment was used to illustrate an application of marginal structural models (MSMs) via inverse probability of treatment weighting (IPTW) approach in the context of non-randomized data on N = 1,000 depressed subjects, initially subjected to "watchful waiting". In simulation we assumed that subjects with worse intermediate outcome have a higher probability of being subsequently assigned to antidepressant treatment while those who receive antidepressant treatment are more likely to reach remission and less likely to reach relapse state. The outcomes from multiple (500) simulated data sets are analyzed using simple unadjusted analysis based on logistic regression and using MSM.

RESULTS

In contrast to unadjusted analysis, but consistent with the treatment assumptions, using MSM via IPTW results in strong evidence of the effectiveness of the antidepressant treatment. Furthermore MSM via IPTW substantially reduces the probability of wrongly rejecting the null hypothesis. However, the instability of weights due to the sparse data and incorrectly specified MSM may still result in inflation of Type I error rates.

CONCLUSIONS

MSMs may allow evaluating the causal effects associated with antidepressant treatment from the data observed in clinical practice.

Antidepressant Utilization and Suicide in Europe: An Ecological Multi-National Study

BACKGROUND

Research concerning the association between use of antidepressants and incidence of suicide has yielded inconsistent results and is the subject of considerable controversy. The first aim is to describe trends in the use of antidepressants and rates of suicide in Europe, adjusted for gross domestic product, alcohol consumption, unemployment, and divorce. The second aim is to explore if any observed reduction in the rate of suicide in different European countries preceded the trend for increased use of antidepressants.

METHODS

Data were obtained for 29 European countries between 1980 and 2009. Pearson correlations were used to explore the direction and magnitude of associations. Generalized linear mixed models and Poisson regression distribution were used to clarify the effects of antidepressants on suicide rates, while an autoregressive adjusted model was used to test the interaction between antidepressant utilization and suicide over two time periods: 1980-1994 and 1995-2009.

FINDINGS

An inverse correlation was observed in all countries between recorded Standardised Death Rate (SDR) for suicide and antidepressant Defined Daily Dosage (DDD), with the exception of Portugal. Variability was marked in the association between suicide and alcohol, unemployment and divorce, with countries depicting either a positive or a negative correlation with the SDR for suicide. Every unit increase in DDD of an antidepressant per 1000 people per day, adjusted for these confounding factors, reduces the SDR by 0.088. The correlation between DDD and suicide related SDR was negative in both time periods considered, albeit more pronounced between 1980 and 1994.

CONCLUSIONS

Suicide rates have tended to decrease more in European countries where there has been a greater increase in the use of antidepressants. These findings underline the importance of the appropriate use of antidepressants as part of routine care for people diagnosed with depression, therefore reducing the risk of suicide.

Follow up of patients who start treatment with antidepressants: treatment satisfaction, treatment compliance, efficacy and safety

BACKGROUND

Measuring satisfaction with treatment has proved useful to ascertain the treatment features that are most important to the patients, and to explain increased treatment compliance. However, there are few studies that relate satisfaction to other clinical or self-perceived health status indicators. Recent studies have shown the close relationship between satisfaction with treatment, treatment compliance, and effectiveness. This study attempts to design and validate a scale to evaluate satisfaction with antidepressant drug therapy, assess treatment compliance (self-reported, validated questionnaire, drug accountability and electronic monitorization system), assess efficacy in reducing depressive symptoms and safety in patients who initiate antidepressant drug therapy, as well as to establish predictors of satisfaction, compliance and effectiveness with these drugs.

METHODS/DESIGN

This is an observational longitudinal study with a cohort of adults initiating treatment with antidepressant drugs. A multi-centre study will be performed in which 20 Primary Care practices from Castilla-La Mancha are expected to participate. An initial interview and follow-up visits at 15 days, 1, 3, 6, 9 and 12 months will be conducted with all study participants. 706 subjects will be studied (95% confidence interval, precision ± 3%, expected rate of non-compliance 50%, expected non-responders and lost to follow up rate 15%). The following measurements will be performed: development and validation of a scale of satisfaction with antidepressant therapy, participant and antidepressant characteristics, treatment compliance evaluation (Haynes-Sackett Test, Morisky-Green Test, drug accountability and Medication Event Monitoring System), depression symptom reduction (Hamilton Depression Rating Scale and Montgomery-Asberg Depression Rating Scale), observation of adverse effects, and beliefs about treatment (The Beliefs about Medicines Questionnaire).

DISCUSSION

Antidepressant drugs are an extraordinarily important therapeutic group in the pharmacy composition; economic repercussions and social impact associated to their use is clear. Despite their well-established efficacy in clinical trials, treatment non-compliance is a major obstacle to their effectiveness in clinical practice. The proposed study brings about useful conclusions to improve the results of these drugs. Additionally, devising a scale specifically designed to evaluate satisfaction with antidepressant treatment could be of interest in healthcare outcomes research.

Vesicular signalling and immune modulation as hedonic fingerprints: proteomic profiling in the chronic mild stress depression model

Extensive preclinical research has focused at unravelling the underlying molecular mechanisms leading to depression and recovery. In this study, we investigated the quantitative changes in protein abundance in the ventral hippocampal granular cell layer. We compared different phenotypes from the chronic mild stress (CMS) model of depression using chronic administration with two selective serotonin reuptake inhibitors (SSRIs), escitalopram and sertraline. We isolated granular cells using Laser-Capture Microdissection (LCM) and we identified their regulated proteins using two-dimensional (2D) differential gel electrophoresis (DIGE) and tandem mass spectrometry (MS/MS). The majority of the proteins we identified were enzymes involved in different metabolic activities. Additional proteins were functionally classified as vesicular proteins and immune system proteins. Rab GDP dissociation inhibitor alpha (GDIA) and syntaxin-binding protein 1 (STXB1) were potential markers for stress reactivity. Dynamin 1 (DYN1), glutathione S-transferase omega-1 (GSTO1) and peroxiredoxin (PRDX6) were associated with treatment response. In addition, an imbalance between different post-translationally modified versions of DYN1 and GSTO1 potentially accounted for SSRI treatment refraction. In the present study, we searched for new markers of stress reactivity and treatment response as well as any underlying molecular mechanisms correlating to the development of anhedonia and antidepressant therapy refraction. Our results pointed towards an essential role of post-translational modifications in both vesicular and immune protein systems.

The drugs don't work? antidepressants and the current and future pharmacological management of depression

Depression is a potentially life-threatening disorder affecting millions of people across the globe. It is a huge burden to both the individual and society, costing over £9 billion in 2000 alone: the World Health Organisation (WHO) cited it as the third leading cause of global disability in 2004 (first in the developed world), and project it will be the leading cause by 2030. The serendipitous discovery of antidepressants has revolutionized both our understanding and management of depression: however, their efficacy in the treatment of depression has long been debated and recently been brought very much into the public limelight by a controversial publication by Kirsch, in which the role of placebo response in antidepressant efficacy trials is highlighted. Whilst antidepressants offer benefits in both the short and long term, important problems persist such as intolerability, delayed therapeutic onset, limited efficacy in milder depression and the existence of treatment-resistant depression.

The clinical pharmacology of depressive states

Antidepressants have good efficacy in the treatment of mood disorders, with effect sizes that have consistently been found to be greater than those of placebo. The more recent antidepressants do not have better efficacy than the compounds discovered 40 to 50 years ago, but they do have a more favorable configuration of side effects, leading to fewer dropouts. This favorable situation has made it possible to prescribe the newer antidepressants in less severe depression and in several anxiety disorders, with considerable benefit to patients. During the last decades, research into the pathophysiology of mood and anxiety disorders has provided much information on the brain circuitry, neurohormones, and neurotransmitters involved in these disorders. In parallel, biological and behavioral work on antidepressants, using animal models and new biochemical techniques, has led to a broader understanding of the mode of action of these drugs. Despite this impressive list of discoveries, much research remains to be done on the clinical, psychological, neuropsychological, physiological, and neurochemical aspects, before we can obtain a coherent description of the pathophysiological mechanisms of depression and its treatment. This will lead to a better ability to predict the quality of drug response and, therefore, to the individualization of treatment.

Placebo response in depression

With its naturally fluctuating course, depression is a highly placebo-responsive condition: mean placebo response rates in antidepressant clinical trials are 30% to 40%. We review the history and terminology of placebo and the proposed mechanisms underlying the placebo response, including the physician-patient relationship and biological, sociocultural, and treatment situation factors. We identify the predictors and patterns of placebo response in depressed patients, both within and outside of the clinical trial context, and differentiate between true drug response and placebo pattern response. We discuss the strategies now being advanced to minimize the placebo response given the increased placebo drift reported in recent trials, and the ethical guidelines governing placebo administration. Potential areas for future research include the identification of biological markers of placebo response, such as functional neuroimaging and quantitative electroencephalography, the development and testing of more sophisticated, alternative research designs, and the design of valid biological tools to assess antidepressant efficacy.

Randomized clinical trials underestimate the efficacy of antidepressants in less severe depression

OBJECTIVE

  Demonstrating the superiority of antidepressants over placebo in randomized clinical trials of antidepressants (RCT-ADs) has been difficult. A recent meta-analysis of six RCT-ADs concluded that the efficacy of antidepressants was 'non-existent to negligible' in mild and moderate depression. The aim of this study was to reanalyze the same data in order to investigate whether the meta-analysis could be biased from the shortcomings of the rating scale used, the Hamilton Depression Rating Scale (HDRS).

METHOD

We got access to the primary data on item and individual level from five of the six meta-analyzed RCT-ADs (597 individuals). We reanalyzed these data by means of item response theory.

RESULTS

Each study showed rapidly decreasing reliability of measurement with diminishing depression; 38% of the combined sample at endpoint was measured with less than half the maximal reliability.

CONCLUSION

The HDRS Scale provides unreliable primary data. Low effect sizes can be expected because of the scale's low precision and low sensitivity to change, particularly in mild and moderate depression. The conclusion of the meta-analysis by Fournier et al. is therefore unfounded. The clinical value of antidepressants cannot be evaluated from unreliable data. It is urgent that better measurement techniques for depression severity are developed.

Optimal Partitioning for Linear Mixed Effects Models: Applications to Identifying Placebo Responders

A long-standing problem in clinical research is distinguishing drug treated subjects that respond due to specific effects of the drug from those that respond to non-specific (or placebo) effects of the treatment. Linear mixed effect models are commonly used to model longitudinal clinical trial data. In this paper we present a solution to the problem of identifying placebo responders using an optimal partitioning methodology for linear mixed effects models. Since individual outcomes in a longitudinal study correspond to curves, the optimal partitioning methodology produces a set of prototypical outcome profiles. The optimal partitioning methodology can accommodate both continuous and discrete covariates. The proposed partitioning strategy is compared and contrasted with the growth mixture modelling approach. The methodology is applied to a two-phase depression clinical trial where subjects in a first phase were treated openly for 12 weeks with fluoxetine followed by a double blind discontinuation phase where responders to treatment in the first phase were randomized to either stay on fluoxetine or switched to a placebo. The optimal partitioning methodology is applied to the first phase to identify prototypical outcome profiles. Using time to relapse in the second phase of the study, a survival analysis is performed on the partitioned data. The optimal partitioning results identify prototypical profiles that distinguish whether subjects relapse depending on whether or not they stay on the drug or are randomized to a placebo.

The small specific effects of antidepressants in clinical trials: what do they mean to psychiatrists?

Although antidepressants continue to be a mainstay for clinicians who treat people suffering from depressive disorders, there have recently been articles published in both the scientific literature and the popular press that have raised questions about the utility of this class of medications. This paper briefly examines recent meta-analyses that have reported small drug versus placebo differences in randomized controlled trials and, from the perspective of a prescribing psychiatrist, discusses the clinical significance of these findings. It is concluded that antidepressants do have relatively modest effects (as compared with placebo) in contemporary randomized controlled trials, and that the contribution of placebo-expectancy factors to individual outcomes is often underestimated. Nevertheless, it is also concluded that the modest benefits of antidepressants in grouped datasets obscure large, specific, and very meaningful therapeutic effects for 10% to 20% of those treated with antidepressants.

Biomarkers of anhedonic-like behavior, antidepressant drug refraction, and stress resilience in a rat model of depression

The aim of the present study was to identify potential biomarkers for depression in the search for novel disease targets and treatment regimens. Furthermore, the study includes a search for biomarkers involved in treatment resistance and stress resilience in order to investigate mechanisms underlying antidepressant drug refraction and stress-coping strategies. Depression-related transcriptomic changes in gene expression profiles were investigated in laser-captured microdissected (LCM) rat hippocampal granular cell layers (GCL) using the chronic mild stress (CMS) rat model of depression and chronic administration of two selective serotonin reuptake inhibitors (SSRIs), escitalopram and sertraline. CMS rats were segregated into diverging groups according to behavioral readouts, and under stringent constraints, the associated differential gene regulations were analyzed. Accordingly, we identified four genes associated with recovery, two genes implicated in treatment resistance, and three genes involved in stress resilience. The identified genes associated with mechanisms of cellular plasticity, including signal transduction, cell proliferation, cell differentiation, and synaptic release. Hierarchical clustering analysis confirmed the subgroup segregation pattern in the CMS model. Thus antidepressant treatment refractors cluster with anhedonic-like rats, and, interestingly, stress-resilient rats cluster with rats undergoing antidepressant-mediated recovery from anhedonia, suggesting antidepressant mechanisms of action to emulate endogenous stress-coping strategies.

The interactive computer interview for mania

OBJECTIVES

The Interactive Computer Interview for Mania (ICI-M) is a computer-administered interview that presents probes to assess symptom severity and utilizes a scoring algorithm to select follow-up questions and rate subject responses in accordance with rating scale anchor points. The current study examines the acceptability, feasibility, and reliability of the ICI-M as a potential method for evaluating the performance of human raters.

METHODS

Participants with a diagnosis of bipolar I or II disorder completed both a live interview of the Young Mania Rating Scale with a human rater (LR) and the ICI-M. A panel of three expert raters reviewed each videotaped LR and assigned a consensus rating (CR). Participants completed a modified version of the Client Satisfaction Questionnaire to assess each method.

RESULTS

Intraclass correlation coefficients were 0.91 between the ICI-M and CR and 0.97 between the LR and CR (n = 100), providing empirical support for the inter-rater reliability of each approach. Coefficient alphas indicated comparable internal consistency reliability: ICI-M = 0.82, LR = 0.83, and CR = 0.84. The ICI-M was significantly more sensitive in detecting symptomatology than the LR (p < 0.001) and the CR (p < 0.001), and resulted in significantly higher ratings than CR on mood, speech, psychotic content, and disruptive-aggressive behavior. While participants endorsed significantly higher overall satisfaction with LR, no significant differences emerged between ICI-M and LR regarding willingness to participate again or ability to understand the questions.

CONCLUSIONS

The ICI-M is a well-accepted and reliable method for assessing manic symptoms. The ICI-M is a tool with adequate sensitivity to elicit symptoms and rate severity and is recommended as a tool to monitor and improve rater performance, not as a replacement of a human rater.

Perceived drug assignment and treatment outcome in smokers given nicotine patch therapy

This study assessed the relationship between treatment outcome and perceived drug assignment in smokers (nicotine patch [NP] or placebo) using abstinence and relapse status. Smokers (N = 424) were randomly assigned to receive either NP or placebo as part of a study that examined the effects of combining NP with self-help programs. Beliefs about drug assignment, assessed at the 12-month follow-up, were obtained from 384 participants. Beliefs were related to abstinence at the 2-month, p < .05, and 6-month follow-ups, p < .05, for the NP group, but not the placebo. Beliefs were not related to abstinence at 12 months for either group. Survival analysis assessing relapse revealed that beliefs were related to relapse status, regardless of actual group assignment. Our results suggest that there is a relationship between perceived drug assignment and treatment outcome. Future studies using multiple treatment outcome measures and assessments of beliefs over time are warranted.

Predicting potential placebo effect in drug treated subjects

Non-specific responses to treatment (commonly known as placebo response) are pervasive when treating mental illness. Subjects treated with an active drug may respond in part due to non-specific aspects of the treatment, i.e, those not related to the chemical effect of the drug. To determine the extent a subject responds due to the chemical effect of a drug, one must disentangle the specific drug effect from the non-specific placebo effect. This paper presents a unique statistical model that allows for the separate prediction of a specific effect and non-specific effects in drug treated subjects. Data from a clinical trial comparing fluoxetine to a placebo for treating depression is used to illustrate this methodology.

Rostral anterior cingulate cortex theta current density and response to antidepressants and placebo in major depression

OBJECTIVE

To assess whether pretreatment theta current density in the rostral anterior cingulate (rACC) and medial orbitofrontal cortex (mOFC) differentiates responders from non-responders to antidepressant medication or placebo in a double-blinded study.

METHODS

Pretreatment EEGs were collected from 72 subjects with Major Depressive Disorder (MDD) who participated in one of three placebo-controlled trials. Subjects were randomized to receive treatment with fluoxetine, venlafaxine, or placebo. Low-resolution brain electromagnetic tomography (LORETA) was used to assess theta current density in the rACC and mOFC.

RESULTS

Medication responders showed elevated rACC and mOFC theta current density compared to medication non-responders (rACC: p=0.042; mOFC: p=0.039). There was no significant difference in either brain region between placebo responders and placebo non-responders.

CONCLUSIONS

Theta current density in the rACC and mOFC may be useful as a biomarker for prediction of response to antidepressant medication.

SIGNIFICANCE

This is the first double-blinded treatment study to examine pretreatment rACC and mOFC theta current density in relation to antidepressant response and placebo response. Results support the potential clinical utility of this approach for predicting clinical outcome to antidepressant treatments in MDD.

Use of clinical neurophysiology for the selection of medication in the treatment of major depressive disorder: the state of the evidence

Approximately 50% of patients with Major Depressive Disorder (MDD) respond to the first antidepressant medication prescribed, and fewer than one-third experience remission of symptoms. The most significant challenge in the management of MDD, therefore, is selection of the antidepressant medication that is most likely to lead to response or to remission for an individual patient. There is a growing body of evidence that certain clinical neurophysiologic techniques may be useful for selecting the medication that is most likely benefit each patient. Use of low resolution electromagnetic tomography (LORETA), loudness dependent auditory evoked potentials (LDAEP), and resting state quantitative electroencephalography (QEEG) in the clinical setting is increasingly supported by studies indicating that these techniques may help identify particular medications that are most likely to lead to response or remission. The current state of evidence supporting the use of each technique is reviewed.

A meta-analytic review of the effects of psychotherapy control conditions for anxiety disorders

BACKGROUND

Little is known about the magnitude of improvement associated with psychotherapy control conditions for adult anxiety disorders. This information is important for the design of psychosocial treatment efficacy studies.

METHOD

We performed a computerized search of treatment outcome studies of anxiety disorders conducted between the first available year and 1 March 2007. In addition, we examined the reference lists from identified articles and asked international experts to identify eligible studies. We included studies that randomly assigned adult patients suffering from anxiety disorders to either cognitive-behavioral treatment or psychotherapy control condition. For each study, the two authors independently selected psychometrically sound measures of anxiety disorder severity. In addition, we collected data on attrition and treatment response.

RESULTS

Of the 1165 studies that were initially identified, 19 studies (454 patients) met inclusion criteria and were included in the analyses. The random effects analysis yielded a pre- to post-treatment Hedges' g effect size of 0.45 (95% confidence interval 0.35-0.46, z=8.50, p<0.001). The mean weighted response and attrition rates were 25.0% and 14.2%, respectively. There was no evidence for publication bias, nor was there a significant relationship between the effect size and diagnostic group, study year or number of treatment sessions.

CONCLUSIONS

Psychotherapy control conditions are associated with significant improvements when administered to adults suffering from anxiety disorders. In addition, they are associated with a relatively low attrition rate. These findings can inform the design of future psychotherapy outcome studies.

Preliminary results of an open label study of heart rate variability biofeedback for the treatment of major depression

Major depressive disorder (MDD) is a common mood disorder that can result in significant discomfort as well as interpersonal and functional disability. A growing body of research indicates that autonomic function is altered in depression, as evidenced by impaired baroreflex sensitivity, changes in heart rate, and reduced heart rate variability (HRV). Decreased vagal activity and increased sympathetic arousal have been proposed as major contributors to the increased risk of cardiovascular mortality in participants with MDD, and baroreflex gain is decreased.

STUDY OBJECTIVES

To assess the feasibility of using HRV biofeedback to treat major depression.

DESIGN

This was an open-label study in which all eleven participants received the treatment condition. Participants attended 10 weekly sessions. Questionnaires and physiological data were collected in an orientation (baseline) session and Treatment Sessions 1, 4, 7 and 10.

MEASUREMENTS AND RESULTS

Significant improvements were noted in the Hamilton Depression Scale (HAM-D) and the Beck Depression Inventory (BDI-II) by Session 4, with concurrent increases in SDNN, standard deviation of normal cardiac interbeat intervals) an electrocardiographic estimate of overall measure of adaptability. SDNN decreased to baseline levels at the end of treatment and at follow-up, but clinically and statistically significant improvement in depression persisted. Main effects for task and session occurred for low frequency range (LF) and SDNN. Increases in these variables also occurred during breathing at one's resonant frequency, which targets baroreflex function and vagus nerve activity, showing that subjects performed the task correctly.

CONCLUSIONS

HRV biofeedback appears to be a useful adjunctive treatment for the treatment of MDD, associated with large acute increases in HRV and some chronic increases, suggesting increased cardiovagal activity. It is possible that regular exercise of homeostatic reflexes helps depression even when changes in baseline HRV are smaller. A randomized controlled trial is warranted.

Pharmacotherapy of Mood Disorders and Treatment Discontinuation

Depression is the most frequent and costly problem in primary care, where most of these patients are seen and treated. In many countries, the public regard antidepressant drugs as 'addictive', partly because of the withdrawal symptoms that can occur when they are discontinued. Indeed, discontinuation (withdrawal) symptoms can follow the stoppage of almost all classes of antidepressants, including selective serotonin receptor inhibitors (SSRIs). This is important because they are widely regarded as drugs of choice for both depression and the anxiety disorders. But is this true withdrawal or merely rebound? The antidepressant discontinuation syndrome is characterised by the time-locked emergence of new, clearly defined and quantifiable signs and symptoms that ensue on stopping or reducing the dose of an antidepressant. Thereby, it meets the criteria for a withdrawal syndrome. The symptoms are not usually severe or protracted. SSRIs vary in their propensity to be associated with a discontinuation syndrome: paroxetine appears to be the most likely. Patients should be warned of the possibility of developing such a reaction, but reassured that it is usually mild and self limiting. Tapering the dose, if practicable, is worthwhile. In severe cases, temporary reinstatement of the SSRI and slower tapering may be necessary. Escalation of antidepressant dosage, or 'street abuse', is rare with antidepressants. The use of antidepressants is generally beneficial, and efforts should be made to optimise our current use of these drugs as well as encouraging the development of newer, better and innovative compounds. To this end, physicians should educate themselves and the public about discontinuation and withdrawal, so that these clinical features can be put in a realistic context.

A comparative meta-analysis of Clinical Global Impressions change in antidepressant trials

Two scales of the Clinical Global Impressions (CGI) Scale are frequently used in antidepressant trials. No research has systematically addressed how CGI change compares to change on established measures such as the Hamilton Depression Rating Scale (HAM-D), Montgomery-Asberg Depression Rating Scale, or Beck Depression Inventory. The current meta-analysis examined 75 antidepressant trials in which the CGI was used along with at least one other popular depression measure. The CGI-Severity scale was significantly more conservative than the HAM-D in rating change in double-blind trials, but not in open trials. The Beck Depression Inventory was significantly more conservative than the CGI-Severity. The CGI-Improvement scale was significantly more liberal than the HAM-D or Montgomery-Asberg Depression Rating Scale. Rater bias or scale content may explain differences between measures. Given the often substantial differences between instruments, researchers should use a variety of measures rather than relying on any single tool in assessing treatment response.

Blindness and bias in a trial of antidepressant medication for chronic tension-type headache

This study aimed to examine penetration of the blind in a randomized, placebo-controlled trial. Neurologists' ratings of improvement and medication side-effects, participants' ratings of improvement and daily diary recordings of headaches were assessed along with participants' and neurologists' guesses about treatment group placement in participants who completed at least 3 months of treatment (N = 169). Despite blinding, treating neurologists successfully identified the medication condition for 82% of participants receiving medication only; trial participants accurately identified their medication condition when receiving active medication (77% of participants), but not when receiving placebo. Concurrent stress-management therapy reduced, but did not eliminate penetration of the blind. Irrespective of drug condition, when participants were improved they were judged to be on active medication and when unimproved they were judged to be on placebo. However, neurologists' ratings of improvement, participants' reports of improvement and daily headache recordings yielded equivalent outcomes. Penetration of the blind needs to be assessed, not assumed in clinical trials in headache. However, penetration of the blind did not produce a prodrug bias as has been asserted by critics. Better methods of assessing and quantifying blindness are needed.

The Placebo Effect in the Pharmacologic Treatment of Patients with Lower Urinary Tract Symptoms

OBJECTIVES

We reviewed placebo responses in randomised controlled trials (RCTs) for pharmacologic treatment of lower urinary tract symptoms (LUTS), including urinary incontinence (UI), overactive bladder, and benign prostatic hyperplasia. Review papers on placebo effects in non-urologic disorders were assessed to compare the magnitude of placebo responses in drugs for LUTS with those reported for other diseases.

METHODS

Data were retrieved from registration trials for LUTS drugs on the Web sites of the Food and Drugs Administration and the European Medicines Agency. Reviews were retrieved from Medline using the MeSH term "placebo effect" (English language; published between 1990 and 2005).

RESULTS

Placebo treatment of LUTS yields reductions in incontinence episodes (IEs) ranging from 32% to 65%, whereas prostate or UI symptom scores are reduced by 9-34%. Genuine drugs decrease IEs by 45-77% and symptom scores by 22-45%. Placebo responses are much lower when objective changes in voided volume or peak flow rate are assessed.

CONCLUSIONS

The placebo effect in LUTS has a strong behavioural component as patients become aware of their voiding habits and potential risk factors. Symptom severity, treatment naivety, study duration, and interaction with health care providers may also influence it. Proper patient selection, study duration, and objective and subjective outcome measures may better separate genuine treatment effects from artefacts. Observational studies with patients representative for real-life situations and covering a sufficient period of time could allow for better understanding of RCT results and their applicability in clinical practice.

Depression in relation to survival among neurosurgical patients with a primary brain tumor: a 5-year follow-up study

OBJECTIVE

The adverse impact of depression in relation to survival among cancer patients is currently a subject of great interest in research. In a 5-year follow-up study, we investigated the association of depression with survival of patients with a primary brain tumor.

METHODS

The study population consisted of 75 patients with a solitary primary brain tumor treated surgically at the Oulu Clinic for Neurosurgery, Oulu University Hospital, in Northern Finland. The patients were interviewed during admission to the hospital for the tumor surgery. Assessment of depression was made using the Beck Depression Inventory and the Crown-Crisp Experiential Index. Information on all deaths within 60 months after tumor operation was collected from the Cause of Death Register, provided by Statistics Finland.

RESULTS

The patients with a high-grade glioma had a survival time of 22.5 months (standard deviation, 21.4 mo), whereas the corresponding time was 50.2 months (standard deviation, 19.9 mo) for patients with a low-grade glioma and 58.2 months (standard deviation, 9.4 mo) for the patients with a histologically benign tumor (P < 0.001, difference between groups, Kruskal-Wallis test). In the subgroup of patients with low-grade gliomas, depressive patients had a significantly shorter survival time compared with nondepressive subjects (P = 0.031, Kaplan-Meier survival analysis). A corresponding difference was not found in patients with high-grade gliomas or benign tumors. Tumor location in one hemisphere compared with bilateral location and wider extent of tumor surgery was associated with better survival in patients with low-grade gliomas and benign tumors but not in patients with high-grade gliomas.

CONCLUSION

Preoperative depression seemed to be a significant prognostic factor for worse survival in low-grade glioma patients. In clinical practice, an evaluation of depression among brain tumor patients by structured and standardized diagnostic methods is needed to distinguish the patients whose depression actually needs treatment. The effective treatment of clinical depression among brain tumor patients and the impact of treatment on the patients' chances of survival should be a focus of future research.

Bias resulting from the use of ‘assay sensitivity’ as an inclusion criterion for meta-analysis

Assay sensitivity has been proposed as a criterion for including psychiatric clinical outcome studies in meta-analyses. The authors assess the performance of assay sensitivity as a method for determining study appropriateness for meta-analysis by calculating expected standard drug vs placebo effect sizes for various combinations of high quality and flawed studies. In the absence of flawed studies, expected effect sizes are close to unbiased only when sample sizes are very large. In the presence of flawed studies, expected effect sizes tend to be substantially biased except under simultaneous conditions of high power, a large proportion of flawed studies, and a population standard vs placebo effect size of flawed studies considerably lower than that of high quality studies. The authors conclude that this method is not robust and can lead to serious bias. Unless it can be shown that specific conditions hold, assay sensitivity should not be used to make quality judgments of studies.

Ensayos clínicos aleatorizados (CONSORT)

It has been repeatedly shown that the information supplied in publications of clinical trials is frequently insufficient or inaccurate and that some methodologic problems are associated with exaggerated estimates of the effect of healthcare interventions. To improve the quality of reports of clinical trials, a group of scientists and editors developed the CONSORT statement (Consolidated Standards of Reporting Trials), a 22-item checklist (plus flow diagram), that can be used by authors, editors, reviewers, and readers. After publication in 1996, CONSORT was adopted by several journals and editorial groups. In 1999, a second version was drawn up, which was published in 2001. This article presents the Spanish translation of the two elements integrating the revised CONSORT, the flow diagram and the 22-item checklist, and provides a short comment on each of them. Previous publications of the CONSORT statement and other useful resources such as examples of what are considered good communications may be obtained from the CONSORT web site (http://www.consort-statement.org).

The growth of psychopharmacology in the 1990s: evidence-based practice or irrational exuberance

The rapid growth in sales of psychotropic medications during the late 1980s and 1990s, eventually reaching $20 billion/year, reflected the increased use of seritonin reuptake inhibitors for depression and atypical antipsychotics for schizophrenia. Recently, however, some of the therapeutic claims for these medications have been challenged, and under-appreciated risks have turned out to be significant liabilities. Drug manufacturers increasingly dominate clinical trials research and evidence suggests that study designs and data presentations have been slanted to show products in a favorable light while unfavorable data were suppressed. At the same time, during the 1990s, potentially independent voices did not effectively or consistently present countervailing views. The extensive financial ties between the pharmaceutical industry and academic researchers, professional associations, and consumer groups may also have discouraged expression of critical views. Additionally, the narrow legal mandate of the FDA to evaluate the safety and efficacy of new drugs only in comparison to placebo (rather than in comparison to other treatments) probably limited its contribution. In the absence of reliable, impartial research on the risk and benefits of psychotropic medications, both before and after they are brought to market, pharmacy benefits management cannot achieve its goal of maximizing health care benefits per dollar spent. Further institutional support is needed for independent research, either conducted or funded by the federal government.

Substance P receptor antagonists in psychiatry: rationale for development and therapeutic potential

Increasing evidence suggests that substance P (SP) and its receptor (neurokinin [NK]-1 receptor [NK1R]) might play an important role in the modulation of stress-related, affective and/or anxious behaviour. First, SP and NK1R are expressed in brain regions that are involved in stress, fear and affective response (e.g. amygdala, hippocampus, hypothalamus and frontal cortex). Second, the SP content in these areas changes upon application of stressful stimuli. Third, the central administration of SP produces a range of fear-related behaviours. In addition, the SP/NK1R system shows significant spatial overlap with neurotransmitters such as serotonin and noradrenaline (norepinephrine), which are known to be involved in the regulation of stress, mood and anxiety. Therefore, it was hypothesised that blockade of the NK1R might have anxiolytic as well as antidepressant effects. Preclinical studies investigating the effects of genetic or pharmacological NK1R inactivation on animal behaviour in assays relevant to depression and anxiety revealed that the behavioural changes resemble those seen with reference antidepressant or anxiolytic drugs. Furthermore, antagonism or genetic inactivation of the NK1R causes alterations in serotonin and norepinephrine neuronal transmission that are likely to contribute to the antidepressant/anxiolytic activity of NK1R antagonists but that are--at least partially--distinct from those produced by established antidepressant drugs. This underlines the conceivable unique mechanism of action of this new class of compounds. In three independent clinical trials with three different compounds (aprepitant [MK-869], L-759274 and CP-122721), an antidepressant effect of NK1R antagonists could be demonstrated. These results, however, have been challenged by recent failed studies with aprepitant. There are numerous indications from preclinical studies that, in addition to SP and NK1R, other neurokinins and/or neurokinin receptors might also be involved in the modulation of stress-related behaviour and that exclusive blockade of the NK1R might not be sufficient to produce consistent anxiolytic and antidepressant effects. One such candidate is the neurokinin-2 receptor (NK2R), and clinical trials to assess the antidepressant effects of NK2R antagonists are currently underway. Of special interest might also be substances that block more than one receptor type such as NK1/2R antagonists or NK1/2/3R antagonists. These compounds may be more efficacious in antagonising the effects of SP than compounds that only block the NK1R.

Methodological issues in clinical trials of antidepressant medications: perspectives from psychotherapy outcome research

Despite their widespread use, the specific efficacy of antidepressant medications has been a source of debate in recent years. Examination of the literature reveals that a significant proportion of the benefit produced in antidepressant trials is duplicated in pill placebo conditions. Furthermore, early trials utilizing active placebos, or medications that mimic the common side effects of antidepressants, showed even smaller differences as compared with active medications. We examine issues surrounding the use of placebo control conditions in antidepressant trials, including the pros and cons of active placebos. We conclude that similar challenges are faced by psychotherapy outcome researchers who have focused more on the separation of specific from nonspecific treatment factors and on the effects of researcher allegiance and patient expectancy on outcome. Within this context, recommendations for improving future antidepressant research are discussed.

Evidence for a combined genetic effect of the 5-HT(1A) receptor and serotonin transporter genes in the clinical outcome of major depressive patients treated with citalopram

In the context of a long-term follow-up study, we analysed the possible implication of the 5-HT(1A) receptor gene (HTR1A) -1018C/G polymorphism in the clinical outcome of major depressive patients treated with citalopram. We had previously reported an association between variation on the SERT gene (SLC6A4) and clinical remission after citalopram treatment. In the present 12-week follow-up study, the combined effect of HTR1A and SLC6A4 genes in clinical outcome and response to citalopram was also evaluated. The sample consisted of 130 patients, all of Spanish origin, who were diagnosed as having a current major depressive episode according to DSM-IV criteria. A 21-item Hamilton Depression Rating Scale was used to assess severity of symptoms at the beginning and during the follow-up to determine the outcome and remission status at week 12. Patients were genotyped for HTR1A gene and, in addition, for two polymorphisms at the CYP2C19 gene, which together account for the 87% of the Caucasian poor metabolizer phenotype. Data were analysed adjusting for the effect of poor metabolizers in clinical response. No independent effect was found for the 5-HT(1A) receptor gene in relation to clinical outcome or remission after citalopram treatment. However, a combined genetic effect of HTR1A and SLC6A4 genes was found to influence the clinical outcome of patients [F(4,102) = 2.89, p= 0.02]. When considering the remission status, an increase of patients carrying the risk genotype combination (S/S-G/G) was found among those subjects who did not reach remission (Fisher's exact test = 0.009). Our results suggest that the combined effect of the serotonin transporter and the 5-HT(1A) receptor genes could be related to the clinical outcome of depressive patients treated with citalopram.

Experience is a biochemical intervention: Reconceptualizing the “biologically based mental illness”

Empirical evidence challenges the discriminant validity of the "biologically based mental illness" (BBMI) construct. Data indicate that interventions such as psychotherapy, placebo, and medication yield similar changes in brain function when effective. Drug and brain imaging studies show that psychological and biochemical phenomena can be manipulated reciprocally. Data suggest that mental disorders are biologically expressed, not epiphenomenal to a biological process. Suggestions are given for further research and alternative conceptualizations that may lead to changes in healthcare policy.

Reducing exposure of clinical research subjects to placebo treatments

The ethics of pill placebo and placebo psychotherapy conditions in clinical research are controversial. Even when not life threatening, mental disorders dramatically diminish the quality of life. Pill-placebo conditions in drug treatment research have been justified on the grounds that a placebo versus standard drug comparison is necessary to test the quality of the study, viz., the assay sensitivity method. The assay sensitivity method of judging study quality, however, results in misclassification of the quality of some studies, leading to bias in effect size estimation in the context of meta-analyses. This bias is of particular concern in relation to studies comparing psychotherapies to psychotropic drugs, which are conducted outside of the Food and Drug Administration (FDA) context. In cases in which control conditions may be justified on grounds other than as essential elements of an assay sensitivity test, statistical methods to reduce the number of study participants exposed to placebo should be strongly considered. Of the methods available, group sequential methods are the most widely used. Group sequential methods involve successive looks at accumulating data, with rules for terminating a trial (or an arm of a trial) early if results are strong enough.