Clinical trials of antidepressant medications are producing meaningless results

All studies are not created equal: A systematic narrative review of bipolar depression clinical trial inclusion/exclusion rules and baseline severity scores

BACKGROUND

Several bipolar depression treatment guidelines have been designed to assist clinicians with medication selection. When ranking medications, none explicitly considered the inclusion/exclusion criteria or baseline severity scores of the reviewed clinical trials. This article aimed to determine if sufficient differences exist in these variables to justify their consideration when designing treatment guidelines.

METHODS

Using Ovid and PubMed databases in May and September 2022, all published, short-term cross-over or parallel-group design studies comparing second generation antipsychotics (SGAs), mood stabilizers, or antidepressants versus placebo in bipolar depressed patients were identified. Included studies must have enrolled adult bipolar I/II depressed patients, randomized patients into two or more treatment groups, utilized a double-blind, prospective design written in English, and had primary outcome results that were statistically significant in favor of the investigational treatment.

RESULTS

Thirty studies met eligibility criteria, comprising a total of 8791 patients. Among those studies, there were seventeen antipsychotic trials, six lithium trials, one lamotrigine trial, three valproate trials, two carbamazepine trials, and two antidepressant trials. The analysis revealed substantial differences among the studies. Although this was seen among all the different drug classes, these differences are clearest when comparing the lithium trials to those of the SGAs.

LIMITATIONS

Limitations included the selection of severity scores from the treatment arm with the most severe score and the exclusive focus on mood stabilizers, antidepressants, and SGAs.

CONCLUSIONS

Severity of the enrolled patient sample and treatment-resistance should be considered in addition to other factors when ranking medications in bipolar depression treatment guidelines.

Pediatric Psychopharmacological Research in the Post EU Regulation 1901/2006 Era

Although the use of psychotropic medications in child and adolescent psychiatry in Germany is on the increase, most compounds are in fact prescribed “off-label” because of a lack of regulatory approval in these age groups. In 2007, the European Parliament introduced Regulation 1901/2006 concerning medicinal products in pediatric populations, with a subsequent amendment in the form of Regulation 1902/2006. The main aim of this legislation was to encourage research and clinical trials in children and adolescents, and thus promote the availability of medications with marketing authorization for these age groups. Furthermore, initiatives such as the European 7th Framework Program of the European Union now offer substantial funding for pediatric pharmacological research. At a recent Congress of the German Society for Child and Adolescent Psychiatry and Psychotherapy (DGKJP), experts from the field and the pharmaceutical industry held a symposium with lay representatives in order to discuss attitudes toward, and experience with, pediatric psychopharmacology research in Germany since 2007. Several areas of concern were identified. The present paper derives from that symposium and provides an overview of these opinions, which remain crucial to the field. A wider discussion of how to facilitate psychopharmacological research in Germany in order to optimize the treatment and welfare of children and adolescents with psychiatric disorders is now warranted.

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.

Study design features affecting outcome in antidepressant trials

BACKGROUND

A key issue in the approval process of antidepressants is the inconsistency of results between antidepressant clinical phase III trials. Identifying factors influencing efficacy data is needed to facilitate interpretation of the results.

METHODS

We reviewed data packages submitted as new drug applications to Swissmedic focusing on pivotal, short-term antidepressant trials. Included studies used HAMD-17 or HAMD-21 as primary measures and enrolled patients aged 18-65 years with a diagnosis of major depression. Due to the hierarchical structure of the data a mixed-effect regression model has been applied with responder rates as primary outcome criterion. Random intercepts were estimated for the different trials, while study design factors were assigned as explanatory fixed effects.

RESULTS

The final dataset was based upon 35 study reports with a total of N=10,835 patients. Significant results were found for study arm (placebo vs. active compound, p<0.001), sample size (p=0.002), duration of treatment (p=0.024), two or more active treatment arms (p=0.022) and the individual drug (p=0.029). Furthermore, a tendency to an association with the outcome was observed for baseline disease severity (p=0.077) and possibility of dosing adaptation (p=0.076).

LIMITATIONS

Due to strict confidentiality agreements, individual drugs are not reported here. Further research should consider additional variables that might have an impact on the results of antidepressant trials.

CONCLUSIONS

Efficacy data in antidepressant trials is significantly affected by various factors. These factors and their potentially confounding role have to be considered in the interpretation of the results.

Placebo, prozac and PLoS: significant lessons for psychopharmacology

Kirsch et al. (2008, Initial severity and antidepressant benefits: a meta-analysis of data submitted to the Food and Drug Administration. PLoS Med 5: e45), conducted a meta-analysis of data from 35 placebo controlled trials of four newer antidepressants. They concluded that while these drugs are statistically significantly superior to placebo in acute depression, the benefits are unlikely to be clinically significant. This paper has attracted much attention and debate in both academic journals and the popular media. In this critique, we argue that Kirsch et al.'s is a flawed analysis which relies upon unusual statistical techniques biased against antidepressants. We present results showing that re-analysing the same data using more appropriate methods leads to substantially different conclusions. However, we also believe that psychopharmacology has lessons to learn from the Kirsch et al. paper. We discuss issues surrounding the interpretation of clinical trials of antidepressants, including the difficulties of extrapolating from randomized controlled trials to the clinic, and the question of failed trials. We call for more research to establish the effectiveness of antidepressants in clinically relevant populations under naturalistic conditions, for example, in relapse prevention, in patients with co-morbidities, and in primary care settings.

Prescribing antidepressants for depression: time to be dimensional and inclusive

The article by Middleton and Moncrieff questions the role of antidepressants in treating depression on both philosophical and practical grounds; namely that depression isn't a brain disease to be treated by a drug and that antidepressants are ineffective except as placebos. We argue that their stance is unhelpful and factually incorrect and that a more dimensional and integrative approach is needed in order to be able to best tailor treatment to individual needs. This involves a personalised assessment of the likely benefits and risks of both psychological and drug approaches when recommending treatment for someone with depression.

Sertraline versus other antidepressive agents for depression

BACKGROUND

The National Institute for Health and Clinical Excellence clinical practice guideline on the treatment of depressive disorder recommended that selective serotonin reuptake inhibitors should be the first-line option when drug therapy is indicated for a depressive episode. Preliminary evidence suggested that sertraline might be slightly superior in terms of effectiveness.

OBJECTIVES

To assess the evidence for the efficacy, acceptability and tolerability of sertraline in comparison with tricyclics (TCAs), heterocyclics, other SSRIs and newer agents in the acute-phase treatment of major depression.

SEARCH STRATEGY

MEDLINE (1966 to 2008), EMBASE (1974 to 2008), the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register and the Cochrane Central Register of Controlled Trials up to July 2008. No language restriction was applied. Reference lists of relevant papers and previous systematic reviews were hand-searched. Pharmaceutical companies and experts in this field were contacted for supplemental data.

SELECTION CRITERIA

Randomised controlled trials allocating patients with major depression to sertraline versus any other antidepressive agent.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data. Discrepancies were resolved with another member of the team. A double-entry procedure was employed by two reviewers. Information extracted included study characteristics, participant characteristics, intervention details and outcome measures in terms of efficacy (the number of patients who responded or remitted), acceptability (the number of patients who failed to complete the study) and tolerability (side-effects).

MAIN RESULTS

A total of 59 studies, mostly of low quality, were included in the review, involving multiple treatment comparisons between sertraline and other antidepressant agents. Evidence favouring sertraline over some other antidepressants for the acute phase treatment of major depression was found, either in terms of efficacy (fluoxetine) or acceptability/tolerability (amitriptyline, imipramine, paroxetine and mirtazapine). However, some differences favouring newer antidepressants in terms of efficacy (mirtazapine) and acceptability (bupropion) were also found. In terms of individual side effects, sertraline was generally associated with a higher rate of participants experiencing diarrhoea.

AUTHORS' CONCLUSIONS

This systematic review and meta-analysis highlighted a trend in favour of sertraline over other antidepressive agents both in terms of efficacy and acceptability, using 95% confidence intervals and a conservative approach, with a random effects analysis. However, the included studies did not report on all the outcomes that were pre-specified in the protocol of this review. Outcomes of clear relevance to patients and clinicians were not reported in any of the included studies.

Major depression: an illness with objective physical signs

Major depression is an illness with objective physical signs occurring with some consistency. These signs are retardation of movements and diminished gestures and expressions. The patient may appear tired, self-concerned, bored, and inattentive and display a loss of interest in the surroundings. Anxiety is a conspicuous and an integral element of affective state and may be expressed by severe restlessness and agitation. Muscle tension, wringing of hands, weeping and moaning, repeating over and over in a monotonous and stereotyped way phrases expressive of misery are all important clinical signs of major depression. Similarly tachycardia, dry tongue/mouth, sweaty palms and/or bodily extremities, cold clammy skin, pallor, pupillary dilatation, tremor, and the fluctuations in blood pressure with wide pulse pressure are all important and give away the underlying distress. These signs have formed an integral part of both the Hamilton Depression Rating Scale and the Montgomery-Asberg Depression Rating Scale as they have a positive correlation with the diagnosis and the severity of illness. Current practice of operational criteria does not help exclude patients with subjective perception of distress and also fails to make room for aetiopathogenesis. The DSM-IV does not include these physical signs as an integral part of the clinical picture of depression, consequently leaving the diagnosis of MDE to subjective criteria and perceptions. This could also explain a large placebo response in recent randomised controlled clinical trials.

Sertraline versus other antidepressive agents for depression

BACKGROUND

The National Institute for Health and Clinical Excellence clinical practice guideline on the treatment of depressive disorder recommended that selective serotonin reuptake inhibitors should be the first-line option when drug therapy is indicated for a depressive episode. Preliminary evidence suggested that sertraline might be slightly superior in terms of effectiveness.

OBJECTIVES

To assess the evidence for the efficacy, acceptability and tolerability of escitalopram in comparison with tricyclics (TCAs), heterocyclics, other SSRIs and newer agents in the acute-phase treatment of major depression.

SEARCH STRATEGY

MEDLINE (1966 to 2008), EMBASE (1974 to 2008), the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register and the Cochrane Central Register of Controlled Trials up to July 2008. No language restriction was applied. Reference lists of relevant papers and previous systematic reviews were hand-searched. Pharmaceutical companies and experts in this field were contacted for supplemental data.

SELECTION CRITERIA

Randomised controlled trials allocating patients with major depression to sertraline versus any other antidepressive agent.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data. Discrepancies were resolved with another member of the team. A double-entry procedure was employed by two reviewers. Information extracted included study characteristics, participant characteristics, intervention details and outcome measures in terms of efficacy (the number of patients who responded or remitted), acceptability (the number of patients who failed to complete the study) and tolerability (side-effects).

MAIN RESULTS

A total of 59 studies, mostly of low quality, were included in the review, involving multiple treatment comparisons between sertraline and other antidepressant agents. Evidence favouring sertraline over some other antidepressants for the acute phase treatment of major depression was found, either in terms of efficacy (fluoxetine) or acceptability/tolerability (amitriptyline, imipramine, paroxetine and mirtazapine). However, some differences favouring newer antidepressants in terms of efficacy (mirtazapine) and acceptability (bupropion) were also found. In terms of individual side effects, sertraline was generally associated with a higher rate of participants experiencing diarrhoea.

AUTHORS' CONCLUSIONS

This systematic review and meta-analysis highlighted a trend in favour of sertraline over other antidepressive agents both in terms of efficacy and acceptability, using 95% confidence intervals and a conservative approach, with a random effects analysis. However, the included studies did not report on all the outcomes that were pre-specified in the protocol of this review. Outcomes of clear relevance to patients and clinicians were not reported in any of the included studies.

The antidepressant debate and the balanced placebo trial design: an ethical analysis

There is ongoing debate about whether randomized, placebo-controlled trials under a double-blind have reliably established the pharmacological efficacy of antidepressants. Numerous meta-analyses of antidepressant efficacy trials, e.g., Kirsch et al. [Kirsch, I., Moore, T. J., Scoboria, A., & Nicholls, S. (2002). The emperor's new drugs: An analysis of antidepressant medication data submitted to the U.S. food and drug administration. Prevention and Treatment, 5, Article 23. (Retrieved July 19, 2007 from http://journals.apa.org/prevention/volume5)], have shown a modest drug-placebo difference but methodological problems with standard trial design preclude a definitive conclusion that this difference results from specific biological effects of antidepressants or the nonspecific factors that have not been adequately excluded. Standard trial design assumes the additivity thesis of pharmacological efficacy, being the assumption that the specific or "true" magnitude of the pharmacological effect is limited to the difference between the drug and placebo responses in a standard trial. If the drug effects are as small as these meta-analyses suggest, then their clinical effectiveness is questionable. If the drug effects are actually larger but masked by placebo effects, then the additivity thesis is not valid and we risk false negative results with standard trial design. Kirsch et al. propose an alternative, four arm balanced placebo trial design (BPTD) that can accurately test the additivity thesis. The BPTD uses antidepressants, active placebos and the intentional deception of research subjects. My focal question is whether the BPTD is ethically defensible. I will explore two objections that can be raised against it: 1) lying to BPTD research subjects violates their autonomy and exploits their illness and 2) the BPTD may not enable us to test the additivity thesis with accuracy, i.e., it may contribute to the masking of drug effects that it aims to avoid. I argue that these objections support the conclusion that the BPTD is ethically indefensible.

Depression research and treatment: Are we skating to where the puck is going to be?

This paper critically reviews empirical findings regarding current key assumptions underlying the nature and treatment of depression which heavily rely on the DSM approach. This review shows that empirical evidence provides little support for these assumptions. In response to these findings, an etiologically based, biopsychosocial, dynamic interactionism model of depression is proposed. This model could foster further integration in research on depression and assist in the development of guidelines for the treatment of depression that are better informed by research findings and more congruent with complex clinical realities.

Fluoxetine versus other types of pharmacotherapy for depression

BACKGROUND

Depression is common in primary care and it is associated with marked personal, social and economic morbidity, and creates significant demands on service providers in terms of workload. Treatment is predominantly pharmaceutical or psychological. Fluoxetine, the first of a group of antidepressant (AD) agents known as selective serotonin reuptake inhibitors (SSRIs), has been studied in many randomised controlled trials (RCTs) in comparison with tricyclic (TCA), heterocyclic and related ADs, and other SSRIs. These comparative studies provided contrasting findings. In addition, systematic reviews of RCTs have always considered the SSRIs as a group, and evidence applicable to this group of drugs might not be applicable to fluoxetine alone. The present systematic review assessed the efficacy and tolerability profile of fluoxetine in comparison with TCAs, SSRIs and newer agents.

OBJECTIVES

To determine the efficacy of fluoxetine, compared with other ADs, in alleviating the acute symptoms of depression, and to review its acceptability.

SEARCH STRATEGY

Relevant studies were located by searching the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register (CCDANCTR), the Cochrane Central Register of Controlled Trials (CENTRAL), Medline (1966-2004) and Embase (1974-2004). Non-English language articles were included.

SELECTION CRITERIA

Only RCTs were included. For trials which have a crossover design only results from the first randomisation period were considered.

DATA COLLECTION AND ANALYSIS

Data were independently extracted by two reviewers using a standard form. Responders to treatment were calculated on an intention-to-treat basis: drop-outs were always included in this analysis. When data on drop-outs were carried forward and included in the efficacy evaluation, they were analysed according to the primary studies; when dropouts were excluded from any assessment in the primary studies, they were considered as treatment failures. Scores from continuous outcomes were analysed including patients with a final assessment or with the last observation carried forward. Tolerability data were analysed by calculating the proportion of patients who failed to complete the study and who experienced adverse reactions out of the total number of randomised patients. The primary analyses used a fixed effects approach, and presented Peto Odds Ratio (PetoOR) and Standardised Mean Difference (SMD).

MAIN RESULTS

On a dichotomous outcome fluoxetine was less effective than dothiepin (PetoOR: 2.09, 95% CI 1.08 to 4.05), sertraline (PetoOR: 1.40, 95% CI 1.11 to 1.76), mirtazapine (PetoOR: 1.64, 95% CI 1.01 to 2.65) and venlafaxine (Peto OR: 1.40, 95% CI 1.15 to 1.70). On a continuous outcome, fluoxetine was more effective than ABT-200 (Standardised Mean Difference (SMD) random effects: - 1.85, 95% CI - 2.25 to - 1.45) and milnacipran (SMD random effects: - 0.38, 95% CI - 0.71 to - 0.06); conversely, it was less effective than venlafaxine (SMD random effect: 0.11, 95% CI 0.00 to 0.23), however these figures were of borderline statistical significance. Fluoxetine was better tolerated than TCAs considered as a group (PetoOR: 0.78, 95% CI 0.68 to 0.89), and was better tolerated in comparison with individual ADs, in particular than amitriptyline (PetoOR: 0.64, 95% CI 0.47 to 0.85) and imipramine (PetoOR: 0.79, 95% CI 0.63 to 0.99), and among newer ADs than ABT-200 (PetoOR: 0.21, 95% CI 0.10 to 0.41), pramipexole (PetoOR: 0.20, 95% CI 0.08 to 0.47) and reboxetine (PetoOR: 0.61, 95% CI 0.40 to 0.94).

AUTHORS' CONCLUSIONS

There are statistically significant differences in terms of efficacy and tolerability between fluoxetine and certain ADs, but the clinical meaning of these differences is uncertain, and no definitive implications for clinical practice can be drawn. From a clinical point of view the analysis of antidepressants' safety profile (adverse effect and suicide risk) remains of crucial importance and more reliable data about these outcomes are needed. Waiting for more robust evidence, treatment decisions should be based on considerations of clinical history, drug toxicity, patient acceptability, and cost. We need for large, pragmatic trials, enrolling heterogeneous populations of patients with depression to generate clinically relevant information on the benefits and harms of competitive pharmacological options. A meta-analysis of individual patient data from the randomised trials is clearly necessary.

Identifying "paradigm failures" contributing to treatment-resistant depression

BACKGROUND

"Treatment resistant depression" is likely to emerge from a number of factors, including application of the wrong diagnostic and treatment models.

METHOD

Current paradigms for managing both depression and treatment resistant depression are considered. We then examine the prevalence of a set of paradigm failures that appeared to contribute to treatment resistant depression in outpatients of a tertiary referral Mood Disorders Unit.

RESULTS

Six illustrative paradigm failures are described and their frequencies within the clinical sample reported. Identified paradigm failures were diagnosing and/or managing a non-melancholic condition as if it were melancholic depression, failure to diagnose and manage bipolar disorder, psychotic depression or melancholic depression, misdiagnosing secondary depression and failure to identify organic determinants.

CONCLUSION

We suggest that the identification of such "paradigm failures"--and of others that can be assumed to operate--has the potential to enrich the assessment and management of depressed patients, and reduce the prevalence of treatment resistance.

Candidate genes for antidepressant response to selective serotonin reuptake inhibitors

Selective serotonin reuptake inhibitors (SSRIs) can safely and successfully treat major depression, although a substantial number of patients benefit only partially or not at all from treatment. Genetic polymorphisms may play a major role in determining the response to SSRI treatment. Nonetheless, it is likely that efficacy is determined by multiple genes, with individual genetic polymorphisms having a limited effect size. Initial studies have identified the promoter polymorphism in the gene coding for the serotonin reuptake transporter as moderating efficacy for several SSRIs. The goal of this review is to suggest additional plausible polymorphisms that may be involved in antidepressant efficacy. These include genes affecting intracellular transductional cascades; neuronal growth factors; stress-related hormones, such as corticotropin-releasing hormone and glucocorticoid receptors; ion channels and synaptic efficacy; and adaptations of monoaminergic pathways. Association analyses to examine these candidate genes may facilitate identification of patients for targeted alternative therapies. Determining which genes are involved may also assist in identifying future, novel treatments.

Hypericum extract LI 160 and fluoxetine in mild to moderate depression: a randomized, placebo-controlled multi-center study in outpatients

Efficacy and tolerability of Hypericum LI 160 was compared to fluoxetine and placebo in mild to moderate Major Depression (DSM-IV) in a 4-week randomized, double-blind trial. One hundred and sixty-three outpatients from 15 general practitioner centers received either 900 mg Hypericum LI 160, 20 mg fluoxetine, or placebo daily. Amelioration was measured by the Hamilton and the Montgomery-Asberg Depression scales. Response and remission rates and global ratings by investigators and patients were measured. Adverse event reports, laboratory screening, vital signs, physical exams and ECG were collected. No significant differences could be observed regarding efficacy measures except for remission rate (Hypericum 24%; fluoxetine 28%; placebo 7 %). Hypericum was significantly better tolerated than fluoxetine. Hypericum LI 160 or fluoxetine were not more effective in short-term treatment in mild to moderate depression than placebo.

Barriers to care in severe mental illness: accounts from perpetrators of intra-familial homicide

OBJECTIVE

To review perceptions of barriers to receiving effective mental health care described by patients who had committed intra-familial homicide in the context of untreated severe mental illness.

METHOD

Semi-structured interviews addressed issues such as support, help-seeking, experience of illness, and what participants felt might have helped prevent the death(s). Transcripts were analysed for themes related to barriers to help-seeking.

RESULTS

Themes identified included: hiding or minimizing difficulties, lack of knowledge or understanding of mental illness, loss of control in the context of illness, seduction by the illness, reality-distorting effects of the illness, distortion of interpersonal relationships, diminished ability to trust and difficulty acknowledging need for medication.

CONCLUSIONS

Barriers to care exist at individual, interpersonal and wider societal levels and need to be addressed at all of them.

Evaluating treatments for the mood disorders: time for the evidence to get real

OBJECTIVE

To detail limitations to level I evidence derived from randomised controlled trials of antidepressant treatments and which is held to be fundamental to the development and validity of treatment guidelines.

METHOD

Recent efficacy studies and meta-analyses of treatments of major depression are considered.

RESULTS

The largest database in psychiatry--demonstrating that all principal treatments are of similar efficacy, and that antidepressant drugs are not distinctly superior to placebo treatment--is unlikely to be valid.

CONCLUSION

Excessive belief in and weighting of the evidence emerging from randomised controlled trials deserves to be criticized. An argument is put for adopting alternative approaches to evaluating the likely effectiveness of any antidepressant treatment.

Treatment options for real-life patients

Our current models of depression and clinical trials data provide inadequate and relatively meaningless clinical information. They do not take into account the multiple phenotypes of depression and often do not include patients with "real-life" clinical depression. Psychiatry is called an evidence-based specialty, and this is supported by the wealth of evidence provided by the antidepressant drug trials. However, if the evidence demonstrated by these trials is not accurate, then psychiatry may fail to provide satisfactory treatment for patients with depression. Trial data commonly show the effect of antidepressant treatment to be indistinguishable from placebo. On first examination it could be said that antidepressant drugs act mainly as placebos, or, even worse, that antidepressant drugs are no better than placebos in effect. However, this view is at odds with the observations of clinicians in everyday practice, and the impact of this perception is worrying, with the pharmaceutical companies, patients and practitioners all being adversely affected. Randomised controlled trials (RCTs) provide limited data about the true effectiveness of an antidepressant. However, such RCTs are required by regulatory authorities for drug approval. Antidepressant effects in "real-life" depression need further investigation. When efficacy data for drug and non-drug treatments for major depression are compared, there are very few differences. This lack of differentiation across treatments allows every therapy to be perceived as efficacious, but also non-specific. This leads to patients being fitted to their therapist's preferred treatment, and not vice versa. This "all roads lead to rome" model is contrary to the rest of medicine, where differential treatment effects are to be expected. Why, therefore, is there confusion? A dimensional model for depression homogenises the multiple underlying subtypes of depression. This leads to treatments being tested as having universal application instead of targeting the specific depressive subtypes. This largely underpins the lack of specificity in RCT evidence. These trials involve patients who bear little resemblance to those who clinicians see in everyday practice. These trials also select and favour natural and rapid responders. Therefore the failure to differentiate between drug and placebo is unsurprising in the RCTs. Our spectrum model seeks to identify clinically meaningful expressions of depression, allowing drugs to be targeted to separate depressive conditions and their underlying cause. This allows a rational model for prevention and long-term management. For example, when treating depression associated with anxiety, selective serotonin reuptake inhibitors (SSRIs) produce a high response in patients with internalised anxious worrying or externalised irritability. Not only do they treat the depression but also the fundamental cause. In summary, efficacy data will continue to provide little meaningful clinical information while treatments are tested as "universal" in reference to non-specific conditions such as "major depression". Through use of the spectrum model, therapy can be better fitted to depression subtype, through identification of clinical phenotypes and their causes.