How long does it take for antidepressant therapies to act?

Validation of a novel online depression symptom severity rating scale: the R8 Depression

BACKGROUND

An automated web-based assessment and monitoring system ( www.psynary.com ) has been developed to assist non-specialist clinicians in managing common mood and anxiety disorders. Psynary promotes the use of standardised outcome measures to assess symptom severity and optimise treatments with the aim of improving outcomes and enabling faster recovery. This paper analyses the results from two parallel studies in New Zealand and Japan (OptiMA-1 NZ and Japan) to assess the validity of the R8 Depression scale, one of the system's core outcome measures.

METHODS

Clinical samples were recruited from a public secondary care and a private psychiatry clinic. Participants completed the outcome measures for the study via the online Psynary system. The R8 Depression scale is a 30-item questionnaire which includes all symptom domains covered in the ICD-10 classification of depression. The Patient Health Questionnaire (PHQ-9) was completed at the same time points as the R8 Depression, with a smaller sample also completing a paper-based Quick Inventory of Depressive Symptomatology (QIDS-SR16). Internal validity was quantified via Cronbach's alpha and Guttman lower bounds method. External validation against the PHQ-9 and QIDS used the Pearson's and Kendall's correlation coefficients. Severity categories were set using a multivariate regression model.

RESULTS

270 patients participated in the study and completed a maximum of 1 baseline and 5 reviews within a 90-day period, giving a total of 1124 assessments with the PHQ-9 also being completed in 1053 of these assessments. R8 Depression normative data was also collected from 204 non-clinical volunteers with 187 of these also completing the PHQ9. Internal reliability scores were all higher than 0.9 (n = 1328). There was overall good external validity when comparing the R8 Depression to the PHQ-9, with a correlation of 0.91 for the combined normative and clinical samples (n = 1240).

CONCLUSIONS

The R8 Depression has been developed as a patient-rated outcome measure for depression for administration on an online system called "Psynary". It has high internal and external validity against current widely used scales. Further work is underway to determine the sensitivity to change of the R8 Depression.

The cholinesterase inhibitor donepezil has antidepressant-like properties in the mouse forced swim test

Finding new antidepressant agents is of high clinical priority given that many cases of major depressive disorder (MDD) do not respond to conventional monoaminergic antidepressants such as the selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants, and monoamine oxidase inhibitors. Recent findings of effective fast-acting antidepressants indicate that there are biological substrates to be taken advantage of for fast relief of depression and that we may find further treatments in this category. In this vein, the cholinergic system may be a relatively overlooked target for antidepressant medications, given its major role in motivation and attention. Furthermore, the classically engaged monoaminergic neurotransmitter systems in depression treatment-serotonin, norepinephrine, and dopamine-interact directly at times with cholinergic signaling. Here we investigate in greater detail how the cholinergic system may impact depression-related behavior, by administering widely ranging doses of the cholinesterase inhibitor drug, donepezil, to C57BL/6J mice in the forced swim test. First, we confirm prior findings that this drug, which is thought to boost synaptic acetylcholine, promotes depression-like behavior at a high dose (2.0 mg/kg, i.p.). But we also find paradoxically that it has an antidepressant-like effect at lower doses (0.02 and 0.2 mg/kg). Further this antidepressant-like effect is not due to generalized hyperactivity, since we did not observe increased locomotor activity in the open field test. These data support a novel antidepressant-like role for donepezil at lower doses as part of an overall u-shaped dose-response curve. This raises the possibility that donepezil could have antidepressant properties in humans suffering from MDD.

In vivo electrophysiological recordings of the effects of antidepressant drugs

Antidepressant drugs are a standard biological treatment for various neuropsychiatric disorders, yet relatively little is known about their electrophysiologic and synaptic effects on mood systems that set moment-to-moment emotional tone. In vivo electrical recording of local field potentials (LFPs) and single neuron spiking has been crucial for elucidating important details of neural processing and control in many other systems, and yet electrical approaches have not been broadly applied to the actions of antidepressants on mood-related circuits. Here we review the literature encompassing electrophysiologic effects of antidepressants in animals, including studies that examine older drugs, and extending to more recently synthesized novel compounds, as well as rapidly acting antidepressants. The existing studies on neuromodulator-based drugs have focused on recording in the brainstem nuclei, with much less known about their effects on prefrontal or sensory cortex. Studies on neuromodulatory drugs have moreover focused on single unit firing patterns with less emphasis on LFPs, whereas the rapidly acting antidepressant literature shows the opposite trend. In a synthesis of this information, we hypothesize that all classes of antidepressants could have common final effects on limbic circuitry. Whereas NMDA receptor blockade may induce a high powered gamma oscillatory state via direct and fast alteration of glutamatergic systems in mood-related circuits, neuromodulatory antidepressants may induce similar effects over slower timescales, corresponding with the timecourse of response in patients, while resetting synaptic excitatory versus inhibitory signaling to a normal level. Thus, gamma signaling may provide a biomarker (or “neural readout”) of the therapeutic effects of all classes of antidepressants.

Folate Augmentation of Treatment--Evaluation for Depression (FolATED): randomised trial and economic evaluation

BACKGROUND

Folate deficiency is associated with depression. Despite the biological plausibility of a causal link, the evidence that adding folate enhances antidepressant treatment is weak.

OBJECTIVES

(1) Estimate the clinical effectiveness and cost-effectiveness of folic acid as adjunct to antidepressant medication (ADM). (2) Explore whether baseline folate and homocysteine predict response to treatment. (3) Investigate whether response to treatment depends on genetic polymorphisms related to folate metabolism.

DESIGN

FolATED (Folate Augmentation of Treatment - Evaluation for Depression) was a double-blind and placebo-controlled, but otherwise pragmatic, randomised trial including cost-utility analysis. To yield 80% power of detecting standardised difference on the Beck Depression Inventory version 2 (BDI-II) of 0.3 between groups (a 'small' effect), FolATED trialists sought to analyse 358 participants. To allow for an estimated loss of 21% of participants over three time points, we planned to randomise 453.

SETTINGS

Clinical - Three centres in Wales - North East Wales, North West Wales and Swansea. Trial management - North Wales Organisation for Randomised Trials in Health in Bangor University. Biochemical analysis - University Hospital of Wales, Cardiff. Genetic analysis - University of Liverpool.

PARTICIPANTS

Four hundred and seventy-five adult patients presenting to primary or secondary care with confirmed moderate to severe depression for which they were taking or about to start ADM, and able to consent and complete assessments, but not (1) folate deficient, vitamin B12 deficient, or taking folic acid or anticonvulsants; (2) misusing drugs or alcohol, or suffering from psychosis, bipolar disorder, malignancy or other unstable or terminal illness; (3) (planning to become) pregnant; or (4) participating in other clinical research.

INTERVENTIONS

Once a day for 12 weeks experimental participants added 5 mg of folic acid to their ADM, and control participants added an indistinguishable placebo. All participants followed pragmatic management plans initiated by a trial psychiatrist and maintained by their general medical practitioners.

MAIN OUTCOME MEASURES

Assessed at baseline, and 4, 12 and 25 weeks thereafter, and analysed by 'area under curve' (main); by analysis of covariance at each time point (secondary); and by multi-level repeated measures (sensitivity analysis): Mental health - BDI-II (primary), Clinical Global Impression (CGI), Montgomery-Åsberg Depression Rating Scale (MADRS), UKU side effects scale, and Mini International Neuropsychiatric Interview (MINI) suicidality subscale; General health - UK 12-item Short Form Health Survey (SF-12), European Quality of Life scale - 5 Dimensions (EQ-5D); Biochemistry - serum folate, B12, homocysteine; Adherence - Morisky Questionnaire; Economics - resource use.

RESULTS

Folic acid did not significantly improve any of these measures. For example it gained a mean of just 2.9 quality-adjusted life-days [95% confidence interval (CI) from -12.7 to 7.0 days] and saved a mean of just £48 (95% CI from -£292 to £389). In contrast it significantly reduced mental health scores on the SF-12 by 3.0% (95% CI from -5.2% to -0.8%).

CONCLUSIONS

The FolATED trial generated no evidence that folic acid was clinically effective or cost-effective in augmenting ADM. This negative finding is consistent with improving understanding of the one-carbon folate pathway suggesting that methylfolate is a better candidate for augmenting ADM. Hence the findings of FolATED undermine treatment guidelines that advocate folic acid for treating depression, and suggest future trials of methylfolate to augment ADM.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN37558856.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 18, No. 48. See the HTA programme website for further project information.

Predicting treatment response in major depressive disorder: the impact of early symptomatic improvement

OBJECTIVE

Antidepressants (ADs) are the mainstay of treatment for major depressive disorder (MDD). Despite their widespread usage, a consensus does not exist as to the timing of clinically significant symptomatic improvement during an AD trial. The objective of this review is to provide practitioners with empirically based recommendations pertaining to the optimal duration of index (initial) AD therapy before a clinical intervention is warranted.

METHODS

We conducted a nonsystematic review, using a combination of a MeSH key word search, Google Scholar, and the Scopus database. Our search strategy focused on research papers reporting on the early symptomatic response to AD therapy.

RESULTS

Available evidence suggests that there are several subpopulations that exist within whole-group data assigned to an AD treatment. Among the responder subgroups, an early responder group (that is, less than 3 weeks) and later responder group (that is, 3 weeks or more) are identified. People who exhibit early partial symptomatic improvement are more likely to respond to therapy thereafter. However, the interpretability of extant evidence is complicated by the use of disparate statistical approaches with differing computational complexity and sample heterogeneity.

CONCLUSIONS

Response outcomes in MDD are heterogeneous. Available data suggest that people may respond early, late, and (or) continuously over time, and may represent distinct subpopulations that provide a proximate indication for treatment response outcomes. Notwithstanding, a pragmatic recommendation would be to consider a treatment intervention (for example, dosage optimization and [or] augmentation) if, after 3 to 4 weeks, symptomatic improvement is insufficient.

The Timing of Antidepressant Effects: A Comparison of Diverse Pharmacological and Somatic Treatments

Currently available antidepressants used to treat major depressive disorder (MDD) unfortunately often take weeks to months to achieve their full effects, commonly resulting in considerable morbidity and increased risk for suicidal behavior. Our lack of understanding of the precise cellular underpinnings of this illness and of the mechanism of action of existing effective pharmacological treatments is a large part of the reason that therapies with a more rapid onset of antidepressant action (ROAA) have not been developed. Other issues that need to be addressed include heterogeneous clinical concepts and statistical models to measure rapid antidepressant effects. This review describes the timing of onset of antidepressant effects for various therapies used to treat MDD. While several agents produce earlier improvement of depressive symptoms (defined as occurring within one week), the response rate associated with such agents can be quite variable. These agents include both currently available antidepressants as well as other pharmacological and non-pharmacological interventions. Considerably fewer treatments are associated with ROAA, defined as occurring within several hours or one day. Treatment strategies for MDD whose sustained antidepressant effects manifest within hours or even a few days would have an enormous impact on public health.

Rapid onset of antidepressant action: a new paradigm in the research and treatment of major depressive disorder

OBJECTIVE

Current therapeutics of depression are similar in their time to antidepressant action and often take weeks to months to achieve response and remission, which commonly results in considerable morbidity and disruption in personal, professional, family, and social life, as well as risk for suicidal behavior. Thus, treatment strategies presenting a rapid improvement of depressive symptoms--within hours or even a few days--and whose effects are sustained would have an enormous impact on public health. This article reviews the published data related to different aspects of rapid improvement of depressive symptoms.

DATA SOURCES

Literature for this review was obtained through a search of the MEDLINE database (1966-2007) using the following keywords and phrases: rapid response, antidepressant, time to, glutamate, sleep, therapeutics, latency, and depression. The data obtained were organized according to the following topics: clinical relevance and time course of antidepressant action, interventions showing evidence of rapid response and its potential neurobiological basis, and new technologies for better understanding rapid anti-depressant actions.

DATA SYNTHESIS

A limited number of prospective studies evaluating rapid antidepressant actions have been conducted. Currently, only a few interventions have been shown to produce antidepressant response in hours or a few days. The neurobiological basis of these rapid antidepressant actions is only now being deciphered.

CONCLUSIONS

Certain experimental treatments can produce antidepressant response in a much shorter period of time than existing medications. Understanding the molecular basis of these experimental interventions is likely to lead to the development of improved therapeutics rather than simply furthering our knowledge of current standard antidepressants.

Limitations of current medical treatments for depression: disturbed circadian rhythms as a possible therapeutic target

The proportion of diagnosed depressives prescribed antidepressants has increased markedly over the last 20 years, mainly following the introduction of the selective serotonin reuptake inhibitors. However, currently available antidepressants have notable limitations, relating to their only moderate efficacy relative to placebo, relatively slow onset of action, possible withdrawal symptoms, and problems of compliance. Sleep disturbances are often used to identify newly presenting depressive patients, and may be part of a more general alteration of bodily rhythms. There are links between pharmacological treatments and circadian rhythms in depression, which might represent another, new option for the development of a therapeutic approach to depression treatment. Many antidepressants affect sleep, some are sedative, and others have been used specifically in severely insomniac depressives. Disturbances in circadian rhythms may be an integral part of depressive mechanisms, and normalising them via an innovative mechanism of antidepressant action may be a fruitful avenue in the search for improved antidepressant agents.

Folate augmentation of treatment - evaluation for depression (FolATED): protocol of a randomised controlled trial

BACKGROUND

Clinical depression is common, debilitating and treatable; one in four people experience it during their lives. The majority of sufferers are treated in primary care and only half respond well to active treatment. Evidence suggests that folate may be a useful adjunct to antidepressant treatment: 1) patients with depression often have a functional folate deficiency; 2) the severity of such deficiency, indicated by elevated homocysteine, correlates with depression severity, 3) low folate is associated with poor antidepressant response, and 4) folate is required for the synthesis of neurotransmitters implicated in the pathogenesis and treatment of depression.

METHODS/DESIGN

The primary objective of this trial is to estimate the effect of folate augmentation in new or continuing treatment of depressive disorder in primary and secondary care. Secondary objectives are to evaluate the cost-effectiveness of folate augmentation of antidepressant treatment, investigate how the response to antidepressant treatment depends on genetic polymorphisms relevant to folate metabolism and antidepressant response, and explore whether baseline folate status can predict response to antidepressant treatment. Seven hundred and thirty patients will be recruited from North East Wales, North West Wales and Swansea. Patients with moderate to severe depression will be referred to the trial by their GP or Psychiatrist. If patients consent they will be assessed for eligibility and baseline measures will be undertaken. Blood samples will be taken to exclude patients with folate and B12 deficiency. Some of the blood taken will be used to measure homocysteine levels and for genetic analysis (with additional consent). Eligible participants will be randomised to receive 5 mg of folic acid or placebo. Patients with B12 deficiency or folate deficiency will be given appropriate treatment and will be monitored in the 'comprehensive cohort study'. Assessments will be at screening, randomisation and 3 subsequent follow-ups.

DISCUSSION

If folic acid is shown to improve the efficacy of antidepressants, then it will provide a safe, simple and cheap way of improving the treatment of depression in primary and secondary care.

TRIAL REGISTRATION

Current controlled trials ISRCTN37558856.

Two-week delay in onset of action of antidepressants: new evidence

Many sources purport that antidepressants have a delayed onset of action, measured in weeks rather than days. Recent data using weekly or daily mood ratings demonstrate that maximum improvement occurs during the first 2 weeks, with some improvement within the first 3 days. Methodological issues may underlie the delayed-onset hypothesis.

Time Course of Response to Antidepressants in Late-Life Major Depression

In the treatment of depression, there is considerable interest in the time course of response and, in particular, the speed with which individuals recover from depressive episodes. Examination of the time course and speed of response is critical for assessing the usefulness of specific treatments. However, while this issue has received attention in mid-life adult populations, it has received little consideration in the context of late-life major depression. The synthesis of empirical reports indicates that, while older adults with depression seem to respond with the same speed as mid-life adults, several factors have consistently been associated with reduced speed of response to antidepressant treatment, including greater severity of depressive symptoms and co-occurring anxiety symptoms. Limited evidence suggests that sleep impairment and genetic factors (e.g. presence of the s allele of the serotonin transporter gene promoter region) may also be associated with reduced speed of response. Some factors have consistently been found to be unrelated to speed of response (demographic characteristics, nonpsychiatric physical illnesses) whereas other factors have only mixed evidence supporting any effect (psychosocial and other clinical factors). While there is little work available to date, some evidence suggests that time course and speed of response affect longer-term outcomes of depression pharmacotherapy; thus, older adults with more rapid versus slower patterns of response may differ in the types of maintenance treatment needed to avert additional depressive episodes. None of potential strategies for accelerating speed of response have been clearly shown to be effective in late-life depression. Future treatment studies for late-life depression should routinely consider not only overall efficacy of a given pharmacotherapy (i.e. total rate of response), but time course and speed of response. To this end, new investigations must be designed to overcome the methodological limitations of prior studies that have examined time course and they should include a range of potential covariates and outcomes of between-patient differences in speed of response. Better understanding of factors related to such differences may suggest new intervention strategies to accelerate response.