Rethinking depression and the actions of antidepressants: uncovering the links between the neural and behavioral elements

Baseline anxiety, and early anxiety/depression improvement in anxious depression predicts treatment outcomes with escitalopram: A CAN-BIND-1 study report

INTRODUCTION

Although anxiety symptoms frequently co-occur with major depressive disorder, few studies examined the prediction of treatment outcomes among participants with anxious depression receiving antidepressants. We investigated whether baseline anxiety, and early improvements in anxiety and depression symptoms predict eventual treatment outcomes.

METHODS

111 participants with anxious depression, defined using ≥ 10 on GAD-7, received escitalopram (10-20 mg) for 8 weeks. Covariate-adjusted logistic regression was conducted to examine the impact of baseline anxiety, and to assess the extent week 2 anxiety (GAD-7) and depression (QIDS-SR) percentage improvement associates with week 8 anxiety (GAD-7) and depression (MADRS) response/remission. Optimum improvement thresholds were identified using receiving-operating-curve analysis and their predictive values assessed.

RESULTS

Greater percentage improvement in anxiety and depression after the first 2 weeks of treatment significantly increased odds of achieving week 8 anxiety and depression response/remission (OR:1.01-1.04, p<0.05). Early anxiety (68.4%/87.2%) and depression (52.2%/83.0%) improvement thresholds around 30 and 40% provided moderate to high positive predictive value (PPV) for predicting week 8 anxiety response/remission, as well as moderate to high negative predictive value (NPV) for predicting week 8 depression response/remission (anxiety:70.8%/91.7%; depression:72.2%/90.1%). Baseline anxiety severity predicted anxiety outcomes at weeks 2 and 8.

LIMITATIONS

Trial lacked placebo group.

CONCLUSION

In anxious depression, early improvement in anxiety may be better than depression in predicting anxiety outcomes, with similar or higher PPVs. Both improvement types perform similarly in predicting depression outcomes, with the lack of improvement predictive of non-response and non-remission. Finally, baseline anxiety predicts eventual anxiety but not depression outcomes.

Mixed States: Historical Impact and Evolution of the Concept

Mixed states have been discussed for more than 2 millennia. The theoretic conception of the coexistence of presumably opposite symptoms of mood or of different psychic domains is well established, although obscured by the presumed separation between bipolar and depressive disorders. Moreover, the lack of response to treatments and severe psychopathology raise important issues requiring urgent solution. The aim of this article was to review the development of the concept of mixed states from the classic literature to modern nosologic systems and to claim for the need of a new paradigm to address the still-open issues about mixed states.

Activation of a ventral hippocampus-medial prefrontal cortex pathway is both necessary and sufficient for an antidepressant response to ketamine

A single sub-anesthetic dose of ketamine exerts rapid and sustained antidepressant effects. Here, we examined the role of the ventral hippocampus (vHipp)-medial prefrontal cortex (mPFC) pathway in ketamine's antidepressant response. Inactivation of the vHipp with lidocaine prevented the sustained, but not acute, antidepressant-like effect of ketamine as measured by the forced swim test (FST). Moreover, optogenetic as well as pharmacogenetic specific activation of the vHipp-mPFC pathway using DREADDs (designer receptors exclusively activated by designer drugs) mimicked the antidepressant-like response to ketamine; importantly, this was pathway specific, in that activation of a vHipp to nucleus accumbens circuit did not do this. Furthermore, optogenetic inactivation of the vHipp/mPFC pathway at the time of FST completely reversed ketamine's antidepressant response. In addition, we found that a transient increase in TrkB receptor phosphorylation in the vHipp contributes to ketamine's sustained antidepressant response. These data demonstrate that activity in the vHipp-mPFC pathway is both necessary and sufficient for the antidepressant-like effect of ketamine.

Neural Implications of Psychotherapy, Pharmacotherapy, and Combined Treatment in Major Depressive Disorder

Numerous clinical trials have been conducted to determine the utility of antidepressant treatment (ADT), psychotherapy, and combined psycho-pharmaco-psychotherapy (PPPT) in treating major depressive disorder (MDD). While all approaches have shown benefit over placebo to varying degrees, the parallel neurophysiological mechanisms that underlie their efficacy have received little attention. The authors will review and discuss a growing body of literature that relates the factors of treatment selection and response to the principles of neuromodulation, with emphasis regarding how neuroimaging and other experimental data reinforce the need for personalized MDD treatment. This manuscript and its theoretical approaches were supported by conducting relevant literature searches of MEDLINE and PubMed electronic databases, prioritizing systemic reviews, and randomized clinical trials using selected MeSH terms. The authors conclude that ADT, psychotherapy, and PPPT all create potentially observable neurofunctional changes and argue that additive and synergistic potentiation of these effects in PPPT may produce more sustained symptom relief than with monotherapy alone.

Hamilton depression rating subscales to predict antidepressant treatment outcome in the early course of treatment

BACKGROUND

Hamilton depression rating scale (HAMD) subscales provide an economic alternative for the full scale; however, their ability to detect onset of improvement in the early course of treatment (EI) has not yet been researched. The present study investigated in patients with major depression (MD) whether the subscales are a comparable option to predict treatment remission in the early course of treatment.

METHODS

Based on data from 210 MD patients of a 6-week randomised, placebo-controlled trial comparing mirtazapine (MIR) and paroxetine (PAR), the discriminative and predictive validity of EI for (stable) remission at treatment end was evaluated for seven subscales and the HAMD17 in the total and in treatment subgroups (MIR vs. PAR). Receiver operating characteristics (ROC) curves (at week 2) and the Clinical Global Impression scales (CGI) (at study endpoint) were used to validate the 20% EI criterion for the subscales.

RESULTS

Only the Evans6 and Toronto7 subscale had almost the same predictive value as the HAMD17 (e.g., sensitivities stable remission Evans6/Toronto7: 96/95% vs. 96% HAMD17). The optimal cut-off for EI to predict remission was just below 20% for most subscales and slightly over 20% for stable remission.

LIMITATIONS

Study sample representativeness, non-independence of subscales, missing external validation criterion, lack of control group.

CONCLUSIONS

The Evans6 and Toronto7 subscales are valuable alternatives in situations, where economic aspects play a larger role. A sum score reduction of ≥20% as definition for EI seems also appropriate for the HAMD subscales, in the total as well as in the antidepressant subgroups.

Agomelatine in the treatment of depressive disorders in clinical practice: multicenter observational CHRONOS study

BACKGROUND

CHRONOS was a large naturalistic study designed to evaluate the effectiveness and safety of agomelatine in the management of patients with major depression in routine clinical practice.

METHODS

Patients (n=6,276) with a moderate or severe major depressive episode without psychotic symptoms were treated initially as outpatients (80.2%) or in psychiatric facilities (19.8%) in 54 regions of the Russian Federation. Patients received a flexible-dosing regimen of agomelatine 25 mg or 50 mg once daily for 8 weeks, with frequent study visits (weeks 1, 2, 3, 4, 6, and 8).

RESULTS

Patients (mean age 44 years, 72.6% female) showed progressive improvement on the 17-item Hamilton Rating Scale for Depression (HAMD-17) total score from 22±6.9 at baseline to 4.7±4.7 at week 8 (P<0.0001). The proportion of responders (HAMD-17 decrease of ≥50%) was 90.1% and the proportion of remitters (HAMD-17 <7) was 79.1% at week 8. All individual HAMD-17 item scores improved rapidly, and the change relative to baseline was significant (P<0.0001) at week 1 and at each subsequent visit in all cases. There were corresponding rapid improvements in Clinical Global Impression Severity and Improvement scores. In the subgroup of patients with more severe illness (HAMD-17 ≥21 at baseline; n=3,478), the proportions of responders and remitters were 92.4% and 72.8%, respectively, at week 8.

CONCLUSION

Agomelatine was effective and well tolerated in a large sample of depressed patients in an observational treatment setting, and showed a rapid onset of benefit across all HAMD-17 items.

Activated depression: mixed bipolar disorder or agitated unipolar depression?

The combination of depression and activation presents clinical and diagnostic challenges. It can occur, in either bipolar disorder or major depressive disorder, as increased agitation as a dimension of depression. What is called agitation can consist of expressions of painful inner tension or as disinhibited goal-directed behavior and thought. In bipolar disorder, elements of depression can be combined with those of mania. In this case, the agitation, in addition to increased motor activity and painful inner tension, must include symptoms of mania that are related to goal-directed behavior or manic cognition. These diagnostic considerations are important, as activated depression potentially carries increased behavioral risk, especially for suicidal behavior, and optimal treatments for depressive episodes differ between bipolar disorder and major depressive disorder.

Pharmacometabolomics of response to sertraline and to placebo in major depressive disorder - possible role for methoxyindole pathway

Therapeutic response to selective serotonin (5-HT) reuptake inhibitors in Major Depressive Disorder (MDD) varies considerably among patients, and the onset of antidepressant therapeutic action is delayed until after 2 to 4 weeks of treatment. The objective of this study was to analyze changes within methoxyindole and kynurenine (KYN) branches of tryptophan pathway to determine whether differential regulation within these branches may contribute to mechanism of variation in response to treatment. Metabolomics approach was used to characterize early biochemical changes in tryptophan pathway and correlated biochemical changes with treatment outcome. Outpatients with MDD were randomly assigned to sertraline (n = 35) or placebo (n = 40) in a double-blind 4-week trial; response to treatment was measured using the 17-item Hamilton Rating Scale for Depression (HAMD₁₇). Targeted electrochemistry based metabolomic platform (LCECA) was used to profile serum samples from MDD patients. The response rate was slightly higher for sertraline than for placebo (21/35 [60%] vs. 20/40 [50%], respectively, χ²(1)  = 0.75, p = 0.39). Patients showing a good response to sertraline had higher pretreatment levels of 5-methoxytryptamine (5-MTPM), greater reduction in 5-MTPM levels after treatment, an increase in 5-Methoxytryptophol (5-MTPOL) and Melatonin (MEL) levels, and decreases in the (KYN)/MEL and 3-Hydroxykynurenine (3-OHKY)/MEL ratios post-treatment compared to pretreatment. These changes were not seen in the patients showing poor response to sertraline. In the placebo group, more favorable treatment outcome was associated with increases in 5-MTPOL and MEL levels and significant decreases in the KYN/MEL and 3-OHKY/MEL; changes in 5-MTPM levels were not associated with the 4-week response. These results suggest that recovery from a depressed state due to treatment with drug or with placebo could be associated with preferential utilization of serotonin for production of melatonin and 5-MTPOL.

Pharmacometabolomic mapping of early biochemical changes induced by sertraline and placebo

In this study, we characterized early biochemical changes associated with sertraline and placebo administration and changes associated with a reduction in depressive symptoms in patients with major depressive disorder (MDD). MDD patients received sertraline or placebo in a double-blind 4-week trial; baseline, 1 week, and 4 weeks serum samples were profiled using a gas chromatography time of flight mass spectrometry metabolomics platform. Intermediates of TCA and urea cycles, fatty acids and intermediates of lipid biosynthesis, amino acids, sugars and gut-derived metabolites were changed after 1 and 4 weeks of treatment. Some of the changes were common to the sertraline- and placebo-treated groups. Changes after 4 weeks of treatment in both groups were more extensive. Pathway analysis in the sertraline group suggested an effect of drug on ABC and solute transporters, fatty acid receptors and transporters, G signaling molecules and regulation of lipid metabolism. Correlation between biochemical changes and treatment outcomes in the sertraline group suggested a strong association with changes in levels of branched chain amino acids (BCAAs), lower BCAAs levels correlated with better treatment outcomes; pathway analysis in this group revealed that methionine and tyrosine correlated with BCAAs. Lower levels of lactic acid, higher levels of TCA/urea cycle intermediates, and 3-hydroxybutanoic acid correlated with better treatment outcomes in placebo group. Results of this study indicate that biochemical changes induced by drug continue to evolve over 4 weeks of treatment and that might explain partially delayed response. Response to drug and response to placebo share common pathways but some pathways are more affected by drug treatment. BCAAs seem to be implicated in mechanisms of recovery from a depressed state following sertraline treatment.

Time matters: pathological effects of repeated psychosocial stress during the active, but not inactive, phase of male mice

Recent findings in rats indicated that the physiological consequences of repeated restraint stress are dependent on the time of day of stressor exposure. To investigate whether this is also true for clinically more relevant psychosocial stressors and whether repeated stressor exposure during the light phase or dark phase is more detrimental for an organism, we exposed male C57BL/6 mice to social defeat (SD) across 19 days either in the light phase between Zeitgeber time (ZT)1 and ZT3 (SDL mice) or in the dark phase between ZT13 and ZT15 (SDD mice). While SDL mice showed a prolonged increase in adrenal weight and an attenuated adrenal responsiveness to ACTH in vitro after stressor termination, SDD mice showed reduced dark phase home-cage activity on observation days 7, 14, and 20, flattening of the diurnal corticosterone rhythm, lack of social preference, and higher in vitro IFNγ secretion from mesenteric lymph node cells on day 20/21. Furthermore, the colitis-aggravating effect of SD was more pronounced in SDD than SDL mice following dextran sulfate sodium treatment. In conclusion, the present findings demonstrate that repeated SD effects on behavior, physiology, and immunology strongly depend on the time of day of stressor exposure. Whereas physiological parameters were more affected by SD during the light/inactive phase of mice, behavioral and immunological parameters were more affected by SD during the dark phase. Our results imply that repeated daily SD exposure has a more negative outcome when applied during the dark/active phase. By contrast, the minor physiological changes seen in SDL mice might represent beneficial adaptations preventing the formation of those maladaptive consequences.

Circadian dimension and severity of depression

The cyclic nature of depressive illness, disturbance of diurnal mood variations, and disturbed sleep-wake and physiological rhythms all suggest that dysfunction of the circadian time-keeping system may underlie the pathophysiology of depression. Circadian misalignment of the phase-delayed type appears to be the most common shift in unipolar disorder patients and misalignment between the timing of sleep and the pacemaker is correlated with depressive symptom severity. Profiles of diurnal mood variation are associated with risks of depression severity and may predict response to treatments. As circadian disturbances are at the core of depression, normalizing circadian rhythm may be a fruitful avenue for new therapeutic targets in depression. The innovative antidepressant agomelatine possesses resynchronizing properties that may be related to its original profile and offers an opportunity to achieve our goals in treating depressed people.

Onset, time course and trajectories of improvement with antidepressants

There is still considerable controversy about the onset and time course of improvement with antidepressants in the treatment of major depressive disorder. Previous studies suggested a delayed-onset hypothesis with therapeutic improvement taking several weeks, but recent meta-analyses have shown support for earlier onset of improvement within the first week or two of treatment. This paper briefly reviews the evidence, focused on antidepressant studies published since 2006, for early onset of improvement within the first 2 weeks of treatment. A PubMed electronic search was conducted with selection of relevant studies from 2007 to March 2012. With the caveat of methodological limitations, results from randomized clinical trials, meta-analyses and naturalistic studies consistently show that: (1) antidepressants in general have early onset of improvement, (2) some antidepressants, including the novel mechanism agent, agomelatine, are associated with early improvement in both core and specific symptoms such as anhedonia and sleep-wake disturbances, and (3) early improvement predicts sustained response and remission. Use of newer statistical methods to examine individual response trajectories may address some of the methodological limitations of previous studies. The predictive value of early improvement has important clinical relevance for antidepressant treatment. Measurement-based assessment for response should occur earlier and more frequently. A lack of improvement (defined as ≤20% reduction from baseline in scores on a depression rating scale) at 2-3 weeks after initiation of an antidepressant should prompt the clinician to consider a change in management.

General and comparative efficacy and effectiveness of antidepressants in the acute treatment of depressive disorders: a report by the WPA section of pharmacopsychiatry

Current gold standard approaches to the treatment of depression include pharmacotherapeutic and psychotherapeutic interventions with social support. Due to current controversies concerning the efficacy of antidepressants in randomized controlled trials, the generalizability of study findings to wider clinical practice and the increasing importance of socioeconomic considerations, it seems timely to address the uncertainty of concerned patients and relatives, and their treating psychiatrists and general practitioners. We therefore discuss both the efficacy and clinical effectiveness of antidepressants in the treatment of depressive disorders. We explain and clarify useful measures for assessing clinically meaningful antidepressant treatment effects and the types of studies that are useful for addressing uncertainties. This includes considerations of methodological issues in randomized controlled studies, meta-analyses, and effectiveness studies. Furthermore, we summarize the differential efficacy and effectiveness of antidepressants with distinct pharmacodynamic properties, and differences between studies using antidepressants and/or psychotherapy. We also address the differential effectiveness of antidepressant drugs with differing modes of action and in varying subtypes of depressive disorder. After highlighting the clinical usefulness of treatment algorithms and the divergent biological, psychological, and clinical efforts to predict the effectiveness of antidepressant treatments, we conclude that the spectrum of different antidepressant treatments has broadened over the last few decades. The efficacy and clinical effectiveness of antidepressants is statistically significant, clinically relevant, and proven repeatedly. Further optimization of treatment can be helped by clearly structured treatment algorithms and the implementation of psychotherapeutic interventions. Modern individualized antidepressant treatment is in most cases a well-tolerated and efficacious approach to minimize the negative impact of otherwise potentially devastating and life-threatening outcomes in depressive disorders.

Agomelatine: a narrative review

Long-term antidepressant treatment success should be viewed as the result of the cumulative effects of treatment at each stage of major depressive disorder (MDD), and as a balance between efficacy and tolerability/safety. Depression is a heterogeneous disorder and different mechanisms of action of different antidepressants probably capitalize on this response heterogeneity. Results from clinical trials with agomelatine, a melatonergic receptor agonist (MT(1)/MT(2)) and 5HT(2C) receptor antagonist, have shown that it is efficacious in both the acute phase and the continuation phase of treatment of depression. Agomelatine's efficacy is observed in different depressive symptom clusters (core depression symptoms, sleep symptoms, anxiety, retardation, somatic symptoms, and work and activities). Active comparator trials show at least comparable efficacy with other antidepressants (paroxetine, venlafaxine, sertraline, fluoxetine) and efficacy has also been demonstrated in severe depression and in treating anxiety symptoms associated with major depression. The tolerability profile shows some clinically significant advantages especially in the lower incidence of treatment emergent sexual dysfunction and of weight gain, two adverse events experienced by patients as most bothersome. Transient aminotransferase elevations without clinical signs of liver damage have been observed more frequently than with placebo (1.1% versus 0.7%), and a hepatic monitoring schedule is therefore recommended.

Pretreatment metabotype as a predictor of response to sertraline or placebo in depressed outpatients: a proof of concept

The purpose of this study was to determine whether the baseline metabolic profile (that is, metabotype) of a patient with major depressive disorder (MDD) would define how an individual will respond to treatment. Outpatients with MDD were randomly assigned to sertraline (up to 150 mg per day) (N=43) or placebo (N=46) in a double-blind 4-week trial. Baseline serum samples were profiled using the liquid chromatography electrochemical array; the output was digitized to create a 'digital map' of the entire measurable response for a particular sample. Response was defined as ≥50% reduction baseline to week 4 in the 17-item Hamilton Rating Scale for Depression total score. Models were built using the one-out method for cross-validation. Multivariate analyses showed that metabolic profiles partially separated responders and non-responders to sertraline or to placebo. For the sertraline models, the overall correct classification rate was 81% whereas it was 72% for the placebo models. Several pathways were implicated in separation of responders and non-responders on sertraline and on placebo including phenylalanine, tryptophan, purine and tocopherol. Dihydroxyphenylacetic acid, tocopherols and serotonin were common metabolites in separating responders and non-responders to both drug and placebo. Pretreatment metabotypes may predict which depressed patients will respond to acute treatment (4 weeks) with sertraline or placebo. Some pathways were informative for both treatments whereas other pathways were unique in predicting response to either sertraline or placebo. Metabolomics may inform the biochemical basis for the early efficacy of sertraline.

Inflammation, sanitation, and consternation: loss of contact with coevolved, tolerogenic microorganisms and the pathophysiology and treatment of major depression

CONTEXT

Inflammation is increasingly recognized as contributing to the pathogenesis of major depressive disorder (MDD), even in individuals who are otherwise medically healthy. Most studies in search of sources for this increased inflammation have focused on factors such as psychosocial stress and obesity that are known to activate inflammatory processes and increase the risk for depression. However, MDD may be so prevalent in the modern world not just because proinflammatory factors are widespread, but also because we have lost contact with previously available sources of anti-inflammatory, immunoregulatory signaling.

OBJECTIVE

To examine evidence that disruptions in coevolved relationships with a variety of tolerogenic microorganisms that were previously ubiquitous in soil, food, and the gut, but that are largely missing from industrialized societies, may contribute to increasing rates of MDD in the modern world.

DATA SOURCES

Relevant studies were identified using PubMed and Ovid MEDLINE.

STUDY SELECTION

Included were laboratory animal and human studies relevant to immune functioning, the hygiene hypothesis, and major depressive disorder identified via PubMed and Ovid MEDLINE searches.

DATA EXTRACTION

Studies were reviewed by all authors, and data considered to be potentially relevant to the contribution of hygiene-related immune variables to major depressive disorder were extracted.

DATA SYNTHESIS

Significant data suggest that a variety of microorganisms (frequently referred to as the "old friends") were tasked by coevolutionary processes with training the human immune system to tolerate a wide array of non-threatening but potentially proinflammatory stimuli. Lacking such immune training, vulnerable individuals in the modern world are at significantly increased risk of mounting inappropriate inflammatory attacks on harmless environmental antigens (leading to asthma), benign food contents and commensals in the gut (leading to inflammatory bowel disease), or self-antigens (leading to any of a host of autoimmune diseases). Loss of exposure to the old friends may promote MDD by increasing background levels of depressogenic cytokines and may predispose vulnerable individuals in industrialized societies to mount inappropriately aggressive inflammatory responses to psychosocial stressors, again leading to increased rates of depression.

CONCLUSION

Measured exposure to the old friends or their antigens may offer promise for the prevention and treatment of MDD in modern industrialized societies.

The noradrenergic action in antidepressant treatments: pharmacological and clinical aspects

Even though noradrenaline has been recognized as one of the key neurotransmitters in the pathophysiology of major depression (MD), noradrenergic compounds have been less extensively utilized in clinical practice, compared to selective serotonin reuptake inhibitors (SSRIs). The development of the first selective noradrenergic reuptake inhibitor (NRI), Reboxetine, has not substantially changed the state of the art. In addition, Atomoxetine, a relatively pure NRI used for the treatment of ADHD, has shown mixed results when administered in augmentation to depressed subjects. Through a Medline search from 2000 to 2010, the present article provides an updated overview of the main pharmacological and clinical aspects of antidepressant classes that, partially or selectively, act on the noradrenergic systems. The noradrenergic action plays an important clinical effect in different antidepressant classes, as confirmed by the efficacy of dual action antidepressants such as the serotonin noradrenaline reuptake inhibitors (SNRIs), the noradrenergic and dopaminergic reuptake inhibitor (NDRI) Bupropion, and other compounds (e.g., Mianserin, Mirtazapine), which enhance the noradrenergic transmission. In addition, many tricyclics, such as Desipramine and Nortriptyline, have prevalent noradrenergic effect. Monoamine oxidase inhibitors (MAOIs), moreover, block the breakdown of serotonin, noradrenaline, dopamine and increase the availability of these monoamines. A novel class of antidepressants--the triple reuptake inhibitors--is under development to selectively act on serotonin, noradrenaline, and dopamine. Finally, the antidepressant effect of the atypical antipsychotic Quetiapine, indicated for the treatment of bipolar depression, is likely to be related to the noradrenergic action of its metabolite Norquetiapine. Even though a pure noradrenergic action might not be sufficient to obtain a full antidepressant effect, a pronoradrenergic action represents an important element for increasing the efficacy of mixed action antidepressants. In particular, the noradrenergic action seemed to be related to the motor activity, attention, and arousal.

Stuck in a rut: rethinking depression and its treatment

The current definition of major depressive disorder (MDD) emerged from efforts to create reliable diagnostic criteria for clinical and research use. However, despite decades of research, the neurobiology of MDD is largely unknown, and treatments are no more effective today than they were 50-70 years ago. Here, we propose that the current conception of depression is misguiding basic and clinical research. Redefinition is necessary and could include a focus on a more narrowly defined set of core symptoms. However, we conclude that depression is better defined as the tendency to enter into, and inability to disengage from, a negative mood state rather than the mood state per se. We also discuss the implications of this revised definition for future clinical and basic research.

Increased sensitivity for angry faces in depressive disorder following 2 weeks of 2-Hz repetitive transcranial magnetic stimulation to the right parietal cortex

According to the cognitive neuropsychological hypothesis of antidepressant action, the onset of subjectively experienced therapeutic effects to treatment is preceded by favourable changes in psychological functioning that can be measured by implicit methods. The aim of this study was to examine additional data to explore this hypothesis in an intention-to-treat repetitive transcranial magnetic stimulation (rTMS) study targeting the right parietal cortex. Changes in depression scores from baseline and the sensitivity for recognizing emotional facial expressions were studied in 28 patients with depressive disorder receiving ten sessions of real (n=14) or sham (n=14) rTMS treatments in a double-blind, sham-controlled design. In the patient group results showed significantly higher sensitivity for recognizing angry facial expressions in response to receiving real compared to receiving sham rTMS treatment. Overall mood improvement was similar across real and sham rTMS treatments. However, the sensitivity for recognizing angry facial expressions was correlated to the percentage decrease in depression scores. These results provide the first preliminary support for the cognitive neuropsychological hypothesis of antidepressant action in rTMS treatment.

The importance of early symptom relief in antidepressant treatment: focus on agomelatine

Antidepressants were traditionally considered to have delayed onset of action, and clinical opinion often stated that patients may not experience noticeable improvement for 4-6 weeks. Recent studies have shown, however, that antidepressants have more rapid onset of effect, within 1-2 weeks, and that this early response may be associated with later sustained response. Moreover, there is emerging evidence that some medications may have faster onset of therapeutic effect than others. The new antidepressant agomelatine, with its novel pharmacological profile as an agonist at melatonergic (MT(1) and MT(2)) receptors and antagonist at 5-HT(2C) receptors, has in several studies produced earlier symptom improvement than comparator selective serotonin reuptake inhibitors and serotonin-noradrenaline reuptake inhibitors. In particular, beneficial effects on sleep and daytime functioning are noticeable as early as the first week of treatment. These therapeutic benefits may, in part, be related to its regulatory effects on circadian and sleep- wake cycles. Agomelatine therefore combines early symptom relief with a favorable side-effect profile and short-term and long-term antidepressant efficacy. These properties suggest that agomelatine can be considered a first-line treatment for patients with major depression.

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.