Effectiveness of pindolol plus serotonin uptake inhibitors in depression: a meta-analysis of early and late outcomes from randomised controlled trials

Treatment resistant depression in elderly

Treatment refractory depression (TRD) in the elderly is a common psychiatric disorder with high comorbidity and mortality. Older adults with TRD often have complicated comorbidities and several predisposing risk factors, which may lead to neuropsychiatric dysfunction and poor response to treatment. Several hypotheses suggest the underlying mechanisms, including vascular, immunological, senescence, or abnormal protein deposition. Treatment strategies for TRD include optimization of current medication dose, augmentation, switching to an alternative agent or class, and combination of different antidepressant classes, as well as nonpharmacological adjuvant interventions such as biophysical stimulation and psychotherapy. In summary, treatment recommendations for TRD in the elderly favor a multimodal approach, combining pharmacological and nonpharmacological treatments.

Associations between β-blockers and psychiatric and behavioural outcomes: A population-based cohort study of 1.4 million individuals in Sweden

BACKGROUND

β-blockers are widely used for treating cardiac conditions and are suggested for the treatment of anxiety and aggression, although research is conflicting and limited by methodological problems. In addition, β-blockers have been associated with precipitating other psychiatric disorders and suicidal behaviour, but findings are mixed. We aimed to examine associations between β-blockers and psychiatric and behavioural outcomes in a large population-based cohort in Sweden.

METHODS AND FINDINGS

We conducted a population-based longitudinal cohort study using Swedish nationwide high-quality healthcare, mortality, and crime registers. We included 1,400,766 individuals aged 15 years or older who had collected β-blocker prescriptions and followed them for 8 years between 2006 and 2013. We linked register data on dispensed β-blocker prescriptions with main outcomes, hospitalisations for psychiatric disorders (not including self-injurious behaviour or suicide attempts), suicidal behaviour (including deaths from suicide), and charges of violent crime. We applied within-individual Cox proportional hazards regression to compare periods on treatment with periods off treatment within each individual in order to reduce possible confounding by indication, as this model inherently adjusts for all stable confounders (e.g., genetics and health history). We also adjusted for age as a time-varying covariate. In further analyses, we adjusted by stated indications, prevalent users, cardiac severity, psychiatric and crime history, individual β-blockers, β-blocker selectivity and solubility, and use of other medications. In the cohort, 86.8% (n = 1,215,247) were 50 years and over, and 52.2% (n = 731,322) were women. During the study period, 6.9% (n = 96,801) of the β-blocker users were hospitalised for a psychiatric disorder, 0.7% (n = 9,960) presented with suicidal behaviour, and 0.7% (n = 9,405) were charged with a violent crime. There was heterogeneity in the direction of results; within-individual analyses showed that periods of β-blocker treatment were associated with reduced hazards of psychiatric hospitalisations (hazard ratio [HR]: 0.92, 95% confidence interval [CI]: 0.91 to 0.93, p < 0.001), charges of violent crime (HR: 0.87, 95% CI: 0.81 to 0.93, p < 0.001), and increased hazards of suicidal behaviour (HR: 1.08, 95% CI: 1.02 to 1.15, p = 0.012). After stratifying by diagnosis, reduced associations with psychiatric hospitalisations during β-blocker treatment were mainly driven by lower hospitalisation rates due to depressive (HR: 0.92, 95% CI: 0.89 to 0.96, p < 0.001) and psychotic disorders (HR: 0.89, 95% CI: 0.85 to 0.93, p < 0.001). Reduced associations with violent charges remained in most sensitivity analyses, while associations with psychiatric hospitalisations and suicidal behaviour were inconsistent. Limitations include that the within-individual model does not account for confounders that could change during treatment, unless measured and adjusted for in the model.

CONCLUSIONS

In this population-wide study, we found no consistent links between β-blockers and psychiatric outcomes. However, β-blockers were associated with reductions in violence, which remained in sensitivity analyses. The use of β-blockers to manage aggression and violence could be investigated further.

Role of central serotonin and noradrenaline interactions in the antidepressants' action: Electrophysiological and neurochemical evidence

The development of antidepressant drugs, in the last 6 decades, has been associated with theories based on a deficiency of serotonin (5-HT) and/or noradrenaline (NA) systems. Although the pathophysiology of major depression (MD) is not fully understood, numerous investigations have suggested that treatments with various classes of antidepressant drugs may lead to an enhanced 5-HT and/or adapted NA neurotransmissions. In this review, particular morpho-physiological aspects of these systems are first considered. Second, principal features of central 5-HT/NA interactions are examined. In this regard, the effects of the acute and sustained antidepressant administrations on these systems are discussed. Finally, future directions including novel therapeutic strategies are proposed.

Astrocyte control of glutamatergic activity: Downstream effects on serotonergic function and emotional behavior

Major depressive disorder (MDD) is a leading cause of disability worldwide, with a poorly known pathophysiology and sub-optimal treatment, based on serotonin (5-hydroxytryptamine, 5-HT) reuptake inhibitors. We review existing theories on MDD, paying special attention to the role played by the ventral anterior cingulate cortex (vACC) or its rodent equivalent, infralimbic cortex (IL), which tightly control the activity of brainstem monoamine neurons (including raphe 5-HT neurons) via descending afferents. Further, astrocytes regulate excitatory synapse activity via glutamate reuptake through astrocytic transporters EAAT1 and EAAT2 (GLAST and GLT-1 in rodents), and alterations of astrocyte number/function have been reported in MDD patients and suicide victims. We recently assessed the impact of reducing GLAST/GLT-1 function in IL on emotional behavior and serotonergic function in rodents. The acute pharmacological blockade of GLT-1 with dihydrokainate (DHK) in rat IL evoked an antidepressant-like effect mediated by local AMPA-R activation and a subsequent enhancement of serotonergic function. No effects were produced by DHK microinfusion in prelimbic cortex (PrL). In the second model, a moderate small interfering RNAs (siRNA)-induced reduction of GLAST and GLT-1 expression in mouse IL markedly increased local glutamatergic neurotransmission and evoked a depressive-like phenotype (reversed by citalopram and ketamine), and reduced serotonergic function and BDNF expression in cortical/hippocampal areas. As for DHK, siRNA microinfusion in PrL did not evoke behavioral/neurochemical effects. Overall, both studies support a critical role of the astrocyte-neuron communication in the control of excitatory neurotransmission in IL, and subsequently, on emotional behavior, via the downstream associated changes on serotonergic function.

Enhancing the efficacy of 5-HT uptake inhibitors in the treatment of attention deficit hyperactivity disorder

Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common childhood behavioural disorders, the frontline treatments for which are drugs with abuse potential. As a consequence, there is an urgent need to develop non addictive drug treatments with equivalent efficacy. Preclinical evidence suggests that selective serotonin uptake inhibitors (SSRIs) are likely to be effective in ADHD, however clinical reports suggest that SSRIs are of limited therapeutic value for the treatment of ADHD. We propose that this disconnect can be explained by the pattern of drug administration in existing clinical trials (administration for short periods of time, or intermittently) leading to inadequate control of the autoregulatory processes which control 5-HT release, most notably at the level of inhibitory 5-HT_1A somatodendritic autoreceptors. These autoreceptors reduce the firing rate of 5-HT neurons (limiting release) unless they are desensitised by a long term, frequent pattern of drug administration. As such, we argue that the participants in earlier trials were not administered SSRIs in a manner which realises any potential benefits of targeting 5-HT in the pharmacotherapy of ADHD. In light of this, we hypothesise that there may be under-researched potential to exploit 5-HT transmission therapeutically in ADHD, either through changing the administration regime, or by pharmacological means. Recent pharmacological research has successfully potentiated the effects of SSRIs in acute animal preparations by antagonising inhibitory 5-HT_1A autoreceptors prior to the administration of the SSRI fluoxetine. We suggest that combination therapies linking SSRIs and 5-HT_1A antagonists are a potential way forward in the development of efficacious non-addictive pharmacotherapies for ADHD.

Monoaminergic system and depression

Major depressive disorder is a severe, disabling disorder that affects around 4.7% of the population worldwide. Based on the monoaminergic hypothesis of depression, monoamine reuptake inhibitors have been developed as antidepressants and nowadays, they are used widely in clinical practice. However, these drugs have a limited efficacy and a slow onset of therapeutic action. Several strategies have been implemented to overcome these limitations, including switching to other drugs or introducing combined or augmentation therapies. In clinical practice, the most often used augmenting drugs are lithium, triiodothyronine, atypical antipsychotics, buspirone, and pindolol, although some others are in the pipeline. Moreover, multitarget antidepressants have been developed to improve efficacy. Despite the enormous effort exerted to improve these monoaminergic drugs, they still fail to produce a rapid and sustained antidepressant response in a substantial proportion of depressed patients. Recently, new compounds that target other neurotransmission system, such as the glutamatergic system, have become the focus of research into fast-acting antidepressant agents. These promising alternatives could represent a new pharmacological trend in the management of depression.

Can we increase speed and efficacy of antidepressant treatments? Part I: General aspects and monoamine-based strategies

Major depressive disorder (MDD) is a severe psychiatric syndrome with high prevalence and socioeconomic impact. Current antidepressant treatments are based on the blockade of serotonin (5-hydroxytryptamine, 5-HT) and/or noradrenaline transporters. These drugs show slow onset of clinical action and limited efficacy, partly due to the activation of physiological negative feed-back mechanisms operating through autoreceptors (5-HT_1A, 5-HT_1B, α₂-adrenoceptors) and postsynaptic receptors (e.g., 5-HT₃). As a result, clinically-relevant doses of reuptake inhibitors increase extracellular (active) 5-HT concentrations in the midbrain raphe nuclei but not in forebrain, as indicated by rodent microdialysis studies and by PET-scan studies in primate/human brain. The prevention of these self-inhibitory mechanisms by antagonists of the above receptors augments preclinical and clinical antidepressant effects. Hence, the mixed ß-adrenoceptor/5-HT_1A antagonist pindolol accelerated, and in some cases enhanced, the clinical action of selective serotonin reuptake inhibitors (SSRI). This strategy has been incorporated into two new multi-target antidepressant drugs, vilazodone and vortioxetine, which combine 5-HT reuptake inhibition and partial agonism at 5-HT_1A receptors. Vortioxetine shows also high affinity for other 5-HT receptors, including excitatory 5-HT₃ receptors located in cortical and hippocampal GABA interneurons. 5-HT₃ receptor blockade by vortioxetine enhances pyramidal neuron activity in prefrontal cortex as well as cortical and hippocampal 5-HT release. It is still too soon to know whether these new antidepressants will represent a real advance over existing drugs in the real world. However, their development opened the way to future antidepressant drugs based on the prevention of local and distal self-inhibitory mechanisms attenuating monoamine activity.

Evidence-based pharmacotherapy of treatment-resistant unipolar depression

Treatment resistance to the antidepressive pharmacotherapy represents one of the most important clinical challenges in the pharmacological management of unipolar depression. In this review, we aimed to summarise the evidence for various pharmacological treatment options in therapy-resistant unipolar depression derived from clinical trials, systematic reviews, meta-analyses and treatment guidelines. The first measure in case of insufficient response to the initial antidepressant monotherapy contains the debarment of 'pseudo-resistance', potentially caused by inadequate dose and treatment duration of the antidepressant, insufficient plasma levels, non-compliance of the patient regarding medication intake or relevant psychiatric and/or somatic comorbidities. Applying a dose escalation of the current antidepressant cannot be generally recommended as evidence-based treatment option and the efficacy depends on the class of antidepressants. There is no compelling evidence for a switch to another, new antidepressant compound after insufficient response to a previous antidepressant. The combination of two antidepressants should be preferentially established with antidepressants characterised by different mechanisms of action (e.g. reuptake inhibitors together with presynaptic autoreceptor inhibitors). At present, the most convincing body of evidence exists for the augmentation of antidepressants with second-generation antipsychotic drugs and lithium. Hence, both strategies are consistently advised by treatment guidelines as pharmacological first-line strategy in treatment-resistant depression.

Pharmacological approaches to the challenge of treatment-resistant depression

Although monoaminergic antidepressants revolutionized the treatment of Major Depressive Disorder (MDD) over a half-century ago, approximately one third of depressed patients experience treatment-resistant depression (TRD). Such patients account for a disproportionately large burden of disease, as evidenced by increased disability, cost, human suffering, and suicide. This review addresses the definition, causes, evaluation, and treatment of unipolar TRD, as well as the major treatment strategies, including optimization, augmentation, combination, and switch therapies. Evidence for these options, as outlined in this review, is mainly focused on large-scale trials or meta-analyses. Finally, we briefly review emerging targets for antidepressant drug discovery and the novel effects of rapidly acting antidepressants, with a focus on ketamine.

Major Depressive Disorder: Understanding the Significance of Residual Symptoms and Balancing Efficacy with Tolerability

INTRODUCTION

Major depressive disorder is a complex and frequent psychiatric condition that poses significant challenges to both the patients who experience it and the physicians who treat them. The goal of therapy is for patients to achieve remission, which requires identifying and measuring symptoms at the outset and throughout treatment to document both response and resistance to treatment. A number of validated instruments are available both for diagnosis of and response to treatment. Many factors affect a patient's ability to achieve remission, but although many patients do achieve remission, a significant number continue to have residual symptoms that cause functional impairment.

METHODS

Review of the literature for treatment of major depression, including mechanisms of action, individualized treatment optimization, residual symptom reduction, and minimization of side effects.

RESULTS

For sustained remission, all symptoms must be treated until they are undetectable. Patients who do not achieve remission after adequate treatment trials should be evaluated for adherence to treatment, as well as comorbid psychiatric and medical disorders. In these cases, consideration should be given to changing therapy by switching, combining, or augmenting initial therapy, as well as referring some patients to a psychiatrist for treatment with specialized modalities. Linking symptoms with malfunctioning brain circuits and neurotransmitters provides a targeted approach for achieving sustained remission. Neurobiology also provides a rational basis for combination therapy in patients with treatment-resistant depression, because it can aid selection of different drugs with different mechanisms of action or of multifunctional/multimodal antidepressant drugs that target more than 1 molecular mechanism.

DISCUSSION

Recent advances and better understanding of neurobiology provide a rational basis for individualizing treatment of patients with major depression.

Is pindolol augmentation effective in depressed patients resistant to selective serotonin reuptake inhibitors? A systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis was conducted to assess the use of pindolol augmentation in depressed patients resistant to selective serotonin reuptake inhibitor (SSRI) therapy.

METHODS

A comprehensive search of PubMed, Cochrane, Embase, Web of Science, and PsychINFO databases from 1970 through December 2013 was conducted. Only randomized controlled trials (RCTs) studied on unipolar SSRI-resistant depressed adults were included. The primary outcome was mean change scores of depressive symptom on the depression rating scales, assessed with standardized mean differences.

RESULTS

Five RCTs consisting of 154 patients met all inclusion and exclusion criteria. The overall pooled effect size in the primary and secondary efficacy analysis showed no significant effects of pindolol plus SSRI therapy (standardized mean difference = -0.43, p = 0.24; OR = 1.92, p = 0.39, respectively). In terms of acceptability, there was no statistical difference in either tolerability or safety between the two groups (OR = 0.46, p = 0.40; OR = 0.90, p = 0.94, respectively). These estimates remained robust through several sensitivity and subgroup analyses, except 7.5 mg-qd pindolol augmentation did show a significant benefit over 2.5-mg tid pindolol augmentation.

CONCLUSIONS

Pindolol augmentation may not be suitable for treatment-resistant depression patients with SSRI-resistant depression. However, once-daily high-dose pindolol (7.5 mg qd) appears to show a promising benefit in these patients.

Developments in the field of antidepressants, where do we go now?

Major depression is a severe psychiatric syndrome with very high prevalence and socio-economic impact. Its pathophysiology is poorly known, yet several neurotransmitter systems and brain areas have been implicated. Selective serotonin (5-hydroxytryptamine, 5-HT) reuptake inhibitors (SSRI) and serotonin and norepinephrine reuptake inhibitors (SNRI) are most used antidepressant treatments. However, these drugs show slow onset of action and limited efficacy, making necessary the use of drug augmentation strategies or more aggressive interventions. Two important observations have emerged in recent years indicating that more rapid and effective antidepressant treatments are possible. Hence, the deep brain stimulation (DBS) of ventral anterior (subgenual) cingulate cortex (Cg25) evokes rapid mood improvements in subgroups of treatment-resistant depressive patients, likely mediated by a functional remodelling of cortico-limbic circuits. On the other hand, the non-competitive NDMA receptor antagonist ketamine can also evoke rapid (e.g., 2h) and persistent (up to 1 wk) improvements in some treatment-resistant patients. Moreover, recent preclinical observations indicate the antidepressant capacity of mGluR agents. Overall, this supports the usefulness of glutamatergic transmission as a new area in antidepressant drug development. On the monoamine side, new preclinical and clinical research should clarify the different roles played by 5-HT receptors in depression as well as the brain areas and circuits responsible for therapeutic improvement. This will lead to the synthesis of new agents blocking the serotonin (and possibly norepinephrine) transporter which will also activate or block 5-HT receptors playing respectively positive (e.g., postsynaptic 5-HT1A, 5-HT4) or negative (e.g., presynaptic 5-HT1A,/1B, 5-HT2A, 5-HT2C,5-HT3, etc.) roles in antidepressant effects.

Electroanalytical detection of pindolol: comparison of unmodified and reduced graphene oxide modified screen-printed graphite electrodes

We demonstrate, for the first time, that the electroanalytical quantification of pindolol is actually possible using bare (unmodified) screen-printed graphite electrodes (SPEs).

Dual serotonergic signals: a key to understanding paradoxical effects?

Neuroscientists have been puzzled by the fact that acute administration of a selective serotonin reuptake inhibitor (SSRI) produces results that are, at times, compatible with either decreases or increases in serotonergic neurotransmission. Furthermore, the underlying cause of the delayed onset of antidepressant effects of SSRI treatment has remained obscure. It has recently been reported that serotonergic raphe neurons co-release glutamate and that serotonergic and glutamatergic components constitute a dual signal with behaviorally distinct effects. We discuss the consequences of these novel findings and propose a framework for understanding the controversial effects of acute SSRI administration. Furthermore, we suggest that the delayed remedial onset of SSRI treatment could be explained by an initial reduction of the glutamatergic component of the dual serotonergic signal.

A review of vilazodone, serotonin, and major depressive disorder

Objective: To review the mechanism of selective serotonin reuptake inhibitor (SSRI)–mediated serotonergic neurotransmission, focusing on serotonin 1A (5-HT_1A) autoreceptors, which are proposed to be involved in delaying therapeutic efficacy. Vilazodone was specifically designed to function both as an SSRI and a partial agonist at 5-HT_1A receptors. This combined mechanism is proposed to decrease time to efficacy, minimize sexual side effects, and provide concomitant anxiolytic properties.

Data Sources: A PubMed search of all English-language articles from January 1990 to January 2013 was conducted using the search terms depression and 5-HT_1A, depression and buspirone, depression and pindolol, and vilazodone.

Study Selection: We found 47 articles and abstracts that were selected for inclusion on the basis of information about the pharmacology of 5-HT_1A receptors and the clinical data on pindolol, buspirone, and vilazodone in depression.

Data Extraction: This review summarizes current literature involving antidepressant activity, the role of 5-HT_1A autoreceptors, and clinical trials involving serotonin reuptake inhibition in conjunction with 5-HT_1A agonists and partial agonists, with a focus on vilazodone.

Results:Vilazodone has demonstrated efficacy in 2 large, randomized, double-blind, placebo-controlled trials in major depressive disorder. Results suggest that vilazodone has a low incidence of sexual side effects and is effective in patients with high levels of anxiety. A pooled analysis shows evidence of significant symptom reduction after only 1 week of therapy.

Conclusions: If future studies corroborate the clinical benefits attributed to its mechanism of action, vilazodone may show potential advantages in terms of onset of action, sexual side effects, and anxiolytic activity in patients with major depressive disorder.

5-HTT and 5-HT(1A) receptor occupancy of the novel substance vortioxetine (Lu AA21004). A PET study in control subjects

Vortioxetine (Lu AA21004) is a new potential substance for the treatment of anxiety and mood disorders. It has high affinity for the 5-HT transporter (5-HTT) and moderate affinity for the 5-HT1A receptor in vitro. Positron emission tomography (PET) has commonly been used to examine the relation between dose/plasma concentration and occupancy to predict relevant dose intervals in a clinical setting. In this study 11 control subjects were examined with PET and [¹¹C]MADAM at baseline, after a single dose and after 9 days of dosing with Lu AA21004 (2.5, 10 or 60 mg) for quantification of 5-HTT occupancy. Four subjects were examined with PET and [¹¹C]WAY 100635 at baseline, after a single dose and after 9 days of dosing of Lu AA21004 (30 mg) for quantification of 5-HT(1A) occupancy. To allow for quantification of binding in the raphe nuclei, PET data were analyzed using wavelet aided parametric imaging. 5-HTT occupancy ranged from 2 (mean, 2.5 mg day 1) to 97% (60 mg day 9). The apparent affinity of Lu AA21004 binding to 5-HTT (KD(ND)) was calculated to 16.7 nM (R=0.95), and the corresponding oral dose (KD(ND)-dose) to 8.5 mg (R=0.91). No significant occupancy of 5-HT(1A) receptors was found after dosing of 30 mg Lu AA21004. Based on the literature and the present [¹¹C]MADAM binding data, a dose of 20-30 mg Lu AA21004 is suggested to give clinically relevant occupancy of the 5-HTT.

Involvement of serotonin 5-HT3 receptors in the modulation of noradrenergic transmission by serotonin reuptake inhibitors: a microdialysis study in rat brain

RATIONALE

Selective serotonin reuptake inhibitors (SSRIs), in addition to being able to enhance serotonergic neurotransmission, are able to modulate other brain systems involved in depression.

OBJECTIVES

This study evaluates the neurochemical effect of the SSRI citalopram on brain noradrenergic activity and the serotonin receptor involved in this effect.

METHODS

Dual-probe microdialysis in the locus coeruleus (LC) and prefrontal cortex (PFC) was performed in freely awake rats.

RESULTS

Systemic citalopram (10 mg/kg, i.p.) increased noradrenaline (NA) in the LC (E max = 141 ± 13%) and simultaneously decreased NA in the PFC (Emax = -46 ± 7%). In the local presence into the LC of the α2-adrenoceptor antagonist RS79948 (1 μM), systemic citalopram increased NA in the LC (Emax = 157 ± 25%) and PFC (Emax = 175 ± 24%). Local citalopram (0.1-100 μM) into the LC induced NA increase in the LC (Emax = 210 ± 25%) and decrease in the PFC (Emax = -38 ± 9%). Local LC citalopram effect was abolished by LC presence of the 5-HT3 receptor antagonist MDL72222 (1 μM) but not the 5-HT1/2 receptor antagonist methiothepin (1 μM). Systemic citalopram in the LC presence of MDL72222 did not modify NA in the LC but increased NA in the PFC (Emax = 158 ± 26%). Local citalopram into the PFC enhanced NA (Emax = 376 ± 18%) in the area, which was prevented by MDL72222.

CONCLUSIONS

The SSRI citalopram modulates central noradrenergic neurotransmission by activation, through endogenous serotonin, of 5-HT3 receptors expressed in the somatodendritic (LC) and terminal (PFC) areas, which subsequently promote an enhancement of local NA. Therefore, 5-HT3 receptors and somatodendritic α2-adrenoceptors in the LC play an important role in the global effect of SSRIs.

Evidence for the benefits of nonantipsychotic pharmacological augmentation in the treatment of depression

Failure to achieve an adequate response after initial antidepressant treatment in patients with depression is common and remains a clinical challenge. In recent years, some atypical antipsychotic agents have been approved by the US Food and Drug Administration for use in an augmentation strategy for major depressive disorder, and other agents are already in common use in clinical practice. We conducted a search of MEDLINE for relevant studies of augmentation strategies using randomized controlled trials and meta-analyses, and we summarize and discuss the various agents other than atypical antipsychotics. Lithium and thyroid hormone augmentation may improve the response of tricyclic antidepressants but not that of selective serotonin reuptake inhibitors. The efficacy of augmentation with modafinil, buspirone, methylphenidate, folic acid, pindolol and lamotrigine is limited or equivocal. Most of the studies have not focused on treatment-resistant depression (TRD). More trials are needed to help develop evidence-based options for augmentation in TRD.

Preclinical and clinical characterization of the selective 5-HT(1A) receptor antagonist DU-125530 for antidepressant treatment

BACKGROUND AND PURPOSE

The antidepressant efficacy of selective 5-HT reuptake inhibitors (SSRI) and other 5-HT-enhancing drugs is compromised by a negative feedback mechanism involving 5-HT(1A) autoreceptor activation by the excess 5-HT produced by these drugs in the somatodendritic region of 5-HT neurones. 5-HT(1A) receptor antagonists augment antidepressant-like effects in rodents by preventing this negative feedback, and the mixed β-adrenoceptor/5-HT(1A) receptor antagonist pindolol improves clinical antidepressant effects by preferentially interacting with 5-HT(1A) autoreceptors. However, it is unclear whether 5-HT(1A) receptor antagonists not discriminating between pre- and post-synaptic 5-HT(1A) receptors would be clinically effective.

EXPERIMENTAL APPROACH

We characterized the pharmacological properties of the 5-HT(1A) receptor antagonist DU-125530 using receptor autoradiography, intracerebral microdialysis and electrophysiological recordings. Its capacity to accelerate/enhance the clinical effects of fluoxetine was assessed in a double-blind, randomized, 6 week placebo-controlled trial in 50 patients with major depression (clinicaltrials.gov identifier NCT01119430).

KEY RESULTS

DU-125530 showed equal (low nM) potency to displace agonist and antagonist binding to pre- and post-synaptic 5-HT(1A) receptors in rat and human brain. It antagonized suppression of 5-hydroxytryptaminergic activity evoked by 8-OH-DPAT and SSRIs in vivo. DU-125530 augmented SSRI-induced increases in extracellular 5-HT as effectively as in mice lacking 5-HT(1A) receptors, indicating a silent, maximal occupancy of pre-synaptic 5-HT(1A) receptors at the dose used. However, DU-125530 addition to fluoxetine did not accelerate nor augment its antidepressant effects.

CONCLUSIONS AND IMPLICATIONS

DU-125530 is an excellent pre- and post-synaptic 5-HT(1A) receptor antagonist. However, blockade of post-synaptic 5- HT(1A) receptors by DU-125530 cancels benefits obtained by enhancing pre-synaptic 5-hydroxytryptaminergic function.

Rethinking 5-HT1A receptors: emerging modes of inhibitory feedback of relevance to emotion-related behavior

The complexities of the involvement of the serotonin transmitter system in numerous biological processes and psychiatric disorders is, to a substantial degree, attributable to the large number of serotonin receptor families and subtypes that have been identified and characterized for over four decades. Of these, the 5-HT(1A) receptor subtype, which was the first to be cloned and characterized, has received considerable attention based on its purported role in the etiology and treatment of mood and anxiety disorders. 5-HT(1A) receptors function both at presynaptic (autoreceptor) and postsynaptic (heteroreceptor) sites. Recent research has implicated distinct roles for these two populations of receptors in mediating emotion-related behavior. New concepts as to how 5-HT(1A) receptors function to control serotonergic tone throughout life were highlights of the proceedings of the 2012 Serotonin Club Meeting in Montpellier, France. Here, we review recent findings and current perspectives on functional aspects of 5-HT(1A) auto- and heteroreceptors with particular regard to their involvement in altered anxiety and mood states.

Acute 5-HT₁A autoreceptor knockdown increases antidepressant responses and serotonin release in stressful conditions

RATIONALE

Identifying the etiological factors in anxiety and depression is critical to develop more efficacious therapies. The inhibitory serotonin(1A) receptors (5-HT(1A)R) located on 5-HT neurons (autoreceptors) limit antidepressant responses and their expression may be increased in treatment-resistant depressed patients.

OBJECTIVES

Recently, we reported that intranasal administration of modified small interference RNA (siRNA) molecules targeting 5-HT(1A)R in serotonergic neurons evoked antidepressant-like effects. Here we extended this finding using marketed siRNAs against 5-HT(1A)R (1A-siRNA) to reduce directly the 5-HT(1A) autoreceptor expression and evaluate its biological consequences under basal conditions and in response to stressful situations.

METHODS

Adult mice were locally infused with vehicle, nonsense siRNA, and 1A-siRNA into dorsal raphe nucleus (DR). 5-HT(1A)R knockout mice (1A-KO) were also used. Histological approaches, in vivo microdialysis, and stress-related behaviors were performed to assess the effects of 5-HT(1A) autoreceptor knockdown.

RESULTS

Intra-DR 1A-siRNA infusion selectively reduced 5-HT(1A)R mRNA and binding levels and canceled 8-OH-DPAT-induced hypothermia. Basal extracellular 5-HT in medial prefrontal cortex (mPFC) did not differ among treatments. However, 1A-siRNA-treated mice displayed less immobility in the tail suspension and forced swim tests, as did 1A-KO mice. This was accompanied by a greater increase in prefrontal 5-HT release during tail suspension test. Moreover, intra-DR 1A-siRNA infusion augmented the increase of extracellular 5-HT in mPFC evoked by fluoxetine, up to the level in 1A-KO mice.

CONCLUSION

Together with our previous report, the present results indicate that acute suppression of 5-HT(1A) autoreceptor expression evokes robust antidepressant-like effects, likely mediated by an increased capacity of serotonergic neurons to release 5-HT in stressful conditions.

A short-term double-blind randomized controlled pilot trial with active or placebo pindolol in patients treated with venlafaxine for major depression

BACKGROUND

Pindolol has been widely investigated as an augmenter of antidepressant drug response. Results have been inconsistent. In this study, we used pindolol together with venlafaxine because of its ability to achieve a rapid onset of serotonin transporter blockade.

AIMS

The object of this study was thus to investigate if pindolol augments the antidepressant response to venlafaxine.

METHODS

Patients with major depression were randomized to either active or placebo pindolol 20 mg retard daily dosage and concomitantly treated with venlafaxine for 19 days. Depression severity was evaluated at four visits. Plasma concentrations of venlafaxine and its major metabolites O-desmethylvenlafaxine (ODV) and N-desmethylvenlafaxine (NDV) and pindolol were analysed. The ratio of ODV/venlafaxine was calculated. A low ratio corresponds to patients being poor metabolizers and a high ratio corresponds to patients being extensive metabolizers.

RESULTS

No statistically significant difference in depression outcome was found between treatment groups. A statistically significant effect was, however, found of the ratio of ODV/venlafaxine on depression outcome, showing an augmenting effect of pindolol in patients with a low ratio, and the reverse in patients with a high ratio.

CONCLUSION

The differential effect of pindolol, on depression outcome, in patients with varying degrees of venlafaxine metabolism into ODV, corresponds to patients being poor or extensive metabolizers of venlafaxine. From this finding, we conclude that only patients who are poor metabolizers of venlafaxine might benefit from pindolol augmentation. This mechanism might explain some of the variability of outcome in pindolol augmentation studies.

Selective siRNA-mediated suppression of 5-HT1A autoreceptors evokes strong anti-depressant-like effects

Depression is a major health problem worldwide. Most prescribed anti-depressants, the selective serotonin reuptake inhibitors (SSRI) show limited efficacy and delayed onset of action, partly due to the activation of somatodendritic 5-HT(1A)-autoreceptors by the excess extracellular serotonin (5-HT) produced by SSRI in the raphe nuclei. Likewise, 5-HT(1A) receptor (5-HT(1A)R) gene polymorphisms leading to high 5-HT(1A)-autoreceptor expression increase depression susceptibility and decrease treatment response. In this study, we report on a new treatment strategy based on the administration of small-interfering RNA (siRNA) to acutely suppress 5-HT(1A)-autoreceptor-mediated negative feedback mechanisms. We developed a conjugated siRNA (C-1A-siRNA) by covalently binding siRNA targeting 5-HT(1A) receptor mRNA with the SSRI sertraline in order to concentrate it in serotonin axons, rich in serotonin transporter (SERT) sites. The intracerebroventricular (i.c.v.) infusion of C-1A-siRNA to mice resulted in its selective accumulation in serotonin neurons. This evoked marked anti-depressant-like effects in the forced swim and tail suspension tests, but did not affect anxiety-like behaviors in the elevated plus-maze. In parallel, C-1A-siRNA administration markedly decreased 5-HT(1A)-autoreceptor expression and suppressed 8-OH-DPAT-induced hypothermia (a pre-synaptic 5-HT(1A)R effect in mice) without affecting post-synaptic 5-HT(1A)R expression in hippocampus and prefrontal cortex. Moreover, i.c.v. C-1A-siRNA infusion augmented the increase in extracellular serotonin evoked by fluoxetine in prefrontal cortex to the level seen in 5-HT(1A)R knockout mice. Interestingly, intranasal C-1A-siRNA administration produced the same effects, thus opening the way to the therapeutic use of C-1A-siRNA. Hence, C-1A-siRNA represents a new approach to treat mood disorders as monotherapy or in combination with SSRI.

Noradrenergic antidepressants increase cortical dopamine: potential use in augmentation strategies

Most antidepressant treatments, based on serotonin (5-HT) and/or norepinephrine (NE) transporter blockade, show limited efficacy and slow onset of action, requiring the use of augmentation strategies. Here we report on a novel antidepressant strategy to selectively increase DA function in prefrontal cortex (PFC) without the potential tolerance problems associated to DA transporter blockade. This approach is based on previous observations indicating that extracellular DA in rat medial PFC (mPFC) - but not in nucleus accumbens (NAc) - arises from noradrenergic terminals and is sensitive to noradrenergic drugs. A low dose of reboxetine (3 mg/kg i.p.; NE reuptake inhibitor) non-significantly increased extracellular DA in mPFC. Interestingly, its combined administration with 5 mg/kg s.c. mirtazapine (non-selective α₂-adrenoceptor antagonist) increased extracellular DA in mPFC (264 ± 28%), but not in NAc. Extracellular NE (but not 5-HT) in mPFC was also enhanced by the combined treatment (472 ± 70%). Repeated (×3) reboxetine + mirtazapine administration produced a moderate additional increase in mPFC DA and markedly reduced the immobility time (-51%) in the forced-swim test. Neurochemical and behavioral effects of the reboxetine + mirtazapine combination persisted in rats pretreated with citalopram (3 mg/kg, s.c.), suggesting its potential usefulness to augment SSRI effects. In situ hybridization c-fos studies were performed to examine the brain areas involved in the above antidepressant-like effects, showing changes in c-fos expression in hippocampal and cortical areas. BDNF expression was also increased in the hippocampal formation. Overall, these results indicate a synergistic effect of the reboxetine + mirtazapine combination to increase DA and NE function in mPFC and to evoke robust antidepressant-like responses.

Intravenous Ketamine for Treatment-Resistant Major Depressive Disorder

OBJECTIVE:

To evaluate the literature regarding the efficacy and safety of intravenous ketamine for treatment-resistant major depressive disorder (MDD).

DATA SOURCES:

A MEDLINE search (1966-September 2011) was performed using the terms treatment-resistant depression and ketamine. The search was restricted to articles published in English and reporting on use of ketamine in humans.

STUDY SELECTION AND DATA EXTRACTION:

All English-language articles identified from the data search were evaluated. Data were eligible for inclusion if they were primary literature and evaluated the efficacy of ketamine for depressive symptoms in treatment-resistant MDD. One case report, 3 case series, 3 open-label trials, and 1 randomized crossover trial were included.

DATA SYNTHESIS:

Several medications are available for treatment-resistant MDD; however, they are often limited by a slow onset of therapeutic effect and tolerability. It has been suggested that ketamine, a rapid-acting, N-methyl-D-aspartate glutamate receptor antagonist, may have antidepressant effects. Case reports, case series, and select trials evaluating ketamine use for depressive symptoms in treatment-resistant MDD have demonstrated a rapid effect for reductions of scores on a number of depression scales; however, its sustainability effect remains unknown. Several studies reported a large or moderate to large effect size for ketamine. Additionally, these studies showed that ketamine use in this patient population is associated with relatively well-tolerated adverse effects.

CONCLUSIONS:

Ketamine for treatment-resistant MDD requires further evaluation before it can be considered a viable treatment option.

Serotonin transporter activity of imidazolidine-2,4-dione and imidazo[2,1-f]purine-2,4-dione derivatives in aspect of their acid-base properties

Affinities of arylpiperazinylalkyl derivatives of imidazo[2,1-f]purine-2,4-dione and imidazolidine-2,4-dione for serotonin transporter and their acid-base properties were evaluated. The dissociation constant (pK(a)) of compounds 1-22 were determinated by potentiometric titration and calculated using pKalc 3.1 module of the Pallas system. The data from experimental methods and computational calculations were compared and suitable conclusions were reached.

Design and synthesis of novel arylpiperazine derivatives containing the imidazole core targeting 5-HT(2A) receptor and 5-HT transporter

Serotonin antagonist reuptake inhibitor (SARI) drugs that block both 5-HT(2) receptors and the serotonin transporters have been developed. The human 5-HT(2A/2C) receptor has been implicated in several neurological conditions, and potent selective 5-HT(2A/2C) ligands may have therapeutic potential for treatment of CNS diseases such as depression. An imidazole moiety usually provides good pharmacokinetic properties as a drug substance, and thus considerable efforts have been devoted to develop imidazole derivatives into drug candidates. The imidazole series of compounds was evaluated against 5-HT(2A/2C) and serotonin reuptake inhibition. A few of the compounds in the series showed promising IC(50) values and antidepressant-like effect in in vivo forced swimming test (FST). On the basis of these results, further lead optimization studies resulted in identifying promising compounds potentially for therapeutic use.

Mechanisms of antidepressant action: an integrated dopaminergic perspective

The molecular mechanisms that cause and maintain the major depressive disorder (MDD) are currently unknown. Consistently, antidepressant treatments are characterized by insufficient success rates. This causes high social costs and severe personal sufferings. In the present review we analyze some of the paradigms that are used to explain MDD, particularly from the perspective of the dopaminergic (DA) system. DA has been more classically associated with psychosis and substance abuse disorders, even though a role of DA in MDD has been proposed as well and some antidepressants with DA profile exist. In the present work, we review some of the molecular mechanisms that underpin MDD from the perspective of the dopaminergic system, in the hope of unifying some of the major theories of MDD - the monoaminergic, inflammatory, epigenetics, neurotrophin and anti-apoptotic theories. Several shared components of these theories are highlighted, partially accounted by the functions of the DA system (see supplementary video).

Depressogenic effects of medications: a review

The literature is filled with reports that link medications with the onset or progression of depression. Because depression is so common in patients with medical illness, assessing whether a medication has in fact caused depression, or whether the relationship is coincidental, can be challenging. In this article, we review the literature on the association between medications and depression. For most agents, there are case reports or small studies linking the medication with the onset of depression, but more rigorous prospective studies are either lacking or found no association between the agent and depression. However, several medications, (eg, barbiturates, vigabatrin, topiramate, flunarizine, corticosteroids, mefloquine, efavirenz, and interferon-α) do appear to cause depression in some patients and should be used with caution in patients at risk for depression.

If at first you don't succeed: a review of the evidence for antidepressant augmentation, combination and switching strategies

Major depressive disorder is a common and disabling illness that leads to significant reductions in quality of life and considerable cost to society. Despite numerous advances in the pharmacological treatment of depression, many patients remain ill despite initial treatment. Beyond first-line treatment, current guidelines recommend either augmentation or switching of the initial antidepressant. In this narrative review, we summarize the data from randomized controlled trials and meta-analyses in order to concisely discuss how the impact of current research can be translated into clinical practice and, ultimately, into lasting improvements in patient outcomes. The augmentation strategies reviewed are lithium, thyroid hormone, pindolol, psychostimulants and second-generation antipsychotics. The data on switching from first-line antidepressants to other antidepressants are also reviewed, and include switching within the same class, switching to other first-line antidepressant classes and switching to less commonly prescribed antidepressants. Finally, the strategy of antidepressant combinations is examined. Overall, the strength of evidence supporting a trial of augmentation or a switch to a new agent is very similar, with remission rates between 25% and 50% in both cases. Our review of the evidence suggests several conclusions. First, although it is true that adjunctive lithium and thyroid hormone have established efficacy, we can only be confident that this is true for use in combination with tricyclic antidepressants (TCAs), and the trials were done in less treatment-resistant patients than those who typically receive TCAs today. Of these two options, triiodothyronine augmentation seems to offer the best benefit/risk ratio for augmentation of modern antidepressants. After failure of a first-line selective serotonin reuptake inhibitor (SSRI), neither a switch within class nor a switch to a different class of antidepressant is unequivocally supported by the data, although switching from an SSRI to venlafaxine or mirtazapine may potentially offer greater benefits. Interestingly, switching from a newer antidepressant to a TCA after a poor response to the former is not supported by strong evidence. Of all strategies to augment response to new-generation antidepressants, quetiapine and aripiprazole are best supported by the evidence, although neither the cost effectiveness nor the longer-term benefit of these strategies has been established. The data to guide later steps in the treatment of resistant depression are sparse. Given the wide variety of options for the treatment of major depressive disorder, and the demonstrated importance of truly adequate treatment to the long-term outcomes of patients facing this illness, it is clear that further well conducted studies are needed.

Pindolol augmentation of serotonin reuptake inhibitors for the treatment of depressive disorder: a systematic review

Adding pindolol to serotonergic antidepressant treatment offers a potential strategy for producing a more rapid onset of action and an enhanced antidepressant effect. This review investigated whether pindolol enhances the efficacy of serotonergic antidepressant treatment in adult patients with depressive disorders at sequential time points up to 6 weeks.

SEARCH STRATEGY

Cochrane Collaboration Depression, Anxiety and Neurosis-Controlled Trials Register plus unpublished trial data.

STUDY SELECTION

Randomised trials including depressed patients, comparing serotonergic antidepressants + pindolol with serotonergic antidepressants + placebo and using depressive symptom clinical outcomes scales.

DATA EXTRACTION

Clinical response at time points up to 6 weeks as defined by >50% depression scale score reduction was extracted for each trial as possible. Eleven studies were identified including unpublished data. The pooled odds ratios for dichotomous response to treatment at time points from 1 to 6 weeks were 2.39 (95% CI 1.40-4.06), 2.39 (1.74-3.29), 1.94 (1.46-2.58), 1.59 (1.16-2.18), 1.42 (0.87-2.31) and 1.28 (0.91-1.81). Time-to-event analysis showed a greater response with pindolol augmentation versus placebo (P = 0.04). There was significant heterogeneity between studies at some time points. Dropout rates did not significantly differ between treatment arms. This review suggests an overall beneficial clinical effect of pindolol augmentation, most clearly up to 4 weeks of treatment.

Pharmacologic approaches to treatment resistant depression: a re-examination for the modern era

IMPORTANCE OF THE FIELD

Treatment-resistant depression (TRD) is common and debilitating. Initial treatment is often insufficient to achieve full remission in a given depressive episode, resulting in more frequent episodes, worsened severity, and major disability.

AREAS COVERED IN THIS REVIEW

This review surveys literature on the diagnosis and pharmacological management of TRD in light of recent developments. Evidence regarding commonly used treatment options is critically examined and key recommendations are offered. The review ends by considering drugs acting on the melatonin, acetylcholine, and glutamate systems that hold promise as future options for TRD.

WHAT THE READER WILL GAIN

Recent trends and research findings have impacted how the evidence supporting different approaches to TRD should be evaluated. For example, many earlier TRD studies employed tricyclics as the primary antidepressant, but tricyclics have now been superseded by selective serotonin reuptake inhibitors (SSRIs) in routine clinical practice. This deficiency has been addressed by the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study, the largest effectiveness study of TRD ever conducted. However, design characteristics of the STAR*D study preclude simple comparisons with earlier studies.

TAKE HOME MESSAGE

A shortcoming of most treatment recommendations for TRD is their reliance on older studies that do not reflect the current preeminence of SSRIs in clinical practice. This has distorted the prioritization of pharmacological strategies for TRD. Efforts to correct this distortion with effectiveness research, designed to better reflect current practice trends, require critical consideration of the strengths and limitations of this approach.

Accelerating response to antidepressant treatment in depression: a review and clinical suggestions

OBJECTIVE

The primary objective of this article is to review the literature regarding the speed of response to antidepressant drugs and potential strategies to accelerate the antidepressant response in new antidepressant-free patients with depression. Based on these data, we try to propose both an effective and safe antidepressant treatment strategy to alleviate depressive symptoms at the earliest opportunity.

DATA SOURCES

Data were identified by searches of Medline (1966 to September 2009) and references from relevant articles and books. Search terms included depression, antidepressant, predictor, response, onset, acceleration, and augmentation. As our focus was on the acute phase treatment of depression, articles relevant to treatment-resistant depression were excluded. Only articles written in English or Japanese were consulted.

DATA SELECTION

Studies, reviews, and books pertaining to the treatment of depression with a special regard to accelerating therapeutic effects were selected.

DATA SYNTHESIS

Most of the available treatment guidelines for major depressive disorders recommend the continuous use of antidepressants for 4 to 8 weeks based on the idea of a delayed onset of response to these drugs. Contrary to this conventional belief, the recent data indicate that antidepressants start to exert their effects within 2 weeks and early non-response could predict a subsequent unfavorable outcome.

CONCLUSIONS

These findings suggest the need of revisiting the timing of an antidepressant switch for early non-responders, whereby switching could be commenced in as early as 2 weeks.

An algorithm for the pharmacological treatment of depression

OBJECTIVE

Non-response to treatment with antidepressants (AD) is a clinical problem.

METHOD

The algorithm for pharmacological treatment of the Dutch multidisciplinary guideline for depression is compared with four other algorithms.

RESULTS

The Dutch algorithm consists of five subsequent steps. Treatment is started with one out of many optional ADs (step 1); in case of non-response after 4-10 weeks, best evidence is for switching to another AD (step 2); next step is augmentation with lithium as the best option (step 3); the next step is a monoamine oxidase inhibitor (MAOI) (step 4); and finally electroconvulsive therapy (step 5). There are major differences with other algorithms regarding timing of augmentation step, best agents for augmentation and role of MAOI.

CONCLUSION

Algorithms for AD treatment vary according to national and local preferences. Although the evidence for most of the treatment strategies is rather meagre, an AD algorithm appears to be an useful instrument in clinical practice.

Arylpiperazine-containing pyrrole 3-carboxamide derivatives targeting serotonin 5-HT(2A), 5-HT(2C), and the serotonin transporter as a potential antidepressant

Arylpiperzine-containing pyrrole 3-carboxamide derivatives were synthesized and evaluated as novel antidepressant compounds. The various analogues were efficiently prepared and bio-assayed for binding to 5-HT(2A), 5-HT(2C) receptor, and 5-HT transporter. Based on their in vitro and in vivo activities as well as selectivity over other neurotransmitter receptors and PK profiles, 33 and 34 were identified as lead compounds. Consequently, this pyrrole series of compounds appears to be promising enough to warrant further investigation.

SSRI response in depression may be influenced by SNPs in HTR1B and HTR1A

OBJECTIVES

Desensitization of serotonin 1A (HTR1A) and 1B (HTR1B) autoreceptors has been proposed to be involved in the delayed onset of response to selective serotonin reuptake inhibitors (SSRIs). Variations in gene expression in these genes may thus affect SSRI response.

METHODS

Here, we test this hypothesis in two samples from the Sequenced Treatment Alternatives to Relieve Depression (STAR*D), and show evidence for involvement of several genetic variants alone and in interaction. Initially, three functional single nucleotide polymorphisms (SNPs) in the HTR1B gene and in the HTR1A gene were analyzed in 153 depressed patients treated with citalopram. The 16-item Quick Inventory of Depressive Symptomatology Clinician scores were evaluated over time with respect to genetic variation.

RESULTS

Individuals homozygous for the -1019 G allele (rs6295) in HTR1A showed the higher baseline 16-item Quick Inventory of Depressive Symptomatology Clinician scores (P=0.033), and by 12 weeks had a significantly lower response rate (P=0.005). HTR1B haplotypes were estimated according to the previously reported in-vitro expression levels. Individuals who were homozygous for the high-expression haplotype showed significantly slower response to citalopram (P=0.034). We then analyzed more SNPs in the extended overall STAR*D sample. Although we could not directly test the same functional SNPs, we found that homozygotes for the G allele at rs1364043 in HTR1A (P=0.045) and the C allele of rs6298 in HTR1B showed better response to citalopram over time (P=0.022). Test for interaction between rs6298 in HTR1B and rs1364043 in HTR1A was significant (overall P=0.032).

CONCLUSION

Our data suggest that an enhanced capacity of HTR1B or HTR1A transcriptional activity may impair desensitization of the autoreceptors during SSRI treatment.

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.

Synthesis and structure-activity relationship of novel lactam-fused chroman derivatives having dual affinity at the 5-HT(1A) receptor and the serotonin transporter

The structure-activity relationship (SAR) for three series of lactam-fused chroman derivatives possessing 3-amino substituents was evaluated. Many compounds exhibited affinities for both the 5-HT(1A) receptor and the 5-HT transporter. Compounds 45 and 53 demonstrated 5-HT(1A) antagonist activities in the in vitro cAMP turnover model.

Does dual antidepressant therapy as initial treatment hasten and increase remission from depression?

BACKGROUND

Only 30%-40% of depressed patients remit after 8 weeks of treatment with an antidepressant. We hypothesized that beginning treatment with two antidepressants would improve remission rates.

METHOD

Relatively treatment-naive depressed outpatients (with DSM-IV diagnoses of major depressive disorder, dysthymic disorder, or depression not otherwise specified) were initially treated with a combination of escitalopram (ESC) plus bupropion (BUP), using rapid dose escalation to ESC 40 mg/day plus BUP 400 to 450 mg/day by study day 15 in an open-label, 8-week study. Remission was defined as a score < or =7 on the 17-item Hamilton Rating Scale for Depression (HAM-D17) at the end of the study. Recruitment occurred between July, 2003, and June, 2006, and the final patient completed the protocol in July, 2006.

RESULTS

Fifty-five patients signed informed consent, 49 of whom received at least one dose of study medication. Of the 49 patients, 28 (57%) were women and 30 (61%) had a current diagnosis of major depressive disorder; the mean age was 38+/-12 years, and the mean pre-treatment HAM-D17 score was 16+/-4. Sixteen (33%) of the patients remitted by study week 2, and 31 (63%) by week 8. Nine patients (18%) dropped out prior to their week 8 visit, 5 of them because of side effects.

LIMITATIONS

The lack of a comparison group and the use of non-blind raters are drawbacks of this study.

CONCLUSIONS

This open-label study suggests that increased numbers of patients may benefit from dual therapy with ESC plus BUP and that the benefit may perhaps include an increased likelihood of early response. Registry: ClinicalTrials.gov: http://www.clinicaltrials.gov/NCT00296712 (Journal of Psychiatric Practice. 2009;15:337-345).