Paroxetine with pindolol augmentation: a double-blind, randomized, placebo-controlled study in depressed in-patients

Recent Developments in Pharmacotherapy of Depression: Bench to Bedside

For the last 70 years, we did not move beyond the monoamine hypothesis of depression until the approval of the S-enantiomer of ketamine, an N-methyl-D-aspartate (NMDA) receptor blocker and the first non-monoaminergic antidepressant characterized by rapid antidepressant and antisuicidal effects. A similar profile has been reported with another NMDA receptor antagonist, dextromethorphan, which has also been approved to manage depression in combination with bupropion. More recently, the approval of a positive allosteric modulator of GABA-A receptors, brexanolone, has added to the list of recent breakthroughs with the relatively rapid onset of antidepressant efficacy. However, multiple factors have compromised the clinical utility of these exciting discoveries in the general population, including high drug acquisition costs, mandatory monitoring requirements, parenteral drug administration, lack of insurance coverage, indirect COVID-19 effects on healthcare systems, and training gaps in psychopharmacology. This narrative review aims to analyze the clinical pharmacology of recently approved antidepressants and discuss potential barriers to the bench-to-bedside transfer of knowledge and clinical application of exciting recent discoveries. Overall, clinically meaningful advances in the treatment of depression have not reached a large proportion of depressed patients, including those with treatment-resistant depression, who might benefit the most from the novel antidepressants.

Comparative efficacy and tolerability of pharmacological treatments for the treatment of acute bipolar depression: A systematic review and network meta-analysis

OBJECTIVE

We investigated the comparative efficacy and tolerability of pharmacological treatment strategies for the treatment of acute bipolar depression.

DATA SOURCES

A systematic review and network meta-analysis was conducted by searching eight registries for published and unpublished, double-blind, randomized controlled trials of pharmacotherapies for the acute treatment of bipolar depression.

DATA EXTRACTION AND SYNTHESIS

PRISMA guidelines were used for abstracting data, while the Cochrane Risk of Bias Tool was used to assess data quality. Data extraction was done independently by two reviewers, with discrepancies resolved by consensus. Data were pooled using a random-effects model.

MAIN OUTCOMES AND MEASURES

Primary outcomes were efficacy (response and remission rate) and acceptability (completion of treatment and dropouts due to adverse events). Summary odds ratios (ORs) were estimated using pairwise and network meta-analysis with random effects.

RESULTS

Identified citations (4,404) included 50 trials comprising 11,448 participants. Escitalopram, phenelzine, moclobemide, carbamazepine, sertraline, lithium, paroxetine, aripiprazole, gabapentin and ziprasidone appear to be ineffective as compared to placebo in treatment of bipolar depression. Divalproex, olanzapine/fluoxetine, olanzapine, quetiapine, cariprazine, and lamotrigine, appear to be effective as compared to placebo in treatment of bipolar depression according to the network meta-analysis. Aripiprazole showed higher discontinuation rates versus placebo due to the appearance of any adverse event. Quetiapine was better than placebo at reducing treatment-emergent affective switches. For Bipolar I Disorder, cariprazine, fluoxetine, imipramine, lamotrigine, lurasidone, olanzapine-fluoxetine, and olanzapine were significantly better than placebo at response, while fluoxetine, imipramine, cariprazine, lurasidone, olanzapine-fluoxetine, and olanzapine were significantly better than placebo at remission.

CONCLUSIONS AND RELEVANCE

These results could serve evidence-based practice and inform patients, physicians, guideline developers, and policymakers on the relative benefits of the different antidepressants, antipsychotics, and mood-stabilizing agents for the treatment of bipolar depression.

REGISTRATION

PROSPERO (CRD42019122172).

Efficacy of off-label augmentation in unipolar depression: A systematic review of the evidence

Treatment of unipolar depression with currently available antidepressants is still unsatisfactory. Augmentation with lithium or second generation antipsychotics is an established practice in non-responders to antidepressant monotherapy, but is also associated with a substantial non-response rate and with non-tolerance. Based on a systematic review of the literature, including meta-analyses, randomized controlled trials (RCTs), non-randomized comparative studies and case studies, off-label augmentation agents (administered in addition to an antidepressant, without FDA approval for treatment of MDD) were identified and evaluated regarding their efficacy using levels of evidence. The agents had to be added to an existing antidepressant regime with the aim of achieving an improved clinical response to an ongoing antidepressant treatment (augmentation) or an earlier onset of effect when starting antidepressant and augmentation agent simultaneously (acceleration). Five substances, modafinil, ketamine, pindolol, testosterone and estrogen (the latter two in hormone-deficient patients) were shown to be clinically effective in high evidence studies. For the six drugs dexamethasone, mecamylamine, riluzole, amantadine, pramipexole and yohimbine clear proof of efficacy was not possible due to low levels of evidence, small sample sizes or discordant results. For the two agents methylphenidate and memantine only studies with negative outcomes could be found. Overall, the quality of study designs was low and results were often contradictory. However, the use of pindolol, ketamine, modafinil, estrogen and testosterone might be an option for depressed patients who are not responding to antidepressant monotherapy or established augmentation strategies. Further high quality studies are necessary and warranted.

The role of 5-HT1A receptors in mediating acute negative effects of antidepressants: implications in pediatric depression

Acute antidepressant exposure elevates the frequency of impulsive behavior and suicidal thoughts in children and adolescents with major depressive disorder (MDD). Long-term antidepressant treatment, however, is beneficial for pediatric MDD, so it is necessary to explore novel treatments that prevent the potentially dangerous consequences of acute antidepressant initiation. In the present study, a treatment strategy designed to reverse the acute negative behavioral effects of antidepressants was tested in rodents. Co-administration of the 5-HT1A receptor (5-HT1AR) antagonist WAY-100635 reversed the negative effects of acute fluoxetine, a serotonin reuptake inhibitor, but not reboxetine, a norepinephrine reuptake inhibitor, supporting the involvement of 5-HT1AR in mediating the negative consequences of acute selective serotonin reuptake inhibitor (SSRI) treatment. No 5-HT1AR antagonists are currently approved for use in pediatric populations, so alternative strategies should be explored. One such strategy was suggested based on the hypothesis that the rate of 5-HT1AR activation and the subsequent inhibition of serotonergic neuron activity caused by acute SSRI administration is proportional to the loading rate of an antidepressant. Existing pharmacological data were examined, and significant correlations were observed between the half-life of antidepressants and the rate of suicide-related events (SREs). Specifically, antidepressants with longer half-lives have lower rates of SREs. On the basis of these data, novel dosing strategies were developed for five antidepressants to mimic the pharmacological profile of the antidepressant with the longest half-life, fluoxetine. These dosing strategies could be used to decrease the rate of SREs associated with acute antidepressant treatment in pediatric MDD until an improved pharmacological treatment is developed.

The integrative management of treatment-resistant depression: a comprehensive review and perspectives

BACKGROUND

Major depressive disorder is a prevalent and disabling illness. Notwithstanding numerous advances in the pharmacological treatment of depression, approximately 70% of patients do not remit after first-line antidepressant treatment.

METHODS

The MEDLINE/PubMed, EMBASE and ClinicalTrials.gov electronic databases were searched from inception to October 1, 2013, for randomized controlled trials (RCT), relevant open-label trials, meta-analyses and ongoing trials of pharmacological and psychotherapeutic approaches to treatment-resistant depression (TRD).

RESULTS

Switching to a different antidepressant is a useful option following nonresponse to a first-line agent. Although widely used in clinical practice, there is limited evidence to support antidepressant combination for TRD. Notwithstanding evidence for lithium or T3 augmentation to be successful in TRD, most studies were carried out when participants were treated with tricyclic antidepressants (TCA). Of the available strategies to augment the response to new-generation antidepressants, the use of some atypical antipsychotics is best supported by evidence. Several novel therapeutic options are currently discussed. Evidence suggests that cognitive therapy (CT) is an effective strategy for TRD.

CONCLUSIONS

The success of switching to a different antidepressant following a first-line agent is supported by evidence, but there is limited evidence for effective combination strategies. Lithium and T3 augmentation of TCA have the strongest evidence base for successful treatment of TRD. The use of augmentation of newer-generation antidepressants with atypical antipsychotics is supported by a growing evidence base. Current evidence supports CT as an effective strategy for TRD. There is a need for additional large-scale RCT of TRD. The development of new antidepressants targeting novel pathways opens a promising perspective for the management of TRD.

Pharmacological approaches to manage persistent symptoms of major depressive disorder: rationale and therapeutic strategies

Major depressive disorder (MDD) is a highly prevalent chronic psychiatric illness associated with significant morbidity, mortality, loss of productivity, and diminished quality of life. Typically, only a minority of patients responds to treatment and meet criteria for remission as residual symptoms may persist, the result of an inadequate course of treatment and/or the presence of persistent side effects. The foremost goal of treatment should be to restore patients to full functioning and eliminate or relieve all MDD symptoms, while being virtually free of troublesome side effects. The current available pharmacological options to manage persistent depressive symptoms include augmentation or adjunctive combination strategies, both of which target selected psychobiological systems and specific mood and somatic symptoms experienced by the patient. As well, non-pharmacological interventions including psychotherapies may be used in either first-line or adjunctive approaches. However, the evidence to date with respect to available adjunct therapies is limited by few studies and those published have utilized only a small number of subjects and lack enough data to allow for a consensus of expert opinion. This underlines the need for further longer term, large population-based studies and those that include comorbid populations, all of which are seen in real world community psychiatry.

Emerging antidepressants to treat major depressive disorder

Depression is a common disorder with an annual risk of a depressive episode in the United States of 6.6%. Only 30-40% of patients remit with antidepressant monotherapy, leaving 60-70% of patients who do not optimally respond to therapy. Unremitted depressive patients are at increased risk for suicide. Considering the prevalence of treatment resistant depression and its consequences, treatment optimization is imperative. This review summarizes the latest treatment modalities for major depressive disorder including pharmacotherapy, electroconvulsive therapy, repetitive transcranial magnetic stimulation and psychotherapy. Through advancements in research to better understand the pathophysiology of depression, advances in treatment will be realized.

Noradrenaline transmission reducing drugs may protect against a broad range of diseases

1 A growing body of evidence suggests that the signalling molecule, noradrenaline (NA), plays a pathophysiological role in a broad range of psychiatric, neurological and peripheral disorders. Both preclinical and clinical data suggest that elevated NA signalling may be involved in the aetiology of major diseases such as depression, Alzheimer's disease and diabetes mellitus. 2 The molecular pathways by which NA may cause the manifestation of disease remain poorly understood, although they may include G protein-coupled receptor modulation of the Ras/MAP kinase, Stat3 and PI3K pathways, among others. In both individual animals and humans, NA tone may be elevated largely due to genetics, but also because of the exposure to marked psychological stress or trauma, or other environmental factors. 3 As NA is involved in the 'fight or flight' response by the sympathetic nervous system, this transmitter may be elevated in a large number of organisms due to evolutionary selection of enhancing responses to immediate environmental dangers. Likewise, acetylcholine signalling by the parasympathetic ('rest and digest') nervous system may be relatively diminished. This putative autonomic imbalance may result in diminished engagement in homeostatic processes, resulting in the emergence and progression of a number of diseases throughout the body. 4 In this scenario, a large number of individuals may benefit from chronic use of pharmacological agents - such as clonidine, guanfacine, propranolol or prazosin - that diminish NA signalling throughout the body. If so, NA transmission lowering drugs may protect against a wide range of diseases.

Neuronal phenotype dependency of agonist-induced internalization of the 5-HT(1A) serotonin receptor

Selective serotonin reuptake inhibitors (SSRI) are aimed at increasing brain 5-HT tone; however, this expected effect has a slow onset after starting SSRI treatment because of initial activation of 5-HT(1A) autoreceptor-mediated negative feedback of 5-HT release. After chronic SSRI treatment, 5-HT(1A) autoreceptors desensitize, which allows 5-HT tone elevation. Because 5-HT(1A) receptor (5-HT(1A)R) internalization has been proposed as a possible mechanism underlying 5-HT(1A) autoreceptor desensitization, we examined whether this receptor could internalize under well controlled in vitro conditions in the LLC-CPK1 cell line and in raphe or hippocampal neurons from rat embryos. To this goal, cells were transfected with recombinant lentiviral vectors encoding N-terminal tagged 5-HT(1A)R, and exposed to various pharmacological conditions. Constitutive endocytosis and plasma membrane recycling of tagged-5-HT(1A)R was observed in LLC-PK1 cells as well as in neurons. Acute exposure (for 1 h) to the full 5-HT(1A)R agonists, 5-HT and 5-carboxamido-tryptamine, but not the partial agonist 8-OH-DPAT, triggered internalization of tagged 5-HT(1A)R in serotonergic neurons only. In contrast, sustained exposure (for 24 h) to all agonists induced tagged-5-HT(1A)R endocytosis in raphe serotonergic neurons and a portion of hippocampal neurons, but not LLC-PK1 cells and partial agonist displayed an effect only in serotonergic neurons. In all cases, agonist-induced tagged 5-HT(1A)R endocytosis was prevented by the 5-HT(1A)R antagonist, WAY-100635, which was inactive on its own. These data showed that agonist-induced 5-HT(1A)R internalization does exist in neurons and depends on agonist efficacy and neuronal phenotype. Its differential occurrence in serotonergic neurons supports the idea that 5-HT(1A)R internalization might underlie 5-HT(1A) autoreceptor desensitization under SSRI antidepressant therapy.

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.

Pooled analysis of sustained response rates for extended release quetiapine fumarate as monotherapy or adjunct to antidepressant therapy in patients with major depressive disorder

BACKGROUND

Clinical trials are not generally powered to analyze outcomes such as sustained response. We evaluated sustained response rates for patients with major depressive disorder receiving quetiapine XR as monotherapy or adjunct therapy.

METHOD

Post hoc analyses of pooled data from four previously reported randomized, placebo-controlled studies of quetiapine XR 150 and 300 mg/day as monotherapy or adjunct therapy to ongoing antidepressant. Sustained response rates (≥50% reduction in MADRS total score at specific timepoint and each subsequent visit until Week 6) were calculated at Weeks 1, 2, and 4; rates were compared using a Cochran-Mantel-Haenszel analysis.

RESULTS

In the monotherapy studies, the proportion of patients experiencing sustained response was greater with quetiapine XR 150 mg/day versus placebo at Week 2 (20.0% vs. 13.3%; p<0.05) and Week 4 (33.3% vs. 23.3%; p<0.01) (observed cases [OC]). The corresponding sustained response rates for quetiapine XR 300 mg/day were 18.0% (p=0.104) and 29.7% (p=0.063), respectively (OC). The proportion of patients experiencing sustained response was greater in the adjunct studies versus placebo at Weeks 2 and 4 for quetiapine XR 150 (Week 2, 30.1% vs. 15.2%, p<0.001; Week 4, 40.1% vs. 32.0%, p<0.05) and 300 mg/day (Week 2, 29.0% vs. 15.2%, p<0.001; Week 4, 42.0% vs. 32.0%, p<0.05) (OC).

LIMITATIONS

Post hoc analyses, acute treatment period; no active comparator.

CONCLUSIONS

Quetiapine XR as monotherapy (150 mg/day at Weeks 2 and 4) or adjunct to ongoing antidepressant therapy (150 and 300 mg/day at Weeks 2 and 4) increased sustained response rates versus placebo.

Antidepressant augmentation and combination in unipolar depression: strong guidance, weak foundations

Depression will be the second leading contributor to the global burden of disease by 2020. In Ireland, in 2009, 6061 people were hospitalised with depressive disorders. This represents a significant economic and social burden. There is growing awareness of the difficulty in treating depression with medications alone. The likelihood that a patient will achieve remission with the first antidepressant tried is around 30%, and the rates are similar for the second antidepressant tried. This falls to around 15% after three trials. Many patients are exposed to pharmacotherapy for extended periods of time with little beneficial effect, but often with side-effects. Patients are therefore in great need of clear information with regard to their chance of success. Clinicians are in need of clear guidance on prescribing strategies which have proven efficacy. However, this guidance often discusses treatment strategies based on varying levels of evidence. Guiding bodies may approach the problem from varying perspectives. The UK National Institute for Health and Clinical Excellence (NICE) has a clear government mandate with regard to provision of not only effective but cost-effective treatments. The British Association of Psychopharmacology (BAP) is an independent body of interested researchers and therefore may discuss prescribing options from the point of view of tertiary care institutions, and university centres. The South London and Maudsley NHS Foundation Trust publish the popular Maudsley guidelines. These are perhaps more pragmatic in nature, but include very low levels of evidence, including case series. The American Psychiatric Association (APA) is an independent member association which also publishes guidelines. These are published in the American Journal of Psychiatry and the latest guidelines were published in October 2010. All these bodies attempt to weigh their advice according to the level of evidence available and aim to provide clinical guidance in difficult situations. The burden on guiding organisations is to provide some direction and clarity in areas that are often unclear or controversial. Clinical guidelines are one method of providing support and guidance to busy clinicians. However, this clinician-centered approach has limitations. The onus is on the authors of the guidance to provide ever-more treatment options. This may mean that conclusions about the efficacy of medications is overstated or the limitations of the literature not fully explored in explanatory notes.

Higher serotonin 1A binding in a second major depression cohort: modeling and reference region considerations

BACKGROUND

Serotonin 1A receptors (5-HT(1A)) are implicated in major depressive disorder (MDD). We previously reported higher 5-HT(1A) binding potential (BP(F)) in antidepressant naive MDD subjects compared with control subjects, while other studies report lower BP(ND). Discrepancies can be related to differences in study population or methodology. We sought to replicate our findings in a novel cohort and determine whether choice of reference region and outcome measure could explain discrepancies.

METHODS

Nine new control subjects and 22 new not recently medicated (NRM) MDD subjects underwent positron emission tomography. BP(F) and BP(ND) were determined using a metabolite and free fraction corrected arterial input function. BP(ND) was also determined using cerebellar gray matter (CGM) and cerebellar white matter (CWM) reference regions as input functions.

RESULTS

BP(F) was higher in the new NRM cohort (p = .037) compared with new control subjects, comparable to the previous cohort (p = .04). Cohorts were combined to examine the reference region and outcome measure. BP(F) was higher in the NRM compared with control subjects (p = .0001). Neither BP(ND) using CWM (p = .86) nor volume of distribution (V(T)) (p = .374) differed between groups. When CGM was used, the NRM group had lower 5-HT(1A) BP(ND) compared with control subjects (p = .03); CGM V(T) was higher in NRM compared with control subjects (p = .007).

CONCLUSIONS

Choice of reference region and outcome measure can produce different 5-HT(1A) findings. Higher 5-HT(1A) BP(F) in MDD was found with the method with fewest assumptions about nonspecific binding and a reference region without receptors.

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.

Pindolol augmentation enhances response outcomes in first depressive episodes

Effectiveness of Pindolol addition to SSRIs is still a matter of debate. Recently, Geretsegger et al. [Geretsegger, C., Bitterlich, W., Stelzig, R., Stuppaeck, C., Bondy, B. and Aichhorn, W. (2008) Paroxetine with Pindolol augmentation: a double-blind, randomized, placebo-controlled study in depressed in-patients. Eur. Neuropsychopharmacol. 18, 141-146.] have found that never-medicated depressed patients showed a significant sustained response with Paroxetine + Pindolol treatment. Also, patients with a first depressive episode displayed a trend for higher sustained response rates with Pindolol co-administration. Re-analysing the data of a previous clinical trial of Fluoxetine + Pindolol [Pérez, V., Gilaberte, I., Faries, D., Alvarez, E. and Artigas, F. (1997). Randomised, double-blind, placebo-controlled trial of Pindolol in combination with Fluoxetine antidepressant treatment. Lancet 349, 1594-1597.], we have found that first depressive episodes are associated with a significant higher percentage of sustained responses when administering Fluoxetine + Pindolol (70.3%) compared to Fluoxetine + Placebo (44%). Moreover, based on a survival analysis, among the patients with a first depressive episode, those who received Fluoxetine + Pindolol achieved a sustained response significantly earlier (19 days) than those on Fluoxetine + Placebo (35 days). Interestingly, none of these effects were observed in the subsample of recurrent patients. The results suggest that Pindolol augmentation accelerates and enhances the action of SSRI at the beginning of the illness.

5-HT(1A) receptor function in major depressive disorder

Dysfunction of the serotonin 1A receptor (5-HT(1A)) may play a role in the genesis of major depressive disorder (MDD). Here we review the pharmacological, post-mortem, positron emission tomography (PET), and genetic evidence in support of this statement. We also touch briefly on two MDD-associated phenotypes, cognitive impairment and somatic pain. The results of pharmacological challenge studies with 5-HT(1A) receptor agonists are indicative of blunted endocrine responses in depressed patients. Lithium, valproate, selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs), and other treatment, such as electroconvulsive shock therapy (ECT), all increase post-synaptic 5-HT(1A) receptor signaling through either direct or indirect effects. Reduced somatodendritic and postsynaptic 5-HT(1A) receptor numbers or affinity have been reported in some post-mortem studies of suicide victims, a result consistent with well-replicated PET analyses demonstrating reduced 5-HT(1A) receptor binding potential in diverse regions such as the dorsal raphe, medial prefrontal cortex (mPFC), amygdala and hippocampus. 5-HT(1A) receptor knockout (KO) mice display increased anxiety-related behavior, which, unlike in their wild-type counterparts, cannot be rescued with antidepressant drug (AD) treatment. In humans, the G allele of a single nucleotide polymorphism (SNP) in the 5-HT(1A) receptor gene (HTR1A; rs6295), which abrogates a transcription factor binding site for deformed epidermal autoregulatory factor-1 (Deaf-1) and Hes5, has been reported to be over-represented in MDD cases. Conversely, the C allele has been associated with better response to AD drugs. We raise the possibility that 5-HT(1A) receptor dysfunction represents one potential mechanism underpinning MDD and other stress-related disorders.

Augmentation strategies for treatment-resistant depression

PURPOSE OF REVIEW

The majority of patients with depression fail to remit on one or more antidepressant trials. These patients have treatment-resistant depression (TRD) with high relapsing rates. Augmentation pharmacotherapy refers to the addition of drugs that are not standard antidepressants in order to enhance the effect of a classical antidepressant drug. This review highlights the current status and future research directions of augmentation treatments for TRD with a special focus on research data published within the past year.

RECENT FINDINGS

Atypical antipsychotics, stimulants, pindolol, lithium, lamotrigine and mecamylamine were tested for efficacy in clinical trials. Most of the trials were not controlled or had limited sample size. Recent data now support the use of some atypical antipsychotics to augment depression resistant to the newer, more selective, antidepressants.

SUMMARY

Lithium and triiodothyronin (T3) augmentation of tricyclic agents remains the best studied strategy. Data converge to demonstrate the efficacy of some atypical antipsychotics as augmenting agents to selective serotonin reuptake inhibitors. Further adequately powered controlled trials on augmentation pharmacotherapy of TRD are necessary.