Dose-response relationship of recent antidepressants in the short-term treatment of depression

Nitrogen-containing heterocyclic compounds: A ray of hope in depression?

Depression is not similar to daily mood fluctuations and temporary emotional responses to day-to-day activities. Depression is not a passing problem; it is an ongoing problem. It deals with different episodes consisting of several symptoms that last for at least 2 weeks. It can be seen for several weeks, months, or years. At its final stage, or can say, in its worst condition, it can lead to suicide. Antidepressants are used to inhibit the reuptake of the neurotransmitters by some selective receptors, which increase the concentration of specific neurotransmitters around the nerves in the brain. Drugs that are currently being used for the management of various types of depression include selective serotonin reuptake inhibitors, tricyclic antidepressants, atypical antidepressants, serotonin, noradrenaline reuptake inhibitors, etc. In this review, we have outlined different symptoms, causes, and recent advancements in nitrogen-containing heterocyclic drug candidates for the management of depression. This article highlights the various structural features along with the structure-activity relationship (SAR) of nitrogen-containing heterocyclics that play a key role in binding at target sites for potential antidepressant action. The in silico studies were carried out to determine the binding interactions of the target ligands with the receptor site to determine the potential role of substitution patterns at core pharmacophoric features. This article will help medicinal chemists, biochemists, and other interested researchers in identifying the potential pharmacophores as lead compounds for further development of new potent antidepressants.

In utero, lactational, or peripartal fluoxetine administration has differential implications on the murine maternal skeleton

The peripartal period is marked by alterations in calcium metabolism to accommodate for embryonic skeletal mineralization and support bone development of offspring in early life, and serotonin plays a critical role in modulating peripartal bone remodeling. Selective serotonin reuptake inhibitors (SSRIs) are commonly used as first-line treatment for psychiatric illness during pregnancy and the postpartum period and considered safe for maternal use during this time frame. In order to evaluate the effect of peripartal alterations of the serotonergic system on maternal skeletal physiology, we treated dams with the SSRI fluoxetine during gestation only, lactation only, or during the entire peripartal period. Overall, we found a low dose of fluoxetine during gestation only had minimal impacts on maternal bone at weaning, but there were implications on maternal skeleton at weaning when dams were exposed during lactation only or during the entire peripartal period. We found that these effects were differential between female mice dosed lactationally or peripartally, and there were also impacts on maternal mammary gland at weaning in both of these groups. Though SSRIs are largely considered safe maternally during the peripartal period, this study raises the question whether safety of SSRIs, specifically fluoxetine, during the peripartal period should be reevaluated.

Poor Neonatal Adaptation After Antidepressant Exposure During the Third Trimester in a Geographically Defined Cohort

Objective

To examine the associations between antidepressant exposure during the third trimester of pregnancy, including individual drugs, drug doses, and antidepressant combinations, and the risk of poor neonatal adaptation (PNA).

Patients and Methods

The Rochester Epidemiology Project medical records-linkage system was used to study infants exposed to selective serotonin reuptake inhibitors (SSRIs; n=1014), bupropion, (n=118), serotonin-norepinephrine reuptake inhibitors (n=80), antidepressant combinations (n=20), or other antidepressants (n=22) during the third trimester (April 11, 2000-December 31, 2013). Poor neonatal adaptation was defined based on a review of medical records. Poisson regression was used to examine the risk of PNA with serotonergic antidepressant and drug combinations compared with that with bupropion monotherapy as well as with high- vs standard-dose antidepressants. When possible, analyses were performed using propensity score (PS) weighting.

Results

Forty-four infants were confirmed cases of PNA. Serotonin-norepinephrine reuptake inhibitor monotherapy, antidepressant combinations, and paroxetine monotherapy were associated with a significantly higher risk of PNA than bupropion monotherapy in unweighted analyses. High-dose SSRI exposure was associated with a significantly increased risk of PNA in unadjusted (relative risk, 2.61; 95% confidence interval, 1.35-5.04) and PS-weighted models (relative risk, 2.29; 95% confidence interval, 1.17-4.48) compared with standard-dose SSRI exposure. The risk of PNA was significantly higher with high-dose paroxetine and sertraline than with standard doses in the PS-weighted analyses. The other risk factors for PNA included maternal anxiety disorders.

Conclusion

Although the frequency of PNA in this cohort was low (3%-4%), the risk of PNA was increased in infants exposed to serotonergic antidepressants, particularly with SSRIs at higher doses, during the third trimester of pregnancy compared with that in infants exposed to standard doses. Potential risk factors for PNA also included third-trimester use of paroxetine (especially at higher doses) and maternal anxiety.

Dose-response effects of selective serotonin reuptake inhibitor monotherapy for the treatment of depression: systematic review of reviews and meta-narrative synthesis

Objective

To assess and clarify the relations between selective serotonin reuptake inhibitor (SSRI) dose efficacy, acceptability (early treatment discontinuation (dropouts)), and tolerability (reported adverse drug effects), and critically evaluate methods previously used to examine SSRI dose-response effects for the treatment of depression in adults.

Design

Systematic review of reviews and meta-narrative synthesis.

Data sources

Embase, Medline, PsycINFO, Scopus, and the Cochrane Collaboration library, from 1975 to December 2021. Reference lists of national depression treatment guidelines were systemically searched by hand.

Eligibility criteria for selecting studies

Reviews assessing SSRI monotherapy dose-response effects for the treatment of depression in adults (age ≥18 years) reporting efficacy, acceptability, or tolerability. Reviews meeting inclusion criteria had a high degree of heterogeneity, due to methodological diversity; therefore, a meta-narrative synthesis approach was applied. Standard daily doses were defined as 20 mg citalopram, fluoxetine, paroxetine; 50 mg sertraline; and 10 mg escitalopram. Risk of bias was assessed using the Risk of Bias in Systematic Reviews tool, in line with Cochrane recommendations.

Results

The search identified 9138 records; 387 full text reports were assessed for eligibility, 42 of which matched the inclusion criteria. The majority, 83% (n=35), of reviews included data for studies with a duration of ≤12 weeks (ie, the acute phase of depression treatment). Of 39 reviews assessing efficacy, the majority (n=26) indicated that individual SSRIs and SSRI class demonstrated flat dose-response effects; standard doses were optimal for efficacy. Acceptability or tolerability were assessed in 28 reviews. Higher than standard daily doses were associated with higher dropout rates and a greater incidence of adverse drug effects (eg, nausea, sexual dysfunction, fatigue, anxiety). Despite a range of methods being reported, there was an overall consensus regarding SSRI dose related efficacy, dropouts, and adverse drug effects.

Conclusion

Standard daily doses of SSRIs for the treatment of depression in adults provide a favourable balance between efficacy, acceptability, and tolerability. Patients are encouraged to talk to their prescriber or community pharmacist if they experience adverse effects or have any concerns about their drug treatments.

Real-world effectiveness of vortioxetine in outpatients with major depressive disorder: functioning and dose effects

BACKGROUND

Functional recovery is an important treatment goal in major depressive disorder (MDD). This study assessed the real-world effectiveness of vortioxetine in patients with MDD, with particular focus on functioning; dose-response was also assessed.

METHODS

This was a non-interventional, prospective, multicenter study conducted in Greece. Adult outpatients with MDD (n = 336) initiating vortioxetine (5-20 mg/day flexible dosing) as treatment for a current major depressive episode were followed for 3 months. Analyses were stratified according to vortioxetine dosage at 3 months: 5-10 mg/day versus 15-20 mg/day. Functioning was assessed using the Sheehan Disability Scale (SDS).

RESULTS

Mean ± standard error SDS total score decreased (improved) from 18.7 ± 0.3 at baseline to 12.9 ± 0.3 after 1 month of vortioxetine treatment and 7.8 ± 0.4 after 3 months (p < 0.001 vs. baseline for all comparisons). Functional recovery (SDS score ≤ 6) was achieved in 14.6% of patients after 1 month of treatment and 48.4% of patients after 3 months. Improvement from baseline in SDS total and domain scores at 3 months was more pronounced in patients receiving vortioxetine 15-20 mg/day than in those receiving vortioxetine 5-10 mg/day. The mean ± standard error change in SDS total score from baseline was 9.2 ± 0.8 in the 5-10 mg/day group and 12.1 ± 0.4 in the 15-20 mg/day group (p < 0.001). Limitations of this study include its non-interventional study design and lack of a control group or active comparator.

CONCLUSIONS

Statistically significant and clinically relevant improvements in functioning were seen in patients with MDD treated with vortioxetine in a real-world setting. Higher doses of vortioxetine were associated with significantly greater improvements in functioning.

Impact of chosen cutoff on response rate differences between selective serotonin reuptake inhibitors and placebo

Response defined as a 50% reduction in the sum score of the Hamilton Depression Rating Scale (HDRS-17-sum) is often used to assess the efficacy of antidepressants. Critics have, however, argued that dichotomising ratings with a cutoff close to the median may lead to scores clustering on either side, the result being inflation of miniscule drug-placebo differences. Using pooled patient-level data sets from trials of three selective serotonin reuptake inhibitors (SSRIs) (citalopram, paroxetine and sertraline) (n = 7909), and from similar trials of duloxetine (n = 3478), we thus assessed the impact of different cutoffs on response rates. Response criteria were based on (i) HDRS-17-sum, (ii) the sum score of the HDRS-6 subscale (HDRS-6-sum) and (iii) the depressed mood item. The separation between SSRI and placebo with respect to response rates increased when HDRS-17-sum was replaced by HDRS-6-sum or depressed mood as effect parameter and was markedly dependent on SSRI dose. With the exception of extreme cutoff values, differences in response rates were largely similar regardless of where the cutoff was placed, and also not markedly changed by the exclusion of subjects close to the selected cutoff (e.g., ±10%). The observation of similar response rate differences between active drugs and placebo for different cutoffs was corroborated by the analysis of duloxetine data. In conclusion, the suggestion that using a cutoff close to the median when defining response has markedly overestimated the separation between antidepressants and placebo may be discarded.

Population Pharmacokinetics of Viloxazine Extended-Release Capsules in Pediatric Subjects With Attention Deficit/Hyperactivity Disorder

Viloxazine extended-release capsules (viloxazine ER; Qelbree) is a novel nonstimulant, recently approved by the US Food and Drug Administration for the treatment of ADHD in pediatrics. Here, we characterize the pharmacokinetics (PK) of viloxazine and its major metabolite, 5-HVLX-gluc, using a population PK model and evaluate the impact of 1-4 days of missed viloxazine ER doses on viloxazine PK. Data from 4 phase 3 trials in pediatric subjects treated with viloxazine ER were used to establish the PK model. Covariate analysis was conducted on the final base model. The impact of 1-4 days of missed doses on steady-state viloxazine PK was evaluated using Monte Carlo simulations. A 1-compartmental linear model with first-order absorption and elimination of the parent drug and first-order metabolite formation and elimination properly described the population PK of viloxazine and 5-HVLX-gluc. Body weight impacted the systemic exposure of viloxazine and 5-HVLX-gluc. Predicted PK parameters at steady state (mean ± standard deviation) in children receiving viloxazine ER were determined. C_max was 1.60 ± 0.70 μg/mL at 100 mg, 2.83 ± 1.31 μg/mL at 200 mg, and 5.61 ± 2.48 μg/mL at 400 mg. AUC_0-t was 19.29 ± 8.88 μg·h/mL at 100 mg, 34.72 ± 16.53 μg·h/mL at 200 mg, and 68.00 ± 28.51 μg·h/mL at 400 mg. PK parameters for adolescents receiving viloxazine ER were also determined. C_max was 2.06 ± 0.90 μg/mL at 200 mg, 4.08 ± 1.67 μg/mL at 400 mg, and 6.49 ± 2.87 μg/mL at 600 mg. AUC_0-t was 25.78 ± 11.55 μg·h/mL at 200 mg, 50.80 ± 19.76 μg·h/mL at 400 mg, and 79.97 ± 36.91 μg·h/mL at 600 mg. Simulations revealed that, regardless of the duration of the dosing interruption, viloxazine concentration returned to steady-state levels after approximately 2 days of once-daily dosing of viloxazine ER.

Low SSRI dosing in clinical practice-a register-based longitudinal study

OBJECTIVE

Since several recent meta-analyses report a dose-response relationship for the antidepressant effect of the selective serotonin reuptake inhibitors (SSRIs), we investigated how these drugs are dosed in clinical practice.

METHODS

Through linkage of nation- or region-wide registers, we describe SSRI doses in 50,365 individuals residing in Region Västra Götaland, Sweden, with an incident diagnosis of depression and initiating SSRI treatment between 2007 and 2016. The primary question was to elucidate to what extent these individuals had been prescribed a daily dose that according to recent meta-analyses is required to elicit the maximum antidepressant effect, that is >20 mg citalopram, >10 mg escitalopram, >10 mg fluoxetine, >10 mg paroxetine or >50 mg sertraline.

RESULTS

In all, 21,049 (54%) out of 38,868 individuals <65 years of age, and 9,131 (79%) out of 11,497 individuals ≥65 years of age, never received an SSRI dose reported to exert maximum antidepressant effect. These prescribing practices were seen for citalopram, escitalopram and sertraline, but not for fluoxetine and paroxetine, and were frequent in both primary and secondary/tertiary care. Suggesting that doses here defined as maximum efficacy doses, when prescribed, are usually not intolerable, between 59% and 68% of individuals <65 years of age received such a dose also for the subsequent prescription, that is as frequently as in those prescribed a sub-maximum efficacy dose (52-69%).

CONCLUSION

Most patients being prescribed an SSRI to treat their depression never receive the dose that according to recent meta-analyses is most likely to effectively combat their condition. The lack of consensus regarding effective dosing of SSRIs may have contributed to this state of affairs.

The Antidiabetic Metformin as an Adjunct to Antidepressants in Patients with Major Depressive Disorder: A Proof-of-Concept, Randomized, Double-Blind, Placebo-Controlled Trial

Metformin (MET) has been reported to have antidepressant effects in animal models and in diabetic patients with depression, owing to its anti-inflammatory, antioxidant, and neuroprotective activity. Accordingly, we proposed that MET would show antidepressant effects in patients with major depressive disorder (MDD) without other comorbidities. In this double-blind placebo-controlled study, 80 adult outpatients with MDD (DSM-IV criteria) and a Hamilton Depression Rating Scale (HAM-D) score >18 were randomized to receive fluoxetine 20 mg once daily plus placebo (n = 40) or fluoxetine 20 mg once daily plus MET 1000 mg once daily for 12 weeks. Patients were assessed by HAM-D score (weeks 0, 4, 8, and 12). The serum levels of TNF-α, IL-1β, IL-6, IGF-1, MDA, CRP, BDNF, and serotonin were measured before and after therapy. Mixed-effects model repeated-measures analysis of covariance was used to compare the HAM-D scores and the biological markers between the two groups. After 4, 8 and 12 weeks, patients in the MET group showed a statistically significant decline in HAM-D score relative to the placebo group (least squares mean difference [LSMD] -2.347, p = 0.000, LSMD -3.369, p = 0.000, and LSMD -3.454, p = 0.000, respectively). Response and remission rates were significantly higher in the MET group (89% and 81%, respectively) than in the placebo group (59% and 46%, respectively). Moreover, the MET group was superior in conserving the measured biological markers compared with the placebo group. Our findings suggest MET as a promising, effective, and safe short-term adjunctive approach in nondiabetic MDD patients. Trial registration ID: NCT04088448.

Comparative efficacy and acceptability of antidepressants, psychotherapies, and their combination for acute treatment of children and adolescents with depressive disorder: a systematic review and network meta-analysis

BACKGROUND

Depressive disorders are common in children and adolescents. Antidepressants, psychotherapies, and their combination are often used in routine clinical practice; however, available evidence on the comparative efficacy and safety of these interventions is inconclusive. Therefore, we sought to compare and rank all available treatment interventions for the acute treatment of depressive disorders in children and adolescents.

METHODS

We did a systematic review and network meta-analysis. We searched PubMed, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, PsycINFO, ProQuest, CINAHL, LiLACS, international trial registries, and the websites of regulatory agencies for published and unpublished randomised controlled trials from database inception until Jan 1, 2019. We included placebo-controlled and head-to-head trials of 16 antidepressants, seven psychotherapies, and five combinations of antidepressant and psychotherapy that are used for the acute treatment of children and adolescents (≤18 years old and of both sexes) with depressive disorder diagnosed according to standard operationalised criteria. Trials recruiting participants with treatment-resistant depression, bipolar disorder, psychotic depression, treatment duration of less than 4 weeks, or an overall sample size of fewer than ten patients were excluded. We extracted data following a predefined hierarchy of outcome measures, and assessed risk of bias and certainty of evidence using validated methods. Primary outcomes were efficacy (change in depressive symptoms) and acceptability (treatment discontinuation due to any cause). We estimated summary standardised mean differences (SMDs) or odds ratios (ORs) with credible intervals (CrIs) using network meta-analysis with random effects. This study was registered with PROSPERO, number CRD42015020841.

FINDINGS

From 20 366 publications, we included 71 trials (9510 participants). Depressive disorders in most studies were moderate to severe. In terms of efficacy, fluoxetine plus cognitive behavioural therapy (CBT) was more effective than CBT alone (-0·78, 95% CrI -1·55 to -0·01) and psychodynamic therapy (-1·14, -2·20 to -0·08), but not more effective than fluoxetine alone (-0·22, -0·86 to 0·42). No pharmacotherapy alone was more effective than psychotherapy alone. Only fluoxetine plus CBT and fluoxetine were significantly more effective than pill placebo or psychological controls (SMDs ranged from -1·73 to -0·51); and only interpersonal therapy was more effective than all psychological controls (-1·37 to -0·66). Nortriptyline (SMDs ranged from 1·04 to 2·22) and waiting list (SMDs ranged from 0·67 to 2·08) were less effective than most active interventions. In terms of acceptability, nefazodone and fluoxetine were associated with fewer dropouts than sertraline, imipramine, and desipramine (ORs ranged from 0·17 to 0·50); imipramine was associated with more dropouts than pill placebo, desvenlafaxine, fluoxetine plus CBT, and vilazodone (2·51 to 5·06). Most of the results were rated as "low" to "very low" in terms of confidence of evidence according to Confidence In Network Meta-Analysis.

INTERPRETATION

Despite the scarcity of high-quality evidence, fluoxetine (alone or in combination with CBT) seems to be the best choice for the acute treatment of moderate-to-severe depressive disorder in children and adolescents. However, the effects of these interventions might vary between individuals, so patients, carers, and clinicians should carefully balance the risk-benefit profile of efficacy, acceptability, and suicide risk of all active interventions in young patients with depression on a case-by-case basis.

FUNDING

National Key Research and Development Program of China.

Analysis of Time-Course, Dose-Effect, and Influencing Factors of Antidepressants in the Treatment of Acute Adult Patients With Major Depression

OBJECTIVE

Model-based meta-analysis was used to describe the time-course and dose-effect relationships of antidepressants and also simultaneously investigate the impact of various factors on drug efficacy.

METHODS

This study is a reanalysis of a published network meta-analysis. Only placebo-controlled trials were included in this study. The change rate in depression rating scale scores from baseline was used as an efficacy indicator because a continuous variable is more likely to reflect subtle differences in efficacy between drugs.

RESULTS

A total 230 studies containing 64 346 patients were included in the analysis. The results showed that the number of study sites (single or multi-center) and the type of setting (inpatient or noninpatient) are important factors affecting the efficacy of antidepressants. After deducting the placebo effect, the maximum pure drug efficacy value of inpatients was 18.4% higher than that of noninpatients, and maximum pure drug efficacy value of single-center trials was 10.2% higher than that of multi-central trials. Amitriptyline showed the highest drug efficacy. The remaining 18 antidepressants were comparable or had little difference. Within the approved dose range, no significant dose-response relationship was observed. However, the time-course relationship is obvious for all antidepressants. In terms of safety, with the exception of amitriptyline, the dropout rate due to adverse events of other drugs was not more than 10% higher than that of the placebo group.

CONCLUSION

The number of study sites and the type of setting are significant impact factors for the efficacy of antidepressants. Except for amitriptyline, the other 18 antidepressants have little difference in efficacy and safety.

Do baseline WAIS-III subtests predict treatment outcomes for depressed inpatients receiving fluoxetine?

This study aimed to determine whether baseline WAIS-III subtests could be associated with treatment outcomes for patients with major depressive disorder (MDD) receiving a 6-week fluoxetine treatment. A total of 131 acutely ill MDD inpatients were enrolled to receive 20 mg of fluoxetine daily for 6 weeks. Eight WAIS-III subtests were administered at baseline. Symptom severity and functional impairment were assessed at baseline, and again at weeks 1, 2, 3, 4, and 6 using the 17-item Hamilton Depression Rating Scale (HAMD-17) and the Modified Work and Social Adjustment Scale (MWSAS), respectively. The generalized estimating equations method was used to analyze the influence of potential predictors over time on the HAMD-17 and MWSAS, after adjusting for covariates. Of the 131 participants, 104 (79.4%) who completed 8 WAIS-III subtests at baseline and had at least one post-baseline assessment were included in the analysis. Patients with lower forward digit span scores were more likely to have poor treatment outcomes, both measured by HAMD-17, and by MWSAS. Forward digit span may be clinically useful in identifying MDD patients with greater treatment difficulty in symptoms and functioning. Other neurocognitive tests to predict treatment outcome require further exploration.

ECT Has Greater Efficacy Than Fluoxetine in Alleviating the Burden of Illness for Patients with Major Depressive Disorder: A Taiwanese Pooled Analysis

BACKGROUND

The burden of major depressive disorder includes suffering due to symptom severity, functional impairment, and quality of life deficits. The aim of this study was to compare the differences between electroconvulsive therapy and pharmacotherapy in reducing such burdens.

METHODS

This was a pooled analysis study including 2 open-label trials for major depressive disorder inpatients receiving either standard bitemporal and modified electroconvulsive therapy with a maximum of 12 sessions or 20 mg/d of fluoxetine for 6 weeks. Symptom severity, functioning, and quality of life were assessed using the 17-item Hamilton Rating Scale for Depression, the Modified Work and Social Adjustment Scale, and SF-36. Side effects following treatment, including subjective memory impairment, nausea/vomiting, and headache, were recorded. The differences between these 2 groups in 17-item Hamilton Rating Scale for Depression, Modified Work and Social Adjustment Scale, quality of life, side effects, and time to response (at least a 50% reduction of 17-item Hamilton Rating Scale for Depression) and remission (17-item Hamilton Rating Scale for Depression ≤7) following treatment were analyzed.

RESULTS

Electroconvulsive therapy (n=116) showed a significantly greater reduction in 17-item Hamilton Rating Scale for Depression, Modified Work and Social Adjustment Scale, and quality of life deficits and had significantly shorter time to response/remission than fluoxetine (n=126). However, the electroconvulsive therapy group was more likely to experience subjective memory impairment and headache.

CONCLUSIONS

Compared with fluoxetine, electroconvulsive therapy was more effective in alleviating the burden of major depressive disorder and had a substantially increased speed of response/remission in the acute phase. Increased education and information about electroconvulsive therapy for clinicians, patients, and their families and the general public is warranted.

Development and evaluation of Desvenlafaxine loaded PLGA-chitosan nanoparticles for brain delivery

Depression is a debilitating psychiatric condition that remains the second most common cause of disability worldwide. Currently, depression affects more than 4 per cent of the world’s population. Most of the drugs intended for clinical management of depression augment the availability of neurotransmitters at the synapse by inhibiting their neuronal reuptake. However, the therapeutic efficacy of antidepressants is often compromised as they are unable to reach brain by the conventional routes of administration. The purpose of the present study was to reconnoiter the potential of mucoadhesive PLGA-chitosan nanoparticles for the delivery of encapsulated Desvenlafaxine to the brain by nose to brain delivery route for superior pharmacokinetic and pharmacodynamic profile of Desvenlafaxine. Desvenlafaxine loaded PLGA-chitosan nanoparticles were prepared by solvent emulsion evaporation technique and optimized for various physiochemical characteristics. The antidepressant efficacy of optimized Desvenlafaxine was evaluated in various rodent depression models together with the biochemical estimation of monoamines in their brain. Further, the levels of Desvenlafaxine in brain and blood plasma were determined at various time intervals for calculation of different pharmacokinetic parameters. The optimized Desvenlafaxine loaded PLGA-chitosan nanoparticles (∼172 nm/+35 mV) on intranasal administration significantly reduced the symptoms of depression and enhanced the level of monoamines in the brain in comparison with orally administered Desvenlafaxine. Nose to brain delivery of Desvenlafaxine PLGA-chitosan nanoparticles also enhanced the pharmacokinetic profile of Desvenlafaxine in brain together with their brain/blood ratio at different time points. Thus, intranasal mucoadhesive Desvenlafaxine PLGA-chitosan nanoparticles could be potentially used for the treatment of depression.

Abandoning personalization to get to precision in the pharmacotherapy of depression

Effectiveness studies and analyses of naturalistic cohorts demonstrate that many patients with major depressive disorder do not experience symptomatic remission with antidepressant treatments. In an effort to better match patients with effective treatments, numerous investigations of predictors or moderators of treatment response have been reported over the past five decades, including clinical features as well as biological measures. However, none of these have entered routine clinical practice; instead, clinicians typically personalize treatment on the basis of patient preferences as well as their own. Here, we review the reasons why it has been challenging to identify and deploy treatment-specific predictors of response, and suggest strategies that may be required to achieve true precision in the pharmacotherapy of depression. We emphasize the need for changes in how depression care is delivered, measured, and used to inform future practice.

Raising the Minimum Effective Dose of Serotonin Reuptake Inhibitor Antidepressants: Adverse Drug Events

This review focuses on the dose-response of serotonin reuptake inhibitor (SRI) antidepressants for efficacy and for adverse drug events (ADEs). Dose-response is identified by placebo-controlled, double-blind, fixed-dose clinical trials comparing various doses for efficacy and for ADEs. Reports from the great majority of clinical trials have consistently found that the minimum SRI effective dose is usually optimal for efficacy in the treatment of depression disorders, even though most American medical practitioners raise the dose when early antidepressant treatment results are negative or partial. To better understand this issue, the medical literature was comprehensively reviewed to ascertain the degree to which SRI medications resulted in a flat dose response for efficacy and then to identify specific ADEs that are dose-dependent. Strong evidence from fixed-dose trial data for the efficacy of nonascendant, minimum effective doses of SRIs was found for the treatment of both major depression and anxiety disorders. Particularly important was the finding that most SRI ADEs have an ascending dose-response curve. These ADEs include sexual dysfunction, hypertension, cardiac conduction risks, hyperglycemia, decreased bone density, sweating, withdrawal symptoms, and agitation. Thus, routinely raising the SRI dose above the minimum effective dose for efficacy can be counter-productive.

A mega-analysis of fixed-dose trials reveals dose-dependency and a rapid onset of action for the antidepressant effect of three selective serotonin reuptake inhibitors

The possible dose-dependency for the antidepressant effect of selective serotonin reuptake inhibitors (SSRIs) remains controversial. We believe we have conducted the first comprehensive patient-level mega-analysis exploring this issue, one incentive being to address the possibility that inclusion of low-dose arms in previous meta-analyses may have caused an underestimation of the efficacy of these drugs. All company-sponsored, acute-phase, placebo-controlled, fixed-dose trials using the Hamilton Depression Rating Scale (HDRS) and conducted to evaluate the effect of citalopram, paroxetine or sertraline in adult major depression were included (11 trials, n=2859 patients). The single-item depressed mood, which has proven a more sensitive measure to detect an antidepressant signal than the sum score of all HDRS items, was designated the primary effect parameter. Doses below or at the lower end of the usually recommended dose range (citalopram: 10-20 mg, paroxetine: 10 mg; sertraline: 50 mg) were superior to placebo but inferior to higher doses, hence confirming a dose-dependency to be at hand. In contrast, among doses above these, there was no indication of a dose-response relationship. The effect size (ES) after exclusion of suboptimal doses was of a more respectable magnitude (0.5) than that usually attributed to the antidepressant effect of the SSRIs. In conclusion, the observation that low doses are less effective than higher ones challenges the oft-cited view that the effect of the SSRIs is not dose-dependent and hence not caused by a specific, pharmacological antidepressant action. Moreover, we suggest that inclusion of suboptimal doses in previous meta-analyses has led to an underestimation of the efficacy of these drugs.

Evaluation of interleukin-6 and serotonin as biomarkers to predict response to fluoxetine

OBJECTIVE

Only 30% of major depressive disorder (MDD) patients achieve complete remission with a serotonergic antidepressant (selective serotonin reuptake inhibitor). We investigated the potential of serotonin (5-HT) and interleukin-6 (IL-6) to serve as functional biomarkers of fluoxetine response.

METHODS

Serum IL-6 and 5-HT were measured in 73 MDD patients (39 responders and 34 non-responders) pre- and 6 weeks post-treatment and in 44 normal controls with ELISA. Fluoxetine and norfluoxetine were measured using LC MS/MS.

RESULTS

IL-6 levels were significantly higher in MDD patients when compared with controls (p < 0.01), and 5-HT levels were significantly lower in non-responders compared with controls (p = 0.0131). Pre- and post-treatment levels of both biomarkers individually and in combination did not significantly differ between responders and non-responders. Area under the receiver operating characteristics curve for the biomarkers was 0.5. Significant correlation was seen between the percentage change in IL-6 and percentage change in Hamilton Rating Scale for Depression score in responders. Fluoxetine and norfluoxetine concentrations were not significantly different in responders and non-responders, and there was no correlation between fluoxetine concentrations and percentage reduction in 5-HT from week 0 to 6.

CONCLUSION

5-HT and IL-6 may not serve as useful markers of response to fluoxetine because of inconsistent results across different studies. Copyright © 2016 John Wiley & Sons, Ltd.

A randomized, double-blinded, placebo-controlled study to evaluate the efficacy and safety of venlafaxine extended release and a long-term extension study for patients with major depressive disorder in Japan

The aim of this study was to assess antidepressant efficacy and safety of venlafaxine extended release in Japanese patients with major depressive disorder (MDD). We carried out a double-blinded, placebo-controlled, randomized study using fixed (75 mg/day) and flexible (75-225 mg/day, most patients attained to 225 mg/day) doses, followed by the long-term, open-labeled, extension study. Outpatients aged at least 20 years diagnosed with MDD were included. The primary efficacy measure was change from baseline in the Hamilton Rating Scale for Depression (HAM-D17) score at week 8; secondary efficacy measures included the Montgomery-Åsberg Depression Rating Scale, the Quick Inventory of Depressive Symptomatology self-report version, HAM-D6, and Clinical Global Impression scales in the double-blinded study. Overall, 538 patients were randomized; significant differences were observed in the primary efficacy variable in the fixed-dose group (-10.76; P=0.031), but not in the flexible-dose (-10.37; P=0.106) group compared with placebo (-9.25). However, the flexible-dose group showed significant efficacy in several secondary measures. Treatment-related adverse events in the treatment period were 51.7 and 67.8% in the fixed-dose and flexible-dose groups, respectively, versus 38.8% with placebo. Throughout the study period, no Japanese-specific adverse events were observed. Thus, venlafaxine extended release was efficacious and safe for MDD treatment in Japan.

Pain Affects Clinical Patterns and Treatment Outcomes for Patients With Major Depressive Disorder Taking Fluoxetine

The aim of the study was to determine whether baseline pain was associated with discernible clinical features and treatment outcomes for patients with major depressive disorder (MDD) receiving 6-week fluoxetine treatment. A total of 131 inpatients with acutely ill MDD were enrolled to receive 20 mg of fluoxetine daily for 6 weeks. Pain was measured by the Short-Form 36 body pain index. Symptom severity, functional impairment, and severity of adverse events were assessed at baseline and again at weeks 1 to 4 and 6 using the 17-item Hamilton Depression Rating Scale, Modified Work and Social Adjustment Scale, and Utvalg for Kliniske Undersogelser Side Effect Rating Scale, respectively. Simple linear regression was employed to examine the clinical variables significantly associated with pain. The generalized estimating equations method was used to analyze the influence of pain on the 17-item Hamilton Depression Rating Scale, Modified Work and Social Adjustment Scale, and Utvalg for Kliniske Undersogelser Side Effect Rating Scale over time. Of the 131 participants, 119 (90.8%) who completed baseline pain measurements and had at least 1 postbaseline assessment were included in the analysis. Patients experiencing greater pain were more likely to have more severe depression, to be at greater risk of suicide, to have functional impairment, to experience stressful life events, and to have poor treatment outcomes. These findings suggest that pain was significantly associated with multiple aspects of patients with MDD. Patients with MDD with higher levels of pain were clinically useful in predicting poor outcomes after acute fluoxetine treatment.

The relationship between symptom relief and functional improvement during acute fluoxetine treatment for patients with major depressive disorder

BACKGROUND

The purpose of this study was to compare the rate of symptom relief to functional improvement and examine the relationships between symptom relief and functional improvement during the acute phase of treatment.

METHODS

A total of 131 acutely ill inpatients with major depressive disorder were enrolled to receive 20mg of fluoxetine daily for 6 weeks. Symptom severity, using the 17-item Hamilton Depression Rating Scale (HAMD-17), and functioning, using the Modified Work and Social Adjustment Scale (MWSAS), were measured regularly. The outcome measures were the HAMD-17 score and MWSAS score at weeks 1, 2, 3, 4, and 6. We compared the effect size and the reduction rate of HAMD-17 to those of MWSAS at week 1, 2, 3, 4, and 6. Structural equation modeling was used to examine relationships among the study variables.

RESULTS

Of the 131 participants, 126 had at least one post-baseline assessment at week 1 and were included in the analysis. The HAMD-17 had a larger effect size and reduction rate than the MWSAS at weeks 1, 2, 3, 4, and 6. Parsimonious model satisfied all indices of goodness-of-fit (Chi-Square/df=1.479, TLI=0.978, CFI=0.986, RMSEA=0.062) and had all paths with significant path coefficients. MWSAS at week 0 predicted HAMD-17 at week 1.

LIMITATION

This was an open-labeled study with small sample size.

CONCLUSION

Depressive symptoms improved more quickly than functioning during the acute phase of treatment. Depressive symptoms and functional impairment are distinct domains, and should be assessed independently.

Environmentally relevant concentrations of citalopram partially inhibit feeding in the three-spine stickleback (Gasterosteus aculeatus)

Selective Serotonin Re-uptake Inhibitors (SSRI) are mood-altering, psychotropic drugs commonly used in the treatment of depression and other psychological illnesses. Many of them are poorly degraded in sewage treatment plants and enter the environment unaltered. In laboratory studies, they have been demonstrated to affect a wide range of behaviours in aquatic organisms. In this study we investigated the effect of a three-week exposure to 0.15 and 1.5 μg/l of the SSRI citalopram dissolved in the ambient water on the feeding behaviour in three-spine stickleback (Gasterosteus aculeatus). Feeding, measured as the number of attacks performed on a piece of frozen bloodworms during a 10-min period, was reduced by 30-40% in fish exposed to both 0.15 and 1.5 μg/l citalopram. The effects of the environmentally relevant concentration 0.15 μg/l on feeding, an important fitness characteristic, suggests that the ecological significance of environmental SSRI exposure may be pronounced.

A placebo-controlled study of three agomelatine dose regimens (10 mg, 25 mg, 25-50 mg) in patients with major depressive disorder

A randomised placebo-controlled "dose relation study" was conducted in 549 patients who met the criteria for major depressive disorder, to evaluate the efficacy and safety of three doses regimens of agomelatine during 6 weeks: low fixed dosage (10 mg/day, n=133), fixed dosage (25 mg/day, n=138) and a flexible dosage with up-titration in case of insufficient improvement at week 2 (25-50 mg/day, n=137). At last post-baseline assessment, there were significant and incremental placebo-agomelatine differences on mean HAM-D₁₇ total scores in favour of each agomelatine dose regimen (2.46 ± 0.76 points, p=0.001 at 10 mg; 4.71+0.75 points, p<0.0001 at 25 mg and 4.92 ± 0.76 points, p<0.0001 at 25-50 mg) with statistically significant differences between 25 mg and 25-50 mg dose regimens compared to the 10 mg dose. The response rate according to HAM-D₁₇ was significantly higher in patients taking agomelatine than those taking placebo (difference of 16.1% at 10 mg p=0.005; 25.9% and 27.4% respectively at 25 mg and 25-50 mg, p<0.0001). The benefit of agomelatine was demonstrated in the subgroup of severely depressed patients in the 25 mg and 25-50 mg/day regimens. Consistent clinical response according to CGI variables and better social functioning were found in patients receiving agomelatine. All dose regimens of agomelatine were well tolerated and no unexpected adverse event was reported. This study provides evidence of a dose effect for agomelatine between 10 mg and the therapeutic dose regimen of agomelatine 25-50 mg: the efficacy of the higher dose regimens being more efficacious than the lowest (10 mg) daily dose. The data support a definitive statement regarding the utility of 25 mg as the threshold dose for initiating agomelatine in depressed patients.

Pharmacogenomic testing and personalized treatment of depression

BACKGROUND

There is wide variation in antidepressant efficacy and tolerability during the treatment of major depressive disorder, a brain disease associated with significant morbidity and mortality risk. The ability to rapidly identify optimal treatment, thereby shortening the time to symptomatic remission, could reduce these risks and associated costs.

CONTENT

Up to 42% of variance in antidepressant response is associated with common genetic variation, and there are over 10 psychotropic medications for which the US Food and Drug Administration-approved labeling reflects a genetic test. Most published studies have examined functional variations in genes of the cytochrome p450 system, relevant to metabolism of many antidepressants. However, there are few data supporting the clinical usefulness of specific pharmacogenetic tests. Randomized trials and cost-effectiveness studies are emerging, but larger-scale studies are needed. Specific challenges in translating genetic association results to clinical practice include need for replication to address risk of type I error, overestimation of effect sizes, absence of data from generalizable cohorts, and absence of comparative data that would suggest one specific intervention over another. Several opportunities to accelerate development and validation of new tools for stratification remain, including integration of these tests with clinical data or other biomarkers and application of electronic health records for test development and investigation.

SUMMARY

Although common genetic variation, particularly in genes of the cytochrome p450 system, has been associated with antidepressant response, evidence that this variation may be successfully applied to guide treatment selection is just emerging. Larger-scale studies facilitated by informatics tools will clarify the usefulness of such tests.

Pharmacogenetics and pharmacogenomics of sexual dysfunction: current status, gaps and potential applications

Although treatment of different types of sexual dysfunction has improved in the past decade with the introduction of phosphodiesterase type 5 inhibitors and selective serotonin reuptake inhibitors, response rates to these targeted therapies are variable. There are a number of studies in the published literature that provide proof-of-concept that genetic variation contributes to the variable response. Pharmacogenomics will most likely be one part of our therapeutic armamentarium in the future and will provide a stronger scientific basis for optimizing drug therapy on the basis of each patient’s genetic constitution. This article will review English language medical literature on the state-of-the-art genetic polymorphisms of drug targets, transporters and signaling molecules as well as pharmacogenetic studies of sexual dysfunction and suggested possible applications. Collectively, the data demonstrate that pharmacogenomics in the field of sexual medicine is still in its infancy. More research will provide further intriguing new discoveries in years to come.

A randomized, double-blind comparison of duloxetine and venlafaxine in the treatment of patients with major depressive disorder

BACKGROUND

Clinical trials assessing antidepressant therapies typically include separate assessments of efficacy (benefit) and adverse events (risk). Global benefit-risk (GBR) assessment allows the simultaneous evaluation of both efficacy and adverse events. The objective was to compare the serotonin and norepinephrine reuptake inhibitors (SNRIs) duloxetine and venlafaxine using GBR assessment.

METHODS

Data were combined from two similarly designed, multicenter, randomized, double-blind, parallel group studies in which patients with major depressive disorder were randomized to either duloxetine 60 mg/day or venlafaxine extended release (XR) 150 mg/day (75 mg/day for the first 2 weeks) for a 6-week fixed dosing period followed by an additional 6 weeks of treatment in which the dose could be increased up to 120 mg/day for duloxetine and 225 mg/day for venlafaxine. Patients completing the study (or receiving study drug for 2 weeks or more) were eligible to enter a taper period where the dose of study drug was gradually reduced over 1-2 weeks prior to drug discontinuation. The primary outcome measure (defined a priori) was the GBR comparison of duloxetine 60 mg/day and venlafaxine XR 150 mg/day after 6 weeks of treatment. In the GBR analysis, benefit was defined as remission at endpoint [17-item Hamilton Depression Rating Scale (HAMD17) 7]. Risk was defined by four categories: patients having either no adverse events (AEs), AEs with no severity rating greater than moderate, AEs with at least one severity rating of severe, or having discontinued with a reason of self-reported adverse event (regardless of any AE severity). Additional efficacy measures included HAMD17 total score and subscales, HAMA, CGI-S, and PGI-I. Safety and tolerability were assessed via analysis of reasons for discontinuation, treatment-emergent adverse events (TEAEs), discontinuation-emergent adverse events, and changes in vital signs, weight, and laboratory analytes.

RESULTS

There were no significant differences between duloxetine 60 mg/day and venlafaxine 150 mg/day as measured by GBR assessment at the end of 6 weeks (-1.418 vs. -1.079, P = 0.217) or 12 weeks (-0.349 vs. -0.121, P = 0.440), nor were there significant differences between treatment groups on the majority of efficacy measures. Significantly more venlafaxine-treated patients (74.5%) completed 12 weeks of treatment compared with duloxetine-treated patients (64.8%, P =.006). Nausea was the most common treatment-emergent adverse event (TEAE) for both drugs, and was significantly higher with duloxetine 60 mg/day compared to venlafaxine 150 mg/day during the first 6 weeks of treatment (43.6% vs. 35.0%, P0.05). During the taper period, significantly more venlafaxine-treated patients reported discontinuation-emergent adverse events (DEAEs) than duloxetine-treated patients. From a safety perspective, significantly more venlafaxine-treated patients (n = 4) than duloxetine-treated patients (n=0, P =.047) experienced sustained elevations of systolic blood pressure during the fixed dosing period. Otherwise, there were few significant differences in safety measures found between treatment groups during 6 and 12 weeks of therapy.

CONCLUSIONS

Duloxetine 60 mg/day and venlafaxine XR 150 mg/day have similar benefit-risk profiles on the basis of a comparison utilizing GBR assessment. The implications of the more subtle differences between these drugs, as well as for interpreting the GBR assessment, are discussed.

Use of effect size to determine optimal dose of duloxetine in major depressive disorder

OBJECTIVE

At effective doses, patients with major depressive disorder (MDD) treated with duloxetine have been found to experience significant symptom improvement as measured by HAMD(17) total score. In addition, duloxetine-treated patients have significantly higher remission and response rates compared with placebo. The objective of this analysis is to determine the optimal dose of duloxetine in MDD.

MATERIALS AND METHODS

Effect size for duloxetine 40mg, 60mg, 80mg, and 120mg per day were estimated using all 6 acute phase III clinical trials in patients with MDD. The tolerability of duloxetine 40mg, 60mg, 80mg, and 120mg were evaluated using pooled data from the 6 studies. The primary efficacy measure in all trials was the HAMD(17) total score, from which were determined the effect size for HAMD(17) change scores, response rates (50% reduction from baseline to endpoint), and remission rates (HAMD(17) total score < or =7).

RESULTS

A total of 1619 randomized patients were included in these studies, of which 632 were treated with placebo; 177 with duloxetine 40mg/day; 251 with 60mg/day; 363 with 80mg/day; and 196 with 120mg/day. An evaluation of increments in effect size between doses consistently showed that the most notable gain in effect size for efficacy was the 40-60mg/day dosage range. All dosages from 60 to 120mg were effective. The tolerability assessment indicated duloxetine at 40-120mg/day is well tolerated. Furthermore, the initial doses of 40-80mg/day were found to have comparable tolerability.

CONCLUSIONS

The effect size analyses demonstrate that duloxetine 40mg has minimum efficacy, and that duloxetine 60-120mg/day is effective in the treatment of patients with MDD. An initial dose less than 60mg/day might provide better tolerability for some patients diagnosed with MDD.

Treatment-resistant depression in adolescents: recognition and management

Approximately 20% of adolescents experience at least one depressive episode by the time they enter their adult years. For most adolescents, depression, although serious, either remits spontaneously or responds to treatment. For a smaller but significant proportion of adolescents, however, depression can be long-lasting and relatively unresponsive to initial treatment. In this article the authors provide an operational definition of treatment-resistant depression, identify factors associated with treatment nonresponse, describe an approach to the management of treatment-resistant depression, and advance suggestions for promising avenues of research.

Treatments in depression

Major depression is believed to be a multifactorial disorder involving predisposing temperament and personality traits, exposure to traumatic and stressful life events, and biological susceptibility. Depression, both unipolar and bipolar, is a "phasic" disease. Stressful life events are known to trigger depressive episodes, while their influence seems to decrease over the course of the illness. This suggests that depression is associated with progressive stress response abnormalities, possibly linked to impairments of structural plasticity and cellular resilience. It therefore appears crucial to adequately treat depression in the early stages of the illness, in order to prevent morphological and functional abnormalities. While evidence suggests that a severely depressed patient needs antidepressant drug therapy and that a non-severely depressed patient may benefit from other approaches (ie, "nonbiological"), little research has been done on the effectiveness of different treatments for depression. The assertion that the clinical efficacy of antidepressants is comparable between the classes and within the classes of those medications may be true from a statistical viewpoint, but is of limited value in practice. The antidepressant drugs may produce differences in therapeutic response and tolerability. Among the possible predictors of outcome in depression treatment, those derived from clinical assessment, neuroendocrine investigations, polysomnographic sleep parameters, genetic variables, and brain imaging techniques have been extensively studied. This article also reviews therapeutic strategies used when initial treatment fails, and describes briefly new concepts in antidepressant therapies such as the regulation of disturbances in circadian rhythms. The treatment of depressive illness does not stop with treatment of acute episodes, and has to be envisaged as a continuous therapeutic intervention, of which we are still not able to determine the optimal duration of treatment and the moment that it should be ceased.

Treatments in depression

Major depression is believed to be a multifactorial disorder involving predisposing temperament and personality traits, exposure to traumatic and stressful life events, and biological susceptibility. Depression, both unipolar and bipolar, is a "phasic" disease. Stressful life events are known to trigger depressive episodes, while their influence seems to decrease over the course of the illness. This suggests that depression is associated with progressive stress response abnormalities, possibly linked to impairments of structural plasticity and cellular resilience. It therefore appears crucial to adequately treat depression in the early stages of the illness, in order to prevent morphological and functional abnormalities. While evidence suggests that a severely depressed patient needs antidepressant drug therapy and that a non-severely depressed patient may benefit from other approaches (ie, "nonbiological"), little research has been done on the effectiveness of different treatments for depression. The assertion that the clinical efficacy of antidepressants is comparable between the classes and within the classes of those medications may be true from a statistical viewpoint, but is of limited value in practice. The antidepressant drugs may produce differences in therapeutic response and tolerability. Among the possible predictors of outcome in depression treatment, those derived from clinical assessment, neuroendocrine investigations, polysomnographic sleep parameters, genetic variables, and brain imaging techniques have been extensively studied. This article also reviews therapeutic strategies used when initial treatment fails, and describes briefly new concepts in antidepressant therapies such as the regulation of disturbances in circadian rhythms. The treatment of depressive illness does not stop with treatment of acute episodes, and has to be envisaged as a continuous therapeutic intervention, of which we are still not able to determine the optimal duration of treatment and the moment that it should be ceased.