Could the underestimation of bipolarity obstruct the search for novel antidepressant drugs?

Clinical pharmacological innovation in the treatment of depression

INTRODUCTION

Deficiencies in standard of care antidepressants are driving novel drug discovery. A new age of antidepressant medications has emerged with the introduction of rapid-acting antidepressants with efficacy in treatment-resistant patients.

AREAS COVERED

The newly approved medicines and those in clinical development for major depressive disorder (MDD) are documented in this scoping review of newly approved and emerging antidepressants. Compounds are evaluated for clinical efficacy, tolerability, and safety and compared to those of standard of care medicines.

EXPERT OPINION

A new age of antidepressant discovery relies heavily on glutamatergic mechanisms. New medicines based upon the model of ketamine have been delivered and are in clinical development. Rapid onset and the ability to impact treatment-resistant depression, raises the question of the best first-line medicines for patients. Drugs with improvements in tolerability are being investigated (e.g. mGlu_2/3 receptor antagonists, AMPA receptor potentiators, and novel NMDA receptor modulators). Multiple companies are working toward the identification of novel psychedelic drugs where the requirement for psychedelic activity is not fully known. Gaps still exist - methods for matching patients with specific medicines are needed, and medicines for the prevention of MDD and its disease progression need research attention.

Evaluating the efficacy and moderators of algorithm-guided antidepressant treatments of major depressive disorder

BACKGROUND

In spite of numerous options, the most efficacious treatment for major depressive disorder (MDD) remains elusive. Algorithm-guided treatments (AGTs) are proposed to address inadequate remission and optimize treatment delivery. This study aimed to evaluate the clinical benefit of AGTs for MDD, and to explore specific moderators of treatment outcomes for individual patients.

METHODS

The study recruited 987 patients with MDD across eight hospitals who were randomly assigned to AGT with escitalopram (AGT-E), AGT with mirtazapine (AGT-M), or treatment-as-usual (TAU). The outcomes were symptom remission, response rate, early improvement rate, subsymptom clusters improvement over time, the mean time to first remission, relapse rate at 6-months posttreatment follow-up, quality of life (QOL), and adverse events.

RESUTLS

No significant differences were observed across groups in outcome, except that TAU showed significantly poorer QOL, higher relapse rates at 6-months posttreatment follow-up, and marginally significantly worse maximal burden of adverse events than the AGT groups. After 6 weeks of treatment initiation, remission rate did not significantly increase with extended treatment. AGT-M outperformed the TAU and AGT-E in treating sleep symptoms. AGT-E was less effective than AGT-M and TAU in patients with severe depression and somatic symptoms (DSSS). The superiority of TAU over AGTs was observed in recurrent MDD patients.

CONCLUSION

Although the superiority of AGTs over TAU was limited by failure of alternative subsequent treatment, AGTs outperformed in QOL and relapse rate. Types of disease episode and DSSS were regarded as specific moderators in treatment of depression. These findings might contribute to future research on targeted antidepressant treatment.

"Novel Psychopharmacology for Depressive Disorders"

Major depressive disorder carries a significant burden and a high risk for suicide. The need for more effective, safer, and faster-acting drugs is, therefore, compelling. The present chapter briefly assesses the most promising agents, focusing on non-monoamine-targeting compounds, namely, the glutamate antagonist ketamine and its enantiomer esketamine. A critical overview of the evidence and the pitfalls associated with current antidepressant drug development is likewise provided in the following text.

The FDA "Black Box" Warning on Antidepressant Suicide Risk in Young Adults: More Harm Than Benefits?

The decision made in the year 2004 by the U.S. Food and Drug Administration (FDA) to require a boxed warning on antidepressants regarding the risk of suicidality in young adults still represents a matter of controversy. The FDA warning was grounded on industry-sponsored trials carried one decade ago or earlier. However, within the past decade, an increasing number of reports have questioned the actual validity of the FDA warning, especially considering a decline in the prescription of the antidepressant drugs associated with an increase in the rate of suicidal events among people with severe depression. The present report provides an overview of the FDA black box warning, also documenting two Major Depressive Disorder patients whose refusal to undergo a pharmacological antidepressant treatment possibly led to an increased risk for suicidal behaviors. The concerns raised by the FDA black box warning need to be considered in real-world clinical practice, stating the associated clinical and public health implications.

Clinical and psychopathological features associated with treatment-emergent mania in bipolar-II depressed outpatients exposed to antidepressants

BACKGROUND

Treatment-emergent affective switch (TEAS), including treatment-emergent mania (TEM), carry significant burden in the clinical management of bipolar depression, whereas the use of antidepressants raises both efficacy, safety and tolerability concerns. The present study assesses the prevalence and clinical correlates of TEM in selected sample of Bipolar Disorder (BD) Type-II (BD-II) acute depression outpatients.

METHODS

Post-hoc analysis of the clinical and psychopathological features associated with TEM among 91 BD-II depressed outpatients exposed to antidepressants.

RESULTS

Second-generation antipsychotics (SGA) (p = .005), lithium (≤ .001), cyclothymic/irritable/hyperthymic temperaments (p = ≤ .001; p = .001; p = .003, respectively), rapid-cycling (p = .005) and depressive mixed features (p = .003) differed between TEM⁺ cases vs. TEM^- controls. Upon multinomial logistic regression, the accounted psychopathological features correctly classified as much as 88.6% of TEM⁺ cases (35/91 overall sample, or 38.46% of the sample), yet not statistically significantly [Exp(B) = .032; p = ns]. Specifically, lithium [B = - 2.385; p = .001], SGAs [B = - 2.354; p = .002] predicted lower rates of TEM⁺ in contrast to the number of lifetime previous psychiatric hospitalizations [B = 2.380; p = .002], whereas mixed features did not [B = 1.267; p = ns].

LIMITATIONS

Post-hoc analysis. Lack of systematic pharmacological history record; chance of recall bias and Berkson's biases. Permissive operational criterion for TEM. Relatively small sample size.

CONCLUSIONS

Cyclothymic temperament and mixed depression discriminated TEM⁺ between TEM^- cases, although only lithium and the SGAs reliably predicted TEM^+/- grouping. Larger-sampled/powered longitudinal replication studies are warranted to allow firm conclusions on the matter, ideally contributing to the identification of clear-cut sub-phenotypes of BD towards patient-tailored-pharmacotherapy.

Progress in bipolar disorder drug design toward the development of novel therapeutic targets: a clinician's perspective

INTRODUCTION

Bipolar disorder (BD) is a considerable burden to the affected individual. The need for novel drug targets and improved drug design (DD) in BD is therefore clear. Areas covered: The following article provides a brief, narrative, clinician-oriented overview of the most promising novel pharmacological targets for BD along with a concise overview regarding the general DD process and the unmet needs relevant to BD. Expert opinion: A number of novel potential drug targets have been investigated. With the notable exception of the kynurenine pathway, available evidence is too scarce to highlight a definitive roadmap for forthcoming DD in BD. BD itself may present with different facets, as it is a polymorphic clinical spectrum. Therefore, promoting clinical-case stratification should be based on precision medicine, rather than on novel biological targets. Furthermore, the full release of raw study data to the scientific community and the development of uniform clinical trial standards (including more realistic outcomes) should be promoted to facilitate the DD process in BD.

The burden of mood-disorder/cerebrovascular disease comorbidity: essential neurobiology, psychopharmacology, and physical activity interventions

Cardio-vascular diseases (CVDs) and CVD-related disorders (including cerebrovascular diseases; CBVDs) are a major public health concern as they represent the leading cause of mortality and morbidity in developed countries. Patients with CVDs and CBVDs co-morbid with mood disorders, especially bipolar disorder (BD) and major depressive disorder (MDD), suffer reduced quality-of-life and significant disability adjusted for years of life and mortality. The relationship between CVDs/CBVDs and mood disorders is likely to be bidirectional. Evidence for shared genetic risk of pathways involved in stress reaction, serotonin or dopamine signalling, circadian rhythms, and energy balance was reported in genome-wide association studies. There is some evidence of a neuroprotective effect of various antidepressants, which may be boosted by physical exercise, especially by aerobic ones. Patients with CVDs/CBVDs should be routinely attentively evaluated for the presence of mood disorders, with tools aimed at detecting both symptoms of depression and of hypomania/mania. Behavioural lifestyle interventions targeting nutrition and exercise, coping strategies, and attitudes towards health should be routinely provided to patients with mood disorders, to prevent the risk of CVDs/CBVDs. A narrative review of the evidence is herein provided, focusing on pharmacological and physical therapy interventions.

The prevalence and predictors of bipolar and borderline personality disorders comorbidity: Systematic review and meta-analysis

INTRODUCTION

Data about the prevalence of borderline personality (BPD) and bipolar (BD) disorders comorbidity are scarce and the boundaries remain controversial. We conducted a systematic review and meta-analysis investigating the prevalence of BPD in BD and BD in people with BPD.

METHODS

Two independent authors searched MEDLINE, Embase, PsycINFO and the Cochrane Library from inception till November 4, 2015. Articles reporting the prevalence of BPD and BD were included. A random effects meta-analysis and meta-regression were conducted.

RESULTS

Overall, 42 papers were included: 28 considering BPD in BD and 14 considering BD in BPD. The trim and fill adjusted analysis demonstrated the prevalence of BPD among 5273 people with BD (39.94 ± 11.78 years, 44% males) was 21.6% (95% CI 17.0-27.1). Higher comorbid BPD in BD were noted in BD II participants (37.7%, 95% CI 21.9-56.6, studies=6) and North American studies (26.2%, 95% CI 18.7-35.3, studies=11). Meta regression established that a higher percentage of males and higher mean age significantly (p<0.05) predicted a lower prevalence of comorbid BPD in BD participants. The trim and fill adjusted prevalence of BD among 1814 people with BPD (32.22 ± 7.35 years, 21.5% male) was 18.5% (95% CI 12.7-26.1).

LIMITATIONS

Paucity of longitudinal/control group studies and accurate treatment records.

CONCLUSIONS

BPD-BD comorbidity is common, with approximately one in five people experiencing a comorbid diagnosis. Based on current diagnostic constructs, and a critical interpretation of results, both qualitative and quantitative syntheses of the evidence prompt out the relevance of differences rather similarities between BD and BPD.

Atypical Antipsychotics in the Treatment of Acute Bipolar Depression with Mixed Features: A Systematic Review and Exploratory Meta-Analysis of Placebo-Controlled Clinical Trials

Evidence supporting the use of second generation antipsychotics (SGAs) in the treatment of acute depression with mixed features (MFs) associated with bipolar disorder (BD) is scarce and equivocal. Therefore, we conducted a systematic review and preliminary meta-analysis investigating SGAs in the treatment of acute BD depression with MFs. Two authors independently searched major electronic databases from 1990 until September 2015 for randomized (placebo-) controlled trials (RCTs) or open-label clinical trials investigating the efficacy of SGAs in the treatment of acute bipolar depression with MFs. A random-effect meta-analysis calculating the standardized mean difference (SMD) between SGA and placebo for the mean baseline to endpoint change in depression as well as manic symptoms score was computed based on 95% confidence intervals (CI). Six RCTs and one open-label placebo-controlled studies (including post-hoc reports) representing 1023 patients were included. Participants received either ziprasidone, olanzapine, lurasidone, quetiapine or asenapine for an average of 6.5 weeks across the included studies. Meta-analysis with Duval and Tweedie adjustment for publication bias demonstrated that SGA resulted in significant improvements of (hypo-)manic symptoms of bipolar mixed depression as assessed by the means of the total scores of the Young Mania Rating Scale (YMRS) (SMD −0.74, 95% CI −1.20 to −0.28, n SGA = 907, control = 652). Meta-analysis demonstrated that participants in receipt of SGA (n = 979) experienced a large improvement in the Montgomery–Åsberg Depression Rating Scale (MADRS) scores (SMD −1.08, 95% CI −1.35 to −0.81, p < 0.001) vs. placebo (n = 678). Publication and measurement biases and relative paucity of studies. Overall, SGAs appear to offer favorable improvements in MADRS and YMRS scores vs. placebo. Nevertheless, given the preliminary nature of the present report, additional original studies are required to allow more reliable and clinically definitive conclusions.

Prevalence and clinical features associated with bipolar disorder polypharmacy: a systematic review

BACKGROUND

Uncertainty exists regarding the prevalence and clinical features associated with the practice of polypharmacy in bipolar disorder (BD), warranting a systematic review on the matter.

METHODS

Three authors independently searched major electronic databases from inception till September 2015. Articles were included that reported either qualitative or quantitative data about the prevalence and clinical features associated with polypharmacy in adult cases of BD.

RESULTS

The operative definitions of polypharmacy adopted across varying studies varied, with concomitant use of two or more psychotropic medications or use of four or more psychotropic medications at once being the most common and the most reliable, respectively. Regardless of type or current mood episode polarity of BD, prevalence rates up to 85% and 36% were found using the most permissive (two or more medications at once) and the most conservative (four or more) operative definitions for polypharmacy, respectively. Point prevalence prescription rates of one or more antidepressant or antipsychotic as part of a polypharmacy regimen occurred in up to 45% or 80% of the cases, respectively, according to the most permissive definition of polypharmacy. In contrast, lithium prescription rates ranged from 13% to 33% in BD patients receiving polypharmacy according to conservative and permissive definitions, possibly suggesting a reduced need for augmentation of combination strategies for those cases of BD with a favorable lifetime lithium response and/or long-lasting treatment as well as less likelihood of lithium response over the time most severe cases possibly exposed to a more complex polypharmacy overall.

LIMITATIONS

"Apples and oranges" bias; publication bias for most recently introduced compounds.

CONCLUSION

Polypharmacy is common among people with BD across varying type and mood episode phases of illness. Special population, including BD patients at high risk of familial load for suicidal behavior, solicit further research as well as the plausible "protective" role of lithium toward polypharmacy in BD. The PROSPERO registration number is CRD42014015084.

Duloxetine-bupropion combination for treatment-resistant atypical depression: a double-blind, randomized, placebo-controlled trial

The efficacy, safety, and tolerability of combined bupropion versus placebo using duloxetine as active reference drug, in patients with a DSM-IV diagnosis of major depression with atypical features and a history of treatment resistance, were evaluated in this preliminary six-week study. Patients (n=46) had a baseline Hamilton Depression Scale (HAM-D) ≥14 and were randomly assigned to 150/300 mg/day bupropion vs. placebo, which was added to 60 to 120 mg/day duloxetine depending on baseline depression severity. Atypical features of depression were assessed using the additional eight-item module of the Structured Interview Guide for the HAM-D with the Atypical Depression Supplement. By week 6, only five (21.7%) patients receiving duloxetine+placebo vs. six (26.1%) patients on the bupropion combination achieved response. No significant difference in final HAM-D scores between the two groups was observed between those patients achieving response. The presence of a higher number of atypical features significantly predicted non-response, with the relevant binary logistic regression model correctly classifying 17 out 22 (77.3%) of non-responders [Exp(B)=0.294; p=0.016] vs. 17 out 23 (73.9%) [Exp(B)=0.353; p=0.028] non-responder cases in the "+placebo" and "+bupropion" groups, respectively. In those patients receiving bupropion, treatment-emergent adverse events leading to withdrawal were more common among those receiving lower doses of the combination drug, and no life-threating dangers were noted. Additional studies, including an adequate course of duloxetine trial, are nonetheless aimed to allow a firm conclusion about the usefulness of the combination of duloxetine and bupropion for treatment-resistant cases of major depression with atypical features.

Electroretinographic modifications induced by agomelatine: a novel avenue to the understanding of the claimed antidepressant effect of the drug?

BACKGROUND

Agomelatine, the first melatonergic antidepressant, has been postulated to enhance the dopaminergic activity at the central nervous system by 5-hydroxytryptamine receptor type 2C (5-HT2C) antagonism, yet the impact of melatonergic agonism on this pathway is unclear. Previous studies employing simplified, yet reliable, proxy (retinal) measures of the central nervous system dopaminergic activity, namely the standard electroretinogram (ERG) technique, suggested a reduction of the dopaminergic activity of the main ERG parameter, the b-wave, by pure melatonin, notably a hormone devoid of any antidepressant activity. Therefore, the antidepressant effects of the melatonergic antidepressant drug agomelatine should be reflected by a differential b-wave trend at ERG versus the effect exerted by pure melatonin, which was eventually found to be due to a contrasting effect on central dopaminergic transmission between the two drugs.

OBJECTIVE AND METHODS

The aim of the present preliminary ERG study carried out on healthy volunteers (n=23) receiving agomelatine was to explore the impact of this antidepressant drug on b-wave amplitude and latency of cones in daylight conditions using standard ERG.

RESULTS

As postulated, agomelatine induced an enhancement of retinal dopaminergic activity, in contrast to what has been previously documented for melatonin.

CONCLUSION

Given the limits of this explorative study, especially the lack of a control group and that of a luminance response function to measure retinal sensitivity, further studies in clinical samples are recommended to allow more tenable conclusions about the potential role of ERG in discriminating between 5-HT antagonism and melatonergic (MT) agonism in relationship to the claimed antidepressant effect of agomelatine.

Sensation seeking in major depressive patients: relationship to sub-threshold bipolarity and cyclothymic temperament

BACKGROUND

High levels of sensation seeking (SS) have been traditionally reported for lifetime bipolar disorder (BD) and/or substance use disorder (SUD) rather than major depressive disorder (MDD). Nonetheless, a renewed clinical attention toward the burden of sub-threshold bipolarity in MDD, solicits for a better assessment of "unipolar" major depressive episodes (MDEs) via characterization of putative differential psychopathological patterns, including SS and predominant affective temperament.

METHODS

Two hundred and eighty currently depressed cases of MDD and 87 healthy controls were screened using the Zuckerman's sensation seeking scale-Form-V, the Hypomania Check List-32-item (HCL-32), the Temperament Evaluation of Memphis, Pisa, Paris and San Diego Auto-questionnaire-110-item, the Barratt Impulsivity Scale-11-item, the State-Trait Anxiety Inventory modules and the Structured Clinical Interview for DSM-IV axis-I disorders. Cases were divided into HCL-32(+)(sub-threshold bipolar)/HCL-32(-)("true" unipolar depressed) depending on the HCL-32 total score.

RESULTS

Upon correlation and multivariate regression analyses, the HCL-32(+) patients showed the highest levels of SS, higher prevalence of cyclothymic temperament, and higher rates of multiple lifetime axis-I co-morbidities, including SUD.

LIMITS

Recall bias on some diagnoses, including BD, grossly matched healthy control group, lack of ad-hoc validated measures for ADHD, SUD, or axis-II disorders.

CONCLUSIONS

In our sample, the occurrence of higher levels of SS in "sub-threshold" bipolar cases outlined a differential psychopathological profile compared to DSM-defined "true unipolar" cases of MDE. If confirmed by replication studies, these findings may aid clinicians in delivering a more accurate diagnosis and a safer use of antidepressants in some MDD cases.

Adjunctive agomelatine therapy in the treatment of acute bipolar II depression: a preliminary open label study

PURPOSE

The circadian rhythm hypothesis of bipolar disorder (BD) suggests a role for melatonin in regulating mood, thus extending the interest toward the melatonergic antidepressant agomelatine as well as type I (acute) or II cases of bipolar depression.

PATIENTS AND METHODS

Twenty-eight depressed BD-II patients received open label agomelatine (25 mg/bedtime) for 6 consecutive weeks as an adjunct to treatment with lithium or valproate, followed by an optional treatment extension of 30 weeks. Measures included the Hamilton depression scale, Pittsburgh Sleep Quality Index, the Clinical Global Impression Scale-Bipolar Version, Young Mania Rating Scale, and body mass index.

RESULTS

Intent to treat analysis results demonstrated that 18 of the 28 subjects (64%) showed medication response after 6 weeks (primary study endpoint), while 24 of the 28 subjects (86%) responded by 36 weeks. When examining primary mood stabilizer treatment, 12 of the 17 (70.6%) valproate and six of the 11 (54.5%) lithium patients responded by the first endpoint. At 36 weeks, 14 valproate treated (82.4%) and 10 lithium treated (90.9%) subjects responded. At 36 weeks, there was a slight yet statistically significant (P = 0.001) reduction in body mass index and Pittsburgh Sleep Quality Index scores compared to respective baseline values, regardless of mood stabilizer/outcome. Treatment related drop-out cases included four patients (14.28%) at week 6 two valproate-treated subjects with pseudo-vertigo and drug-induced hypomania, respectively, and two lithium-treated subjects with insomnia and mania, respectively. Week 36 drop outs were two hypomanic cases, one per group.

CONCLUSION

Agomelatine 25 mg/day was an effective and well-tolerated adjunct to valproate/lithium for acute depression in BD-II, suggesting the need for confirmation by future double blind, controlled clinical trials.

The argument of antidepressant drugs in the treatment of bipolar depression: mixed evidence or mixed states?

INTRODUCTION

The role of antidepressant drugs in acute and maintenance treatment of bipolar depression is a matter of debate that cannot be decided from the evidence available in the current literature.

AREAS COVERED

This review includes two sections: in the first, important contributions from the current literature, emphasizing randomized controlled trials (RCTs) and meta-analysis, highlight current controversies and methodological issues; in the second, the impact of mixed depressive features in bipolar depression is evaluated from a psychopathological perspective.

EXPERT OPINION

Methodological issues may complicate evaluation of the evidence from RCTs regarding antidepressants and mixed states. Moreover, nosological constructs may also contribute to the inconclusive findings, by introducing heterogeneity in patient selection and diagnosis. Acknowledging the impact of mixed features in the course of bipolar depression, essentially by the careful reading of classical Kraepelinian contributions, could enhance clinical management. This would in turn allow a more judicious use of antidepressants, ideally helping to shed some light on the much controversial 'antidepressant-related suicidality', and help to further clarify the reasons for the current literature discordance on this topic.