Rational site-directed pharmacotherapy for major depressive disorder

Psychopharmacological properties and therapeutic profile of the antidepressant venlafaxine

Major depression (MD) is one of the most common psychiatric disorders worldwide. Currently, the first-line treatment for MD targets the serotonin system but these drugs, notably the selective serotonin reuptake inhibitors, usually need 4 to 6 weeks before the benefit is felt and a significant proportion of patients shows an unsatisfactory response. Numerous treatments have been developed to circumvent these issues as venlafaxine, a mixed serotonin-norepinephrine reuptake inhibitor that binds and blocks both the SERT and NET transporters. Despite this pharmacological profile, it is difficult to have a valuable insight into its ability to produce more robust efficacy than single-acting agents. In this review, we provide an in-depth characterization of the pharmacological properties of venlafaxine from in vitro data to preclinical and clinical efficacy in depressed patients and animal models of depression to propose an indirect comparison with the most common antidepressants. Preclinical studies show that the antidepressant effect of venlafaxine is often associated with an enhancement of serotonergic neurotransmission at low doses. High doses of venlafaxine, which elicit a concomitant increase in 5-HT and NE tone, is associated with changes in different forms of plasticity in discrete brain areas. In particular, the hippocampus appears to play a crucial role in venlafaxine-mediated antidepressant effects notably by regulating processes such as adult hippocampal neurogenesis or the excitatory/inhibitory balance. Overall, depending on the dose used, venlafaxine shows a high efficacy on depressive-like symptoms in relevant animal models but to the same extent as common antidepressants. However, these data are counterbalanced by a lower tolerance. In conclusion, venlafaxine appears to be one of the most effective treatments for treatment of major depression. Still, direct comparative studies are warranted to provide definitive conclusions about its superiority.

Double-blind, randomized, placebo-controlled pilot study of the phosphodiesterase-3 inhibitor cilostazol as an adjunctive to antidepressants in patients with major depressive disorder

AIMS

Cilostazol (CLS) has shown antidepressant effect in cardiovascular patients, post-stroke depression, and animal models through its neurotrophic and antiinflammatory activities. Consequently, we aimed to investigate its safety and efficacy in patients with MDD by conducting double-blind, randomized, placebo-controlled pilot study.

METHODS

80 participants with MDD (DSM-IV criteria) and Hamilton Depression Rating Scale (HDRS) score >20 were treated with CLS 50 mg or placebo twice daily plus escitalopram (ESC) 20 mg once daily for six weeks. Patients were evaluated by HDRS scores (weeks 0, 2, 4, and 6). Serum levels of CREB1, BDNF, 5-HT, TNF-α, NF- κB, and FAM19A5 were assessed pre- and post-treatment.

RESULTS

Co-administration of CLS had markedly decreased HDRS score at all-time points compared to the placebo group (p < 0.001). Early improvement, response, and remission rates after 6 weeks were significantly higher in the CLS group (90%, 90%, 80%, respectively) than in the placebo group (25%, 65%, 50% respectively) (p < 0.001). Moreover, the CLS group was superior to the placebo group in modulation of the measured neurotrophic and inflammatory biomarkers.

CONCLUSION

CLS is safe and effective short-term adjunctive therapy in patients with MDD with no other comorbid conditions. Trial registration ID:NCT04069819.

Validation of the Oxford Depression Questionnaire: Sensitivity to change, minimal clinically important difference, and response threshold for the assessment of emotional blunting

BACKGROUND

The Oxford Depression Questionnaire (ODQ) is a patient-reported scale for assessing emotional blunting in patients with major depressive disorder (MDD). This analysis was undertaken to further validate the scale in patients experiencing emotional blunting while receiving antidepressant treatment.

METHODS

Patients with MDD who experienced inadequate depressive-symptom resolution and emotional blunting on selective serotonin reuptake inhibitor or serotonin-noradrenaline reuptake inhibitor monotherapy (adequate dose for ≥6 weeks) were switched to vortioxetine 10-20 mg/day. ODQ total scores were assessed excluding and including the "antidepressant-as-cause" domain (ODQ-20 and ODQ-26, respectively). Anchor- and distribution-based methods were used to determine the minimal clinically important difference in ODQ scores in terms of change from baseline to week 8 of antidepressant treatment.

RESULTS

After 8 weeks of vortioxetine treatment, the mean change in ODQ-20 and ODQ-26 scores from baseline was -24.8 and -30.1 points, respectively. Greater mean changes from baseline in ODQ-20 and ODQ-26 scores were seen in patients reporting no emotional blunting vs those still experiencing emotional blunting after 8 weeks of vortioxetine treatment (ODQ-20: -27.0 vs -22.6 points; ODQ-26: -32.8 vs -27.5 points, respectively). In patients considered clinically minimally improved (Clinical Global Impression-Improvement score, 3) after 8 weeks of vortioxetine treatment, respective mean (standard deviation) change in ODQ-20 and ODQ-26 score from baseline was -15.5 (18.1) and -20.0 (20.5) points.

LIMITATIONS

Short study duration.

CONCLUSIONS

These results provide further validation of the clinical utility of the ODQ for assessing emotional blunting in patients with MDD. The suggested minimal clinically important difference for change in ODQ-20 and ODQ-26 scores is 16 and 20 points, respectively, after 8 weeks of antidepressant treatment.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03835715.

Effectiveness of Vortioxetine on Emotional Blunting in Patients with Major Depressive Disorder with inadequate response to SSRI/SNRI treatment

INTRODUCTION

Inadequate treatment response and emotional blunting are common challenges with selective serotonin reuptake inhibitors/serotonin-noradrenaline reuptake inhibitors (SSRIs/SNRIs) for major depressive disorder (MDD). We investigated the effectiveness of vortioxetine on emotional blunting in patients with partial response to treatment with SSRIs/SNRIs.

METHODS

Patients with MDD who experienced a partial response to SSRI/SNRI monotherapy at adequate dose for ≥6 weeks were switched to 8 weeks of vortioxetine treatment 10-20 mg/day (Study NCT03835715). Key inclusion criteria were Montgomery-Åsberg Depression Rating Scale (MADRS) total score >21 and <29, current major depressive episode <12 months, Oxford Depression Questionnaire (ODQ) total score ≥50, and confirmation of emotional blunting by standardized screening question. Emotional blunting was assessed by ODQ and depressive symptoms by MADRS. Other outcomes assessed included motivation and energy (Motivation and Energy Inventory [MEI]), cognitive performance (Digit Symbol Substitution Test [DSST]), and overall functioning (Sheehan Disability Scale [SDS]).

RESULTS

At week 8, patients (N=143) had improved by -29.8 points (p<0.0001) in ODQ total score; 50% reported no emotional blunting in response to standardized screening question. Significant improvements were observed on the DSST, MEI, and SDS at all time points assessed, and 47% of patients were in remission (MADRS total score ≤10) at week 8. The most common treatment-emergent adverse events included nausea, headache, dizziness, vomiting, and diarrhea.

LIMITATIONS

No prospective phase before medication switch.

CONCLUSION

Vortioxetine 10-20 mg effectively improved emotional blunting, overall functioning, motivation and energy, cognitive performance, and depressive symptoms in patients with MDD with partial response to SSRI/SNRI therapy and emotional blunting.

[A review of the antidepressant properties of ketamine]

Major depression is a frequent and disabling disorder. Despite great developments in the field of psychopharmacology since the 1950's, delayed onset of action and treatment resistance to current pharmacological options, such as serotonin reuptake inhibitors, remain a therapeutic challenge. The recent discovery of the rapid antidepressant action of ketamine, an NMDA (N-methyl-D-aspartate) receptor antagonist, has brought a revolution to this field. This paper presents a comprehensive review of the clinical research on the antidepressant properties of ketamine as well as its presumed mechanisms of action.

Mechanism of Action of Atypical Antipsychotic Drugs in Mood Disorders

Atypical antipsychotic drugs were introduced in the early 1990s. Unlike typical antipsychotics, which are effective only against positive symptoms of schizophrenia, atypical antipsychotics are effective against negative and cognitive symptoms as well. Furthermore, they are effective not only in psychotic but also in affective disorders, on their own or as adjuncts to antidepressant drugs. This review presents the neural mechanisms of currently existing atypical antipsychotics and putative antipsychotics currently being investigated in preclinical and clinical studies and how these relate to their effectiveness in mood disorders such as depression, anxiety, and post-traumatic stress disorder (PTSD). Typical antipsychotics act almost exclusively on the dopamine system. Atypical drugs, however, modulate serotonin (5-HT), norepinephrine, and/or histamine neurotransmission as well. This multimodal mechanism of action putatively underlies the beneficial effect of atypical antipsychotics in mood and anxiety disorders. Interestingly, novel experimental drugs having dual antipsychotic and antidepressant therapeutic potential, such as histamine, adenosine, and trace amine-associated receptors (TAAR) ligand, are also characterized by a multimodal stimulatory effect on central 5-HT, norepinephrine, and/or histamine transmission. The multimodal stimulatory effect on central monoamine neurotransmission may be thus primarily responsible for the combined antidepressant and antipsychotic therapeutic potential of certain central nervous system (CNS) drugs.

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.

Treatment Response of Add-On Esketamine Nasal Spray in Resistant Major Depression in Relation to Add-On Second-Generation Antipsychotic Treatment

In this meta-analysis, we aimed to estimate and compare the efficacy of add-on treatment of antidepressants with esketamine nasal spray and second-generation antipsychotics in patients with nonpsychotic major depressive disorder and inadequate response to antidepressants. Searching for acute-phase, double-blind, placebo-controlled, randomized trials, we found 22 second-generation antipsychotic (n = 8363) and 3 intranasal esketamine (n = 641) studies. Mean change in the Montgomery Åsberg Depression Rating Scale total score served as outcome. We determined a higher mean difference (vs placebo) for the pooled esketamine nasal spray trials (mean difference = 4.09, 95% confidence interval: 2.01 to 6.17) than for the pooled second-generation antipsychotic augmentation trials (mean difference  = 2.05, 95% confidence interval: 1.51 to 2.59). Thus, the effect size for intranasal esketamine was nearly twice as high as those for the second-generation antipsychotics. This indicates high efficacy of add-on esketamine nasal spray in treatment-resistant major depressive disorder compared with other well-established, evidence-based pharmacological options such as augmentation with second-generation antipsychotics.

Concurrent antipsychotic use in older adults treated with antidepressants in Asia

AIM

Depressive disorders are common in old age. Antipsychotics (APs) are often used as an adjunctive treatment with antidepressants (ADs) in this population but its patterns of use in Asia are not known. This study explored the rate of combination of APs and ADs in older adult psychiatric patients in Asia.

METHODS

This is a secondary analysis of the database of a multicentre study which recorded participants' basic demographical and clinical data in standardised format in 10 Asian countries and territories. The data were analysed using univariate and multivariate logistic regression analyses.

RESULTS

A total of 955 older adult psychiatric in- and outpatients were included in this study. The proportion of concurrent AP and AD use was 32.0%, ranging from 23.3% in Korea to 44.0% in Taiwan. Multivariate logistic regression analysis found that younger age, inpatient status and diagnosis of schizophrenia, anxiety and other mental disorders were significantly related to a higher proportion of concurrent use of APs and ADs.

CONCLUSION

Around a third of older adult psychiatric patients had concurrent AP and AD use in the Asian countries/regions surveyed. Considering the uncertain effectiveness and questionable safety of the AP and AD combination in this patient population, such should be cautiously used.

Overcoming Resistance to Selective Serotonin Reuptake Inhibitors: Targeting Serotonin, Serotonin-1A Receptors and Adult Neuroplasticity

Major depressive disorder (MDD) is the most prevalent mental illness contributing to global disease burden. Selective serotonin (5-HT) reuptake inhibitors (SSRIs) are the first-line treatment for MDD, but are only fully effective in 30% of patients and require weeks before improvement may be seen. About 30% of SSRI-resistant patients may respond to augmentation or switching to another antidepressant, often selected by trial and error. Hence a better understanding of the causes of SSRI resistance is needed to provide models for optimizing treatment. Since SSRIs enhance 5-HT, in this review we discuss new findings on the circuitry, development and function of the 5-HT system in modulating behavior, and on how 5-HT neuronal activity is regulated. We focus on the 5-HT1A autoreceptor, which controls 5-HT activity, and the 5-HT1A heteroreceptor that mediates 5-HT actions. A series of mice models now implicate increased levels of 5-HT1A autoreceptors in SSRI resistance, and the requirement of hippocampal 5-HT1A heteroreceptor for neurogenic and behavioral response to SSRIs. We also present clinical data that show promise for identifying biomarkers of 5-HT activity, 5-HT1A regulation and regional changes in brain activity in MDD patients that may provide biomarkers for tailored interventions to overcome or bypass resistance to SSRI treatment. We identify a series of potential strategies including inhibiting 5-HT auto-inhibition, stimulating 5-HT1A heteroreceptors, other monoamine systems, or cortical stimulation to overcome SSRI resistance.

Optimized regimens of combined medications for the treatment of major depressive disorder: a double-blind, randomized-controlled trial

INTRODUCTION

This study investigated if optimized dose regimens of escitalopram and bupropion combination from treatment initiation can be superior to either drug alone in speed of onset, remission rate, and maintenance of therapeutic efficacy.

METHODS

Patients from a single site (N=85) within a larger double-blind 12-week trial (N=245) showed a lower dropout rate (14% vs 40%) and used higher doses; therefore, this cohort was analyzed separately. Uniquely at this single site, after 12 weeks, non-remitters on a single drug received the other one in addition and combination non-remitters underwent a switch of escitalopram for duloxetine for a 6-week period. Escitalopram could be given up to 40 mg/day and bupropion up to 450 mg/day. A 6-month prolongation was then implemented in remitters, maintaining the double-blind design throughout. Remission was defined as ≤7 on the 17-item Hamilton Rating Scale for Depression, as in the initial publication.

RESULTS

At week 2, combination treatment was superior in remission rate (5/28) compared with both bupropion (0/26) and escitalopram monotherapies (0/31; P=0.03 and P=0.02, respectively). The week 12 remission rate of combination treatment showed a higher rate (15/28) relative to bupropion monotherapy (7/26; P=0.04), but not statistically different from escitalopram monotherapy (11/31; P=0.13). The 6-week augmentation produced remission in 7/21 monotherapy non-remitters and 0/6 in the switch group (P=0.13). Remission was sustained in 28/31 patients enrolled in the 6-month maintenance.

CONCLUSION

These results suggest that combination of escitalopram and bupropion from treatment initiation is superior to either monotherapy in speed of onset. The addition of a second drug in non-remitters can lead to additional remissions, as shown with other combinations of medications. Treatment prolongation using optimized regimens leads to low relapse rates.

Antidepressant combination versus antidepressants plus second-generation antipsychotic augmentation in treatment-resistant unipolar depression

Patients with treatment-resistant unipolar depression (TRD) are treated with antidepressant combinations (ADs) or with second-generation antipsychotics plus AD (SGA+AD) augmentation; however, the clinical characteristics, the factors associated independently with response to SGA+AD, and the outcome trajectories have not yet been characterized. We performed a naturalistic study on the latest stable trial (medication unchanged for about 3 months) in 86 TRD patients with resistance to at least two ADs trials, who received ADs (n=36) or SGA+AD (n=50) treatments. Montgomery-Asberg Depression Rating Scale (MADRS), Hamilton-Depression Rating Scale (HAM-D17), and other scales were administered before (T0) and after the latest 3-month stable trial (T3). Compared to ADs, the SGA+AD group showed increased percentage of depression with psychotic features, comorbidity for personality disorders and substance use disorders (SUD), higher number of failed ADs pharmacotherapies and depressive symptoms at T0 on all scales (P<0.001). Compared to T0, both treatments significantly decreased depressive symptoms on MADRS and HAM-D17 at T3 (P<0.001); however, the SGA+AD augmentation produced a greater decline in mean score. Logistic regression analysis indicated that psychotic features, personality disorders, and SUD were independently associated with SGA+AD treatment. Given the greater improvement in depression following SGA+AD augmentation, SGA augmentation should be indicated as a first-line treatment in severe TRD with psychotic features, SUD, and personality disorders.

A proposal for a psychopharmacology-pharmacotherapy catalogue of learning objectives and a curriculum in Europe

Objectives Post-graduate training for specialisation in psychiatry and psychotherapy is part of a 4-6-year programme. This paper aims to inform on the general situation of teaching and training of psychopharmacology-psychopharmacotherapy in Europe. It presents the need for a psychopharmacotherapy education in psychiatric training programmes. Arguments as well as a proposal for a catalogue of learning objectives and an outline of a psychopharmacology curriculum are presented. Methods Based on their experience and on an analysis of the literature, the authors, experts in psychopharmacology-pharmacotherapy teaching, critically analyse the present situation and propose the development of a curriculum at the European level. Results Teaching programmes vary widely between European countries and, generally, teaching of psychopharmacology and pharmacotherapy does not exceed two-dozen hours. This is insufficient if one considers the central importance of psychopharmacology. A psychopharmacology-psychopharmacotherapy curriculum for the professional training of specialists in psychiatry and psychotherapy is proposed. Conclusions As the number of hours of theoretical teaching and practical training is insufficient, a catalogue of learning objectives should be established, which would then be part of a comprehensive curriculum at the European level. It could be inspired partly by those few previously proposed by other groups of authors and organisations.

Adjunctive treatment of brexpiprazole with fluoxetine shows a rapid antidepressant effect in social defeat stress model: Role of BDNF-TrkB signaling

Addition of low doses of the atypical antipsychotic drug brexpiprazole with selective serotonin reuptake inhibitors (SSRIs) could promote antidepressant effect in patients with major depressive disorder although the precise mechanisms underlying the action of the combination are unknown. Combination of low dose of brexpiprazole (0.1 mg/kg) and SSRI fluoxetine (10 mg/kg) could promote a rapid antidepressant effect in social defeat stress model although brexpiprazole or fluoxetine alone did not show antidepressant effect. Furthermore, the combination significantly improved alterations in the brain-derived neurotrophic factor (BDNF) - TrkB signaling and dendritic spine density in the prefrontal cortex, hippocampus, and nucleus accumbens in the susceptible mice after social defeat stress. Interestingly, TrkB antagonist ANA-12 significantly blocked beneficial effects of combination of brexpiprazole and fluoxetine on depression-like phenotype. These results suggest that BDNF-TrkB signaling plays a role in the rapid antidepressant action of the combination of brexpiprazole and fluoxetine.