New approaches to the pharmacological management of major depressive disorder

Fluoxetine in the Management of Major Depressive Disorder in Children and Adolescents: A Meta-Analysis of Randomized Controlled Trials

Background

Fluoxetine is a serotonin-specific reuptake inhibitor antidepressant and is the only approved pharmacological treatment for major depressive disorder (MDD) in children and adolescent.

Methods

We searched the published randomized controlled-trials to review fluoxetine efficacy and tolerability using the databases PubMed, EudraCT, ClinicalTrials.gov, and Cochrane Central Register of Controlled Trials for fluoxetine role in managing MDD in children and adolescents. A meta-analysis was conducted using the identified 7 clinical trials to assess efficacy using the outcomes: Children's Depression Rating Scale-Revised (CDRS-R), Clinical Global Impressions-Severity of Illness (CGI-S) and Clinical Global Impressions-Improvement (CGI-I) response rate. The risk of discontinuation due to adverse effects and common side effects were examined.

Results

The mean difference in change from baseline for CDRS-R was -2.72 (95% confidence interval [CI], -3.96, -1.48) favoring fluoxetine treatment (P < .001). Similarly, mean difference for CGI-S was -0.21 (95% CI, -0.36, -0.06). The risk ratio (RR) of discontinuing due to adverse events was 0.98 (95% CI, 0.54, 1.83), with RR for headache side effects 1.34 (95% CI, 1.03, 1.74) and rash 2.6 (95% CI, 1.32, 5.14).

Conclusion

Fluoxetine demonstrates significant improvements in symptom intensity control in young patients suffering from MDD and is considered well tolerated with similar rates of trials discontinuation; however, fluoxetine was associated with a higher risk of headache and rash side effects. These findings will guide psychiatrists and pharmacists in their clinical role for supporting the care of young mental health patients.

Venlafaxine protects against chronic stress-related behaviors in mice by activating the mTORC1 signaling cascade

BACKGROUND

Recent studies have suggested the role of mammalian target of rapamycin complex 1 (mTORC1) in the pathophysiology of depression. Although venlafaxine was thought to be a serotonin and norepinephrine reuptake inhibitor (SNRI), its pharmacological mechanism remain elusive. In this study, the effects of venlafaxine on the mTORC1 system were studied in both chronic unpredictable mild stress (CUMS) and chronic social defeat stress (CSDS) models.

METHOD

First, we examined whether repeated venlafaxine treatment reversed the effects of CUMS and CSDS on the mTORC1 signaling cascade in both the hippocampus and medial prefrontal cortex (mPFC). Second, several selective pharmacological inhibitors of the mTORC1 system, including rapamycin, LY294002 and U0126, were used together to determine whether the protective effects of venlafaxine against the CUMS and CSDS models were prevented by mTORC1 system blockade. Finally, genetic knockdown of mTORC1 by mTORC1-shRNA was further adopted to test whether mTORC1 was necessary for the anti-stress effects of venlafaxine in mice.

RESULT

Our results showed that the decreasing effects of CUMS and CSDS on the mTORC1 signaling cascade in the hippocampus and mPFC were restored by venlafaxine, and the use of rapamycin, LY294002, U0126 and mTORC1-shRNA fully abolished the anti-stress actions of venlafaxine in mice.

CONCLUSION

The mTORC1 system is involved in the pharmacological mechanism of venlafaxine.

Higher serum VGF protein levels discriminate bipolar depression from major depressive disorder

Misdiagnosis between major depressive disorder (MDD) and bipolar depression (BD) is quite common. Our previous study found significantly lower serum VGF (non-acronymic) in MDD patients. However, it is unclear whether same changes occur in BD patients. Therefore, we aimed to investigate the relationship between serum VGF levels in BD and MDD patients. General information, scores of 17-item Hamilton Depression Rating Scale (HDRS), and fasting blood samples of all participants including 30 MDD patients, 20 BD patients, and 30 healthy controls (HC) were collected. Serum VGF levels were measured by Enzyme-linked immunosorbent assay kits. Pearson correlation analysis was used to analyze correlations between serum VGF levels and clinical information. Receiver operating characteristic (ROC) curve and likelihood ratios (LRs) were used to analyze the differential potential of serum VGF. Serum VGF levels were significantly lower in MDD patients but higher in BD patients compared with HC (both P_Tukey < 0.01). No correlation was found between serum VGF levels and any data of subjects. The optimal cutoff for serum VGF in discriminating BD patients from MDD patients was ≥1093.85 pg/ml (AUC = 0.990, sensitivity of 95%, specificity of 100% and accuracy of 95%). LRs further confirmed the differential efficiency of serum VGF in distinguishing BD and MDD patients with +LR of infinity and -LR of 0. The results suggest that serum VGF level changed significantly in MDD and BD patients and serum VGF may be an indicator for differentiating BD patients from MDD patients.

Involvement of NMDA and AMPA receptors in the antidepressant-like activity of antidepressant drugs in the forced swim test

BACKGROUND

The involvement of glutamate system (particularly the NMDA and AMPA receptors) in the mechanism of antidepressant activity was demonstrated in preclinical and clinical studies.

METHODS

In the present study, we investigated the effect of NMDA and AMPA receptors' ligands (agonists and antagonists) on the antidepressant-like activity of escitalopram, milnacipran, imipramine and reboxetine in the forced swim test in mice.

RESULTS

Antidepressant activity (reduction in immobility time) of escitalopram and milnacipran but not of imipramine and reboxetine was antagonized by N-methyl-D-aspartate acid. CGP37849 (antagonist of the NMDA receptor) enhanced the antidepressant activity of all examined antidepressants. On the other hand, CX614 (a potentiator/positive allosteric modulator of the AMPA receptor) enhanced the antidepressant activity of imipramine and reboxetine but not of escitalopram and milnacipran in this test. NBQX (the AMPA receptor antagonist) did not influence the antidepressant activity of all tested agents.

CONCLUSIONS

The data indicate the complex interactions following the activation or blockade of the NMDA and AMPA receptors with antidepressant drugs. The general phenomenon is the enhancing effect of the NMDA receptor antagonism on the antidepressant activity. Moreover, is can be concluded that the activity of antidepressants with a serotonergic mechanism of action can be inhibited by NMDA activation, while antidepressants with a noradrenergic mechanism of action are dependent on AMPA receptor transmission.

A 10-week memantine treatment in bipolar depression: a case report. Focus on depressive symptomatology, cognitive parameters and quality of life

Memantine and other glutamatergic agents have been currently investigated in some off-label indications due to glutamatergic involvement in several psychoneurological disorders. We assumed that memantine similarly to ketamine may positively influence mood, moreover having a potential to improve cognition and general quality of life. We report a case of a 49-year-old male hospitalized during a manic and a subsequent moderate depressive episode. After an ineffective use of lithium, olanzapine and antidepressive treatment with mianserin, memantine was added up to 20 mg per day for 10 weeks. The mental state was assessed using the Hamilton Depression Rating Scale, the Young Mania Rating Scale, the Hamilton Anxiety Scale, the Clinical Global Inventory, the World Health Organization Quality of Life Scale and psychological tests. After 10 weeks the patient achieved a partial symptomatic improvement in mood, anxiety and quality of sleep, but his activity remained insufficient. We also observed an improvement in the parameters of cognitive functioning and quality of life. There was neither significant mood variations during the memantine use nor mood changes after its termination. No significant side effects were noted during the memantine treatment. We conclude that using memantine in bipolar depression may improve mood, cognitive functioning and quality of life.

Molecular adaptation to chronic antidepressant treatment: evidence for a more rapid response to the novel α₂-adrenoceptor antagonist/5-HT-noradrenaline reuptake inhibitor (SNRI), S35966, compared to the SNRI, venlafaxine

Evidence of early changes in neural plasticity may aid the prediction of rapid-onset antidepressant drugs. Here we compared the dual α₂-adrenoceptor antagonist/5-HT-noradrenaline reuptake inhibitor (SNRI), S35966, to the SNRI, venlafaxine, with regards to their effect on rat brain expression of a panel of neural plasticity-related genes: Arc, BDNF, and VGLUT1, as well as Homer1a and Shank1B (not studied previously). Abundance of mRNA was determined by in-situ hybridization in cortical and hippocampal regions 2 h and 16 h following drug administration for 14, 7 and 1 d. After 14 d, both S35966 and venlafaxine increased mRNA of all genes, including Homer1a and Shank1B, and effects were similarly time- and region-dependent. After 7 d, S35966 elevated Arc, Shank1B and BDNF mRNA, whereas venlafaxine increased Shank1B mRNA only. Finally, after 1 d (acute administration), S35966 increased Arc and Homer1a mRNA whereas venlafaxine had no effect on any gene examined. In summary, a 14-d course of treatment with S35966 or venlafaxine induced similar region- and time-dependent increases in expression of neural plasticity-related genes including Shank1B and Homer1a. Some genes responded earlier to S35966, suggesting that drugs with combined α₂-adrenoceptor antagonist/SNRI properties may elicit more rapid changes in markers of neural plasticity than a SNRI alone.

Treatment-resistant depression: therapeutic trends, challenges, and future directions

BACKGROUND

Patients with major depression respond to antidepressant treatment, but 10%-30% of them do not improve or show a partial response coupled with functional impairment, poor quality of life, suicide ideation and attempts, self-injurious behavior, and a high relapse rate. The aim of this paper is to review the therapeutic options for treating resistant major depressive disorder, as well as evaluating further therapeutic options.

METHODS

In addition to Google Scholar and Quertle searches, a PubMed search using key words was conducted, and relevant articles published in English peer-reviewed journals (1990-2011) were retrieved. Only those papers that directly addressed treatment options for treatment-resistant depression were retained for extensive review.

RESULTS

Treatment-resistant depression, a complex clinical problem caused by multiple risk factors, is targeted by integrated therapeutic strategies, which include optimization of medications, a combination of antidepressants, switching of antidepressants, and augmentation with non-antidepressants, psychosocial and cultural therapies, and somatic therapies including electroconvulsive therapy, repetitive transcranial magnetic stimulation, magnetic seizure therapy, deep brain stimulation, transcranial direct current stimulation, and vagus nerve stimulation. As a corollary, more than a third of patients with treatment-resistant depression tend to achieve remission and the rest continue to suffer from residual symptoms. The latter group of patients needs further study to identify the most effective therapeutic modalities. Newer biomarker-based antidepressants and other drugs, together with non-drug strategies, are on the horizon to address further the multiple complex issues of treatment-resistant depression.

CONCLUSION

Treatment-resistant depression continues to challenge mental health care providers, and further relevant research involving newer drugs is warranted to improve the quality of life of patients with the disorder.