Lamotrigine: when and where does it act in affective disorders? A systematic review

Testosterone Replacement Therapy in the Treatment of Depression

BACKGROUND

Depression is a common disorder that affects millions globally and is linked to reduced quality of life and mortality. Its pathophysiology is complex and there are several forms of treatment proposed in the literature with differing side effect profiles. Many patients do not respond to treatment which warrants augmentation with other treatments and the investigation of novel treatments. One of these treatments includes testosterone therapy which evidence suggests might improve depressed mood in older patients with low levels of testosterone and helps restore physical impairments caused by age-related hormonal changes.

OBJECTIVE

The objective of this review is to synthesize information regarding clinical depression, its treatment options, and the efficacy and safety of testosterone treatment for the treatment of depression.

METHODS

This review utilized comprehensive secondary and tertiary data analysis across many academic databases and published work pertaining to the topic of interest.

RESULTS

Within some subpopulations such as men with dysthymic disorder, treatment resistant depression, or low testosterone levels, testosterone administration yielded positive results in the treatment of depression. Additionally, rodent models have shown that administering testosterone to gonadectomized male animals reduces symptoms of depression. Conversely, some studies have found no difference in depressive symptoms after treatment with testosterone when compared with placebo. It was also noted that over administration of testosterone is associated with multiple adverse effects and complications.

CONCLUSION

The current evidence provides mixed conclusions on the effectiveness of testosterone therapy for treating depression. More research is needed in adult men to see if declining testosterone levels directly influence the development of depression.

The effectiveness of lamotrigine for persistent depressive disorder: A case report

Aim

Persistent depressive disorder (PDD) was first introduced in the Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM‐5), which encompasses numerous different conditions, including dysthymia, recurrent major depressive disorder, double depression, and chronic major depression. SSRIs are the first‐line drugs for treatment of PDD; however, not all patients respond to SSRI treatment.

Case presentation

We describe a woman who was diagnosed with PDD. At the age of 38, the patient presented with anxiety, reduced energy, marked tiredness, and sleep disturbances. She was prescribed with three antidepressants (paroxetine, duloxetine, and mirtazapine), which were not effective in relieving her symptoms. She was also prescribed bromazepam, which was also not effective. Subsequently, she was switched to lamotrigine, which resulted in a marked improvement in symptoms. The antidepressants and bromazepam were gradually tapered and discontinued.

Conclusion

This case demonstrates that lamotrigine may be effective for treating patients with antidepressant resistant PDD and suggests that it may be a promising alternative to combination therapy of antidepressants and benzodiazepines in the treatment of PDD.

The patient's depressive and anxiety symptoms remitted and relapsed repeatedly during taking combination therapy. After switching to lamotrigine monotherapy, the symptoms have improved and continued remission for a long time.

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

OBJECTIVE

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

DATA SOURCES

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

DATA EXTRACTION AND SYNTHESIS

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

MAIN OUTCOMES AND MEASURES

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

RESULTS

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

CONCLUSIONS AND RELEVANCE

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

REGISTRATION

PROSPERO (CRD42019122172).

Lamotrigine augmentation in treatment-resistant unipolar depression: A comprehensive meta-analysis of efficacy and safety

OBJECTIVE

Augmentation strategies are commonly applied when an individual is unresponsive to antidepressant monotherapy. Lamotrigine is currently considered at best only as second line augmentation for treatment-resistant unipolar depression while its clinical efficacy and safety profiles remain inconclusive. We intended to assess the therapeutic effects and safety profiles of lamotrigine augmentation in patients with treatment-resistant unipolar depression by conducting a meta-analysis.

METHODS

MEDLINE, Embase, EBSCO, Cochrane, Web of Science, Scopus, Wanfang and Ariniti databases were searched. Coprimary outcomes, including changes in severity of depression and response rate, were measured in this study. Secondary outcomes were defined as the safety profile of the intervention, including reported discontinuation rate and adverse events.

RESULTS

Eight double-blinded randomized controlled trials with 677 patients overall were included. Significant improvements in Hamilton Rating Scale for Depression scores and response rates were shown in lamotrigine augmentation groups compared with control groups, of which the pooled result of six Chinese studies showed positive effects of Hamilton Rating Scale for Depression improvement while the pooled result of two non-Chinese studies was statistically non-significant. Patients with more severe illness and longer duration of illness were more effectively treated with lamotrigine augmentation. The magnitude of depression improvement after lamotrigine augmentation was higher in patients treated with selective serotonin reuptake inhibitors than those treated with serotonin-norepinephrine reuptake inhibitors. Lamotrigine augmentation is well-tolerated in terms of all-cause discontinuation rate and adverse events.

CONCLUSIONS

Lamotrigine augmentation may serve as a possible choice for patients with treatment-resistant unipolar depression and further trials are warranted to clarify the optimal dosage of lamotrigine augmentation together with the treatment duration and safety over time.

Mixed states in bipolar disorder - changes in DSM-5 and current treatment recommendations

OBJECTIVE

Mixed states in affective disorders represent a particular challenge in clinical routine, characterized by a complicated course of treatment and a worse treatment response.

METHODS

Clinical features of mixed states and the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria are presented and critical discussed. We then performed a systematic review using the terms 'bipolar', 'mixed' and 'randomized' to evaluate current treatment options.

RESULTS

For pharmacological treatment of mixed states in total, there is still insufficient data from RCTs. However, there is some evidence for efficacy in mixed states from RCTs for atypical antipsychotics, especially olanzapine, aripiprazole and asenapine as well as mood stabilizers as valproate and carbamazepine.

CONCLUSIONS

Mixed states are of a high clinical relevance and the DSM-5 criteria substantially reduced the diagnostic threshold. Besides advantages of a better characterization of patients with former DSM-IV-defined mixed episodes, disadvantages arise for example differential diagnoses with a substantial overlap in symptoms such as borderline personality disorders. Atypical antipsychotics, valproate and carbamazepine demonstrated efficacy in a limited sample of RCTs.

LIMITATIONS

The number of RCTs in the treatment of mixed states is highly limited. Furthermore, nearly all studies were funded by pharmaceutical companies which may lead to an underestimation of classical mood stabilizers such as lithium.

Mixed States in Bipolar Disorder: Etiology, Pathogenesis and Treatment

Many bipolar disorder patients exhibit mixed affective states, which portend a generally more severe illness course and treatment resistance. In the previous renditions of Diagnostic and Statistical Manual mixed states were narrowly defined in the context of bipolar I disorder, but with the advent of DSM-5 the term “mixed episode” was dropped and replaced by “mixed features” specifier which could be broadly applied to manic, hypomanic and depressive episodes in both the bipolar spectrum and major depressive disorders. This paradigm shift reflected their significance in the prognosis and overall management of mood disorders, so that the clinicians should thoroughly familiarize themselves with the contemporary notions surrounding these conditions. The purpose of this manuscript is to bring to light the current conceptualizations regarding the etiology, pathogenesis and treatment of mixed states. To achieve this goal, in June 2016 an extensive literature search was undertaken using the PubMed database. Some exploratory terms utilized included “mixed states”, “mixed episodes”, “switching”, “rapid cycling” cross referenced with “bipolar disorder”. Focusing on the most relevant and up to date studies, it was revealed that mixed states result from genetic susceptibility in the circadian and dopamine neurotransmission apparatuses and disturbance in the intricate catecholamine-acetylcholine neurotransmission balance which leads to mood fluctuations. The management of mixed states is challenging with atypical antipsychotics, newer anticonvulsants and electroconvulsive therapy emerging as the foremost treatment options. In conclusion, while progress has been made in the neurobiological understanding of mixed states, the currently available therapeutic modalities have only shown limited effectiveness.

A pilot open series of lamotrigine in DBT-treated eating disorders characterized by significant affective dysregulation and poor impulse control

BACKGROUND

There is little effective psychopharmacological treatment for individuals with eating disorders who struggle with pervasive, severe affective and behavioral dysregulation.

METHODS

This pilot open series evaluated lamotrigine, a mood stabilizer, in the treatment of patients with eating disorders who did not respond adequately to antidepressant medications. Nine women with anorexia nervosa- or bulimia nervosa-spectrum eating disorders in partial hospital or intensive outpatient dialectical behavior therapy (DBT)-based eating disorder treatment took lamotrigine for 147 ± 79 days (mean final dose = 161.1 ± 48.6 mg/day). Participants completed standardized self-report measures of emotion dysregulation and impulsivity after lamotrigine initiation and approximately biweekly thereafter. Mood and eating disorder symptomatology were measured at lamotrigine initiation and at time of final assessment.

RESULTS

Lamotrigine and concurrent DBT were associated with large reductions in self-reported affective and behavioral dysregulation (ps < 0.01). Eating disorder and mood symptoms decreased moderately.

CONCLUSIONS

Although our findings are limited by the confounds inherent in an open series, lamotrigine showed initial promise in reducing emotional instability and behavioral impulsivity in severely dysregulated eating-disordered patients. These preliminary results support further investigation of lamotrigine for eating disorders in rigorous controlled trials.

Towards the Molecular Foundations of Glutamatergic-targeted Antidepressants

BACKGROUND

Depression affects over 120 million individuals of all ages and is the leading cause of disability worldwide. The lack of objective diagnostic criteria, together with the heterogeneity of the depressive disorder itself, makes it challenging to develop effective therapies. The accumulation of preclinical data over the past 20 years derived from a multitude of models using many divergent approaches, has fueled the resurgence of interest in targeting glutamatergic neurotransmission for the treatment of major depression.

OBJECTIVE

The emergence of mechanistic studies are advancing our understanding of the molecular underpinnings of depression. While clearly far from complete and conclusive, they offer the potential to lead to the rational design of more specific therapeutic strategies and the development of safer and more effective rapid acting, long lasting antidepressants.

METHODS

The development of comprehensive omics-based approaches to the dysregulation of synaptic transmission and plasticity that underlies the core pathophysiology of MDD are reviewed to illustrate the fundamental elements.

RESULTS

This review frames the rationale for the conceptualization of depression as a "pathway disease". As such, it culminates in the call for the development of novel state-of-the-art "-omics approaches" and neurosystems biological techniques necessary to advance our understanding of spatiotemporal interactions associated with targeting glutamatergic-triggered signaling in the CNS.

CONCLUSION

These technologies will enable the development of novel psychiatric medications specifically targeted to impact specific, critical intracellular networks in a more focused manner and have the potential to offer new dimensions in the area of translational neuropsychiatry.

Management of bipolar depression with lamotrigine: an antiepileptic mood stabilizer

The efficacy of lamotrigine in the treatment of focal epilepsies have already been reported in several case reports and open studies, which is thought to act by inhibiting glutamate release through voltage-sensitive sodium channels blockade and neuronal membrane stabilization. However, recent findings have also illustrated the importance of lamotrigine in alleviating the depressive symptoms of bipolar disorder, without causing mood destabilization or precipitating mania. Currently, no mood stabilizers are available having equal efficacy in the treatment of both mania and depression, two of which forms the extreme sides of the bipolar disorder. Lamotrigine, a well established anticonvulsant has received regulatory approval for the treatment and prevention of bipolar depression in more than 30 countries worldwide. Lamotrigine, acts through several molecular targets and overcomes the major limitation of other conventional antidepressants by stabilizing mood from “below baseline” thereby preventing switches to mania or episode acceleration, thus being effective for bipolar I disorder. Recent studies have also suggested that these observations could also be extended to patients with bipolar II disorder. Thus, lamotrigine may supposedly fulfill the unmet requirement for an effective depression mood stabilizer.

Ketamine and other potential glutamate antidepressants

The need for rapid acting antidepressants is widely recognised. There has been much interest in glutamate mechanisms in major depressive disorder (MDD) as a promising target for the development of new antidepressants. A single intravenous infusion of ketamine, a N-methyl-d-aspartate (NMDA) receptor antagonist anaesthetic agent, can alleviate depressive symptoms in patients within hours of administration. The mechanism of action appears to be in part through glutamate release onto non-NMDA receptors including α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and metabotropic receptors. However these are also reported effects on 5-HT, dopamine and intracellular effects on the mammalian target of rapamycin (mTOR) pathway. The effects of SSRI (Selective Serotonin Reuptake Inhibitor) antidepressants may also involve alterations in NMDA function. The article reviews the effect of current antidepressants on NMDA and examines the efficacy and mechanism of ketamine. Response to ketamine is also discussed and comparison with other glutamate drugs including lamotrigine, amantadine, riluzole, memantine, traxoprodil, GLYX-13, MK-0657, RO4917523, AZD2066 and Coluracetam. Future studies need to link the rapid antidepressant effects seen with ketamine to inflammatory theories in MDD.

Informing DSM-5: biological boundaries between bipolar I disorder, schizoaffective disorder, and schizophrenia

BACKGROUND

The fifth version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) opted to retain existing diagnostic boundaries between bipolar I disorder, schizoaffective disorder, and schizophrenia. The debate preceding this decision focused on understanding the biologic basis of these major mental illnesses. Evidence from genetics, neuroscience, and pharmacotherapeutics informed the DSM-5 development process. The following discussion will emphasize some of the key factors at the forefront of the debate.

DISCUSSION

Family studies suggest a clear genetic link between bipolar I disorder, schizoaffective disorder, and schizophrenia. However, large-scale genome-wide association studies have not been successful in identifying susceptibility genes that make substantial etiological contributions. Boundaries between psychotic disorders are not further clarified by looking at brain morphology. The fact that symptoms of bipolar I disorder, but not schizophrenia, are often responsive to medications such as lithium and other anticonvulsants must be interpreted within a larger framework of biological research.

SUMMARY

For DSM-5, existing nosological boundaries between bipolar I disorder and schizophrenia were retained and schizoaffective disorder preserved as an independent diagnosis since the biological data are not yet compelling enough to justify a move to a more neurodevelopmentally continuous model of psychosis.

A systematic review on the role of anticonvulsants in the treatment of acute bipolar depression

Despite the high morbidity and mortality associated with bipolar depression, the optimal treatment for this phase is still a matter of debate. The aim of the current review was to provide updated evidence about the efficacy and tolerability of anticonvulsants in the treatment of acute bipolar depression. A comprehensive review of randomized controlled trials (RCTs) evaluating the use of anticonvulsants for the treatment of acute bipolar depression up to June 2011 was conducted by means of the PubMed-Medline database. Eligibility criteria included active comparator-controlled or placebo-controlled randomized studies involving monotherapy or combination therapy. A total of 18 RCTs fulfilled the inclusion criteria. Studies supported the efficacy of divalproex as monotherapy in acute bipolar depression but small sample size was a common methodological limitation. Findings were inconclusive for lamotrigine and carbamazepine although overall lamotrigine may have a beneficial but modest effect. Negative results were found for levetiracetam and gabapentin but the evidence base on these agents is scant. All anticonvulsants were generally well tolerated. No double-blind RCTs were found for the use of other anticonvulsants such as oxcarbazepine, licarbazepine, zonisamide, retigabine, pregabalin, tiagabine, felbamate and vigabatrine in the acute treatment of bipolar depression. To sum up, taking into consideration the efficacy and tolerability profiles of anticonvulsants, current evidence supports the use of divalproex and lamotrigine in the treatment of acute bipolar depression. However, available data for most other anticonvulsants are inconclusive and further RCTs with larger sample sizes are needed before drawing firm conclusions.

New approaches in the treatment of bipolar depression

Patients with bipolar disorder more frequently suffer from depression than from mania. Indeed depressive symptomatology represents the majority of the illness burden experienced by bipolar patients and is also associated with elevated suicide risk. The treatment of bipolar depression differs from that of recurrent major depression in that the efficacy of conventional antidepressant drugs is not well-established. Some evidence-based treatments for bipolar depression are available and include the anticonvulsant drug, lamotrigine, and the atypical antipsychotic, quetiapine. Lithium also has some benefits in the prevention of depression and its use is associated with a significant reduction in suicidal behaviour. Several other treatments are in clinical development including dopamine agonists, glutamatergic modulating drugs and antioxidants. The role of these interventions in management is uncertain. The clinical uncertainties in the pharmacological treatment of bipolar depression mean that treatment has to be individualised and empirical; there is also an important role for psychological therapies, which again need to be tailored to suit the needs of the individual patient and their family.

A critical review of the recent literature and selected therapy guidelines since 2006 on the use of lamotrigine in bipolar disorder

The anticonvulsant drug lamotrigine (LTG), a sodium channel blocker and inhibitor of glutamate release, has been found to have antidepressant effects in the treatment of bipolar disorder. It is recommended by certain therapy guidelines as a first-line agent for acute and maintenance therapy in bipolar depression, but there have been only some promising results of placebo-controlled trials on its acute antidepressant effects, and the recommendation in therapy guidelines has been reconsidered. On the contrary, positive results for maintenance therapy could be confirmed, and LTG is still a well-tolerated option, especially in patients with predominant depressive episodes. Antimanic effects are not shown in the literature, and its use is not advised in any guidelines that were examined. In conclusion, the findings of the present review article on treatment guidelines for bipolar disorder question the role of LTG in acute depressive states, and critically discusses its use, particularly in acute depressive states.

Effect of lamotrigine and carbamazepine on corticotropin-releasing factor-associated serotonergic transmission in rat dorsal raphe nucleus

Corticotropin-releasing factor (CRF) and serotonin are important transmitters of the pathophysiology of mood disorder. To clarify the mechanisms of action of lamotrigine (LTG) and carbamazepine (CBZ), we determined their effects on serotonin release associated with CRF in rat dorsal raphe nucleus (DRN) and median prefrontal cortex (mPFC) using dual-probe microdialysis. Neither perfusion with CRF1 nor CRF2 antagonists into DRN-affected serotonin release in DRN and mPFC. Perfusion of 10 μM CRF into DRN increased serotonin release in both regions, whereas 0.1 μM CRF decreased and had no effect on serotonin release in DRN and mPFC, respectively. Pre-perfusion with CRF1 antagonist into DRN inhibited 0.1 μM CRF-induced serotonin reduction, whereas pre-perfusion with CRF2 antagonist in DRN inhibited 10 μM CRF-induced serotonin elevation, without affecting 0.1 μM CRF-induced serotonin reduction. LTG perfusion concentration dependently decreased serotonin releases in DRN and mPFC. Therapeutic and supratherapeutic concentrations of CBZ increased and decreased serotonin releases in both regions, respectively. Pre-perfusion with sub-therapeutic concentration LTG inhibited CRF1-induced serotonin reduction without affecting CRF2-induced serotonin release, whereas pre-perfusion with therapeutic concentration of LTG inhibited both CRF1- and CRF2-actions. In contrast, both therapeutic and supratherapeutic concentrations of CBZ inhibited CRF2-induced serotonin release without affecting CRF1-induced serotonin reduction. Neither LTG nor CBZ affected the CRF-induced cAMP production in cells over-expressing CRF1 and CRF2 receptors. This study demonstrated that inhibition of CRF2-receptor-mediated serotonergic transmission is a mechanism shared by LTG and CBZ, two clinically related compounds, whereas LTG but not CBZ inhibits CRF1-receptor-mediated serotonergic transmission. Therefore, these mechanisms may contribute to the clinical actions of these agents.

Imaging brain signal transduction and metabolism via arachidonic and docosahexaenoic acid in animals and humans

The polyunsaturated fatty acids (PUFAs), arachidonic acid (AA, 20:4n-6) and docosahexaenoic acid (DHA, 22:6n-3), important second messengers in brain, are released from membrane phospholipid following receptor-mediated activation of specific phospholipase A(2) (PLA(2)) enzymes. We developed an in vivo method in rodents using quantitative autoradiography to image PUFA incorporation into brain from plasma, and showed that their incorporation rates equal their rates of metabolic consumption by brain. Thus, quantitative imaging of unesterified plasma AA or DHA incorporation into brain can be used as a biomarker of brain PUFA metabolism and neurotransmission. We have employed our method to image and quantify effects of mood stabilizers on brain AA/DHA incorporation during neurotransmission by muscarinic M(1,3,5), serotonergic 5-HT(2A/2C), dopaminergic D(2)-like (D(2), D(3), D(4)) or glutamatergic N-methyl-d-aspartic acid (NMDA) receptors, and effects of inhibition of acetylcholinesterase, of selective serotonin and dopamine reuptake transporter inhibitors, of neuroinflammation (HIV-1 and lipopolysaccharide) and excitotoxicity, and in genetically modified rodents. The method has been extended for the use with positron emission tomography (PET), and can be employed to determine how human brain AA/DHA signaling and consumption are influenced by diet, aging, disease and genetics.