Understanding the molecular mechanisms underlying mood stabilizer treatments in bipolar disorder: Potential involvement of epigenetics

The epigenetic mechanism of metabolic risk in bipolar disorder

Bipolar disorder (BD) is a complex and severe mental illness that causes significant suffering to patients. In addition to the burden of depressive and manic symptoms, patients with BD are at an increased risk for metabolic syndrome (MetS). MetS includes factors associated with an increased risk of atherosclerotic cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM), which may increase the mortality rate of patients with BD. Several studies have suggested a link between BD and MetS, which may be explained at an epigenetic level. We have focused on epigenetic mechanisms to review the causes of metabolic risk in BD.

Evaluation of drug prescribing patterns and therapeutic drug monitoring practice using electronic medical records

Therapeutic drug monitoring (TDM) is performed for drugs with narrow therapeutic indices. At Seoul National University Hospital (SNUH) and Seoul National University Bundang Hospital (SNUBH), TDM services are provided for various drugs such as antibiotics and antiepileptics. This study aimed to identify prescription patterns over time using electronic medical records and analyze their relationship with TDM practice. Data were collected from a clinical data warehouse from 2007 to 2020, and the number of patients, total number of drug administration days, serum level tests, and TDM were calculated. The ratio was calculated as the number of serum level tests or TDM to the total number of drug administration days. The study included 136,427 and 162,927 patients from SNUH and SNUBH who were prescribed 11 specified drugs. Each drug showed different prescription patterns over time, and the serum level test and TDM also changed with prescription pattern changes. Serum level test or TDM of antibiotics was frequently used compared to antiepileptics. As some drugs' usage and test for drugs have decreased newly developed drugs are replacing old drugs. It is recommended that TDM services include these new drugs as well for an effective and safe therapy.

Transcriptomics and miRNomics data integration in lymphoblastoid cells highlights the key role of immune-related functions in lithium treatment response in Bipolar disorder

BACKGROUND

Bipolar Disorder (BD) is a complex mental disease characterized by recurrent episodes of mania and depression. Lithium (Li) represents the mainstay of BD pharmacotherapy, despite the narrow therapeutic index and the high variability in treatment response. However, although several studies have been conducted, the molecular mechanisms underlying Li therapeutic effects remain unclear.

METHODS

In order to identify molecular signatures and biological pathways associated with Li treatment response, we conducted transcriptome and miRNome microarray analyses on lymphoblastoid cell lines (LCLs) from 20 patients diagnosed with BD classified as Li responders (n = 11) or non-responders (n = 9).

RESULTS

We found 335 mRNAs and 77 microRNAs (miRNAs) significantly modulated in BD responders versus non-responders. Interestingly, pathway and network analyses on these differentially expressed molecules suggested a modulatory effect of Li on several immune-related functions. Indeed, among the functional molecular nodes, we found NF-κB and TNF. Moreover, networks related to these molecules resulted overall inhibited in BD responder patients, suggesting anti-inflammatory properties of Li. From the integrative analysis between transcriptomics and miRNomics data carried out using miRComb R package on the same samples from patients diagnosed with BD, we found 97 significantly and negatively correlated mRNA-miRNA pairs, mainly involved in inflammatory/immune response.

CONCLUSIONS

Our results highlight that Li exerts modulatory effects on immune-related functions and that epigenetic mechanisms, especially miRNAs, can influence the modulation of different genes and pathways involved in Li response. Moreover, our data suggest the potentiality to integrate data coming from different high-throughput approaches as a tool to prioritize genes and pathways.

Mathematical Model of Interaction of Therapist and Patients with Bipolar Disorder: A Systematic Literature Review

Mood swings in patients with bipolar disorder (BD) are difficult to control and can lead to self-harm and suicide. The interaction between the therapist and BD will determine the success of therapy. The interaction model between the therapist and BD begins by reviewing the models that were previously developed using the Systematic Literature Review and Bibliometric methods. The limit of articles used was sourced from the Science Direct, Google Scholar, and Dimensions databases from 2009 to 2022. The results obtained were 67 articles out of a total of 382 articles, which were then re-selected. The results of the selection of the last articles reviewed were 52 articles. Using VOSviewer version 1.6.16, a visualization of the relationship between the quotes “model”, “therapy”, “emotions”, and “bipolar disorder” can be seen. This study also discusses the types of therapy that can be used by BD, as well as treatment innovations and the mathematical model of the therapy itself. The results of this study are expected to help further researchers to develop an interaction model between therapists and BD to improve the quality of life of BD.

Transcriptional biomarkers of response to pharmacological treatments in severe mental disorders: A systematic review

Variation in the expression level and activity of genes involved in drug disposition and action in tissues of pharmacological importance have been increasingly investigated in patients treated with psychotropic drugs. Findings are promising, but reliable predictive biomarkers of response have yet to be identified. Here we conducted a PRISMA-compliant systematic search of PubMed, Scopus and PsycInfo up to 12 September 2020 for studies investigating RNA expression levels in cells or biofluids from patients with major depressive disorder, schizophrenia or bipolar disorder characterized for response to psychotropic drugs (antidepressants, antipsychotics or mood stabilizers) or adverse effects. Among 5497 retrieved studies, 123 (63 on antidepressants, 33 on antipsychotics and 27 on mood stabilizers) met inclusion criteria. Studies were either focused on mRNAs (n = 96), microRNAs (n = 19) or long non-coding RNAs (n = 1), with only a minority investigating both mRNAs and microRNAs levels (n = 7). The most replicated results include genes playing a role in inflammation (antidepressants), neurotransmission (antidepressants and antipsychotics) or mitochondrial function (mood stabilizers). Compared to those investigating response to antidepressants, studies focused on antipsychotics or mood stabilizers more often showed lower sample size and lacked replication. Strengths and limitations of available studies are presented and discussed in light of the specific designs, methodology and clinical characterization of included patients for transcriptomic compared to DNA-based studies. Finally, future directions of transcriptomics of psychopharmacological interventions in psychiatric disorders are discussed.

Mini review: Recent advances on epigenetic effects of lithium

Lithium (Li) remains the first line long-term treatment of bipolar disorders notwithstanding a high inter-individual variability of response. Significant research effort has been undertaken to understand the molecular mechanisms underlying Li cellular and clinical effects in order to identify predictive biomarkers of response. Li response has been shown to be partly heritable, however mechanisms that do not rely on DNA variants could also be involved. In recent years, modulation of epigenetic marks in relation with the level of Li response has appeared increasingly plausible. Recent results in this field of research have provided new insights into the molecular processes involved in Li effects. In this review, we examined the literature investigating the involvement of three epigenetic mechanisms (DNA methylation, noncoding RNAs and histone modifications) in Li clinical efficacy in bipolar disorder.

ACC Glu/GABA ratio is decreased in euthymic bipolar disorder I patients: possible in vivo neurometabolite explanation for mood stabilization

Bipolar disorder (BD) is characterized by unstable mood states ranging from mania to depression. Although there is some evidence that mood instability may result from an imbalance between excitatory glutamatergic and inhibitory GABA-ergic neurotransmission, few proton magnetic resonance spectroscopy (¹H-MRS) studies have measured these two neurometabolites simultaneously in BD. The enzyme glutamic acid decarboxylase (GAD1) catalyzes the decarboxylation of glutamate (Glu) to GABA, and its single nucleotide polymorphisms (SNPs) might influence Glu/GABA ratio. Thus, we investigated Glu/GABA ratio in the dorsal anterior cingulate cortex (dACC) of euthymic BD type I patients and healthy controls (HC), and assessed the influence of both mood stabilizers and GAD1 SNPs on this ratio. Eighty-eight subjects (50 euthymic BD type I patients and 38 HC) underwent 3T ¹H-MRS in the dACC (2 × 2 × 4.5 cm³) using a two-dimensional JPRESS sequence and all subjects were genotyped for 4 SNPs in the GAD1 gene. BD patients had lower dACC Glu/GABA ratio compared to HC, where this was influenced by anticonvulsant and antipsychotic medications, but not lithium. The presence of GAD1 rs1978340 allele A was associated with higher Glu/GABA ratio in BD, while patients without this allele taking mood stabilizers had a lower Glu/GABA ratio. The lowering of dACC Glu/GABA could be one explanation for the mood stabilizing action of anticonvulsants and antipsychotics in BD type I euthymia. Therefore, this putative role of Glu/GABA ratio and the influence of GAD1 genotype interacting with mood stabilization medication should be confirmed by further studies involving larger samples and other mood states.ClincalTrials.gov registration: NCT01237158.

Factors influencing lithium versus valproate prescription preference in the maintenance treatment of bipolar patients: a report from the Italian Early Career Psychiatrists (SOPSI-GG)

BACKGROUND

Objective of the present manuscript is to investigate, among Italian early career psychiatrists (ECPs), prescriber and patient-related factors associated with lithium or valproate preference to treat patients affected by Bipolar Disorder (BD).

METHODS

An on-line survey was carried out among 252 ECPs, investigating their prescription patterns in relation to lithium and the differences with prescription of valproate. Collected data were compared according to lithium or valproate prescription preference in the long-term treatment of BD by χ² tests for qualitative variables.

RESULTS

Over two thirds of ECPs preferred lithium over valproate for the maintenance treatment of BD. Less than half of the sample used lithium as first-line agent for mania or major depression, and less than one third for mixed episodes. Factors associated with lithium preference as first-line maintenance treatment include perception of having a good knowledge of lithium (p < 0.001) and complete satisfaction with education on lithium (p < 0.001). One of the main factors to prefer valproate was the concern about long-term side effects of lithium (p < 0.001).

CONCLUSIONS

Type of education, source of information, clinical experience and safety concerns influence the choice of lithium versus valproate in the long-term treatment of BD. Present findings may guide educational training of ECPs.KEY POINTSLithium has been less prescribed in the last years for long-term treatment of Bipolar Disorder.Educational and clinical factors seem to influence the attitude to prescribe lithium.Only half of the Italian early career psychiatrists declare to have at least an adequate knowledge of lithium.Residency program in psychiatry should consider the implementation of education on lithium.

Differential DNA Methylation of the Genes for Amyloid Precursor Protein, Tau, and Neurofilaments in Human Traumatic Brain Injury

Traumatic brain injury (TBI) is an established risk factor for neurodegenerative disorders and dementias. Epigenetic modifications, such as DNA methylation, may alter the expression of genes without altering the DNA sequence in response to environmental factors. We hypothesized that DNA methylation changes may occur in the injured human brain and be implicated in the neurodegenerative aftermath of TBI. The DNA methylation status of genes related to neurodegeneration; for example, amyloid beta precursor protein (APP), microtubule associated protein tau (MAPT), neurofilament heavy (NEFH), neurofilament medium (NEFM), and neurofilament light (NEFL), was analyzed in fresh, surgically resected human brain tissue from 17 severe TBI patients and compared with brain biopsy samples from 19 patients with idiopathic normal pressure hydrocephalus (iNPH). We also performed an epigenome-wide association study (EWAS) comparing TBI patients with iNPH controls. Thirty-eight CpG sites in the APP, MAPT, NEFH, and NEFL genes were differentially methylated by TBI. Among the top 20 differentially methylated CpG sites, 11 were in the APP gene. In addition, the EWAS evaluating 828,888 CpG sites revealed 308 differentially methylated CpG sites in genes related to cellular/anatomical structure development, cell differentiation, and anatomical morphogenesis. These preliminary findings provide the first evidence of an altered DNA methylome in the injured human brain, and may have implications for the neurodegenerative disorders associated with TBI.

Role of epigenetic regulatory enzymes in animal models of mania induced by amphetamine and paradoxical sleep deprivation

It is known that bipolar disorder has a multifactorial aetiology where the interaction between genetic and environmental factors is responsible for its development. Because of this, epigenetics has been largely studied in psychiatric disorders. The present study aims to evaluate the effects of histone deacetylase inhibitors on epigenetic enzyme alterations in rats or mice submitted to animal models of mania induced by dextro-amphetamine or sleep deprivation, respectively. Adult male Wistar rats were subjected to 14 days of dextro-amphetamine administration, and from the eighth to the fourteenth day, the animals were treated with valproate and sodium butyrate in addition to dextro-amphetamine injections. Adult C57BL/6 mice received 7 days of valproate or sodium butyrate administration, being sleep deprived at the last 36 hr of the protocol. Locomotor and exploratory activities of rats and mice were evaluated in the open-field test, and histone deacetylase, DNA methyltransferase, and histone acetyltransferase activities were assessed in the frontal cortex, hippocampus, and striatum. Dextro-amphetamine and sleep deprivation induced hyperactivity and increased histone deacetylase and DNA methyltransferase activities in the animal's brain. Valproate and sodium butyrate were able to reverse hyperlocomotion induced by both animal models, as well as the alterations on histone deacetylase and DNA methyltransferase activities. There was a positive correlation between enzyme activities and number of crossings for both models. Histone deacetylase and DNA methyltransferase activities also presented a positive correlation between theirselves. These results suggest that epigenetics can play an important role in BD pathophysiology as well as in its treatment.

The Korean Medication Algorithm Project for Bipolar Disorder (KMAP-BP): Changes in preferred treatment strategies and medications over 16 years and five editions

OBJECTIVES

The Korean Medication Algorithm Project for Bipolar Disorder (KMAP-BP) is based on expert consensus and has been revised five times since 2002. This study evaluated the changes in treatment strategies advocated by the KMAP-BP over time.

METHODS

The five editions of the KMAP-BP were reviewed, and the recommendations of the KMAP-BP were compared with those of other bipolar disorder (BP) treatment guidelines.

RESULTS

The most preferred option for the initial treatment of mania was a combination of a mood stabilizer (MS) and an atypical antipsychotic (AAP). Either MS or AAP monotherapy was also considered a first-line strategy for mania, but not for all types of episodes, including mixed/psychotic mania. In general, although lithium and valproic acid were commonly recommended, valproic acid has been increasingly preferred for all phases of BP. The most notable changes over time included the increasing preference for AAPs for all phases of BP, and lamotrigine for the depressive and maintenance phases. The use of antidepressants for BP has gradually decreased, but still represents a first-line option for severe and psychotic depression.

CONCLUSIONS

In general, the recommended strategies of the KMAP-BP were similar to those of other guidelines, but differed in terms of the emphasis on rapid effectiveness, which is often desirable in actual clinical situations. The major limitation of the KMAP-BP is that it is a consensus-based rather than an evidence-based tool. Nevertheless, it may confer advantages in actual clinical practice.

Differences in telomere length between patients with bipolar disorder and controls are influenced by lithium treatment

Aim: To assess the role of lithium treatment in the relationship between bipolar disorder (BD) and leukocyte telomere length (LTL). Materials & methods: We compared LTL between 131 patients with BD, with or without a history of lithium treatment, and 336 controls. We tested the association between genetically determined LTL and BD in two large genome-wide association datasets. Results: Patients with BD with a history lithium treatment showed longer LTL compared with never-treated patients (p = 0.015), and similar LTL compared with controls. Patients never treated with lithium showed shorter LTL compared with controls (p = 0.029). Mendelian randomization analysis showed no association between BD and genetically determined LTL. Conclusion: Our data support previous findings showing that long-term lithium treatment might protect against telomere shortening.

Dissecting the Epigenetic Changes Induced by Non-Antipsychotic Mood Stabilizers on Schizophrenia and Affective Disorders: A Systematic Review

BACKGROUND

Epimutations secondary to gene-environment interactions have a key role in the pathophysiology of major psychiatric disorders. In vivo and in vitro evidence suggest that mood stabilizers can potentially reverse epigenetic deregulations found in patients with schizophrenia or mood disorders through mechanisms that are not yet fully understood. However, their activity on epigenetic processes has made them a research target for therapeutic approaches.

METHODS

We conducted a comprehensive literature search of PubMed and EMBASE for studies investigating the specific epigenetic changes induced by non-antipsychotic mood stabilizers (valproate, lithium, lamotrigine, and carbamazepine) in animal models, human cell lines, or patients with schizophrenia, bipolar disorder, or major depressive disorder. Each paper was reviewed for the nature of research, the species and tissue examined, sample size, mood stabilizer, targeted gene, epigenetic changes found, and associated psychiatric disorder. Every article was appraised for quality using a modified published process and those who met a quality score of moderate or high were included.

RESULTS

A total of 2,429 records were identified; 1,956 records remained after duplicates were removed and were screened via title, abstract and keywords; 129 records were selected for full-text screening and a remaining of 38 articles were included in the qualitative synthesis. Valproate and lithium were found to induce broader epigenetic changes through different mechanisms, mainly DNA demethylation and histones acetylation. There was less literature and hence smaller effects attributable to lamotrigine and carbamazepine could be associated overall with the small number of studies on these agents. Findings were congruent across sample types.

CONCLUSIONS

An advanced understanding of the specific epigenetic changes induced by classic mood stabilizers in patients with major psychiatric disorders will facilitate personalized interventions. Further related drug discovery should target the induction of selective chromatin remodeling and gene-specific expression effects.

Whole Genome Expression Analyses of miRNAs and mRNAs Suggest the Involvement of miR-320a and miR-155-3p and their Targeted Genes in Lithium Response in Bipolar Disorder

Lithium is the mainstay in the maintenance of bipolar disorder (BD) and the most efficacious pharmacological treatment in suicide prevention. Nevertheless, its use is hampered by a high interindividual variability and important side effects. Genetic and epigenetic factors have been suggested to modulate lithium response, but findings so far have not allowed identifying molecular targets with predictive value. In this study we used next generation sequencing to measure genome-wide miRNA expression in lymphoblastoid cell lines from BD patients excellent responders (ER, n = 12) and non-responders (NR, n = 12) to lithium. These data were integrated with microarray genome-wide expression data to identify pairs of miRNA/mRNA inversely and significantly correlated. Significant pairs were prioritized based on strength of association and in-silico miRNA target prediction analyses to select candidates for validation with qRT-PCR. Thirty-one miRNAs were differentially expressed in ER vs. NR and inversely correlated with 418 genes differentially expressed between the two groups. A total of 331 of these correlations were also predicted by in-silico algorithms. miR-320a and miR-155-3p, as well as three of their targeted genes (CAPNS1 (Calpain Small Subunit 1) and RGS16 (Regulator of G Protein Signaling 16) for miR-320, SP4 (Sp4 Transcription Factor) for miR-155-3p) were validated. These miRNAs and mRNAs were previously implicated in psychiatric disorders (miR-320a and SP4), key processes of the central nervous system (CAPNS1, RGS16, SP4) or pathways involved in mental illnesses (miR-155-3p). Using an integrated approach, we identified miRNAs and their targeted genes potentially involved in lithium response in BD.

Zinc finger proteins in psychiatric disorders and response to psychotropic medications

Zinc finger proteins are a large family of abundantly expressed small motifs that play a crucial role in a wide range of physiological and pathophysiological mechanisms. Findings published so far support an involvement of zinc fingers in psychiatric disorders. Most of the evidence has been provided for the zinc finger protein 804A (ZNF804A) gene, which has been suggested to be implicated in schizophrenia and bipolar disorder. This evidence has been corroborated by a wide range of functional studies showing that ZNF804A regulates the expression of genes involved in cell adhesion and plays a crucial role in neurite formation and maintenance of dendritic spines. On the other hand, far less is known on other zinc finger proteins and their involvement in psychiatric disorders. In this review, we discussed studies exploring the role of zinc finger proteins in schizophrenia, bipolar disorder, and major depressive disorder as well as in pharmacogenetics of psychotropic drugs.

The Role of Pharmacogenomics in Bipolar Disorder: Moving Towards Precision Medicine

Bipolar disorder (BD) is a common and disabling psychiatric condition with a severe socioeconomic impact. BD is treated with mood stabilizers, among which lithium represents the first-line treatment. Lithium alone or in combination is effective in 60% of chronically treated patients, but response remains heterogenous and a large number of patients require a change in therapy after several weeks or months. Many studies have so far tried to identify molecular and genetic markers that could help us to predict response to mood stabilizers or the risk for adverse drug reactions. Pharmacogenetic studies in BD have been for the most part focused on lithium, but the complexity and variability of the response phenotype, together with the unclear mechanism of action of lithium, limited the power of these studies to identify robust biomarkers. Recent pharmacogenomic studies on lithium response have provided promising findings, suggesting that the integration of genome-wide investigations with deep phenotyping, in silico analyses and machine learning could lead us closer to personalized treatments for BD. Nevertheless, to date none of the genes suggested by pharmacogenetic studies on mood stabilizers have been included in any of the genetic tests approved by the Food and Drug Administration (FDA) for drug efficacy. On the other hand, genetic information has been included in drug labels to test for the safety of carbamazepine and valproate. In this review, we will outline available studies investigating the pharmacogenetics and pharmacogenomics of lithium and other mood stabilizers, with a specific focus on the limitations of these studies and potential strategies to overcome them. We will also discuss FDA-approved pharmacogenetic tests for treatments commonly used in the management of BD.

Pharmacogenetics in Psychiatry

Mental illness represents a major health issue both at the individual and at the socioeconomical level. This is partly due to the current suboptimal treatment options: existing psychotropic medications, including antidepressants, antipsychotics, and mood stabilizers, are effective only in a subset of patients or produce partial response and they are often associated with debilitating side effects that discourage adherence. Pharmacogenetics is the study of how genetic information impacts on drug response/side effects with the goal to provide tailored treatments, thereby maximizing efficacy and tolerability. The first pharmacogenetic studies focused on candidate genes, previously known to be relevant to the pharmacokinetics and pharmacodynamics of psychotropic drugs. Results were mainly inconclusive, but some replicated candidates were identified and included as pharmacogenetic biomarkers in drug labeling and in some commercial kits. With the advent of the genomic revolution, it became possible to study the genetic variation on an unprecedented scale, throughout the whole genome with no need of a priori hypothesis. This may lead to the personalized prescription of existing medications and potentially to the development of innovative ones, thanks to new insights into the genetics of mental illness. Promising findings were obtained, but methods for the generation and analysis of genome-wide and sequencing data are still in evolution. Future pharmacogenetic tests may consist of hundreds/thousands of polymorphisms throughout the genome or selected pathways in order to take into account the complex interactions across variants in a number of genes.

Distinct lithium-induced gene expression effects in lymphoblastoid cell lines from patients with bipolar disorder

Lithium is the most commonly prescribed medication for the treatment of bipolar disorder (BD), yet the mechanisms underlying its beneficial effects are still unclear. We aimed to compare the effects of lithium treatment in lymphoblastoid cell lines (LCLs) from BD patients and controls. LCLs were generated from sixty-two BD patients (based on DSM-IV) and seventeen healthy controls matched for age, sex, and ethnicity. Patients were recruited from outpatient clinics from February 2012 to October 2014. LCLs were treated with 1mM lithium for 7 days followed by microarray gene expression assay and validation by real-time quantitative PCR. Baseline differences between groups, as well as differences between vehicle- and lithium-treated cells within each group were analyzed. The biological significance of differentially expressed genes was examined by pathway enrichment analysis. No significant differences in baseline gene expression (adjusted p-value < 0.05) were detected between groups. Lithium treatment of LCLs from controls did not lead to any significant differences. However, lithium altered the expression of 236 genes in LCLs from patients; those genes were enriched for signaling pathways related to apoptosis. Among those genes, the alterations in the expression of PIK3CG, SERP1 and UPP1 were validated by real-time PCR. A significant correlation was also found between circadian functioning and CEBPG and FGF2 expression levels. In summary, our results suggest that lithium treatment induces expression changes in genes associated with the apoptosis pathway in BD LCLs. The more pronounced effects of lithium in patients compared to controls suggest a disease-specific effect of this drug.

Lithium Pharmacogenetics: Where Do We Stand?

Preclinical Research Bipolar disorder (BPD) is a chronic and disabling psychiatric disorder with a prevalence of 0.8-1.2% in the general population. Although lithium is considered the first-line treatment, a large percentage of patients do not respond sufficiently. Moreover, lithium can induce severe side effects and has poor tolerance and a narrow therapeutic index. The genetics of lithium response has been largely investigated, but findings have so far failed to identify reliable biomarkers to predict clinical response. This has been largely determined by the highly complex phenotipic and genetic architecture of lithium response. To this regard, collaborative initiatives hold the promise to provide robust and standardized methods to disantenagle this complexity, as well as the capacity to collect large samples of patietnts, a crucial requirement to study the genetics of complex phenotypes. The International Consortium on Lithium Genetics (ConLiGen) has recently published the largest study so far on lithium response reporting significant associations for two long noncoding RNAs (lncRNAs). This result provides relevant insights into the pharmacogenetics of lithium supporting the involvement of the noncoding portion of the genome in modulating clinical response. Although a vast body of research is engaged in dissecting the genetic bases of response to lithium, the several drawbacks of lithium therapy have also stimulated multiple efforts to identify new safer treatments. A drug repurposing approach identified ebselen as a potential lithium mimetic, as it shares with lithium the ability to inhibit inositol monophosphatase. Ebselen, an antioxidant glutathione peroxidase mimetic, represents a valid and promising example of new potential therapeutic interventions for BD, but the paucity of data warrant further investigation to elucidate its potential efficacy and safety in the management of BPD. Nevertheless, findings provided by the growing field of pharmacogenomic research will ultimately lead to the identification of new molecular targets and safer treatments for BPD. Drug Dev Res 77 : 368-373, 2016. © 2016 Wiley Periodicals, Inc.