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The mood stabilizer lithium represents a cornerstone in the long term treatment of bipolar disorder (BD), although with substantial interindividual variability in clinical response. This variability appears to be modulated by genetics, which has been significantly investigated in the last two decades with some promising findings. In addition, recently, the interest in the role of epigenetics has grown significantly, since the exploration of these mechanisms might allow the elucidation of the gene-environment interactions and explanation of missing heritability. In this article, we provide an overview of the most relevant findings regarding the pharmacogenomics and pharmacoepigenomics of lithium response in BD. We describe the most replicated findings among candidate gene studies, results from genome-wide association studies (GWAS) as well as post-GWAS approaches supporting an association between high genetic load for schizophrenia, major depressive disorder or attention deficit/hyperactivity disorder and poor lithium response. Next, we describe results from studies investigating epigenetic mechanisms, such as changes in methylation or noncoding RNA levels, which play a relevant role as regulators of gene expression. Finally, we discuss challenges related to the search for the molecular determinants of lithium response and potential future research directions to pave the path towards a biomarker guided approach in lithium treatment.

Proton-pump inhibitors (PPIs) are used to suppress gastric acid secretion in several gastrointestinal conditions. While these drugs are generally well tolerated, their long-term use may be associated with different adverse effects, including migraine. We analyzed the association between treatment with PPIs (omeprazole, esomeprazole, lansoprazole, pantoprazole and rabeprazole) and migraine prevalence in the UK Biobank cohort through a cross-sectional analysis (using baseline data for 468,280 participants, 16,390 of whom had migraine) and a longitudinal analysis (including 145,007 participants with no migraine at baseline, of whom 3786 had probable migraine without aura [MWOA] and 9981 probable migraine with aura [MWA] or both MWOA and MWA at an average follow-up time of 10.06 years). We also evaluated the modulating role of the metabolizer phenotype of CYP2C19, the major enzyme involved in PPI clearance. Treatment with PPIs was associated with higher migraine prevalence at baseline (odds ratio [OR] = 1.25, p < 0.0001). CYP2C19 rapid metabolizer phenotype was associated with lower prevalence of migraine exclusively in participants treated with PPIs (OR = 0.89, p = 0.029). In addition, treatment with PPIs was associated with higher incidence of both probable MWOA (OR = 1.24, p = 0.002) and MWA (OR = 1.43, p < 0.0001) at follow-up. Treatment with PPIs and CYP2C19 poor metabolizer status were associated with higher incidence of probable chronic migraine exclusively in men. Our results suggest a significant association between treatment with PPIs and migraine in this large population-based cohort and support a potential relevant role of gender and CYP2C19 phenotype.

Background: Migraine and depression are highly prevalent and partly overlapping disorders that cause strong limitations in daily life. Patients tend to respond poorly to the therapies available for these diseases. OnabotulinumtoxinA has been proven to be an effective treatment for both migraine and depression. While many studies have addressed the effect of onabotulinumtoxinA in migraine or depression separately, a growing body of evidence suggests beneficial effects also for patients comorbid with migraine and depression. The current meta-analysis systematically investigates to what extent onabotulinumtoxinA is efficient in migraineurs with depression.

Methods: A systematic literature search was performed based on PubMed, Scopus and Web of Science from the earliest date till October 30th, 2020. Mean, standard deviation (SD) and sample size have been used to evaluate improvement in depressive symptoms and migraine using random- effects empirical Bayes model.

Results: Our search retrieved 259 studies, eight of which met the inclusion criteria. OnabotulinumtoxinA injections administered to patients with both chronic migraine and major depressive disorder led to mean reduction of - 8.94 points (CI [ - 10.04,- 7.84], p < 0.01) in the BDI scale, of - 5.90 points (CI [ - 9.92,- 1.88], p < 0.01) in the BDI-II scale and of - 6.19 points (CI [ - 9.52,- 2.86], p < 0.01) in the PHQ-9 scale, when evaluating depressive symptoms. In the case of the migraine-related symptoms, we found mean reductions of - 4.10 (CI [ - 7.31,- 0.89], p = 0.01) points in the HIT6 scale, - 32.05 (CI [ - 55.96,- 8.14], p = 0.01) in the MIDAS scale, - 1.7 (CI [ - 3.27,- 0.13], p = 0.03) points in the VAS scale and of - 6.27 (CI [ - 8.48,- 4.07], p < 0.01) migraine episodes per month. Comorbid patients showed slightly better improvements in BDI, HIT6 scores and migraine frequency compared to monomorbid patients. The latter group manifested better results in MIDAS and VAS scores.

Conclusion: Treatment with onabotulinumtoxinA leads to a significant reduction of disease severity of both chronic migraine and major depressive disorder in patients comorbid with both diseases. Comparative analyses suggest an equivalent strong effect in monomorbid and comorbid patients, with beneficial effects specifically seen for certain migraine features.

The severity of symptoms as well as efficacy of antidepressants in major depressive disorder (MDD) is modified by single nucleotide polymorphisms (SNPs) in different genes, which may contribute in an additive or synergistic fashion. We aimed to investigate depression severity in participants with MDD under treatment with antidepressants in relation to the combinatory effect of selected genetic variants combined using a genetic risk score (GRS). The sample included 150 MDD patients on regular AD therapy from the population‐based Swiss PsyCoLaus cohort. We investigated 44 SNPs previously associated with antidepressant response by ranking them with regard to their association to the Center for Epidemiologic Studies Short Depression Scale (CES‐D) score using random forest. The three top scoring SNPs (rs12248560, rs878567, rs17710780) were subsequently combined into an unweighted GRS, which was included in linear and logistic regression models using the CES‐D score, occurrence of a major depressive episode (MDE) during follow‐up and regular antidepressant treatment during the 6 months preceding follow‐up assessment as outcomes. The GRS was associated with MDE occurrence (p = .02) and ln CES‐D score (p = .001). The HTR1A rs878567 variant was associated with ln CES‐D after adjustment for demographic and clinical variables [p = .02, lower scores for minor allele (G) carriers]. Additionally, rs12248560 (CYP2C19 ) CC homozygotes showed a six‐fold higher likelihood of regular AD therapy at follow‐up compared to minor allele homozygotes [TT; ultrarapid metabolizers (p = .03)]. Our study suggests that the cumulative consideration of pharmacogenetic risk variants more reliably reflects the impact of the genetic background on depression severity than individual SNPs.

OBJECTIVE: Migraine and major depressive disorder show a high rate of comorbidity, but little is known about the associations between the subtypes of major depressive disorder and migraine. In this cross-sectional study we aimed at investigating a) the lifetime associations between the atypical, melancholic, combined and unspecified subtype of major depressive disorder and migraine with and without aura and b) the associations between major depressive disorder and its subtypes and the severity of migraine.

METHODS: A total of 446 subjects with migraine (migraine without aura: n = 294; migraine with aura: n = 152) and 2511 controls from the population-based CoLaus/PsyCoLaus study, Switzerland, were included. Associations between major depressive disorder subtypes and migraine characteristics were tested using binary logistic or linear regression.

RESULTS: Melancholic, combined and unspecified major depressive disorder were associated with increased frequency of migraine with aura, whereas only melancholic major depressive disorder was associated with increased frequency of migraine without aura. Lifetime and unspecified major depressive disorder were associated with severe migraine intensity among subjects with migraine with aura but not migraine without aura, while combined major depressive disorder was associated with higher migraine frequency independently from migraine subtype.

CONCLUSION: This study suggests that melancholic but not atypical major depressive disorder is associated with migraine and migraine subtypes. Future studies exploring pathophysiological mechanisms shared between melancholic depression and migraine are warranted.

Lithium is the mainstay treatment in the management of bipolar disorder. A growing body of findings suggests that lithium could be considered a neuroprotective agent that might slow the progression of neurobiological abnormalities in Alzheimer's disease and possibly in other neurodegenerative disorders. Additionally, the effect of lithium on telomere length, as well as the increased overall survival associated with microdoses of lithium in drinking water, led to hypothesize that lithium might have "antiaging" properties. In this review, we summarize available evidence from preclinical and clinical studies investigating the potential beneficial effects of lithium in the antiaging arena and in neurodegenerative disorders, as well as the putative underlying molecular mechanisms, including inhibition of the glycogen synthase kinase-3 (GSK-3) enzyme, reduction of oxidative stress and counteraction of telomere shortening. Additionally, we present a timely overview of currently active clinical trials that might enhance our understanding of the beneficial properties of lithium and highlight the potential for drug repurposing.

Patients with bipolar disorder (BD) show higher frequency of obesity and type 2 diabetes (T2D), but the underlying genetic determinants and molecular pathways are not well studied. Using large publicly available datasets, we (1) conducted a gene-based analysis using MAGMA to identify genes associated with BD and body mass index (BMI) or T2D and investigated their functional enrichment; and (2) performed two meta-analyses between BD and BMI, as well as BD and T2D using Metasoft. Target druggability was assessed using the Drug Gene Interaction Database (DGIdb). We identified 518 and 390 genes significantly associated with BD and BMI or BD and T2D, respectively. A total of 52 and 12 genes, respectively, were significant after multiple testing correction. Pathway analyses conducted on nominally significant targets showed that genes associated with BD and BMI were enriched for the Neuronal cell body Gene Ontology (GO) term (p = 1.0E-04; false discovery rate (FDR) = 0.025) and different pathways, including the Signaling by Hedgehog pathway (p = 4.8E -05, FDR = 0.02), while genes associated with BD and T2D showed no specific enrichment. The meta-analysis between BD and BMI identified 64 relevant single nucleotide polymorphisms (SNPs). While the majority of these were located in intergenic regions or in a locus on chromosome 16 near and in the NPIPL1 and SH2B1 genes (best SNP: rs4788101, p = 2.1E-24), five were located in the ETV5 gene (best SNP: rs1516725, p= 1E-24), which was previously associated with both BD and obesity, and one in the RPGRIP1L gene (rs1477199, p = 5.7E-09), which was also included in the Signaling by Hedgehog pathway. The meta-analysis between BD and T2D identified six significant SNPs, three of which were located in ALAS1 (best SNP: rs352165, p = 3.4E-08). Thirteen SNPs associated with BD and BMI, and one with BD and T2D, were located in genes which are part of the druggable genome. Our results support the hypothesis of shared genetic determinants between BD and BMI and point to genes involved in Hedgehog signaling as promising targets.

Mood disorders are associated with an increased risk of aging-related diseases, which greatly contribute to the excess morbidity and mortality observed in affected individuals. Clinical and molecular findings also suggest that mood disorders might be characterized by a permanent state of low-grade inflammation. At the cellular level, aging translates into telomeres shortening. Intriguingly, inflammation and telomere shortening show a bidirectional association: a pro-inflammatory state seems to contribute to aging and telomere dysfunction, and telomere attrition is able to induce low-grade inflammation. Several independent studies have reported shorter telomere length and increased levels of circulating inflammatory cytokines in mood disorders, suggesting a complex interplay between altered inflammatory-immune responses and telomere dynamics in the etiopathogenesis of these disorders. In this review, we critically discuss studies investigating the role of telomere attrition and inflammation in the pathogenesis and course of mood disorders, and in pharmacological treatments with psychotropic medications.

Schizophrenia (SCZ) is a severe psychiatric disorder affecting approximately 23 million people worldwide. It is considered the eighth leading cause of disability according to the Wood Health Organization and is associated with a significant reduction in life expectancy. Antipsychotics represent the first-choice treatment in SCZ, but approximately 30% of patients fail to respond to acute treatment. These patients are generally defined as treatment-resistant and are eligible for clozapine treatment. Treatment-resistant patients show a more severe course of the disease, but it has been suggested that treatment-resistant schizophrenia (TRS) may constitute a distinct phenotype that is more than just a more severe form of SCZ. TRS is heritable, and genetics has been shown to play an important role in modulating response to antipsychotics. Important efforts have been put into place in order to better understand the genetic architecture of TRS, with the main goal of identifying reliable predictive markers that might improve the management and quality of life of TRS patients. However, the number of candidate gene and genome-wide association studies specifically focused on TRS is limited, and to date, findings do not allow the disentanglement of its polygenic nature. More recent studies implemented polygenic risk score, gene-based and machine learning methods to explore the genetics of TRS, reporting promising findings. In this review, we present an overview on the genetics of TRS, particularly focusing our discussion on studies implementing polygenic approaches.

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.