A systematic review of calcium channel antagonists in bipolar disorder and some considerations for their future development

Pre-cluster symptoms in a Taiwanese cohort of cluster headache: symptom profiles and clinical predictions

BACKGROUND

Pre-cluster symptoms (PCSs) are symptoms preceding cluster bouts and might have implications for the treatment of cluster headache (CH). This study investigated the prevalence of PCSs, and their utility in predicting upcoming bouts as well as the associations with therapeutic efficacy.

METHODS

We prospectively collected data from patients with CH. Each patient received a structured interview and completed questionnaire surveys during CH bouts. In sub-study 1, we cross-sectionally analyzed the prevalence, symptomatology, and predictability of upcoming bouts. Overall, 34 PCSs, divided into seven categories, were queried, including head and neck pain, cranial autonomic symptoms, restlessness, fatigue or mood changes, sleep alterations, constitutional symptoms, and generalized pain. In sub-study 2, we recorded the weekly frequency of CH attacks after the initiation of verapamil concurrently with a 14-day transitional therapy based on the patients' headache diary. A responder to verapamil was defined as a patient who have a reduction from baseline of at least 50% in the weekly frequency of CH attacks 4 weeks after the initiation of verapamil.

RESULTS

A total of 168 CH patients (women/men: 39/129) completed the study. In sub-study 1, we found 149 (88.7%) experienced PCSs, with a median of 24 (IQR 18 to 72) hours before the bouts. Up to 57.7% of patients with PCS reported that they could predict upcoming bouts. Among the seven categories of PCSs, head and neck pain was the most common (81.0%) and was associated with a higher predictability of upcoming bouts (odds ratio [OR] = 4.0; 95% confidence interval [CI] 1.7-9.6). In sub-study 2, we found two categories of PCSs were associated with the response to verapamil: sleep alteration (OR = 2.5 [95% CI = 1.3-4.8], p = 0.004) and ≥ 1 cranial autonomic symptoms (OR = 2.7 [95% CI = 1.4-5.1], p = 0.003).

CONCLUSION

PCSs were very common in CH and could be used to predict upcoming bouts. Different symptom categories of PCSs may have different clinical implications.

Leveraging the Genetics of Psychiatric Disorders to Prioritize Potential Drug Targets and Compounds

Background

Genetics has the potential to inform biologically relevant drug treatment and repurposing which may ultimately improve patient care. In this study, we combine methods which leverage the genetics of psychiatric disorders to prioritize potential drug targets and compounds.

Methods

We used the largest available genome-wide association studies, in European ancestry, of four psychiatric disorders [i.e., attention deficit hyperactivity disorder (ADHD), bipolar disorder, depression, and schizophrenia] along with genes encoding drug targets. With this data, we conducted drug enrichment analyses incorporating the novel and biologically specific GSA-MiXeR tool. We then conducted a series of molecular trait analyses using large-scale transcriptomic and proteomic datasets sampled from brain and blood tissue. This included the novel use of the UK Biobank proteomic data for a proteome-wide association study of psychiatric disorders. With the accumulated evidence, we prioritize potential drug targets and compounds for each disorder.

Findings

We reveal candidate drug targets shared across multiple disorders as well as disorder-specific targets. Drug prioritization indicated genetic support for several currently used psychotropic medications including the antipsychotic paliperidone as the top ranked drug for schizophrenia. We also observed genetic support for other commonly used psychotropics (e.g., clozapine, risperidone, duloxetine, lithium, and valproic acid). Opportunities for drug repurposing were revealed such as cholinergic drugs for ADHD, estrogens for depression, and gabapentin enacarbil for schizophrenia. Our findings also indicate the genetic liability to schizophrenia is associated with reduced brain and blood expression of CYP2D6, a gene encoding a metabolizer of drugs and neurotransmitters, suggesting a genetic risk for poor drug response and altered neurotransmission.

Interpretation

Here we present a series of complimentary and comprehensive analyses that highlight the utility of genetics for informing drug development and repurposing for psychiatric disorders. Our findings present novel opportunities for refining psychiatric treatment.

Natural L-type calcium channels antagonists from Chinese medicine

L-type calcium channels (LTCCs), the largest subfamily of voltage-gated calcium channels (VGCCs), are the main channels for Ca2+ influx during extracellular excitation. LTCCs are widely present in excitable cells, especially cardiac and cardiovascular smooth muscle cells, and participate in various Ca2+-dependent processes. LTCCs have been considered as worthy drug target for cardiovascular, neurological and psychological diseases for decades. Natural products from Traditional Chinese medicine (TCM) have shown the potential as new drugs for the treatment of LTCCs related diseases. In this review, the basic structure, function of LTCCs, and the related human diseases caused by structural or functional abnormalities of LTCCs, and the natural LTCCs antagonist and their potential usages were summarized.

Causal relationship between genetic proxies for calcium channel blockers and the risk of depression: a drug-target Mendelian randomization study

Background

Calcium channel blockers (CCBs) are widely used in the clinical management of hypertension. Depression, a common comorbidity of hypertension, is an important issue in the management of hypertension. However, the impact of CCBs on depression risk remains controversial. We aim to investigate the causal effect of CCBs on depression through drug-target Mendelian randomization (MR) analysis.

Methods

To proxy CCBs, we utilized the genetic variations located in or around drug target genes that were related to systolic blood pressure (SBP). Coronary artery disease (CAD) served as the positive control outcome. Genetic summary data of SBP, CAD, and depression were obtained from genome-wide association studies (GWAS) based on European population. Inverse variance weighted (IVW) method was applied as the main analysis to estimate the causal effect. Cochran's Q test, MR-Egger intercept, MR pleiotropy residual sum and outlier (MR-PRESSO) and leave-one-out sensitivity analysis were used to test the robustness of the results. Meta-analysis was applied to further confirm whether causal relationships existed between CCBs and depression.

Results

The IVW results failed to reveal any causal relationship between genetic proxies for CCBs and depression (P > 0.05). Cochran's Q test showed no evidence of heterogeneity (P > 0.05). The MR-Egger intercept test suggested no evidence of directional pleiotropy, and the MR pleiotropy residual sum and outlier (MR-PRESSO) global test for horizontal pleiotropy was also not significant (P > 0.05). Leave-one-out analysis did not reveal any genetic variant that influenced the results. In addition, the meta-analysis further confirmed the absence of a causal relationship.

Conclusion

The present study indicates no association of genetic proxies for CCBs with depression. Further studies are necessary to provide definitive evidence.

Genetic proxies for antihypertensive drugs and mental disorders: Mendelian randomization study in European and East Asian populations

BACKGROUND

Mental disorders are among the top causes of disease burden worldwide. Existing evidence regarding the repurposing of antihypertensives for mental disorders treatment is conflicting and cannot establish causation.

METHODS

We used Mendelian randomization to assess the effects of angiotensin-converting-enzyme inhibitors (ACEIs), beta blockers (BBs), and calcium channel blockers (CCBs) on risk of bipolar disorder (BD), major depression disorder (MDD), and schizophrenia (SCZ). We used published genetic variants which are in antihypertensive drugs target genes and correspond to systolic blood pressure (SBP) in Europeans and East Asians, and applied them to summary statistics of BD (cases = 41,917; controls = 371,549 in Europeans), MDD (cases = 170,756; controls = 329,443 in Europeans and cases = 15,771; controls = 178,777 in East Asians), and SCZ (cases = 53,386; controls = 77,258 in Europeans and cases = 22,778; controls = 35,362 in East Asians) from the Psychiatric Genomics Consortium. We used inverse variance weighting with MR-Egger, weighted median, weighted mode, and Mendelian Randomization Pleiotropy RESidual Sum and Outlier. We performed gene-specific analysis and utilized various methods to address potential pleiotropy.

RESULTS

After multiple testing correction, genetically proxied ACEIs were associated with an increased risk of SCZ in Europeans (odds ratio (OR) per 5 mmHg lower in SBP 2.10, 95% CI 1.54 to 2.87) and East Asians (OR per 5 mmHg lower in SBP 2.51, 95% CI 1.38 to 4.58). Genetically proxied BBs were not associated with any mental disorders in both populations. Genetically proxied CCBs showed no benefits on mental disorders.

CONCLUSIONS

Antihypertensive drugs have no protection for mental disorders but potential harm. Their long-term use among hypertensive patients with, or with high susceptibility to, psychiatric illness needs careful evaluation.

Approaches for Increasing Cerebral Efflux of Amyloid-β in Experimental Systems

Amyloid protein-β (Aβ) concentrations are increased in the brain in both early onset and late onset Alzheimer's disease (AD). In early onset AD, cerebral Aβ production is increased and its clearance is decreased, while increased Aβ burden in late onset AD is due to impaired clearance. Aβ has been the focus of AD therapeutics since development of the amyloid hypothesis, but efforts to slow AD progression by lowering brain Aβ failed until phase 3 trials with the monoclonal antibodies lecanemab and donanemab. In addition to promoting phagocytic clearance of Aβ, antibodies lower cerebral Aβ by efflux of Aβ-antibody complexes across the capillary endothelia, dissolving Aβ aggregates, and a "peripheral sink" mechanism. Although the blood-brain barrier is the main route by which soluble Aβ leaves the brain (facilitated by low-density lipoprotein receptor-related protein-1 and ATP-binding cassette sub-family B member 1), Aβ can also be removed via the blood-cerebrospinal fluid barrier, glymphatic drainage, and intramural periarterial drainage. This review discusses experimental approaches to increase cerebral Aβ efflux via these mechanisms, clinical applications of these approaches, and findings in clinical trials with these approaches in patients with AD or mild cognitive impairment. Based on negative findings in clinical trials with previous approaches targeting monomeric Aβ, increasing the cerebral efflux of soluble Aβ is unlikely to slow AD progression if used as monotherapy. But if used as an adjunct to treatment with lecanemab or donanemab, this approach might allow greater slowing of AD progression than treatment with either antibody alone.

CaMKK2 as an emerging treatment target for bipolar disorder

Current pharmacological treatments for bipolar disorder are inadequate and based on serendipitously discovered drugs often with limited efficacy, burdensome side-effects, and unclear mechanisms of action. Advances in drug development for the treatment of bipolar disorder remain incremental and have come largely from repurposing drugs used for other psychiatric conditions, a strategy that has failed to find truly revolutionary therapies, as it does not target the mood instability that characterises the condition. The lack of therapeutic innovation in the bipolar disorder field is largely due to a poor understanding of the underlying disease mechanisms and the consequent absence of validated drug targets. A compelling new treatment target is the Ca2+-calmodulin dependent protein kinase kinase-2 (CaMKK2) enzyme. CaMKK2 is highly enriched in brain neurons and regulates energy metabolism and neuronal processes that underpin higher order functions such as long-term memory, mood, and other affective functions. Loss-of-function polymorphisms and a rare missense mutation in human CAMKK2 are associated with bipolar disorder, and genetic deletion of Camkk2 in mice causes bipolar-like behaviours similar to those in patients. Furthermore, these behaviours are ameliorated by lithium, which increases CaMKK2 activity. In this review, we discuss multiple convergent lines of evidence that support targeting of CaMKK2 as a new treatment strategy for bipolar disorder.

A pilot pharmacogenetic study of calcium channel blocker treatment of bipolar mania

Common genetic variants located in calcium channel genes are important markers of genetic susceptibility for bipolar disorder (BD). Previous clinical trials with Calcium Channel Blocker (CCB) medication improved mood stability for some BD patients. We hypothesize that manic patients who carried calcium channel risk variants would differentially benefit from treatment with CCBs. In this pilot study, 50 BD patients (Chinese: 39; US: 11) who were hospitalized for manic episodes were given add-on CCB treatment. We determined genotypes for each patient. There was a significant decrease in the Young Mania Rating Scale (YMRS) after add-on medication treatment. Of note, two intronic variants of the Calcium Voltage-Gated Channel Subunit Alpha1 B (CACNA1B) were associated with treatment outcomes for manic patients: rs2739258 and rs2739260. BD rs2739258/rs2739260 AG-allele carriers had a better treatment response with add-on CCB than those carrying the AA or GG genotypes by survival analysis. Although these findings did not pass multiple testing correction, this study suggests that single-nucleotide polymorphisms (SNPs) residing in calcium channel genes could be predictors for response to add-on CCB treatment of bipolar mania patients, and that calcium channel genes may be involved in treatment responses for BD.

New "drugs and targets" in the GWAS era of bipolar disorder

OBJECTIVE

Due to the phenotypic heterogeneity and etiological complexity of bipolar disorder (BD), many patients do not respond well to the current medications, and developing novel effective treatment is necessary. Whether any BD genome-wide association study (GWAS) risk genes were targets of existing drugs or novel drugs that can be repurposed in the clinical treatment of BD is a hot topic in the GWAS era of BD.

METHODS

A list of 425 protein-coding BD risk genes was distilled through the BD GWAS, and 4479 protein-coding druggable targets were retrieved from the druggable genome. The overlapped genes/targets were subjected to further analyses in DrugBank, Pharos, and DGIdb datasets in terms of their FDA status, mechanism of action and primary indication, to identify their potential for repurposing.

RESULTS

We identified 58 BD GWAS risk genes grouped as the druggable targets, and several genes were given higher priority. These BD risk genes were targets of antipsychotics, antidepressants, antiepileptics, calcium channel antagonists, as well as anxiolytics and analgesics, either existing clinically-approved drugs for BD or the drugs than can be repurposed for treatment of BD in the future. Those genes were also likely relevant to BD pathophysiology, as many of them encode ion channel, ion transporter or neurotransmitter receptor, or the mice manipulating those genes are likely to mimic the phenotypes manifest in BD patients.

CONCLUSIONS

This study identifies several targets that may facilitate the discovery of novel treatments in BD, and implies the value of conducting GWAS into clinical translation.

L-type calcium channel regulation of dopamine activity in the ventral tegmental area to nucleus accumbens pathway: Implications for substance use, mood disorders and co-morbidities

L-type calcium channels (LTCCs), including the Cav1.2 and Cav1.3 LTCC subtypes, are important regulators of calcium entry into neurons, which mediates neurotransmitter release and synaptic plasticity. Cav1.2 and Cav1.3 are encoded by the CACNA1C and CACNA1D genes, respectively. These genes are implicated in substance use disorders and depression in humans, as demonstrated by genetic-wide association studies (GWAS). Pre-clinical models have also revealed a critical role of LTCCs on drug and mood related behavior, including the co-morbidity of substance use and mood disorders. Moreover, LTCCs have been shown to regulate the neuronal firing of dopamine (DA) neurons as well as drug and stress-induced plasticity within the ventral tegmental area (VTA) to nucleus accumbens (NAc) pathway. Thus, LTCCs are interesting targets for the treatment of neuropsychiatric diseases. In this review, we provide a brief introduction to voltage-gated calcium channels, specifically focusing on the LTCCs. We place particular emphasis on the ability of LTCCs to regulate DA neuronal activity and downstream signaling in the VTA to NAc pathway, and how such processes mediate substance use and mood disorder-related behavioral responses. We also discuss the bi-directional control of VTA LTCCs on drug and mood-related behaviors in pre-clinical models, with implications for co-morbid psychiatric diagnosis. We conclude with a section on the clinical implications of LTCC blockers, many which are already FDA approved as cardiac medications. Thus, pre-clinical and clinical work should examine the potential of LTCC blockers to be repurposed for neuropsychiatric illness. This article is part of the Special Issue on 'L-type calcium channel mechanisms in neuropsychiatric disorders'.

[Nimodipine in treatment of bipolar disorder]

The purpose of this review is to correlate current data on the molecular mechanisms of action of the drug Nimodipine with its clinical effects and applicability in mental disorders belonging to the spectrum of affective pathology. The article discusses the prospects for using the calcium channel blocker nimodipine as a method of both mono and combination therapy for bipolar disorders with various types of course. Nimodipine is a selective blocker of voltage-dependent calcium channels, a dihydropyridine derivative. By blocking L type calcium channels, it prevents the entry of calcium ions into the cell. Due to its pronounced ability to penetrate the blood-brain barrier, it has a selective effect on brain neurons and has a vasodilating, antihypertensive and normotimic effect. Nimodipine blocks LTCC channels in brain neurons, thereby influencing synaptic plasticity, transmitter release and excitation-transcription coupling, which makes it possible to influence various clinical conditions with pathology in the area of affect, including bipolar disorders with ultra-rapid cycling, and also, in cases with high resistance and intolerance to other mood stabilizers.

The association of anxiety and other clinical features with CACNA1C rs1006737 in patients with depression

Background

The CACNA1C protein is a L-type calcium channel, which influence affective disorders.

Purpose

The purpose of the present study was to examine the possible association between the different genotypes of rs100677 CACNA1C gene and anxiety and other clinical symptoms in patients with unipolar depression.

Patients and controls

A total of 754 patients and 708 controls from the Danish Psychiatric Biobank participated.

Results

A significant correlation was found between anxiety and the A allele. It was further found that patients with the A allele more often were treated with electroconvulsive therapy and patients with the AA phenotype had the highest age.

Limitations

The only information about controls was their sex and that they were recruited from the blood bank. Two types of inclusion criteria were used. The clinical data were not complete for all patients.

CACNA1C (CaV1.2) and other L-type calcium channels in the pathophysiology and treatment of psychiatric disorders: Advances from functional genomics and pharmacoepidemiology

A role for voltage-gated calcium channels (VGCCs) in psychiatric disorders has long been postulated as part of a broader involvement of intracellular calcium signalling. However, the data were inconclusive and hard to interpret. We review three areas of research that have markedly advanced the field. First, there is now robust genomic evidence that common variants in VGCC subunit genes, notably CACNA1C which encodes the L-type calcium channel (LTCC) Ca_V1.2 subunit, are trans-diagnostically associated with psychiatric disorders including schizophrenia and bipolar disorder. Rare variants in these genes also contribute to the risk. Second, pharmacoepidemiological evidence supports the possibility that calcium channel blockers, which target LTCCs, might have beneficial effects on the onset or course of these disorders. This is especially true for calcium channel blockers that are brain penetrant. Third, long-range sequencing is revealing the repertoire of full-length LTCC transcript isoforms. Many novel and abundant CACNA1C isoforms have been identified in human and mouse brain, including some which are enriched compared to heart or aorta, and predicted to encode channels with differing functional and pharmacological properties. These isoforms may contribute to the molecular mechanisms of genetic association to psychiatric disorders. They may also enable development of therapeutic agents that can preferentially target brain LTCC isoforms and be of potential value for psychiatric indications.

Allopurinol, dipyridamole and calcium channel blockers in the treatment of bipolar disorder - A nationwide cohort study

BACKGROUND

Improved treatments for bipolar disorder (BD) are needed. Drug repurposing aims to find novel targets for drugs that have been used for other indications. This study investigated the risk of psychiatric hospitalization associated with use of calcium-channel blockers (CCBs; dihydropyridines, diltiazem, verapamil) and adenosine modulators (allopurinol, dipyridamole) in BD in within-individual design.

METHODS

Individuals diagnosed with BD (ICD-10: F30-F31) were identified from the inpatient, specialized outpatient, sickness absence, and disability pension registers during 1996-2018 in Finland (N = 60,045). The main outcome was hospitalization due to affective symptoms (ICD-10: F30-F39). Within-individual models in stratified Cox regression were used and adjusted hazard ratios (aHR) with 95 % confidence intervals (CIs) reported.

RESULTS

Use of CCBs was associated with a decreased risk of hospitalization due to affective symptoms (aHR 0.83, 95 % CI 0.78-0.88) when all CCBs were analyzed together. Of specific CCBs, use of diltiazem (0.71, 0.55-0.91) and dihydropyridines (0.83, 0.78-0.89) were associated with a decreased risk but verapamil was not (0.93, 0.73-1.19). Use of adenosine modulators in general was associated with a decreased risk of hospitalizations due to affective symptoms (0.87, 0.79-0.96). Both allopurinol (0.85, 0.74-0.97) and dipyridamole (0.89, 0.78-1.00) were associated with a marginally decreased risk. Thiazide diuretic use as a negative control was not associated with the risk of hospitalization due to affective symptoms (0.97, 0.83-1.13).

LIMITATIONS

Due to the observational nature of this study, causation cannot be confirmed.

CONCLUSIONS

Dihydropyridines and diltiazem were associated with a decreased risk of psychiatric hospitalization in bipolar disorder. Results for allopurinol and dipyridamole were inconclusive.

Brain-penetrant calcium channel blockers are associated with a reduced incidence of neuropsychiatric disorders

Calcium channel blockers (CCBs) differ in their ability to penetrate into the brain. Pharmacoepidemiological studies suggest that CCBs as a class may have beneficial effects on the risks and outcomes of some psychiatric and neurological disorders. It is plausible but unknown whether this effect relates to their brain penetrance. To address this, we used the TriNetX electronic health records network to identify people prescribed a brain-penetrant CCB (BP-CCB), or those given amlodipine, a CCB with low brain penetrability. We created cohorts of patients who, prior to first CCB exposure, either had to have, or could not have had, a recorded ICD-10 diagnosis in any of the following categories: psychotic disorder; affective disorder (including bipolar disorder and major depressive disorder); anxiety disorder; substance use disorder; sleep disorder; delirium; dementia, or movement disorder. Cohort pairs were propensity score matched for age, sex, race, blood pressure, body mass index, and a range of other variables. The outcomes were the incidence of these disorders measured over a two-year exposure period. Matched cohort sizes ranged from 17,896 to 49,987. In people with no prior history of psychiatric or neurodegenerative disorder, there was a significantly lower incidence of most disorders with BP-CCBs compared to amlodipine, with risk ratios ranging from 0.64 to 0.88 and an overall risk ratio of 0.88, i.e. a risk reduction of 12%. In people who did have a prior psychiatric or neurodegenerative diagnosis, differences were much smaller, but again showed lower risks for several disorders with BP-CCBs compared to amlodipine. The differences were somewhat more marked in women and in people less than 60 years old. Results were similar when comparing BP-CCBs with verapamil and diltiazem. We also compared BP-CCBs with angiotensin receptor blockers, and found an overall risk ratio of 0.94 in favour of BP-CCBs, but with differential effects across disorders including a higher risk of psychotic disorder and dementia, but a lower risk for anxiety and sleep disorders. In some analyses, there was evidence of residual confounding even after the extensive matching, in that negative control outcomes showed a reduced incidence with BP-CCBs relative to the comparator cohort. In summary, CCBs that readily penetrate the brain are associated with a lower incidence of neuropsychiatric disorders, especially first diagnoses, compared to CCBs which do not. This may reflect their blockade of neuronal voltage-gated calcium channels. The findings encourage repurposing trials using existing BP-CCBs, and suggest that novel BP-CCBs with enhanced and more selective central actions might have greater therapeutic potential for psychiatric and neurodegenerative disorders.

New drug targets in psychiatry: Neurobiological considerations in the genomics era

After a period of withdrawal, pharmaceutical companies have begun to reinvest in neuropsychiatric disorders, due to improvements in our understanding of these disorders, stimulated in part by genomic studies. However, translating this information into disease insights and ultimately into tractable therapeutic targets is a major challenge. Here we consider how different sources of information might be integrated to guide this process. We review how an understanding of neurobiology has been used to advance therapeutic candidates identified in the pre-genomic era, using catechol-O-methyltransferase (COMT) as an exemplar. We then contrast with ZNF804A, the first genome-wide significant schizophrenia gene, and draw on some of the lessons that these and other examples provide. We highlight that, at least in the short term, the translation of potential targets for which there is orthogonal neurobiological support is likely to be more straightforward and productive than that those relying solely on genomic information. Although we focus here on information from genomic studies of schizophrenia, the points are broadly applicable across major psychiatric disorders and their symptoms.

Antihypertensive drugs and brain function: mechanisms underlying therapeutically beneficial and harmful neuropsychiatric effects

A bidirectional relationship exists between hypertension and psychiatric disorders, including unipolar and bipolar depression, anxiety, post-traumatic stress disorder (PTSD), psychosis, schizophrenia, mania, and dementia/cognitive decline. Repurposing of antihypertensive drugs to treat mental disorders is thus being explored. A systematic knowledge of the mechanisms of action and clinical consequences of the use of antihypertensive agents on neuropsychiatric functions has not been achieved yet. In this article, we review the putative role of antihypertensive agents in psychiatric disorders, discuss the targets and mechanisms of action, and examine how and to what extent specific drug classes/molecules may trigger, worsen, or mitigate psychiatric symptoms. In addition, we review pharmacokinetics (brain penetration of drugs) and pharmacogenetics data that add important information to assess risks and benefits of antihypertensive drugs in neuropsychiatric settings. The scientific literature shows robust evidence of a positive effect of α1 blockers on PTSD symptoms, nightmares and sleep quality, α2 agonists on core symptoms, executive function and quality of life in Attention-Deficit/Hyperactivity Disorder, PTSD, Tourette's syndrome, and β blockers on anxiety, aggression, working memory, and social communication. Renin-angiotensin system modulators exert protective effects on cognition, depression, and anxiety, and the loop diuretic bumetanide reduced the core symptoms of autism in a subset of patients. There is no evidence of clear benefits of calcium channel blockers in mood disorders in the scientific literature. These findings are mainly from preclinical studies; clinical data are still insufficient or of anecdotal nature, and seldom systematic. The information herewith provided can support a better therapeutic approach to hypertension, tailored to patients with, or with high susceptibility to, psychiatric illness. It may prompt clinical studies exploring the potential benefit of antihypertensive drugs in selected patients with neuropsychiatric comorbidities that include outcomes of neuropsychiatric interest and specifically assess undesirable effects or interactions.

Phenotypes, mechanisms and therapeutics: insights from bipolar disorder GWAS findings

Genome-wide association studies (GWAS) have reported substantial genomic loci significantly associated with clinical risk of bipolar disorder (BD), and studies combining techniques of genetics, neuroscience, neuroimaging, and pharmacology are believed to help tackle clinical problems (e.g., identifying novel therapeutic targets). However, translating findings of psychiatric genetics into biological mechanisms underlying BD pathogenesis remains less successful. Biological impacts of majority of BD GWAS risk loci are obscure, and the involvement of many GWAS risk genes in this illness is yet to be investigated. It is thus necessary to review the progress of applying BD GWAS risk genes in the research and intervention of the disorder. A comprehensive literature search found that a number of such risk genes had been investigated in cellular or animal models, even before they were highlighted in BD GWAS. Intriguingly, manipulation of many BD risk genes (e.g., ANK3, CACNA1C, CACNA1B, HOMER1, KCNB1, MCHR1, NCAN, SHANK2 etc.) resulted in altered murine behaviors largely restoring BD clinical manifestations, including mania-like symptoms such as hyperactivity, anxiolytic-like behavior, as well as antidepressant-like behavior, and these abnormalities could be attenuated by mood stabilizers. In addition to recapitulating phenotypic characteristics of BD, some GWAS risk genes further provided clues for the neurobiology of this illness, such as aberrant activation and functional connectivity of brain areas in the limbic system, and modulated dendritic spine morphogenesis as well as synaptic plasticity and transmission. Therefore, BD GWAS risk genes are undoubtedly pivotal resources for modeling this illness, and might be translational therapeutic targets in the future clinical management of BD. We discuss both promising prospects and cautions in utilizing the bulk of useful resources generated by GWAS studies. Systematic integrations of findings from genetic and neuroscience studies are called for to promote our understanding and intervention of BD.

The risk of developing cardiovascular disease in bipolar disorder. Biological factors and therapy

Background. Bipolar disorder (BD) is one of the most common mental disorders characterized by alternating episodes of mania/hypomania and depression, as well as the possibility of developing mixed conditions. Correct and timely diagnosis of BD is important due to the presence of a high suicidal risk and a high predisposition to the development of cardiovascular disease (CVD). The risk of CVD is higher in ВD than in other mental disorders. Materials and methods. A sample assessment was made of current studies focusing on the vascular-bipolar link. The search was carried out in the PubMed and eLIBRARY databases for the following keywords: bipolar disorder, psychopharmacology, cardiovascular disease, biological mediators. Results. There are several biological factors which explain the close association and common pathogenetic mechanisms of BD and CVD. The most interesting of them are inflammation, oxidative stress, and brain-derived neurotrophic factor. Neuroimaging methods have shown similar structural brain changes in people with BD and with CVD. There is some evidence of the efficacy of statins and angiotensin-converting enzyme inhibitors in reducing cardio-vascular risk factors in BD patients. Conclusion. The predisposition of patients of BD to CVD is beyond doubt. It is necessary to consider the peculiarities of the course of BD and conduct active monitoring and preventive measures to reduce the risk of developing life-threatening CVDs. Further research focused on the pathogenetic relationship between BD and CVD could provide more insight into this area.

Calcium Channel Antagonists for Mood Disorders

PURPOSE

Development of new thymoleptic medications has primarily centered on anticonvulsants and antipsychotic drugs. Based on our studies of intracellular calcium ion signaling in mood disorders, we were interested in the use of novel medications that act on this mechanism of neuronal activation as potential mood stabilizers.

METHOD

We reviewed the dynamics of the calcium second messenger system and the international body of data demonstrating increased baseline and stimulated intracellular calcium levels in peripheral cells of patients with bipolar mood disorders. We then examined studies of the effect of established mood stabilizers on intracellular calcium ion levels and on mechanisms of mobilization of this second messenger. After summarizing studies of calcium channel blocking agents, whose primary action is to attenuate hyperactive intracellular calcium signaling, we considered clinical experience with this class of medications and the potential for further research.

FINDINGS

Established mood stabilizers normalize increased intracellular calcium ion levels in bipolar disorder patients. Most case series and controlled studies suggest an antimanic and possibly mood stabilizing effect of the calcium channel blocking medications verapamil and nimodipine, with fewer data on isradipine. A relatively low risk of teratogenicity and lack of cognitive adverse effects or weight gain suggest possible applications in pregnancy and in patients for whom these are considerations.

IMPLICATIONS

Medications that antagonize hyperactive intracellular signaling warrant more interest than they have received in psychiatry. Further experience will clarify the applications of these medications alone and in combination with more established mood stabilizers.

Using induced pluripotent stem cells to investigate human neuronal phenotypes in 1q21.1 deletion and duplication syndrome

Copy Number Variation (CNV) at the 1q21.1 locus is associated with a range of neurodevelopmental and psychiatric disorders in humans, including abnormalities in head size and motor deficits. Yet, the functional consequences of these CNVs (both deletion and duplication) on neuronal development remain unknown. To determine the impact of CNV at the 1q21.1 locus on neuronal development, we generated induced pluripotent stem cells from individuals harbouring 1q21.1 deletion or duplication and differentiated them into functional cortical neurons. We show that neurons with 1q21.1 deletion or duplication display reciprocal phenotype with respect to proliferation, differentiation potential, neuronal maturation, synaptic density and functional activity. Deletion of the 1q21.1 locus was also associated with an increased expression of lower cortical layer markers. This difference was conserved in the mouse model of 1q21.1 deletion, which displayed altered corticogenesis. Importantly, we show that neurons with 1q21.1 deletion and duplication are associated with differential expression of calcium channels and demonstrate that physiological deficits in neurons with 1q21.1 deletion or duplication can be pharmacologically modulated by targeting Ca²⁺ channel activity. These findings provide biological insight into the neuropathological mechanism underlying 1q21.1 associated brain disorder and indicate a potential target for therapeutic interventions.

Psychological and pharmacological interventions for depression in patients with coronary artery disease

BACKGROUND

Depression occurs frequently in individuals with coronary artery disease (CAD) and is associated with a poor prognosis.

OBJECTIVES

To determine the effects of psychological and pharmacological interventions for depression in CAD patients with comorbid depression.

SEARCH METHODS

We searched the CENTRAL, MEDLINE, Embase, PsycINFO, and CINAHL databases up to August 2020. We also searched three clinical trials registers in September 2021. We examined reference lists of included randomised controlled trials (RCTs) and contacted primary authors. We applied no language restrictions.

SELECTION CRITERIA

We included RCTs investigating psychological and pharmacological interventions for depression in adults with CAD and comorbid depression. Our primary outcomes included depression, mortality, and cardiac events. Secondary outcomes were healthcare costs and utilisation, health-related quality of life, cardiovascular vital signs, biomarkers of platelet activation, electrocardiogram wave parameters, non-cardiac adverse events, and pharmacological side effects.

DATA COLLECTION AND ANALYSIS

Two review authors independently examined the identified papers for inclusion and extracted data from the included studies. We performed random-effects model meta-analyses to compute overall estimates of treatment outcomes.

MAIN RESULTS

Thirty-seven trials fulfilled our inclusion criteria. Psychological interventions may result in a reduction in end-of-treatment depression symptoms compared to controls (standardised mean difference (SMD) -0.55, 95% confidence interval (CI) -0.92 to -0.19, I² = 88%; low certainty evidence; 10 trials; n = 1226). No effect was evident on medium-term depression symptoms one to six months after the end of treatment (SMD -0.20, 95% CI -0.42 to 0.01, I² = 69%; 7 trials; n = 2654). The evidence for long-term depression symptoms and depression response was sparse for this comparison. There is low certainty evidence that psychological interventions may result in little to no difference in end-of-treatment depression remission (odds ratio (OR) 2.02, 95% CI 0.78 to 5.19, I² = 87%; low certainty evidence; 3 trials; n = 862). Based on one to two trials per outcome, no beneficial effects on mortality and cardiac events of psychological interventions versus control were consistently found. The evidence was very uncertain for end-of-treatment effects on all-cause mortality, and data were not reported for end-of-treatment cardiovascular mortality and occurrence of myocardial infarction for this comparison. In the trials examining a head-to-head comparison of varying psychological interventions or clinical management, the evidence regarding the effect on end-of-treatment depression symptoms is very uncertain for: cognitive behavioural therapy compared to supportive stress management; behaviour therapy compared to person-centred therapy; cognitive behavioural therapy and well-being therapy compared to clinical management. There is low certainty evidence from one trial that cognitive behavioural therapy may result in little to no difference in end-of-treatment depression remission compared to supportive stress management (OR 1.81, 95% CI 0.73 to 4.50; low certainty evidence; n = 83). Based on one to two trials per outcome, no beneficial effects on depression remission, depression response, mortality rates, and cardiac events were consistently found in head-to-head comparisons between psychological interventions or clinical management. The review suggests that pharmacological intervention may have a large effect on end-of-treatment depression symptoms (SMD -0.83, 95% CI -1.33 to -0.32, I² = 90%; low certainty evidence; 8 trials; n = 750). Pharmacological interventions probably result in a moderate to large increase in depression remission (OR 2.06, 95% CI 1.47 to 2.89, I² = 0%; moderate certainty evidence; 4 trials; n = 646). We found an effect favouring pharmacological intervention versus placebo on depression response at the end of treatment, though strength of evidence was not rated (OR 2.73, 95% CI 1.65 to 4.54, I² = 62%; 5 trials; n = 891). Based on one to four trials per outcome, no beneficial effects regarding mortality and cardiac events were consistently found for pharmacological versus placebo trials, and the evidence was very uncertain for end-of-treatment effects on all-cause mortality and myocardial infarction. In the trials examining a head-to-head comparison of varying pharmacological agents, the evidence was very uncertain for end-of-treatment effects on depression symptoms. The evidence regarding the effects of different pharmacological agents on depression symptoms at end of treatment is very uncertain for: simvastatin versus atorvastatin; paroxetine versus fluoxetine; and escitalopram versus Bu Xin Qi. No trials were eligible for the comparison of a psychological intervention with a pharmacological intervention.

AUTHORS' CONCLUSIONS

In individuals with CAD and depression, there is low certainty evidence that psychological intervention may result in a reduction in depression symptoms at the end of treatment. There was also low certainty evidence that pharmacological interventions may result in a large reduction of depression symptoms at the end of treatment. Moderate certainty evidence suggests that pharmacological intervention probably results in a moderate to large increase in depression remission at the end of treatment. Evidence on maintenance effects and the durability of these short-term findings is still missing. The evidence for our primary and secondary outcomes, apart from depression symptoms at end of treatment, is still sparse due to the low number of trials per outcome and the heterogeneity of examined populations and interventions. As psychological and pharmacological interventions can seemingly have a large to only a small or no effect on depression, there is a need for research focusing on extracting those approaches able to substantially improve depression in individuals with CAD and depression.

Ion Channel Dysfunction and Neuroinflammation in Migraine and Depression

Migraine and major depression are debilitating disorders with high lifetime prevalence rates. Interestingly these disorders are highly comorbid and show significant heritability, suggesting shared pathophysiological mechanisms. Non-homeostatic function of ion channels and neuroinflammation may be common mechanisms underlying both disorders: The excitation-inhibition balance of microcircuits and their modulation by monoaminergic systems, which depend on the expression and function of membrane located K⁺, Na⁺, and Ca⁺² channels, have been reported to be disturbed in both depression and migraine. Ion channels and energy supply to synapses not only change excitability of neurons but can also mediate the induction and maintenance of inflammatory signaling implicated in the pathophysiology of both disorders. In this respect, Pannexin-1 and P2X7 large-pore ion channel receptors can induce inflammasome formation that triggers release of pro-inflammatory mediators from the cell. Here, the role of ion channels involved in the regulation of excitation-inhibition balance, synaptic energy homeostasis as well as inflammatory signaling in migraine and depression will be reviewed.

Genetic contributions to bipolar disorder: current status and future directions

Bipolar disorder (BD) is a highly heritable mental disorder and is estimated to affect about 50 million people worldwide. Our understanding of the genetic etiology of BD has greatly increased in recent years with advances in technology and methodology as well as the adoption of international consortiums and large population-based biobanks. It is clear that BD is also highly heterogeneous and polygenic and shows substantial genetic overlap with other psychiatric disorders. Genetic studies of BD suggest that the number of associated loci is expected to substantially increase in larger future studies and with it, improved genetic prediction of the disorder. Still, a number of challenges remain to fully characterize the genetic architecture of BD. First among these is the need to incorporate ancestrally-diverse samples to move research away from a Eurocentric bias that has the potential to exacerbate health disparities already seen in BD. Furthermore, incorporation of population biobanks, registry data, and electronic health records will be required to increase the sample size necessary for continued genetic discovery, while increased deep phenotyping is necessary to elucidate subtypes within BD. Lastly, the role of rare variation in BD remains to be determined. Meeting these challenges will enable improved identification of causal variants for the disorder and also allow for equitable future clinical applications of both genetic risk prediction and therapeutic interventions.

Targeting synaptic plasticity in schizophrenia: insights from genomic studies

Patients with schizophrenia experience cognitive dysfunction and negative symptoms that do not respond to current drug treatments. Historical evidence is consistent with the hypothesis that these deficits are due, at least in part, to altered cortical synaptic plasticity (the ability of synapses to strengthen or weaken their activity), making this an attractive pathway for therapeutic intervention. However, while synaptic transmission and plasticity is well understood in model systems, it has been challenging to identify specific therapeutic targets for schizophrenia. New information is emerging from genomic findings, which converge on synaptic plasticity and provide a new window on the neurobiology of schizophrenia. Translating this information into therapeutic advances will require a multidisciplinary and collaborative approach.

Investigation of genetic loci shared between bipolar disorder and risk-taking propensity: potential implications for pharmacological interventions

Patients with bipolar disorder (BD) often show increased risk-taking propensity, which may contribute to poor clinical outcome. While these two phenotypes are genetically correlated, there is scarce knowledge on the shared genetic determinants. Using GWAS datasets on BD (41,917 BD cases and 371,549 controls) and risk-taking (n = 466,571), we dissected shared genetic determinants using conjunctional false discovery rate (conjFDR) and local genetic covariance analysis. We investigated specificity of identified targets using GWAS datasets on schizophrenia (SCZ) and attention-deficit hyperactivity disorder (ADHD). The putative functional role of identified targets was evaluated using different tools and GTEx v. 8. Target druggability was evaluated using DGIdb and enrichment for drug targets with genome for REPositioning drugs (GREP). Among 102 loci shared between BD and risk-taking, 87% showed the same direction of effect. Sixty-two were specifically shared between risk-taking propensity and BD, while the others were also shared between risk-taking propensity and either SCZ or ADHD. By leveraging pleiotropic enrichment, we reported 15 novel and specific loci associated with BD and 22 with risk-taking. Among cross-disorder genes, CACNA1C (a known target of calcium channel blockers) was significantly associated with risk-taking propensity and both BD and SCZ using conjFDR (p = 0.001 for both) as well as local genetic covariance analysis, and predicted to be differentially expressed in the cerebellar hemisphere in an eQTL-informed gene-based analysis (BD, Z = 7.48, p = 3.8E-14; risk-taking: Z = 4.66, p = 1.6E-06). We reported for the first time shared genetic determinants between BD and risk-taking propensity. Further investigation into calcium channel blockers or development of innovative ligands of calcium channels might form the basis for innovative pharmacotherapy in patients with BD with increased risk-taking propensity.

Genome-wide association study of more than 40,000 bipolar disorder cases provides new insights into the underlying biology

Bipolar disorder is a heritable mental illness with complex etiology. We performed a genome-wide association study of 41,917 bipolar disorder cases and 371,549 controls of European ancestry, which identified 64 associated genomic loci. Bipolar disorder risk alleles were enriched in genes in synaptic signaling pathways and brain-expressed genes, particularly those with high specificity of expression in neurons of the prefrontal cortex and hippocampus. Significant signal enrichment was found in genes encoding targets of antipsychotics, calcium channel blockers, antiepileptics and anesthetics. Integrating expression quantitative trait locus data implicated 15 genes robustly linked to bipolar disorder via gene expression, encoding druggable targets such as HTR6, MCHR1, DCLK3 and FURIN. Analyses of bipolar disorder subtypes indicated high but imperfect genetic correlation between bipolar disorder type I and II and identified additional associated loci. Together, these results advance our understanding of the biological etiology of bipolar disorder, identify novel therapeutic leads and prioritize genes for functional follow-up studies.

Association of Antihypertensive Drug Target Genes With Psychiatric Disorders: A Mendelian Randomization Study

IMPORTANCE

Observational studies have reported associations between antihypertensive medication and psychiatric disorders, although the reported direction of association appears to be dependent on drug class.

OBJECTIVE

To estimate the potential effect of different antihypertensive drug classes on schizophrenia, bipolar disorder, and major depressive disorder.

DESIGN, SETTING, AND PARTICIPANTS

This 2-sample mendelian randomization study assessed the association between a single-nucleotide variant (SNV) and drug target gene expression derived from existing expression quantitative trait loci (eQTL) data in blood (sample 1) and the SNV-disease association from published case-control genome-wide association studies (sample 2). Significant associations were corroborated using published brain eQTL and protein QTL data. Participants included 40 675 patients with schizophrenia and 64 643 controls, 20 352 patients with bipolar disorder and 31 358 controls, and 135 458 patients with major depressive disorder and 344 901 controls. Blood eQTL levels were measured in 31 684 individuals from 37 cohorts (eQTLGen consortium); prefrontal cortex eQTLs were measured from the PsychENCODE resource in 1387 individuals; and protein QTLs were measured in cerebral spinal fluid from 544 individuals and plasma from 818 individuals. Data were collected from October 4, 2019, to June 1, 2020, and analyzed from October 14, 2019, to June 6, 2020.

EXPOSURES

Expression levels of antihypertensive drug target genes as proxies for drug exposure, and genetic variants robustly associated with the expression of these genes as mendelian randomization instruments.

MAIN OUTCOMES AND MEASURES

Risk for schizophrenia, bipolar disorder, and major depressive disorder.

RESULTS

A 1-SD lower expression of the angiotensin-converting enzyme (ACE) gene in blood was associated with lower systolic blood pressure of 4.0 (95% CI, 2.7-5.3) mm Hg, but increased risk of schizophrenia (odds ratio [OR], 1.75; 95% CI, 1.28-2.38; P = 3.95 × 10-4). A concordant direction of association was also observed between ACE expression in prefrontal cortex (OR, 1.33; 95% CI, 1.13-1.56) and ACE protein levels in cerebral spinal fluid (OR per 1-SD decrease, 1.12; 95% CI, 1.05-1.19) and plasma (OR per 1-SD decrease, 1.04; 95% CI, 1.01-1.07). We found no evidence for an association between genetically estimated SBP and schizophrenia risk.

CONCLUSIONS AND RELEVANCE

Findings suggest an adverse association of lower ACE messenger RNA and protein levels with schizophrenia risk. These findings warrant greater pharmacovigilance and further investigation into the effect of ACE inhibitors, particularly those that are centrally acting, on psychiatric symptoms in patients with schizophrenia, as well as the role of ACE inhibitor use in late-onset schizophrenia.

Onset and recurrence of psychiatric disorders associated with anti-hypertensive drug classes

The major anti-hypertensive (AHT) drug classes have been associated with differential risks of psychiatric disorders. However, existing data are limited largely to depression, and confounding variables have not always been controlled for. We sought to fill the evidence gap, using TriNetX Analytics, an electronic health records network. Amongst 58.6 million patients aged 18-90 years, patients prescribed a calcium channel blocker (CCB) were compared with those taking a diuretic, angiotensin-converting enzyme inhibitor (ACEI), angiotensin receptor blocker (ARB), or β-blocker. Cohorts were propensity score-matched for age, sex, race, and blood pressure. Over a 2-year exposure period, we measured the incidence and risk ratio of a first diagnosis (ICD-10 codes), or a recurrence, of psychotic, affective, and anxiety disorders, as well as substance use disorders and sleep disorders. Cohort sizes ranged from 33,734 to 322,814. CCBs were associated with a lower incidence of psychotic, affective, and anxiety disorders than β-blockers (risk ratios 0.69-0.99) and a higher incidence than ARBs (risk ratios 1.04-2.23) for both first and recurrent diagnoses. Comparisons of CCBs with ACEIs or diuretics showed smaller risk ratios that varied between disorders, and between first episode and recurrence. AHT classes were also associated with the incidence of substance use and sleep disorders. Results remained largely unchanged after more extensive cohort matching for additional potential confounders. In a secondary analysis, a comparison between ARBs and ACEIs showed lower rates of psychotic, affective, and substance use disorders with ARBs, but higher risks of anxiety and sleep disorders. In conclusion, AHT classes are differentially associated with the incidence of psychiatric disorders. ARBs show the most advantageous profile and β-blockers the least. The apparent beneficial effects of ARBs merit further study.

The relationship between antihypertensive medications and mood disorders: analysis of linked healthcare data for 1.8 million patients

BACKGROUND

Recent work suggests that antihypertensive medications may be useful as repurposed treatments for mood disorders. Using large-scale linked healthcare data we investigated whether certain classes of antihypertensive, such as angiotensin antagonists (AAs) and calcium channel blockers, were associated with reduced risk of new-onset major depressive disorder (MDD) or bipolar disorder (BD).

METHOD

Two cohorts of patients treated with antihypertensives were identified from Scottish prescribing (2009-2016) and hospital admission (1981-2016) records. Eligibility for cohort membership was determined by a receipt of a minimum of four prescriptions for antihypertensives within a 12-month window. One treatment cohort (n = 538 730) included patients with no previous history of mood disorder, whereas the other (n = 262 278) included those who did. Both cohorts were matched by age, sex and area deprivation to untreated comparators. Associations between antihypertensive treatment and new-onset MDD or bipolar episodes were investigated using Cox regression.

RESULTS

For patients without a history of mood disorder, antihypertensives were associated with increased risk of new-onset MDD. For AA monotherapy, the hazard ratio (HR) for new-onset MDD was 1.17 (95% CI 1.04-1.31). Beta blockers' association was stronger (HR 2.68; 95% CI 2.45-2.92), possibly indicating pre-existing anxiety. Some classes of antihypertensive were associated with protection against BD, particularly AAs (HR 0.46; 95% CI 0.30-0.70). For patients with a past history of mood disorders, all classes of antihypertensives were associated with increased risk of future episodes of MDD.

CONCLUSIONS

There was no evidence that antihypertensive medications prevented new episodes of MDD but AAs may represent a novel treatment avenue for BD.

Blood pressure in bipolar disorder: evidence of elevated pulse pressure and associations between mean pressure and mood instability

BACKGROUND

Bipolar disorder (BD) is associated with excess and premature cardiovascular mortality. Elevated blood pressure (BP) is a leading contributor to cardiovascular risk. However, few studies have examined BP in BD in comparison to other psychiatric disorders. Furthermore, the association between BP and mood instability is not presently clear despite increasing interest in repurposing existing antihypertensive medications as possible novel BD treatments. Thus we examined BP differences between BD and borderline personality disorder (BPD), a disorder with a similar symptom profile through chronic mood instability.

METHODS

A total of 106 adults (38 BD, 25 BPD, and 43 healthy controls), evaluated in the Automated Monitoring of Symptom Severity (AMoSS) study, completed a week-long home blood pressure monitoring assessment and ecological momentary assessment of mood. We examined group-wise differences in mean BP and BP variability and their association with mood instability.

RESULTS

BD individuals had a significantly wider resting pulse pressure (40.8 ± 7.4, mmHg) compared to BPD (35.7 ± 5.3, mmHg, P = 0.03) and control participants (37.3 ± 6.3, mmHg, P = 0.036). Systolic BP was negatively associated with sad mood instability, and all measures of mean BP (systolic, diastolic, and mean arterial pressure) were negatively associated with positive mood instability.

CONCLUSIONS

This study demonstrates BP differences between BD and healthy and clinical controls that are within a normotensive range. Early pulse pressure widening may be a modifiable pathophysiological feature of BD that confers later cardiovascular risk. BP may be an important transdiagnostic predictor of mood instability and a potential explicit treatment target.

Adenosine modulators and calcium channel blockers as add-on treatment for schizophrenia

Relapses remain common among individuals with schizophrenia indicating a need for improved treatments. Creating a completely new drug molecule is expensive and time consuming, and therefore drug repurposing should be considered. Aim of this study was to investigate the risk of psychiatric rehospitalization associated with use of adenosine modulators (AMs) and calcium channel blockers (CCBs) in schizophrenia. Individuals diagnosed with schizophrenia (N = 61,889) in inpatient care between 1972–2014 in Finland were included. The follow-up lasted from 1996 to 2017. Main exposures were use of AMs (allopurinol and dipyridamole) and CCBs (dihydropyridines, diltiazem, and verapamil). Thiazide diuretics were used as a negative control. Within-individual models in stratified Cox regression were used and adjusted hazard ratios (HR) with 95% confidence intervals (CIs) are reported. Use of AMs was associated with a reduced risk of psychiatric rehospitalization on drug class level (HR 0.74, 95% CI 0.65–0.84, P < 0.0001), as well as on the level of individual drugs (allopurinol HR 0.82, 95% CI 0.70–0.97, P = 0.02; dipyridamole HR 0.65, 95% CI 0.55–0.77, P < 0.0001). Use of CCBs was associated with a reduced risk of psychiatric rehospitalization on drug class level (HR 0.81, 95% CI 0.77–0.86, P < 0.0001). From the different CCBs, only exposure to dihydropyridines was associated with a reduced risk (HR 0.79, 95% CI 0.74–0.84, P < 0.0001). No effect was observed for the negative control, thiazide diuretics (HR 0.96, 0.90–1.02, P = 0.20). The effects of dipyridamole and dihydropyridines were more pronounced among younger persons and combination of AMs, and CCBs was associated with a lower risk than either drug class as monotherapy. These results indicate a need for randomized controlled trials of these drugs.

Development of phenotypic assays for identifying novel blockers of L-type calcium channels in neurons

L-type calcium channels (LTCCs) are highly expressed in the heart and brain and are critical for cardiac and neuronal functions. LTCC-blocking drugs have a long and successful record in the clinic for treating cardiovascular disorders. In contrast, establishment of their efficacy for indications of the central nervous system remains challenging given the tendency of existing LTCC drugs being functionally and mechanistically more selective for peripheral tissues. LTCCs in vivo are large macromolecular complexes consisting of a pore-forming subunit and other modulatory proteins, some of which may be neuro-specific and potentially harbor mechanisms for neuronal selectivity. To exploit the possibility of identifying mechanistically novel and/or neuro-selective blockers, we developed two phenotypic assays—a calcium flux-based primary screening assay and a patch clamp secondary assay, using rat primary cortical cultures. We screened a library comprised of 1278 known bioactive agents and successfully identified a majority of the potent LTCC-blocking drugs in the library. Significantly, we identified a previously unrecognized LTCC blocker with a novel mechanism, which was corroborated by patch clamp and binding studies. As such, these phenotypic assays are robust and represent an important step towards identifying mechanistically novel and neuro-selective LTCC blockers.

Advances toward precision medicine for bipolar disorder: mechanisms & molecules

Given its chronicity, contribution to disability and morbidity, and prevalence of more than 2%, the effective treatment, and prevention of bipolar disorder represents an area of significant unmet medical need. While more than half a century has passed since the introduction of lithium into widespread use at the birth of modern psychopharmacology, that medication remains a mainstay for the acute treatment and prevention of recurrent mania/hypomania and depression that characterize bipolar disorder. However, the continued limited understanding of how lithium modulates affective behavior and lack of validated cellular and animal models have resulted in obstacles to discovering more effective mood stabilizers with fewer adverse side effects. In particular, while there has been progress in developing new pharmacotherapy for mania, developing effective treatments for acute bipolar depression remain inadequate. Recent large-scale human genetic studies have confirmed the complex, polygenic nature of the risk architecture of bipolar disorder, and its overlap with other major neuropsychiatric disorders. Such discoveries have begun to shed light on the pathophysiology of bipolar disorder. Coupled with broader advances in human neurobiology, neuropharmacology, noninvasive neuromodulation, and clinical trial design, we can envision novel therapeutic strategies informed by defined molecular mechanisms and neural circuits and targeted to the root cause of the pathophysiology. Here, we review recent advances toward the goal of better treatments for bipolar disorder, and we outline major challenges for the field of translational neuroscience that necessitate continued focus on fundamental research and discovery.

Targeting microglia L-type voltage-dependent calcium channels for the treatment of central nervous system disorders

Calcium (Ca2+ ) is a ubiquitous mediator of a multitude of cellular functions in the central nervous system (CNS). Intracellular Ca2+ is tightly regulated by cells, including entry via plasma membrane Ca2+ permeable channels. Of specific interest for this review are L-type voltage-dependent Ca2+ channels (L-VDCCs), due to their pleiotropic role in several CNS disorders. Currently, there are numerous approved drugs that target L-VDCCs, including dihydropyridines. These drugs are safe and effective for the treatment of humans with cardiovascular disease and may also confer neuroprotection. Here, we review the potential of L-VDCCs as a target for the treatment of CNS disorders with a focus on microglia L-VDCCs. Microglia, the resident immune cells of the brain, have attracted recent attention for their emerging inflammatory role in several CNS diseases. Intracellular Ca2+ regulates microglia transition from a resting quiescent state to an "activated" immune-effector state and is thus a valuable target for manipulation of microglia phenotype. We will review the literature on L-VDCC expression and function in the CNS and on microglia in vitro and in vivo and explore the therapeutic landscape of L-VDCC-targeting agents at present and future challenges in the context of Alzheimer's disease, Parkinson's disease, Huntington's disease, neuropsychiatric diseases, and other CNS disorders.

Translational genomics and beyond in bipolar disorder

Genome-wide association studies (GWAS) have revealed multiple genomic loci conferring risk of bipolar disorder (BD), providing hints for its underlying pathobiology. However, there are still remaining questions to answer. For example, discordance exists between BD heritability estimated with earlier epidemiological evidence and that calculated based on common GWAS variations. Where is the "missing heritability"? How can we explain the biology of the disease based on genetic findings? In this review, we summarize the accomplishments and limitations of current BD GWAS, and discuss potential reasons for the "missing heritability." In addition, progresses of research for the biological mechanisms underlying BD genetic risk using brain tissues, reprogrammed cells, and model animals are reviewed. While our knowledge of BD genetic basis is significantly promoted by these efforts, the complexities of gene regulation in the genome, the spatial-temporal heterogeneity during brain development, and the limitations of different experimental models should always be considered. Notably, several genes have been widely studied given their relatively well-characterized involvement in BD (e.g., CACAN1C and ANK3), and findings of these genes are summarized to both outline possible biological mechanisms of BD and describe examples of translating GWAS discoveries into the pathophysiology.

Cellular calcium in bipolar disorder: systematic review and meta-analysis

Calcium signalling has long been implicated in bipolar disorder, especially by reports of altered intracellular calcium ion concentrations ([Ca²⁺]). However, the evidence has not been appraised critically. We carried out a systematic review and meta-analysis of studies of cellular calcium indices in bipolar disorder. 2281 records were identified and 117 screened, of which 32 were eligible and 21 were suitable for meta-analyses. The latter each involved up to 642 patients and 404 control subjects. We found that basal free intracellular [Ca²⁺] is increased in bipolar disorder, both in platelets and in lymphocytes. The effect size is 0.55, with an estimated elevation of 29%. It is observed in medication-free patients. It is present in mania and bipolar depression, but data are equivocal for euthymia. Cells from bipolar disorder individuals also show an enhanced [Ca²⁺] response to stimulation with 5-HT or thrombin, by an estimated 25%, with an effect size of 0.63. In studies which included other diagnoses, intracellular basal [Ca²⁺] was higher in bipolar disorder than in unipolar depression, but not significantly different from schizophrenia. Functional parameters of cellular Ca²⁺ (e.g. calcium transients), and neuronal [Ca²⁺], have been much less investigated, and no firm conclusions can be drawn. In summary, there is a robust, medium effect size elevation of basal and stimulated free intracellular [Ca²⁺] in bipolar disorder. The results suggest altered calcium functioning in the disorder, and encourage further investigations into the underlying mechanisms, and the implications for pathophysiology and therapeutics.

Disruption of Cav1.2-mediated signaling is a pathway for ketamine-induced pathology

The general anesthetic ketamine has been repurposed by physicians as an anti-depressant and by the public as a recreational drug. However, ketamine use can cause extensive pathological changes, including ketamine cystitis. The mechanisms of ketamine's anti-depressant and adverse effects remain poorly understood. Here we present evidence that ketamine is an effective L-type Ca2+ channel (Cav1.2) antagonist that directly inhibits calcium influx and smooth muscle contractility, leading to voiding dysfunction. Ketamine prevents Cav1.2-mediated induction of immediate early genes and transcription factors, and inactivation of Cav1.2 in smooth muscle mimics the ketamine cystitis phenotype. Our results demonstrate that ketamine inhibition of Cav1.2 signaling is an important pathway mediating ketamine cystitis. In contrast, Cav1.2 agonist Bay k8644 abrogates ketamine-induced smooth muscle dysfunction. Indeed, Cav1.2 activation by Bay k8644 decreases voiding frequency while increasing void volume, indicating Cav1.2 agonists might be effective drugs for treatment of bladder dysfunction.

Antihypertensive Drugs and Risk of Depression: A Nationwide Population-Based Study

Hypertension, cardiovascular diseases, and cerebrovascular diseases are associated with an increased risk of depression, but it remains unclear whether treatment with antihypertensive agents decreases or increases this risk. The effects of individual drugs are also unknown. We used Danish population-based registers to systematically investigate whether the 41 most used individual antihypertensive drugs were associated with an altered risk of incident depression. Analyses of diuretics were included for comparisons. Participants were included in the study in January 2005 and followed until December 2015. Two different outcome measures were included: (1) a diagnosis of depressive disorder at a psychiatric hospital as an inpatient or outpatient and (2) a combined measure of a diagnosis of depression or use of antidepressants. Continued use of classes of angiotensin agents, calcium antagonists, and β-blockers was associated with significantly decreased rates of depression, whereas diuretic use was not. Individual drugs associated with decreased depression included 2 of 16 angiotensin agents: enalapril and ramipril; 3 of 10 calcium antagonists: amlodipine, verapamil, and verapamil combinations; and 4 of 15 β-blockers: propranolol, atenolol, bisoprolol, and carvedilol. No drug was associated with an increased risk of depression. In conclusion, real-life population-based data suggest a positive effect of continued use of 9 individual antihypertensive agents. This evidence should be used in guiding prescriptions for patients at risk of developing depression including those with prior depression or anxiety and patients with a family history of depression.

Rates of delirium associated with calcium channel blockers compared to diuretics, renin-angiotensin system agents and beta-blockers: An electronic health records network study

BACKGROUND

Antihypertensive drugs, especially calcium channel blockers, have been associated with differential rates of a number of neuropsychiatric outcomes. Delirium is commonly attributed to medication, including antihypertensive drugs, but delirium incidence has not been compared directly between antihypertensive drug classes.

METHODS

Using a federated electronic health records network of 25.5 million people aged 50 years or older, we measured rates of delirium over a two-year period in patients prescribed calcium channel blockers compared to the other main antihypertensive drug classes. Extensive propensity score matching was used to create cohorts matched for a range of demographic factors and delirium risk factors. Negative control outcomes were also measured.

RESULTS

Cohort sizes ranged from 54,000-577,000. Delirium was more common with calcium channel blockers than with renin-angiotensin system agents (~40% higher) but less common than with beta-blockers (~20% lower). These differences remained when patients with a range of other delirium risk factors were excluded, and they were not paralleled by the negative control outcomes. Comparisons between calcium channel blockers and diuretics produced inconclusive results.

CONCLUSIONS

Calcium channel blockers are associated with higher rates of delirium than renin-angiotensin system agents, but lower rates compared to beta-blockers. The findings add to the list of factors which may be considered when choosing antihypertensive drug class.

Call to action regarding the vascular-bipolar link: A report from the Vascular Task Force of the International Society for Bipolar Disorders

OBJECTIVES

The association of bipolar disorder with early and excessive cardiovascular disease was identified over a century ago. Nonetheless, the vascular-bipolar link remains underrecognized, particularly with regard to how this link can contribute to our understanding of pathogenesis and treatment.

METHODS

An international group of experts completed a selective review of the literature, distilling core themes, identifying limitations and gaps in the literature, and highlighting future directions to bridge these gaps.

RESULTS

The association between bipolar disorder and vascular disease is large in magnitude, consistent across studies, and independent of confounding variables where assessed. The vascular-bipolar link is multifactorial and is difficult to study given the latency between the onset of bipolar disorder, often in adolescence or early adulthood, and subsequent vascular disease, which usually occurs decades later. As a result, studies have often focused on risk factors for vascular disease or intermediate phenotypes, such as structural and functional vascular imaging measures. There is interest in identifying the most relevant mediators of this relationship, including lifestyle (eg, smoking, diet, exercise), medications, and systemic biological mediators (eg, inflammation). Nonetheless, there is a paucity of treatment studies that deliberately engage these mediators, and thus far no treatment studies have focused on engaging vascular imaging targets.

CONCLUSIONS

Further research focused on the vascular-bipolar link holds promise for gleaning insights regarding the underlying causes of bipolar disorder, identifying novel treatment approaches, and mitigating disparities in cardiovascular outcomes for people with bipolar disorder.

Verapamil and Alzheimer's Disease: Past, Present, and Future

Verapamil is a phenylalkylamine class calcium channel blocker that for half a century has been used for the treatment of cardiovascular diseases. Nowadays, verapamil is also considered as a drug option for the treatment of several neurological and psychiatric disorders, such as cluster headache, bipolar disorders, epilepsy, and neurodegenerative diseases. Here, we review insights into the potential preventive and therapeutic role of verapamil on Alzheimer’s disease (AD) based on limited experimental and clinical data. Pharmacological studies have shown that verapamil has a wide therapeutic spectrum, including antihypertensive, anti-inflammatory, and antioxidative effects, regulation of the blood-brain barrier function, due to its effect on P-glycoprotein, as well as adjustment of cellular calcium homeostasis, which may result in the delay of AD onset or ameliorate the symptoms of patients. However, the majority of the AD individuals are on polypharmacotherapy, and the interactions between verapamil and other drugs need to be considered. Therefore, for an appropriate and successful AD treatment, a personalized approach is more than necessary. A well-known narrow pharmacological window of verapamil efficacy may hinder this approach. It is therefore important to note that the verapamil efficacy may be conditioned by different factors. The onset, grade, and brain distribution of AD pathological hallmarks, the time-sequential appearances of AD-related cognitive and behavioral dysfunction, the chronobiologic and gender impact on calcium homeostasis and AD pathogenesis may somehow be influencing that success. In the future, such insights will be crucial for testing the validity of verapamil treatment on animal models of AD and clinical approaches.

Voltage-gated calcium channel blockers for psychiatric disorders: genomic reappraisal

We reappraise the psychiatric potential of calcium channel blockers (CCBs). First, voltage-gated calcium channels are risk genes for several disorders. Second, use of CCBs is associated with altered psychiatric risks and outcomes. Third, research shows there is an opportunity for brain-selective CCBs, which are better suited to psychiatric indications.

The Emerging Neurobiology of Bipolar Disorder

(Reprinted with permission from Trends in Neurosciences, January 2018, Vol. 41, No. 1 ).

Association between CANCA1C gene rs1034936 polymorphism and alcohol dependence in bipolar disorder

INTRODUCTION

Bipolar disorder (BD) is a highly heritable and disabling mental illness, commonly associated with substance abuse, being alcohol abuse the most frequent. Comorbid BD and substance abuse disorders are often associated with high levels of health service utilization and destabilization of the course of illness resulting in poor treatment outcomes. Although recent genome-wide association studies have detected a number of risk genes for BD, the data is still sparse and inconclusive for those genes that may contribute to the increased risk of comorbid alcohol abuse (AA) in BD. The primary aim of the present study was to investigate the effects of 46 single-nucleotide polymorphisms (SNPs) within eight genes on different phenotypes of BD patients, such as comorbid alcohol abuse. We further assessed clinical variables associated with AA.

METHODS

One-hundred fifty-eight BD I and II patients were enrolled in a naturalistic cohort study. Genomic DNA of 92 patients was extracted from whole blood using standard procedures and 46 tag SNPs in eight genes of interest (ANK, CACNA1C, CACNB2, FKBP5, GRM7, ITIH3, SYNE1 and TCF4) were genotyped.

RESULTS

Seventy-one patients out of 158 (45%) satisfied diagnostic criteria for comorbid AA. Among 46 SNPs analyzed, the only SNP associated with comorbid AA was rs1034936 polymorphism in the CANCA1C gene. This polymorphism was also associated with lifetime cocaine abuse, manic switch and current atypical antipsychotics.

CONCLUSIONS

Our findings suggest a role of rs1034936 CACNA1C gene variant in BD-AA group. Despite their preliminary nature, the present results may provide new insight on mechanisms underlying AA in BD.

Long-read sequencing reveals the complex splicing profile of the psychiatric risk gene CACNA1C in human brain

RNA splicing is a key mechanism linking genetic variation with psychiatric disorders. Splicing profiles are particularly diverse in brain and difficult to accurately identify and quantify. We developed a new approach to address this challenge, combining long-range PCR and nanopore sequencing with a novel bioinformatics pipeline. We identify the full-length coding transcripts of CACNA1C in human brain. CACNA1C is a psychiatric risk gene that encodes the voltage-gated calcium channel Ca_V1.2. We show that CACNA1C's transcript profile is substantially more complex than appreciated, identifying 38 novel exons and 241 novel transcripts. Importantly, many of the novel variants are abundant, and predicted to encode channels with altered function. The splicing profile varies between brain regions, especially in cerebellum. We demonstrate that human transcript diversity (and thereby protein isoform diversity) remains under-characterised, and provide a feasible and cost-effective methodology to address this. A detailed understanding of isoform diversity will be essential for the translation of psychiatric genomic findings into pathophysiological insights and novel psychopharmacological targets.