Publications by authors named "Dirk Smit"

Experiencing a traumatic event may lead to Posttraumatic Stress Disorder (PTSD), including symptoms such as flashbacks and hyperarousal. Individuals suffering from PTSD are at increased risk of cardiovascular disease (CVD), but it is unclear why. This study assesses shared genetic liability and potential causal pathways between PTSD and CVD.

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  • Sudden cardiac death significantly impacts the life expectancy of individuals with schizophrenia, possibly linked to arrhythmic disorders, although the exact relationship remains unclear.
  • The study aimed to explore genetic connections and possible causal influences between schizophrenia and various heart-related conditions, utilizing extensive genetic data from large-scale studies.
  • Findings revealed minimal global genetic correlation, but specific genetic regions showed strong links, suggesting that schizophrenia risk may increase the likelihood of developing certain arrhythmias like Brugada syndrome and affect heart rate during activities.
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  • - MDD and CVD commonly occur together, leading to higher health risks, and they share many genetic risk factors, with notable genetic overlaps found in specific brain regions like the thalamus.
  • - The research identified seven genetic loci linked to both disorders and highlighted that factors like inflammation and lifestyle contribute to the shared risk between MDD and atherosclerotic CVD.
  • - The findings suggest that genetic predisposition to MDD increases the risk of CVD, while the reverse is less evident, indicating a specific immunometabolic subtype of MDD that may be targeted for better prevention of CVD.
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  • Major depressive disorder (MDD) and cardiovascular disease (CVD) often occur together, leading to increased health issues and mortality rates.
  • A study discovered that many genetic risk factors for CVD overlap with those for MDD, indicating a shared biological basis, particularly involving specific brain regions and cell types.
  • The findings suggest that genetic predisposition to MDD can increase the risk of developing CVD, while lifestyle and metabolic factors also play significant roles, potentially creating an immunometabolic subtype of MDD more closely linked with CVD.
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  • Obsessive-compulsive disorder (OCD) affects about 1% of people and has a strong genetic component, but previous studies have not fully explained its genetic causes or biological mechanisms.
  • A large genome-wide association study (GWAS) analyzed data from over 53,000 OCD cases and over 2 million control participants, identifying 30 significant genetic markers related to OCD and suggesting a 6.7% heritability from SNPs.
  • The research also found 249 candidate risk genes linked to OCD, particularly in specific brain regions, and showed genetic correlations with various psychiatric disorders, laying the groundwork for further studies and potential treatments.
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Background And Aims: Experiencing a traumatic event may lead to Posttraumatic Stress Disorder (PTSD), including symptoms such as flashbacks and hyperarousal. Individuals suffering from PTSD are at increased risk of cardiovascular disease (CVD), but it is unclear why. This study assesses shared genetic liability and potential causal pathways between PTSD and CVD.

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While 1-2% of individuals meet the criteria for a clinical diagnosis of obsessive-compulsive disorder (OCD), many more (~13-38%) experience subclinical obsessive-compulsive symptoms (OCS) during their life. To characterize the genetic underpinnings of OCS and its genetic relationship to OCD, we conducted the largest genome-wide association study (GWAS) meta-analysis of parent- or self-reported OCS to date (N = 33,943 with complete phenotypic and genome-wide data), combining the results from seven large-scale population-based cohorts from Sweden, the Netherlands, England, and Canada (including six twin cohorts and one cohort of unrelated individuals). We found no genome-wide significant associations at the single-nucleotide polymorphism (SNP) or gene-level, but a polygenic risk score (PRS) based on the OCD GWAS previously published by the Psychiatric Genetics Consortium (PGC-OCD) was significantly associated with OCS (P = 3.

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The aesthetic values that individuals place on visual images are formed and shaped over a lifetime. However, whether the formation of visual aesthetic value is solely influenced by environmental exposure is still a matter of debate. Here, we considered differences in aesthetic value emerging across three visual domains: abstract images, scenes, and faces.

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Major depressive disorder (MDD) and cardiovascular disease (CVD) are often comorbid, resulting in excess morbidity and mortality. Using genomic data, this study elucidates biological mechanisms, key risk factors, and causal pathways underlying their comorbidity. We show that CVDs share a large proportion of their genetic risk factors with MDD.

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Background: An important contributor to the decreased life expectancy of individuals with schizophrenia is sudden cardiac death. While arrhythmic disorders play an important role in this, the nature of the relation between schizophrenia and arrhythmia is not fully understood.

Methods: We leveraged summary-level data of large-scale genome-wide association studies of schizophrenia (53,386 cases 77,258 controls), arrhythmic disorders (atrial fibrillation, 55,114 cases 482,295 controls; Brugada syndrome, 2,820 cases 10,001 controls) and electrocardiogram traits (heart rate (variability), PR interval, QT interval, JT interval, and QRS duration, n=46,952-293,051).

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Scientific and engineering capabilities in hydrocarbon supply chains developed over decades in international oil and gas companies (IOCs) uniquely position these companies to drive rapid scale-up and transition to a net-zero emission economy. Flexible large-scale production of energy carriers such as hydrogen, ammonia, methanol, and other synthetic fuels produced with low- or zero-emission renewable power, nuclear energy, or hydrogen derived from natural gas with carbon capture and storage will enable long-distance transport and permanent storage options for clean energy. Use of energy carriers can overcome the inherent constraints of a fully electrified energy system by providing the energy and power densities, as well as transport and storage capacity, required to achieve energy supply and security in a net-zero emission economy, and over time allow optimization to the lowest cost for a consumer anywhere on the globe.

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There is a pressing need to rapidly, and massively, scale up negative carbon strategies such as carbon capture and storage (CCS). At the same time, large-scale CCS can enable ramp-up of large-scale hydrogen production, a key component of decarbonized energy systems. We argue here that the safest, and most practical strategy for dramatically increasing CO storage in the subsurface is to focus on regions where there are multiple partially depleted oil and gas reservoirs.

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. Deep brain stimulation is a treatment option for patients with refractory obsessive-compulsive disorder. A new generation of stimulators hold promise for closed loop stimulation, with adaptive stimulation in response to biologic signals.

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Objective: Deep brain stimulation (DBS) is an effective treatment for refractory obsessive-compulsive disorder (OCD) yet neural markers of optimized stimulation parameters are largely unknown. We aimed to describe (sub-)cortical electrophysiological responses to acute DBS at various voltages in OCD.

Methods: We explored how DBS doses between 3-5 V delivered to the ventral anterior limb of the internal capsule of five OCD patients affected electroencephalograms and intracranial local field potentials (LFPs).

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Introduction: People with misophonia experience strong negative emotional responses to sounds and associated stimuli-mostly human produced-to an extent that it may cause impairment in social functioning. The exact nature of the disorder remains a matter of ongoing research and debate. Here, we investigated the genetic etiology of misophonia to understand contributing genetic factors and shed light on individual differences in characteristics that are related to the disorder.

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Hoarding Disorder (HD) is a mental disorder characterized by persistent difficulties discarding or parting with possessions, often resulting in cluttered living spaces, distress, and impairment. Its etiology is largely unknown, but twin studies suggest that it is moderately heritable. In this study, we pooled phenotypic and genomic data from seven international cohorts (N = 27,537 individuals) and conducted a genome wide association study (GWAS) meta-analysis of parent- or self-reported hoarding symptoms (HS).

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There is broad interest in discovering quantifiable physiological biomarkers for psychiatric disorders to aid diagnostic assessment. However, finding biomarkers for autism spectrum disorder (ASD) has proven particularly difficult, partly due to high heterogeneity. Here, we recorded five minutes eyes-closed rest electroencephalography (EEG) from 186 adults (51% with ASD and 49% without ASD) and investigated the potential of EEG biomarkers to classify ASD using three conventional machine learning models with two-layer cross-validation.

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It has been known for a long time that individuals diagnosed with autism spectrum disorder perceive the world differently. In this study, we investigated how people with or without autism perceive visual and auditory information. We know that an auditory and a visual stimulus do not have to be perfectly synchronous for us to perceive them as synchronous: first, when the two are within a certain time window (temporal binding window), the brain will tell us that they are synchronous.

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Background: Mental health and cognitive achievement are partly heritable, highly polygenic, and associated with brain variations in structure and function. However, the underlying neural mechanisms remain unclear.

Methods: We investigated the association between genetic predispositions to various mental health and cognitive traits and a large set of structural and functional brain measures from the UK Biobank (N = 36,799).

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  • - This study investigates the cell adhesion molecule 2 (CADM2) gene, which is linked to various behavioral traits, aiming to understand its influence across different psycho-behavioral characteristics.
  • - By analyzing data from the UK Biobank involving up to 453,349 participants, researchers found significant associations between CADM2 and 50 different traits, including cognitive abilities and risk-taking behaviors.
  • - The study highlights that CADM2's expression in brain, lung, mammary, and adipose tissues is significantly related to these traits, suggesting a shared biological basis among them.
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This study aims to disentangle the contribution of genetic liability, educational attainment (EA), and their overlap and interaction in lifetime smoking. We conducted genome-wide association studies (GWASs) in UK Biobank (N = 394,718) to (i) capture variants for lifetime smoking, (ii) variants for EA, and (iii) variants that contribute to lifetime smoking independently from EA ('smoking-without-EA'). Based on the GWASs, three polygenic scores (PGSs) were created for individuals from the Netherlands Twin Register (NTR, N = 17,805) and the Netherlands Mental Health Survey and Incidence Study-2 (NEMESIS-2, N = 3090).

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Objectives: This cluster-randomized controlled community trial aimed to assess the efficacy and costs of fluoride varnish (FV) application for caries prevention in a high-risk population in South Africa.

Methods: 513 children aged 4-8 years from two schools in a township in South Africa were randomly allocated by class to the FV or Control (CO) groups. In addition to supervised toothbrushing with fluoridated toothpaste in both groups, FV was applied in 3-month intervals by trained local non-professional assistants.

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