Publications by authors named "Alexander Viktorin"
Background: The contribution of genetic and environmental factors to susceptibility to nervous system tumors remains unclear. We performed a quantitative genetic study using a sibling design to estimate the heritability of nervous system tumors, as well as the proportion of the risk of these tumors, which is attributable to environmental factors.
Methods: We conducted a population-based cohort study using Swedish National Register data.
Article Synopsis
- The study focuses on postpartum depression (PPD), a hereditary form of major depressive disorder, using genome-wide association studies (GWAS) to explore its genetic basis across various populations.
- It analyzed data from 18,770 PPD cases and 58,461 controls, finding no single-nucleotide polymorphisms (SNPs) that met genome-wide significance, though it highlighted significant genetic correlations with other mental health conditions.
- The findings suggest that PPD is polygenic and heritable, potentially involving unique genetic factors despite its close relationship with major depressive disorder and implicate specific brain neurons associated with its treatment.
Background: Attention deficit hyperactivity disorder (ADHD) is associated with an increased risk of poor mental health. However, the understanding of ADHD-related burden and impairments in women during the postpartum period is limited. The aim with the present study was to examine the risk of depression and anxiety disorders during the postpartum period among women with and without an ADHD diagnosis.
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- Immunoglobulin A (IgA) plays a crucial role in immune response to food and pathogens and is linked to various conditions like celiac disease and inflammatory bowel disease.
- A genome-wide association study examined blood IgA levels in over 41,000 people, identifying 20 key genetic loci that affect IgA levels, including novel genes.
- Findings suggest genetic factors influencing IgA can impact diseases such as IgA nephropathy and type 2 diabetes, with African ancestry showing higher IgA levels and more IgA-increasing genetic variants.
Antidepressant medication is used extensively to treat bipolar depression despite uncertain efficacy. The cytochrome P450 (CYP) 2C19 enzyme metabolize several antidepressants, and polymorphisms in the corresponding gene CYP2C19 influence plasma concentration and hence treatment outcomes in major depressive disorder. Here, we investigate if CYP2C19 polymorphisms are associated with antidepressant treatment patterns and the risk of mania when antidepressants are used in bipolar disorder.
View Article and Find Full Text PDFBackground: Sex differences in incidence and/or presentation of schizophrenia (SCZ), major depressive disorder (MDD), and bipolar disorder (BIP) are pervasive. Previous evidence for shared genetic risk and sex differences in brain abnormalities across disorders suggest possible shared sex-dependent genetic risk.
Methods: We conducted the largest to date genome-wide genotype-by-sex (G×S) interaction of risk for these disorders using 85,735 cases (33,403 SCZ, 19,924 BIP, and 32,408 MDD) and 109,946 controls from the PGC (Psychiatric Genomics Consortium) and iPSYCH.
Background: Accurate estimation of daily dosage and duration of medication use is essential to pharmacoepidemiological studies using electronic healthcare databases. However, such information is not directly available in many prescription databases, including the Swedish Prescribed Drug Register.
Objective: To develop and validate an algorithm for predicting prescribed daily dosage and treatment duration from free-text prescriptions, and apply the algorithm to ADHD medication prescriptions.
Background: Increasing numbers of reproductive-aged women are using attention-deficit/hyperactivity disorder (ADHD) medications. Findings from studies exploring the safety of these medications during pregnancy are mixed, and it is unclear whether associations reflect causal effects or could be partially or fully explained by other factors that differ between exposed and unexposed offspring.
Objectives: The aim of this systematic review was to evaluate the adverse pregnancy-related and offspring outcomes associated with exposure to prescribed ADHD medication during pregnancy with a focus on how studies to date have handled the influence of confounding.
Minimal phenotyping refers to the reliance on the use of a small number of self-reported items for disease case identification, increasingly used in genome-wide association studies (GWAS). Here we report differences in genetic architecture between depression defined by minimal phenotyping and strictly defined major depressive disorder (MDD): the former has a lower genotype-derived heritability that cannot be explained by inclusion of milder cases and a higher proportion of the genome contributing to this shared genetic liability with other conditions than for strictly defined MDD. GWAS based on minimal phenotyping definitions preferentially identifies loci that are not specific to MDD, and, although it generates highly predictive polygenic risk scores, the predictive power can be explained entirely by large sample sizes rather than by specificity for MDD.
View Article and Find Full Text PDFBackground: There is a clinical concern that prescribing methylphenidate, the most common pharmacological treatment for attention-deficit hyperactivity disorder (ADHD), might increase the risk of psychotic events, particularly in young people with a history of psychosis. We aimed to determine whether the risk of psychotic events increases immediately after initiation of methylphenidate treatment or, in the longer term, 1 year after treatment initiation in adolescents and young adults with and without a previously diagnosed psychotic disorder.
Methods: In this cohort study, we used population-based observational data from the Swedish Prescribed Drug Register, the National Patient Register, and the Total Population Register, three population-based registers containing data on all individuals in Sweden, to attain data on sex, birth, death, migration, medication use, and psychotic events for all eligible participants.
Importance: Prenatal exposure to certain medications has been hypothesized to influence the risk of autism spectrum disorders (ASD). However, the underlying effects on the neurotransmitter systems have not been comprehensively assessed.
Objective: To investigate the association of early-life interference with different neurotransmitter systems by prenatal medication exposure on the risk of ASD in offspring.
Article Synopsis
- A study investigated the genetic overlap between 25 brain disorders using data from over 1.2 million individuals, finding that psychiatric disorders share more genetic risk compared to neurological disorders, which seem more distinct.
- The research identified significant relationships between these disorders and various cognitive measures, suggesting shared underlying traits.
- Simulations were conducted to understand how factors like sample size and diagnosis accuracy influence genetic correlations, emphasizing the role of common genetic variations in the risk of brain disorders.
Background: Concerns about teratogenicity and maternal and offspring complications restrict the use of lithium during pregnancy for the treatment of mood disorders. We aimed to investigate the association between in-utero lithium exposure and risk of pregnancy complications, delivery outcomes, neonatal morbidity, and congenital malformations.
Methods: In this meta-analysis, primary data from pregnant women and their children from six international cohorts based in the community (Denmark, Sweden, and Ontario, Canada) and in clinics (the Netherlands, UK, and USA) were analysed.
Objective: To examine the association between paternal antidepressant use at conception and offspring preterm birth, malformations, autism spectrum disorder, and intellectual disability.
Design: Observational prospective cohort study with regression methods, and negative control comparison.
Setting: Sweden nationwide.
Importance: The association of maternal use of folic acid and multivitamin supplements before and during pregnancy with the risk of autism spectrum disorder (ASD) in offspring is unclear.
Objective: To examine the associations between the use of maternal folic acid and multivitamin supplements before and during pregnancy and the risk of ASD in offspring.
Design, Setting, And Participants: A case-control cohort study of 45 300 Israeli children born between January 1, 2003, and December 31, 2007, were followed up from birth to January 26, 2015, for the risk of ASD.
Background: Previous research has found that maternal stress during pregnancy increases the risk of offspring asthma. However, whether this association is consistent with a causal interpretation has never been tested. The objective is to determine whether there is a critical exposure period for maternal depression or anxiety on offspring asthma or whether cumulative exposure is most important, and to investigate evidence of confounding.
View Article and Find Full Text PDFImportance: Maternal antidepressant medication use during pregnancy has previously been associated with adverse outcomes in offspring, but to our knowledge, the association with intellectual disability (ID) has not been investigated.
Objectives: To examine the association of maternal antidepressant medication use during pregnancy with ID in offspring and investigate the importance of parental mental illness for such an association.
Design, Setting, And Participants: A population-based cohort study of 179 007 children born from January 1, 2006, through December 31, 2007, with complete parental information from national registers who were followed up from birth throughout 2014.
Objective: The authors sought to determine the risk of treatment-emergent mania associated with methylphenidate, used in monotherapy or with a concomitant mood-stabilizing medication, in patients with bipolar disorder.
Method: Using linked Swedish national registries, the authors identified 2,307 adults with bipolar disorder who initiated therapy with methylphenidate between 2006 and 2014. The cohort was divided into two groups: those with and those without concomitant mood-stabilizing treatment.
Genome-wide Association for Major Depression Through Age at Onset Stratification: Major Depressive Disorder Working Group of the Psychiatric Genomics Consortium.
Biol Psychiatry
February 2017
Article Synopsis
- Major depressive disorder (MDD) is a complex mood disorder with genetic factors, but previous studies failed to find consistent genetic variants, prompting research into how age at onset affects genetic risk.
- The study involved analyzing cases based on age of onset through genome-wide association studies, finding one significant genetic variant associated with adult-onset MDD, as well as evidence of differing genetic profiles between earlier and adult-onset MDD.
- Results indicate that earlier-onset MDD shares more genetic similarities with schizophrenia and bipolar disorder, highlighting the importance of considering age at onset in genetic research of MDD.