Publications by authors named "Jan Haavik"

Background: Attention-deficit/hyperactivity disorder (ADHD) is a common neuro-developmental disorder that often persists into adulthood. Moreover, it is frequently accompanied by bipolar disorder (BD) as well as borderline personality disorder (BPD). It is unclear whether these disorders share underlying pathomechanisms, given that all three are characterized by alterations in affective states, either long or short-term.

View Article and Find Full Text PDF
Article Synopsis
  • There is considerable evidence suggesting that changes in dopamine signaling are linked to neuropsychiatric disorders like ADHD and other behavioral traits over the past 40 years.
  • The review focuses on the key elements of dopamine signaling in the brain, particularly looking at enzymes, transporters, and receptors involved in this process, with a specific focus on areas related to ADHD.
  • While dopamine is implicated in ADHD, there's limited support for the notion that a general lack of dopamine is the primary issue; future research should explore how dopamine interacts with other neurotransmitters and its role during brain development in different clinical subgroups.*
View Article and Find Full Text PDF

The observation that the risk of developing Alzheimer's disease is reduced in individuals with high premorbid cognitive functioning, higher educational attainment, and occupational status has led to the 'cognitive reserve' hypothesis. This hypothesis suggests that individuals with greater cognitive reserve can tolerate a more significant burden of neuropathological changes before the onset of cognitive decline. The underpinnings of cognitive reserve remain poorly understood, although a shared genetic basis between measures of cognitive reserve and Alzheimer's disease has been suggested.

View Article and Find Full Text PDF

The aromatic amino acid hydroxylases (AAAHs) phenylalanine hydroxylase, tyrosine hydroxylase, and tryptophan hydroxylases 1 and 2 are structurally related enzymes that contain an active site iron atom and depend on tetrahydrobiopterin (BH) as cosubstrate. Due to their important roles in synthesis of serotonin, dopamine, noradrenaline, and adrenaline and their involvement in cardiovascular, neurological, and endocrine disorders, AAAHs have been targeted by substrate analogs, iron chelators, and allosteric ligands. Phenylalanine hydroxylase is also off-target of the histone deacetylase (HDAC) inhibitor panobinostat.

View Article and Find Full Text PDF
Article Synopsis
  • Researchers analyzed genetic data from nearly 130,000 cancer patients and over 730,000 healthy controls to identify variants linked to cancer risk across 22 cancer types.
  • Four high-risk genes were found: BIK (prostate cancer), ATG12 (colorectal cancer), TG (thyroid cancer), and CMTR2 (lung cancer and melanoma).
  • Additionally, two genes, AURKB (general cancer risk) and PPP1R15A (breast cancer), were associated with decreased cancer risk, indicating potential pathways for cancer prevention strategies.
View Article and Find Full Text PDF

Alzheimer's disease (AD) is a multifactorial disease with both genetic and environmental factors contributing to its etiology. Previous evidence has implicated disturbed insulin signaling as a key mechanism that plays a role in both neurodegenerative diseases such as AD and comorbid somatic diseases such as diabetes mellitus type 2 (DM2). In this study, we analysed available genome-wide association studies (GWASs) of AD and somatic insulin-related diseases and conditions (SID), i.

View Article and Find Full Text PDF

Current genetic research on obsessive-compulsive disorder (OCD) supports contributions to risk specifically from common single nucleotide variants (SNVs), along with rare coding SNVs and small insertion-deletions (indels). The contribution to OCD risk from rare copy number variants (CNVs), however, has not been formally assessed at a similar scale. Here we describe an analysis of rare CNVs called from genotype array data in 2248 deeply phenotyped OCD cases and 3608 unaffected controls from Sweden and Norway.

View Article and Find Full Text PDF
Article Synopsis
  • The study examines the impact of maternal organic food consumption during pregnancy on the risk of ADHD and autism symptoms in children at age 8, using data from a large Norwegian cohort study.
  • It evaluates dietary habits through a food frequency questionnaire and assesses children's behavior through standardized symptom scores, controlling for factors like maternal mental health.
  • The findings indicate minimal association between organic food intake and ADHD or autism symptoms, suggesting that increased consumption has negligible effects on these developmental disorders.
View Article and Find Full Text PDF

Age at menopause (AOM) has a substantial impact on fertility and disease risk. While many loci with variants that associate with AOM have been identified through genome-wide association studies (GWAS) under an additive model, other genetic models are rarely considered. Here through GWAS meta-analysis under the recessive model of 174,329 postmenopausal women from Iceland, Denmark, the United Kingdom (UK; UK Biobank) and Norway, we study low-frequency variants with a large effect on AOM.

View Article and Find Full Text PDF

Background: Adolescents with attention-deficit / hyperactivity disorder (ADHD) have an increased risk of self-harm. The risk of self-harm among adolescents who display an elevated level of ADHD symptoms, but without a formal diagnosis, is not well-studied and understood.

Objective: To investigate the relationship between self-reported symptoms of ADHD and self-harm in a population-based sample of adolescents.

View Article and Find Full Text PDF

Deficits in memory performance have been linked to a wide range of neurological and neuropsychiatric conditions. While many studies have assessed the memory impacts of individual conditions, this study considers a broader perspective by evaluating how memory recall is differentially associated with nine common neuropsychiatric conditions using data drawn from 55 international studies, aggregating 15,883 unique participants aged 15-90. The effects of dementia, mild cognitive impairment, Parkinson's disease, traumatic brain injury, stroke, depression, attention-deficit/hyperactivity disorder (ADHD), schizophrenia, and bipolar disorder on immediate, short-, and long-delay verbal learning and memory (VLM) scores were estimated relative to matched healthy individuals.

View Article and Find Full Text PDF

Background: The inclusion of biomarkers could improve diagnostic accuracy of attention-deficit/hyperactivity disorder (ADHD). One potential biomarker is the ADHD polygenic score (PGS), a measure of genetic liability for ADHD. This study aimed to investigate if the ADHD PGS can provide additional information alongside ADHD rating scales and examination of family history of ADHD to distinguish between ADHD cases and controls.

View Article and Find Full Text PDF
Article Synopsis
  • 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.
View Article and Find Full Text PDF
Article Synopsis
  • Essential tremor (ET) is a common neurological disorder, but its biological causes are still not well understood.
  • A comprehensive study involving over 16,000 ET cases identified 12 genetic variants linked to the disorder, suggesting several potential causal genes, including CA3 and CPLX1.
  • The findings also reveal associations between ET and other conditions like Parkinson's disease, depression, and anxiety, which could lead to new therapeutic targets for treatment.
View Article and Find Full Text PDF
Article Synopsis
  • The study investigates the relationship between insulin resistance (IR)-related conditions, like type 2 diabetes and obesity, and neuropsychiatric disorders, highlighting the complexity of their co-occurrence as a public health issue.
  • Researchers used genome-wide association studies (GWASs) with a large sample size to analyze genetic correlations between these conditions, identifying various genomic regions with significant local correlations.
  • The findings suggest that these correlated regions are linked to important biological pathways, indicating potential targets for treatments and a need for an integrated approach to understanding and managing these interconnected health problems.
View Article and Find Full Text PDF
Article Synopsis
  • Four GWAS studies on obsessive-compulsive disorder (OCD) have been conducted, showing a SNP-heritability of 28% but revealing only one significant SNP so far.
  • A new meta-analysis significantly increased the sample size to analyze 37,015 OCD cases against 948,616 controls, identifying 15 independent genome-wide significant loci, 14 of which were novel.
  • The research highlighted genetic correlations between OCD and various psychiatric disorders, while also mapping the genetic basis and biological pathways associated with OCD susceptibility.
View Article and Find Full Text PDF
Article Synopsis
  • - Current research on OCD suggests that rare copy number variants (CNVs) may play a significant role in increasing risk, particularly large CNVs that overlap with protein-coding regions.
  • - An analysis involving over 2,200 OCD cases and 3,600 controls showed that OCD cases had a higher incidence of these large CNVs, especially deletions affecting crucial genes.
  • - Findings indicated that certain genetic variations were linked with comorbid autism in OCD patients and poorer treatment response, highlighting the need for further investigation into rare genetic factors in OCD.
View Article and Find Full Text PDF
Article Synopsis
  • Maternal diet quality, particularly fiber intake during pregnancy, may play a significant role in reducing ADHD symptoms in children.
  • A large study involving over 21,000 families found that higher maternal fiber intake was linked to lower ADHD symptom levels in offspring at ages 3, 5, and 8.
  • The research suggests that low fiber intake during pregnancy could increase the risk of ADHD symptoms in children, regardless of genetic and environmental factors.
View Article and Find Full Text PDF

Background: Although often intended for long-term treatment, discontinuation of medication for ADHD is common. However, cross-national estimates of discontinuation are missing due to the absence of standardised measures. The aim of this study was to determine the rate of ADHD treatment discontinuation across the lifespan and to describe similarities and differences across countries to guide clinical practice.

View Article and Find Full Text PDF

Background: Noninvasive neurostimulation treatments are increasingly being used to treat major depression, which is a common cause of disability worldwide. While electroconvulsive therapy (ECT) and transcranial magnetic stimulation (TMS) are both effective in treating depressive episodes, their mechanisms of action are, however, not completely understood. ECT is given under general anesthesia, where an electrical pulse is administered through electrodes placed on the patient's head to trigger a seizure.

View Article and Find Full Text PDF
Article Synopsis
  • Migraine is a complicated neurovascular condition with varying symptoms, traditionally studied as a single type in genome-wide association studies (GWAS), but this research focuses on two main subtypes: migraine with aura (MA) and migraine without aura (MO).
  • The study analyzed large datasets from six European populations, identifying four new gene variants associated with MA and classifying 13 variants for MO, highlighting a significant frameshift variant in PRRT2 linked to MA and epilepsy.
  • Additionally, testing on rare variants showed that loss-of-function mutations in SCN11A provide strong protection against migraine, while another variant affecting KCNK5 offers large protection against both migraine and brain aneurysms, suggesting new avenues for treatment.
View Article and Find Full Text PDF

Phenylketonuria (PKU) is an autosomal recessive metabolic disorder caused by mutations in the phenylalanine hydroxylase (PAH) gene, resulting in phenylalanine accumulation and impaired tyrosine production. In Tyrosinemia type 1 (TYRSN1) mutations affect fumarylacetoacetate hydrolase, leading to accumulation of toxic intermediates of tyrosine catabolism. Treatment of TYRSN1 with nitisinone results in extreme tissue levels of tyrosine.

View Article and Find Full Text PDF

Neurodevelopmental disorders (NDDs) impact multiple aspects of an individual's functioning, including social interactions, communication, and behaviors. The underlying biological mechanisms of NDDs are not yet fully understood, and pharmacological treatments have been limited in their effectiveness, in part due to the complex nature of these disorders and the heterogeneity of symptoms across individuals. Identifying genetic loci associated with NDDs can help in understanding biological mechanisms and potentially lead to the development of new treatments.

View Article and Find Full Text PDF
Article Synopsis
  • Carriers of specific genetic variants (1q21.1 distal and 15q11.2 BP1-BP2) show both regional and global brain structure differences compared to noncarriers, but analyzing these differences can be complicated.
  • The study used MRI data from various groups (carriers and noncarriers) to assess how regional brain characteristics diverge from overall brain structure differences.
  • Findings revealed that certain brain regions in carriers exhibited distinct patterns of cortical surface area and thickness that deviated from the global average, suggesting more complex effects of these genetic variants on brain development.
View Article and Find Full Text PDF