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Publications (410)
Road traffic injuries are the leading cause of death for young adults, and parents play a major role in shaping their traffic behaviour. Higher impulsivity (predictor of higher traffic risk) has been shown to be dependent on family relations and the serotonin transporter gene promoter polymorphism (5-HTTLPR). The specific mechanisms for the inherit...
Introduction:
The role of catechol-O-methyltransferase (COMT) in catecholamine neurotransmitter metabolism has led to the investigation of variants of the corresponding gene in the etiology of different psychiatric disorders, but the results are inconclusive.
Methods:
We have examined the relationship between COMT Val158Met single nucleotide pol...
Modification of mRNA by methylation is involved in post-transcriptional regulation of gene expression by affecting the splicing, transport, stability and translation of mRNA. Methylation of adenosine at N6 (m6A) is the most common and most important cellular modification occurring in the mRNA of eukaryotes. Evidence that m6A mRNA methylation is inv...
Congenital absence of monoamine oxidase A (MAO-A) activity predisposes to antisocial impulsive behaviour, and the MAOA uVNTR low-expressing genotype (MAOA-L) together with childhood maltreatment is associated with similar phenotypes in males. A possible explanation of how family environment may lead to such behaviour involves DNA methylation. We ha...
Objective:
Neuropeptide Y (NPY) is a powerful regulator of anxious states, including social anxiety, but evidence from human genetic studies is limited. Associations of common gene variants with behaviour have been described as subject to birth cohort effects especially if the behaviour is socially motivated. This study aimed to examine the associ...
Background
Human aggression is influenced by an interplay between genetic predisposition and experience across the life span. This interaction is thought to occur through epigenetic mechanisms, inducing differential gene expression, thereby moderating neuronal cell and circuit function, and thus shaping aggressive behaviour.
Methods
Genome‐wide DN...
Sex differences are apparent in numerous behavioural characteristics. In order to compare and characterize male and female variability of exploratory behaviour, 365 male and 401 female rats were assessed in a task where a bimodal response distribution had previously been established in males. Female rats had significantly higher exploratory activit...
Lower platelet monoamine oxidase (MAO) activity has been associated with problem behaviors, including criminal behavior, but not all studies agree. We have examined platelet MAO activity and antisocial behavior involving police contact in a longitudinal birth cohort study. The sample included both birth cohorts (original n = 1238) of the Estonian C...
The research field of psychiatric animal modeling has ever been striving toward better validation of tests and models, and this includes attempts to standardize them. Nevertheless, animal models of mood and anxiety are used in many modifications. This is the outcome of a variety of objective reasons, ranging from the sensitivity of behavior to a la...
Objectives
Risk taking behaviour, including in traffic, is related to impulsivity and aggressiveness, and so is unhealthy lifestyle. The serotonin transporter gene promoter polymorphism (5-HTTLPR) has been associated with impulsivity, aggression, alcohol use, speed limit exceeding and traffic accidents. The aim of this study was to examine whether...
Introduction:
The interaction of environmental and inherited factors determines how a young person becomes involved in problem behaviours such as drinking alcohol. We have investigated whether the association of family relationships with early experience with alcohol is related to variation in the serotonin transporter gene promoter region (5-HTTL...
Background
Impulsivity is a psychiatric vulnerability factor strongly associated with substance abuse but also with unhealthy diet. Whether these associations extend to specific nutrients is largely unknown. Therefore, we investigated the longitudinal association between diet, cardiorespiratory fitness, and two impulsivity dimensions in a represent...
ADHD is a major burden in adulthood, where co-morbid conditions such as depression, substance use disorder and obesity often dominate the clinical picture. ADHD has substantial shared heritability with other mental disorders, contributing to comorbidity. However, environmental risk factors exist but their interaction with genetic makeup, especially...
Background:
Road traffic injuries are a leading cause of death for young adults, and young drivers with higher expression of symptoms of attention deficit-hyperactivity disorder (ADHD) could pose an even greater risk in traffic. Dopaminergic dysfunction has been found to occur in ADHD, with the dopamine transporter (DAT) gene VNTR polymorphism (DA...
Rationale
Platelet monoamine oxidase (MAO) activity, a marker of central serotonergic capacity, has been associated with a variety of problem behaviours. However, studies on platelet MAO activity and addictive drugs have not consistently linked MAO activity with addiction or reported to predict illicit substance use initiation or frequency.
Object...
Objective
Cholecystokinin is a neuropeptide with a role in the neurobiology of adaptive behaviour that is implicated in anxiety disorders, while the underlying mechanisms currently remain insufficiently explained. The rs2941026 variation in the cholecystokinin B receptor gene has previously been associated with trait anxiety. Our aim was to investi...
Autobiographical memory is a cognitive function strongly related to emotional processing as autobiographical memory often includes emotional content. The COMT gene Val 158 Met polymorphism is associated with both cognitive and emotional processing. COMT gene Val 158 Met polymorphism effects on the emotional content and quality of Estonian schoolchi...
Background
Numbers of psychiatric beds (general, forensic, and residential) and prison populations have been considered to be indicators of institutionalisation of people with mental illnesses. The present study aimed to assess changes of those indicators across Central Eastern Europe and Central Asia (CEECA) over the last three decades to capture...
Purpose
Research on first-episode psychosis early intervention has shown significant positive effects on psychopathological, functional and quality-of-life outcome measures. The effects reported have however been short-term and there is still only limited information about the long-term effects. This article will present the short-term results of a...
Neuropeptide S (NPS) is a peptide neurotransmitter that in animal studies promotes wakefulness and arousal with simultaneous anxiety reduction, in some inconsistency with results in humans. We examined the effect of NPS on rat ultrasonic vocalizations (USV) as an index of affective state and on behaviour in novel environments in rats with persisten...
Fifty-kHz ultrasonic vocalizations (USVs) in response to an imitation of rough-and-tumble play (‘tickling’) have been associated with positive affective states and rewarding experience in the rat. This USV response can be used as a measure of inter-individual differences in positive affect. We have previously shown that rats with persistently low p...
The exact mechanism how serotonergic and dopaminergic systems relate to one another in working memory (WM) updating is unknown. Platelet monoamine oxidase (MAO) has been used as a marker for central serotonergic capacity, and catechol-O-methyltransferase (COMT) as a marker for central dopaminergic capacity. This study aimed to describe the interact...
Objective
Neuropeptide Y affects several physiological functions, notably appetite regulation. We analysed the association between four single nucleotide polymorphisms (SNP) in the NPY gene (rs5574, rs16147, rs16139, rs17149106) and measures of obesity, dietary intake, physical activity, blood pressure, glucose and lipid metabolism from adolescence...
Previous research has shown that dopaminergic dysregulation and early life stress interact to impact on aspects of impulse control. This study aimed to explore the potentially interactive effects of the rs6277 polymorphism of the dopamine D2 receptor gene (DRD2), stressful or supportive environment and sex on behavioural and self-reported measures...
Attention‐deficit/hyperactivity disorder (ADHD) is a prevalent disorder in childhood and identifying risk factors associated with developing ADHD during childhood and adolescence is relevant from a clinical and epidemiological point of view. This work examines (1) whether overweight/obesity and low cardiorespiratory fitness (CRF) are associated wit...
People prone to mood disorders and anxiety typically show increased sensitivity to task‑irrelevant stimulation signifying threat. Better knowledge about the brain mechanisms mediating this sensitivity as well as about individual inherited differences in how these mechanisms function is a precondition for developing improved vulnerability screening,...
Background: Recently, RBFOX1, a gene encoding an RNA binding protein, has consistently been associated with aggressive and antisocial behavior. Several loci in the gene have been nominally associated with aggression in genome-wide association studies, the risk alleles being more frequent in the general population. We have hence examined the associa...
Attention distractibility in a low load visual search experiment with a rare irrelevant distractor could be an objective continuous measure in adulthood that correlates well with the symptoms of attention deficit throughout lifespan. This was studied using a birth cohort representative sample in a longitudinal study. The expected correlations were...
Individual differences in updating emotional facial expressions in working memory are not fully understood. Here we focused on the effects of high trait anxiety and high depressiveness in men and women on updating schematic emotional facial expressions (sad, angry, scheming, happy, neutral). A population representative sample of young adults was di...
Limbic system associated membrane protein (Lsamp) is a neural adhesion protein which has been recently found to be differentially expressed between serotonergic neuron subtypes. We have previously shown elevated serotonin (5-HT) turnover rate in Lsamp-deficient mice. The purpose of the current study was to elucidate the role of Lsamp in serotonergi...
Orexins/hypocretins maintain wakefulness, increase appetite and participate in the coordination of stress response. We have recently provided evidence on the role of orexins in aggression, showing the association of the HCRTR1 genotype
(rs2271933 G>A; leading to amino acid substitution Ile408Val) with aggressiveness or breach of law in four indepen...
Adult antisocial behaviour has precursors in childhood and adolescence and is most successfully treated using childhood interventions. The aim of this study was to identify and validate robust risk factors for antisocial behaviour involving police contact in a data-driven, hypothesis-free framework. Antisocial behavior involving police contact (20/...
Objective
One factor potentially contributing to obesity is reward sensitivity. We investigated the association between reward sensitivity and measures of obesity from 9 to 33 years of age, paying attention to the inner structure of reward sensitivity.
Methods
The sample included both birth cohorts (originally n = 1176) of the Estonian Children Pe...
Objective
Reward sensitivity is an increasingly used construct in psychiatry yet its possible inner structure and relationship with other affective variables is not well known.
Methods
A reward sensitivity measurement scale was constructed on the basis of large item pool collected from birth cohort representative samples (the Estonian Children Per...
Background:
Individual differences in behavioural traits influence susceptibility to addictive disorders. Drug addiction involves changes in gene expression, proposed to occur via DNA methylation (DNAm).
Aims:
To investigate DNAm changes in reward-related brain structures (nucleus accumbens (NAc), lateral habenula (LHb)) in response to cocaine e...
Background:
Levels of physical activity and variation in physical activity and sedentary time by place and person in European children and adolescents are largely unknown. The objective of the study was to assess the variations in objectively measured physical activity and sedentary time in children and adolescents across Europe.
Methods:
Six da...
Ketamine is a noncompetitive antagonist of glutamatergic N-methyl-d-aspartate receptors. Its acute effects on healthy volunteers and schizophrenia patients mimic some acute psychotic, but also cognitive and negative symptoms of schizophrenia, and subchronic treatment with ketamine has been used as an animal model of psychotic disorders. Glutamaterg...
Background and aims
FTO variants are among genetic variants frequently associated with obesity. We analyzed the association between FTO rs1421085 polymorphism and obesity, dietary intake, cardiorespiratory fitness, physical activity and socioeconomic status (SES) from age 9 to 25 years.
Methods and results
The sample included both birth cohorts (o...
Background: Numbers of psychiatric beds (general, forensic, and residential) and prison populations have been considered to be indicators of institutionalization. The present study aimed to assess changes of those indicators across Central Eastern Europe and Central Asia (CEECA) over the last three decades to capture how care has developed during t...
Purpose: While the pivotal role of pharmacotherapy in psychiatry is universal, significant regional differences exist in drug use patterns. Herewith we compare the use of ATC psychotropic drugs (N05, psycholeptics and N06A, antidepressants) in 2010–2015 in the three Baltic Countries with reference to the Nordic Countries.
Methods: Data were obtaine...
Major psychiatric disorders including alcohol use disorder are considered multigenic and the smallness of effects of individual genes may be attributed to either complex biological mechanisms or geneenvironment interactions. The latter explanation is highlighted by the relatively fast changes in secular trends and in cohort effects on alcohol use d...
Objective:
Severe behavioural issues such as impulsive action and suicide have since long been associated with low levels of cholesterol. While it is known that cholesterol plays a role in neural development and hence low levels of serum lipids could have long-term effects on behaviour, there are no longitudinal studies showing association of seru...
Background and aims
Higher cardiorespiratory fitness (CRF) has been suggested to reduce the risk of metabolic syndrome (MetS). We aimed to longitudinally examine the changes of CRF on MetS and its risk factors from adolescence to adulthood.
Methods and results
At the age of 15 years, 1076 subjects were recruited from 2 cohorts. CRF was measured on...
Background:
The development of obesity has a large genetic component, and the gene encoding the transcription factor 2 beta (TFAP2B) has been identified as one of the responsible factors. We investigated the effect of TFAP2B intron 2 variable number tandem repeat (VNTR) genotype on obesity, insulin resistance and dietary intake from 15 to 33 years...
Nitric oxide signalling has been implicated in impulsive and aggressive traits and behaviours in both animals and humans. In the present study, we investigated the effects of a functional variable number of tandem repeats (VNTR) polymorphism in exon 1f (ex1f) of the nitric oxide synthase 1 (NOS1) gene (NOS1 ex1f-VNTR) and stressful life events on a...
Animal models of depression are certainly needed but the question in the title has been raised owing to the controversies in the interpretation of the readout in a number of tests, to the perceived lack of progress in the development of novel treatments and to the expressed doubts in whether animal models can offer anything to make a true breakthro...
Background:
Individual vulnerability to stress manifests in the interaction of innate properties and environment. There is a growing interest in the individual variability in vulnerability to stress and how it contributes to the development of psychiatric disorders. Intake of palatable substances is often measured in animal models. We have previou...
Objective
Road traffic injuries are the leading cause of death among young people. Recognition of the contribution of impulsive behaviour may help novice drivers to behave more safely. Previously a brief intervention focusing on impulsive traffic behaviour conducted by psychologists in driving schools had been effective. The aim of this study was a...
Melanocortin 4 receptor (MC4R) plays a key role in regulation of appetite activated by its main ligand α-melanocyte-stimulating hormone (α-MSH) in both central and peripheral targets. α-MSH also binds to circulating immunoglobulins (Igs) but the functional significance of such immune complexes (ICs) in MC4R signaling in normal and pathological cond...
Orexins, alternatively called hypocretins, are neuropeptides with crucial role in maintaining wakefulness. The orexin system is thought to mediate a coordinated defense response but thus far investigated from the flight, but never fight, response perspective. An HCRTR1 gene variant (rs2271933 G > A) leading to amino acid substitution (Ile408Val) ha...
Making decisions when an objectively correct option is not obvious, involves different neurobiological mechanisms than “veridical” decision making. The dorsolateral prefrontal cortex (DLPFC) exhibits a distinct pattern of prefrontal activation in non-veridical cognition, but little is known about the role of underlying neurobiological endophenotype...
The RBFOX1 gene (or A2BP1) encodes a splicing factor important for neuronal development that has been related to autism spectrum disorder and other neurodevelopmental phenotypes. Evidence suggests that this gene contributes to aggressive behavior. Suggestive associations with RBFOX1 have been identified in genome-wide association studies (GWAS) of...
Alcohol use, high-risk drinking, and alcohol use disorder are on the rise and their prevalence in populations can significantly increase within only a few years. This suggests that the genetic underpinnings of alcohol use and abuse must interact with changes in the environment that at the macrolevel should become observable as birth cohort effects....
Objective
Individual biological predispositions should play a role in risky driving behaviour. Platelet monoamine oxidase (MAO) activity, dopamine transporter gene ( DAT1 ) and neuropeptide S receptor 1 ( NPSR1 ) gene polymorphisms have been identified as markers of impulsivity, alcohol use and excessive risk-taking. We aimed to find out how this k...
Emotional memory may be modulated by BDNF Val66Met and 5-HTTLPR polymorphisms. However, the influence of these genetic variants on the overnight retention of emotional memories has not been investigated in humans. Thirty-six healthy female students were selected to participate in this study based on 5-HTTLPR genotype status (L’/L’, L’/S’, S’/S’). P...
Attention-deficit/hyperactivity disorder (ADHD) is often comorbid with other psychiatric conditions in adults. Yet, less is known about its relationship with common metabolic disorders and how sex and ageing affect the overall comorbidity patterns of adult ADHD. We aimed to examine associations of adult ADHD with several common psychiatric and meta...
International Classification of Diseases (ICD) codes (Swedish version) for ADHD and comorbidities.
(DOCX)
The psychopathology of depression is highly complex and the outcome of studies on animal models is divergent. In order to find brain regions that could be metabolically distinctively active across a variety of mouse depression models and to compare the interconnectivity of brain regions of wild-type and such genetically modified mice, histochemical...
Background:
Corticotrophin-releasing hormone receptor-1 gene (CRHR1) variants have been implicated in mental health. However, little is known of the effects of CRHR1 on long-term mental health and behavior in presence of environmental stressors. We assess the effects of CRHR1 variant (rs17689918)-by-environment interactions on emotionality and beh...
High level of positive affectivity acts as a protective factor against adverse effects of stress and decreases vulnerability to mood disorders and drug abuse. Fifty-kHz ultrasonic vocalizations (50-kHz USV) index the level of positive affect in the rat, whereas stable, trait-like inter-individual differences in terms of vocalization activity exist....
Road traffic accidents are a serious public health issue, and real-life traffic offences are an excellent indicator of the behavioural tendencies of impulsivity and risk-taking. We have previously reported on short-term efficacy of a brief intervention in driving schools to reduce traffic risks (Paaver et al., Accid. Anal. Prev., 2013; 50, 430-437)...
Purpose of review:
To summarize the recent findings on the association of cholesterol levels with impulsivity and violence.
Recent findings:
Several authors have recently highlighted the importance of confounding factors that mask the association between cholesterol and impulsivity or violent behaviour. In particular, demographic factors and pre...
Catechol-O-methyl transferase (COMT) is a key player in neurotransmission by catecholamines, and the functional COMT Val108/158Met polymorphism is strongly related to prefrontal reactivity and to dopamine levels. As dopamine is a critically important neurotransmitter in cognition, emotion and motivation, we addressed the potential impact of this ge...
Genetic and environmental interactive influences on predisposition to develop alcohol use disorder (AUD) account for the high heterogeneity among AUD patients and make research on the risk and resiliency factors complicated. Several attempts have been made to identify the genetic basis of AUD; however, only few genetic polymorphisms have consistent...
It is unclear whether cardiorespiratory fitness (CRF) remains associated with metabolic risk if controlled for central adiposity and other confounders, thus the aim of this study was to investigate the independent effect of CRF on metabolic syndrome risk factors in relatively homogeneous age group of young adults. In this cross-sectional study 828...
The RBFOX1 gene (or A2BP1) encodes a splicing factor important for neuronal development that has been related to autism spectrum disorder and other neurodevelopmental phenotypes. Evidence from complementary sources suggests that this gene contributes to aggressive behavior. Suggestive associations with RBFOX1 have been identified in genome-wide ass...
Measurement of anxiety is desirable for the benefit of drug development and understanding the brain function and mental well-being. Animal models offer the advantages of detailed neurobiological analysis, experimental manipulation of specific components in the brain circuits that underlie psychopathology, and the possibility of screening novel drug...
Deficits in social behaviour are common in psychopathological conditions e.g., depression, autism and schizophrenia. In rats, sociability, defined as the engagement of an animal in non-aggressive social contact with a conspecific in a neutral arena, is as a persistent trait. To elucidate the neuroanatomy of social behaviour in animal models, long t...
Studies on the neurobiological basis of risk-taking behavior have most often focused on the serotonin system. The promoter region of the gene encoding the serotonin transporter contains a polymorphic site (5-HTTLPR) that is important for the transcriptional activity, and studies have demonstrated its association with brain activity and behavior. An...
Background:
Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in the synthesis of serotonin. We examined whether the TPH2 polymorphism -703G/T (rs4570625) is associated with aggressiveness and impulsivity, and the prevalence of psychiatric disorders, in a population-representative sample.
Methods:
We used self and proxy reports on aggress...
Research of GABRA2 gene in alcohol use and impulse control suggests its role in aggressive behaviour. The purpose of the present study was to examine the effects of GABRA2 genotype and stressful life events on aggressive behaviour, alcohol use frequency and occurrence of alcohol use disorder in a population representative sample of adolescents foll...
It is unclear if positive, negative, or neutral emotional expressions have an advantage in short-term recognition. Moreover, it is unclear from previous studies of working memory for emotional faces whether effects of emotions comprise response bias or sensitivity. The aim of this study was to compare how schematic emotional expressions (sad, angry...
Sensitivity to threatening or otherwise unpleasant visual stimuli has become a widely used measure of potential vulnerability/resilience. Basically, experiments using this strategy present brief stimuli, often followed by a mask, and individuals' sensitivity is measured. However, it has not been asked whether the individual differences in threat de...
Background:
Oxytocin is an important regulator of social relationships and has been implicated in development of substance use and addiction. We examined the association of a variance in the oxytocin receptor gene (OXTR rs53576 polymorphism) with alcohol use in a population-representative sample, and potential moderation by social functioning.
Me...
