Genetic and environmental causes of variation in adolescent anxiety symptoms: a multiple-rater twin study

The Influence of Genetic and Environmental Factors on Anxiety among Chinese Adolescents: A Twin Study

This study explored the influence of genetic and environmental factors on adolescent anxiety. Ninety-eight monozygotic and dizygotic twins from Chongqing, China (aged 15-18 years) were assessed for anxiety with the Self-Rating Anxiety Scale (SAS). The Parenting Styles and Dimensions Questionnaire (PSDQ) and Strengths and Difficulties Questionnaire (SDQ) were applied to assess environmental factors. Venous blood was drawn from the twins for zygosity determination. Structural equation modeling was performed to evaluate the effects of additive genetic factors (A), common environmental factors (C), and individual-specific environmental factors (E) on adolescent anxiety. The estimates of A and E on adolescent anxiety were 0.34 (95% CI = 0.12-0.53) and 0.66 (95% CI:0.47-0.89), respectively. The environment played an important role in adolescent anxiety. Adolescent anxiety was significantly positively correlated with peer relations (r = 0.606, p < 0.05) and negatively correlated with prosocial behavior (r = 0.207, p < 0. 05). No sex differences were observed. Adolescent anxiety was influenced by both genetic and environmental factors. The individual-specific environmental factors played an important role. Consideration of these variables will facilitate the targeted and individualized implementation of specific interventions for adolescent anxiety.

Evidence for distinct genetic and environmental influences on fear acquisition and extinction

BACKGROUND

Anxiety disorders are highly prevalent with an early age of onset. Understanding the aetiology of disorder emergence and recovery is important for establishing preventative measures and optimising treatment. Experimental approaches can serve as a useful model for disorder and recovery relevant processes. One such model is fear conditioning. We conducted a remote fear conditioning paradigm in monozygotic and dizygotic twins to determine the degree and extent of overlap between genetic and environmental influences on fear acquisition and extinction.

METHODS

In total, 1937 twins aged 22-25 years, including 538 complete pairs from the Twins Early Development Study took part in a fear conditioning experiment delivered remotely via the Fear Learning and Anxiety Response (FLARe) smartphone app. In the fear acquisition phase, participants were exposed to two neutral shape stimuli, one of which was repeatedly paired with a loud aversive noise, while the other was never paired with anything aversive. In the extinction phase, the shapes were repeatedly presented again, this time without the aversive noise. Outcomes were participant ratings of how much they expected the aversive noise to occur when they saw either shape, throughout each phase.

RESULTS

Twin analyses indicated a significant contribution of genetic effects to the initial acquisition and consolidation of fear, and the extinction of fear (15, 30 and 15%, respectively) with the remainder of variance due to the non-shared environment. Multivariate analyses revealed that the development of fear and fear extinction show moderate genetic overlap (genetic correlations 0.4-0.5).

CONCLUSIONS

Fear acquisition and extinction are heritable, and share some, but not all of the same genetic influences.

Factors associated with gender and sex differences in anxiety prevalence and comorbidity: A systematic review

Background: The prevalence and comorbidity of anxiety disorders are significantly different between women and men, with research showing a greater impact on women. The aim of this review was to identify the psychosocial and biological factors that have been considered to explain this gender and sex difference in prevalence and determine whether these factors are related to any anxiety comorbidity differences between men and women. Methods: Following the PRISMA guidelines, we carried out a systematic review of studies published between 2008 and 2021 in PsycINFO and PubMed databases. Empirical and review studies evaluating psychosocial and biological factors that could influence the difference in prevalence and comorbidity between men and women were included. A qualitative narrative synthesis was performed to describe the results. Results: From 1012 studies, 44 studies were included. Retrieved articles were categorized depending on their object of study: psychosocial factors (n = 21), biological factors (n = 16), or comorbidity (n = 7). Results showed that differences in anxiety between women and men have been analyzed by psychosocial and biological factors but rarely together. Among the psychosocial factors analyzed, masculinity may be a protective factor for anxiety development, while femininity can be a risk factor. In the studies that took biological factors into account, the potential influence of brain structures, genetic factors, and fluctuations in sexual hormones are pointed out as causes of greater anxiety in women. Concerning comorbidity, the results noted that women tend to develop other internalizing disorders (e.g. depression), while men tend to develop externalizing disorders (e.g. substance abuse). Conclusions: For an accurate understanding of differences between women and men in anxiety, both biological and psychosocial factors should be considered. This review highlights the need to apply the biopsychosocial model of health and the gender perspective to address differences in anxiety between sexes.

Genome-wide Association Meta-analysis of Childhood and Adolescent Internalizing Symptoms

OBJECTIVE

To investigate the genetic architecture of internalizing symptoms in childhood and adolescence.

METHOD

In 22 cohorts, multiple univariate genome-wide association studies (GWASs) were performed using repeated assessments of internalizing symptoms, in a total of 64,561 children and adolescents between 3 and 18 years of age. Results were aggregated in meta-analyses that accounted for sample overlap, first using all available data, and then using subsets of measurements grouped by rater, age, and instrument.

RESULTS

The meta-analysis of overall internalizing symptoms (INToverall) detected no genome-wide significant hits and showed low single nucleotide polymorphism (SNP) heritability (1.66%, 95% CI = 0.84-2.48%, neffective = 132,260). Stratified analyses indicated rater-based heterogeneity in genetic effects, with self-reported internalizing symptoms showing the highest heritability (5.63%, 95% CI = 3.08%-8.18%). The contribution of additive genetic effects on internalizing symptoms appeared to be stable over age, with overlapping estimates of SNP heritability from early childhood to adolescence. Genetic correlations were observed with adult anxiety, depression, and the well-being spectrum (|rg| > 0.70), as well as with insomnia, loneliness, attention-deficit/hyperactivity disorder, autism, and childhood aggression (range |rg| = 0.42-0.60), whereas there were no robust associations with schizophrenia, bipolar disorder, obsessive-compulsive disorder, or anorexia nervosa.

CONCLUSION

Genetic correlations indicate that childhood and adolescent internalizing symptoms share substantial genetic vulnerabilities with adult internalizing disorders and other childhood psychiatric traits, which could partially explain both the persistence of internalizing symptoms over time and the high comorbidity among childhood psychiatric traits. Reducing phenotypic heterogeneity in childhood samples will be key in paving the way to future GWAS success.

Associations Between Anxiety Symptoms and Health-Related Quality of Life: A Population-Based Twin Study in Sri Lanka

Anxiety not only concerns mental wellbeing but also negatively impacts other areas of health. Yet, there is limited research on (a) the genetic and environmental aetiology of such relationships; (b) sex differences in aetiology and (c) non-European samples. In this study, we investigated the genetic and environmental variation and covariation of anxiety symptoms and eight components of health-related quality of life (QoL), as measured by the short form health survey (SF-36), using genetic twin model fitting analysis. Data was drawn from the Colombo Twin and Singleton Study (COTASS), a population-based sample in Sri Lanka with data on twins (N = 2921) and singletons (N = 1027). Individual differences in anxiety and QoL traits showed more shared environmental (family) effects in women. Men did not show familial effects. Anxiety negatively correlated with all eight components of QoL, mostly driven by overlapping unique (individual-specific) environmental effects in both sexes and overlapping shared environmental effects in women. This is the first study in a South Asian population supporting the association between poor mental health and reduced QoL, highlighting the value of integrated healthcare services. Associations were largely environmental, on both individual and family levels, which could be informative for therapy and intervention.

Intergenerational transmission of anxiety: linking parental anxiety to infant autonomic hyperarousal and fearful temperament

BACKGROUND

Autonomic hyperarousal has been proposed as a dispositional risk factor for anxiety disorders (ADs). Therefore, we studied physiological arousal in offspring of fathers and mothers with and without ADs and whether infant hyperarousal predicts subsequent fearful temperament.

METHODS

Infants (N = 128; age = 4 months) did a novel stimuli task (exposure to visual, olfactory, and acoustic stimuli and an unfamiliar male) and a habituation task (exposure to a repeated acoustic stimulus). Heart rate (HR) and heart rate variability (HRV) were measured during baseline, stimuli and post-stimuli rest. Parents' AD status and severity were measured using a diagnostic interview and their fearful temperament using a questionnaire. Child fearful temperament was measured at 4 months, 1 year and 2.5 years with observations during structured tasks.

RESULTS

Parents' fearful temperament (significant in the habituation task), AD status (significant in the novel stimuli task) and AD severity (significant in both tasks) predicted a higher HR in their infants. Infants' higher HR reactivity to novel stimuli and diminished HR recovery at 4 months predicted a more fearful temperament during infancy and toddlerhood. Infants' higher HR at 4 months predicted a more fearful temperament at 2.5 years.

CONCLUSIONS

Parental prenatal anxiety (disorders) predicted infants' autonomic arousal, which in turn predicted later fearful temperament in children. Outcomes suggest that autonomic hyperarousal is a dispositional risk factor of ADs.

Higher Anxiety Is Associated with Lower Cardiovascular Autonomic Function in Female Twins

Anxiety symptoms co-occur with cardiovascular health problems, with increasing evidence suggesting the role of autonomic dysfunction. Yet, there is limited behavior genetic research on underlying mechanisms. In this twin study, we investigated the phenotypic, genetic and environmental associations between a latent anxiety factor and three cardiovascular autonomic function factors: interbeat interval (IBI, time between heart beats), heart rate variability (HRV, overall fluctuation of heart-beat intervals) and baroreflex sensitivity (BRS, efficiency in regulating blood pressure [BP]). Multivariate twin models were fit using data of female twins (N = 250) of the Twin Interdisciplinary Neuroticism Study (TWINS). A significant negative association was identified between latent anxiety and BRS factors (r = -.24, 95% CI [-.40, -.07]). Findings suggest that this relationship was mostly explained by correlated shared environmental influences, and there was no evidence for pleiotropic genetic or unique environmental effects. We also identified negative relationships between anxiety symptoms and HRV (r = -.17, 95% CI [-.34, .00]) and IBI factors (r = -.13, 95% CI [-.29, .04]), though these associations did not reach statistical significance. Findings implicate that higher anxiety scores are associated with decreased efficiency in short-term BP regulation, providing support for autonomic dysfunction with anxiety symptomatology. The baroreflex system may be a key mechanism underlying the anxiety-cardiovascular health relationship.

Parental overcontrol x OPRM1 genotype interaction predicts school-aged children's sympathetic nervous system activation in response to performance challenge

Parental overcontrol (OC), the excessive regulation of a child's behavior, cognition, and emotion, is associated with the development of child anxiety. While studies have shown that genetic factors may increase sensitivity to stress, genetic vulnerability to parental OC has not been examined in anxiety etiology. A functional polymorphism in the mu opioid receptor OPRM1 (A118G, rs1799971) has been shown to impact stress reactivity. Using a community sample of children (N = 85, 9-12 years old), we examined the main and interactive effects of maternal OC and child OPRM1 genotype in predicting children's sympathetic nervous system reactivity during a performance stressor. Neither OC nor genotype predicted children's electrodermal activity (EDA); however, the interaction between OC and child genotype significantly predicted stress reactivity, as indexed by EDA, during the challenging task. Among children with the minor G-allele, higher maternal OC was associated with higher reactivity. In A homozygotes, maternal OC was not associated with EDA, suggesting a diathesis-stress pattern of gene x environment interaction. We discuss implications for anxiety etiology and intervention.

Etiological Influences on Perceptions of Parenting: A Longitudinal, Multi-Informant Twin Study

Children and their parents often differ in their perception of the relationship they share. As this relationship changes developmentally, the nature of these differences may also change. Longitudinal genetic designs can be used to investigate the developmental etiologies of shared and distinct perceptions. In this study, we used longitudinal psychometric models to analyze child and parent reports of negative parenting for 6417 twin pairs from the Twins Early Development Study at ages 9, 12 and 14 years. Within-time cross-reporter correlations, indicating the degree to which children and parents perceived negative parenting behaviors similarly at each age, were moderate (r = .44 - .46). Longitudinal genetic analyses revealed these shared perceptions to be relatively stable during the transition into adolescence, with this stability driven by a combination of children's genetic factors and family-wide environmental factors. In contrast, child- and parent-specific perceptions of parenting were predominantly age-specific, a developmental pattern underpinned by child genetic factors and a combination of family-wide and unique environmental influences. These results and their implications are discussed in the context of interplay between reciprocal interactions, subjective insight and developmental behavioral change in the parent-child relationship.

Common Etiological Sources of Anxiety, Depression, and Somatic Complaints in Adolescents: A Multiple Rater twin Study

Somatic complaints in children and adolescents may be considered part of a broader spectrum of internalizing disorders that include anxiety and depression. Previous research on the topic has focused mainly on the relationship between anxiety and depression without investigating how common somatic symptoms relate to an underlying factor and its etiology. Based on the classical twin design with monozygotic and dizygotic twins reared together, our study aimed to explore the extent to which the covariation between three phenotypes in adolescent girls and boys can be represented by a latent internalizing factor, with a focus on both common and specific etiological sources. A population-based sample of twins aged 12-18 years and their mothers and fathers (N = 1394 families) responded to questionnaire items measuring the three phenotypes. Informants' ratings were collapsed using full information maximum likelihood estimated factor scores. Multivariate genetic analyses were conducted to examine the etiological structure of concurrent symptoms. The best fitting model was an ACE common pathway model without sex limitation and with one substantially heritable (44%) latent factor shared by the phenotypes. Concurrent symptoms also resulted from shared (25%) and non-shared (31%) environments. The factor loaded most on depression symptoms and least on somatic complaints. Trait-specific influences explained 44% of depression variance, 59% of anxiety variance, and 65% of somatic variance. Our results suggest the presence of a general internalizing factor along which somatic complaints and mental distress can be modeled. However, specific influences make the symptom types distinguishable.

The genetic basis of quality of life in healthy Swedish women: a candidate gene approach

BACKGROUND

Quality of life (QoL) is an increasingly important parameter in clinical practice as it predicts mortality and poor health outcomes. It is hypothesized that one may have a genetic predisposition for QoL. We therefore related 139 candidate genes, selected through a literature search, to QoL in healthy females.

METHODS

In 5,142 healthy females, background characteristics (i.e. demographic, clinical, lifestyle, and psychological factors) were assessed. QoL was measured by the EORTC QLQ-C30, which consists of 15 domains. For all women genotype information was available. For each candidate gene, single nucleotide polymorphisms (SNPs) were identified based on their functional (n = 2,663) and physical annotation (n = 10,649). SNPs were related to each QoL-domain, while controlling for background characteristics and population stratification. Finally, gene-based analyses were performed relating the combined effect of 10,649 SNPs (selected based on physical annotation) for each gene, to QoL using the statistical software package VEGAS.

RESULTS

Overall, we found no relation between genetic variations (SNPs and genes) and 14 out of 15 QoL-domains. The strongest association was found between cognitive functioning and the top SNP rs1468951 (p = 1.21E-05) in the GSTZ1 gene. Furthermore, results of the gene-based test showed that the combined effect of 11 SNPs within the GSTZ1 gene is significantly associated with cognitive functioning (p = 2.60E-05).

CONCLUSION

If validated, the involvement of GSTZ1 in cognitive functioning underscores its heritability which is likely the result of differences in the dopamine pathway, as GSTZ1 contributes to the equilibrium between dopamine and its neurotoxic metabolites via the glutathione redox cycle.