Childhood problem behavior and parental divorce: evidence for gene-environment interaction

Thyroid function test abnormalities-isolated TPOAb+, SCH and hypothyroxinemia and preschool children's neurodevelopment

OBJECTIVE

Thyroid function test abnormalities are frequent and associated with the offspring's adverse neurodevelopment. This study aimed to examine the relationship between maternal thyroid function test abnormalities before 20 gestational weeks and children's cognitive, emotional and behavioural development at 3-6 years of age.

PATIENTS AND MEASUREMENTS

A total of 2243 mother-child pairs were included in the final analysis. Maternal thyroid function was evaluated retrospectively during the children's preschool period. The serum thyrotrophin, free thyroxine and thyroid peroxidase antibodies (TPOAb) were detected by chemiluminescence immunoassay during the follow-up period. The neurodevelopmental status of preschoolers aged 3-6 years was evaluated by parental versions of The Behavior Rating Inventory of Executive Function-Preschool and The Strengths and Difficulties Questionnaires. The associations between maternal thyroid function test abnormalities and preschoolers' neurodevelopment were examined using Poisson regression models.

RESULTS

After adjusting for potential confounders in Poisson regression analyses, it showed that maternal isolated TPOAb positivity before 20 gestational weeks may be associated with the increased risk of abnormalities in peer problems (odds ratio [OR] = 1.90, 95% confidence interval [CI]: 1.26, 287). Maternal isolated SCH before 20 gestational weeks was observed to be related with increased risk of abnormalities in inhibition (OR = 2.73, 95% CI: 1.37, 5.41), working memory (OR = 1.67, 95% CI: 1.04, 2.70), conduct problems (OR = 1.80, 95% CI: 1.05, 3.09), hyperactivity (OR = 1.94, 95% CI:1.08, 3.49) and total difficulties (OR = 1.94, 95% CI: 1.13, 3.34). Maternal isolated hypothyroxinemia before 20 gestational was observed to be related with increased risk of abnormalities in peer problems (OR = 2.71, 95% CI: 1.17, 6.27).

CONCLUSIONS

Thyroid function test abnormalities before 20 gestational weeks may be associated with children's neurodevelopment at 3-6 years of age.

Sex-Specific Effect of Thyroid Peroxidase Antibody and Thyroglobulin Antibody Exposure During Pregnancy on Preschoolers' Emotional and Behavioral Development: A Birth Cohort Study

Background: Epidemiological and experimental studies suggest that thyroid peroxidase antibody (TPOAb)- and thyroglobulin antibody (TGAb)-positive exposure during gestation may contribute to offspring's adverse neural development. However, limited knowledge is available on the association between joint exposure on TPOAb and TGAb and children's emotional and behavioral development. Furthermore, the sex-specific effect on the developmental process of preschoolers' emotions and behaviors is unknown. The present research intends to examine the sex-specific effect of TPOAb- and TGAb-positive exposure in gestation on the developmental process of preschoolers' emotions and behaviors. Methods: A total of 2455 mother-child pairs were included from the Ma'anshan Birth Cohort study. The serum TPOAb and TGAb of pregnant women was measured retrospectively by electrochemical immunoassay during the follow-up period. Preschoolers' emotional and behavioral development was assessed by a child behavior checklist 1.5-5. Growth mixture modeling was adopted to fit thyroid antibody (TAb) trajectories. Poisson regression models were used, stratifying by sex, to examine the association between TAb trajectories, as well as four categories of maternal TAb exposure and preschoolers' emotional and behavioral problems. Results: Boys born to mothers with TPOAb positivity in the first, second, and third trimesters of pregnancy had an increased risk of autism spectrum problems after adjusting for confounders, with relative risk (RR) [confidence interval, CI] of 2.01 [1.24-3.27], 2.15 [1.08-4.26], and 2.13 [1.20-3.79], respectively. Maternal TGAb positivity and TPOAb negativity in the first trimester were associated with a high risk of attention-deficit/hyperactivity problems in boys (RR = 1.74 [CI 1.01-2.99]). The prevalence of depressive problems in girls was 33.3% after exposure to TPOAb alone in the third trimester of pregnancy. Exposure to TPOAb alone in the third trimester of pregnancy was associated with an increased risk of depressive problems in girls (RR = 1.78 [CI 1.09-2.90]). Conclusions: Maternal TPOAb positivity in all three trimesters was associated with the risk of autism spectrum problems in boys. Isolated maternal TGAb positivity in the first trimester was associated with attention-deficit/hyperactivity problems in boys, whereas isolated maternal TPOAb positivity in the third trimester was associated with depressive problems in girls.

A Critical Review of Statistical Methods for Twin Studies Relating Exposure to Early Life Health Conditions

When investigating disease etiology, twin data provide a unique opportunity to control for confounding and disentangling the role of the human genome and exposome. However, using appropriate statistical methods is fundamental for exploiting such potential. We aimed to critically review the statistical approaches used in twin studies relating exposure to early life health conditions. We searched PubMed, Scopus, Web of Science, and Embase (2011–2021). We identified 32 studies and nine classes of methods. Five were conditional approaches (within-pair analyses): additive-common-erratic (ACE) models (11 studies), generalized linear mixed models (GLMMs, five studies), generalized linear models (GLMs) with fixed pair effects (four studies), within-pair difference analyses (three studies), and paired-sample tests (two studies). Four were marginal approaches (unpaired analyses): generalized estimating equations (GEE) models (five studies), GLMs with cluster-robust standard errors (six studies), GLMs (one study), and independent-sample tests (one study). ACE models are suitable for assessing heritability but require adaptations for binary outcomes and repeated measurements. Conditional models can adjust by design for shared confounders, and GLMMs are suitable for repeated measurements. Marginal models may lead to invalid inference. By highlighting the strengths and limitations of commonly applied statistical methods, this review may be helpful for researchers using twin designs.

The Complex Role of Parental Separation in the Association between Family Conflict and Child Problem Behavior

Parental separation is a major adverse childhood experience. Parental separation is generally preceded by conflict, which is itself a risk factor for child problem behavior. Whether parental separation independent of conflict has negative effects on child problem behavior is unclear. This study was embedded in Generation R, a population-based cohort followed from fetal life until age 9 years. Information on family conflict was obtained from 5,808 mothers and fathers. The 4-way decomposition method was used to apportion the effects of prenatal family conflict and parental separation on child problem behavior into 4 nonoverlapping components. Structural equation modeling was used to test bidirectional effects of child problem behavior and family conflict over time. Family conflict from pregnancy onward and parental separation each strongly predicted child problem behavior up to preadolescence according to maternal and paternal ratings. Using the 4-way decomposition method, we found evidence for a strong direct effect of prenatal family conflict on child problem behavior, for reference interaction, and for mediated interaction. The evidence for interaction implies that prenatal family conflict increased the children's vulnerability to the harmful effect of parental separation. There was no evidence of a pure indirect effect of parental separation on child problem behavior. Overall, results indicated that if parental separation occurs in families with low levels of conflict, parental separation does not predict more child problem behavior. Moreover, the bidirectional pattern suggested that child problem behavior influences the persistence of family conflict.

Typologies of Post-divorce Coparenting and Parental Well-Being, Parenting Quality and Children's Psychological Adjustment

The aim of this study was to identify post-divorce coparenting profiles and examine whether these profiles differentiate between levels of parents' well-being, parenting practices, and children's psychological problems. Cluster analysis was conducted with Portuguese heterosexual divorced parents (N = 314) to yield distinct post-divorce coparenting patterns. Clusters were based on parents' self-reported coparenting relationship assessed along four dimensions: agreement, exposure to conflict, undermining/support, and division of labor. A three cluster solution was found and replicated. Parents in the high-conflict coparenting group exhibited significantly lower life satisfaction, as well as significantly higher divorce-related negative affect and inconsistent parenting than parents in undermining and cooperative coparenting clusters. The cooperative coparenting group reported higher levels of positive family functioning and lower externalizing and internalizing problems in their children. These results suggested that a positive coparenting alliance may be a protective factor for individual and family outcomes after parental divorce.

Parental Divorce or Death During Childhood and Adolescence and Its Association With Mental Health

Despite the severity of the loss of a parent and the frequency of parental divorce, few studies compared their impact on mental health in the general adult population. The aim of this study was to estimate the prevalence, sociodemographic correlates, and psychiatric comorbidity of parental loss and parental divorce during childhood and adolescence. Data were drawn from the National Epidemiologic Survey on Alcohol and Related Conditions, a nationally representative sample of US adults (n = 43,093). Of the 43,093 participants, parental divorce during childhood or adolescence was reported by 5776 participants, whereas 3377 experienced parental death during childhood or adolescence. Participants reporting a history of parental divorce present a significantly higher prevalence of psychiatric disorders, particularly alcohol and drug use disorders compared with control subjects. While participants experiencing the death of a parent reported a poorer overall health, the prevalence of psychiatric disorder after 17 years of age was not significantly higher than that of the control subjects.

Genetics of aggressive behavior: An overview

The Research Domain Criteria (RDoC) address three types of aggression: frustrative non-reward, defensive aggression and offensive/proactive aggression. This review sought to present the evidence for genetic underpinnings of aggression and to determine to what degree prior studies have examined phenotypes that fit into the RDoC framework. Although the constructs of defensive and offensive aggression have been widely used in the animal genetics literature, the human literature is mostly agnostic with regard to all the RDoC constructs. We know from twin studies that about half the variance in behavior may be explained by genetic risk factors. This is true for both dimensional, trait-like, measures of aggression and categorical definitions of psychopathology. The non-shared environment seems to have a moderate influence with the effects of shared environment being unclear. Human molecular genetic studies of aggression are in an early stage. The most promising candidates are in the dopaminergic and serotonergic systems along with hormonal regulators. Genome-wide association studies have not yet achieved genome-wide significance, but current samples are too small to detect variants having the small effects one would expect for a complex disorder. The strongest molecular evidence for a genetic basis for aggression comes from animal models comparing aggressive and non-aggressive strains or documenting the effects of gene knockouts. Although we have learned much from these prior studies, future studies should improve the measurement of aggression by using a systematic method of measurement such as that proposed by the RDoC initiative.

A supportive family environment in childhood enhances the level and heritability of sense of coherence in early adulthood

PURPOSE

To analyze the effects of genetic and environmental factors on sense of coherence (SOC) in young adulthood and whether family environment measured in childhood modifies these effects.

METHODS

SOC was measured at 20-27 years of age in 3,193 Finnish twins using the Antonovsky's 13-item short scale. The twins and their parents had rated their emotional family environment independently when the twins were 12 years of age. The data were analyzed using applications of structural linear equation modeling to twin data.

RESULTS

Females rated SOC 2.42 points lower than males. Additive genetic factors explained 39% of the variation of SOC in males and 49% in females, whereas the rest of the variation was explained by environmental factors unique to each twin individual. For the dimensions of SOC, the highest genetic correlation was found between comprehensibility and manageability (0.90 in males and 0.97 in females). SOC was strongest in the participants who had reported supportive family atmosphere and low relational tensions to parents in childhood. These participants also had higher genetic variance and lower unique environmental variance of SOC when compared to those who reported emotionally more stressful family environment. The results were similar when we used parental rating of family environment.

CONCLUSION

Genetic factors are important for SOC, but genetic influences are much greater in supportive family environments. This emphasizes the importance of childhood home for the development of strong SOC.

Adverse life events as risk factors for behavioural and emotional problems in a 7-year follow-up of a population-based child cohort

BACKGROUND AND AIM

The aim of the study was to identify risk factors for significant changes in emotional and behavioural problem load in a community-based cohort of Danish children aged 9-16 years, the risk factors being seven parental and two child-related adverse life events.

METHODS

Data on emotional and behavioural problems was obtained from parents filling in the Child Behavior Checklist (CBCL) when the child was 8-9 and again when 15 years old. Data on risk factors was drawn from Danish registers. Analysis used was logistic regression for crude and adjusted change.

RESULTS

Parental divorce significantly raised the odds ratio of an increase in emotional and behavioural problems; furthermore, the risk of deterioration in problem behaviour rose significantly with increasing number of adverse life events. By dividing the children into four groups based on the pathway in problem load (increasers, decreasers, high persisters and low persisters), we found that children with a consistently high level of behavioural problems also had the highest number of adverse life events compared with any other group.

CONCLUSIONS

Family break-up was found to be a significant risk factor. This supports findings in previous studies. The fact that no other risk factor proved to be of significance might be due to lack of power in the study. Children experiencing high levels of adverse life events are at high risk of chronic problem behaviour. Thus these risk factors should be assessed in daily clinical practice.

Overview of Behavioral Genetics Research for Family Researchers

This article provides an overview of the methods, assumptions, and key findings of behavioral genetics methodology for family researchers with a limited background. We discuss how family researchers can utilize and contribute to the behavioral genetics field, particularly in terms of conducting research that seeks to explain shared environmental effects. This can be done, in part, by theoretically controlling for genetic confounds in research that seeks to determine cause-and-effect relationships among family variables and individual outcomes. Gene-environment correlation and interaction are especially promising areas for the family researcher to address. Given the methodological advancements in the field, we also briefly comment on new methods in molecular genetics for studying psychological mental health disorders.

Severe life stress and oxidative stress in the brain: from animal models to human pathology

SIGNIFICANCE

Severe life stress (SLS), as opposed to trivial everyday stress, is defined as a serious psychosocial event with the potential of causing an impacting psychological traumatism.

RECENT ADVANCES

Numerous studies have attempted to understand how the central nervous system (CNS) responds to SLS. This response includes a variety of morphological and neurochemical modifications; among them, oxidative stress is almost invariably observed. Oxidative stress is defined as disequilibrium between oxidant generation and the antioxidant response.

CRITICAL ISSUES

In this review, we discuss how SLS leads to oxidative stress in the CNS, and how the latter impacts pathophysiological outcomes. We also critically discuss experimental methods that measure oxidative stress in the CNS. The review covers animal models and human observations. Animal models of SLS include sleep deprivation, maternal separation, and social isolation in rodents, and the establishment of hierarchy in non-human primates. In humans, SLS, which is caused by traumatic events such as child abuse, war, and divorce, is also accompanied by oxidative stress in the CNS.

FUTURE DIRECTIONS

The outcome of SLS in humans ranges from resilience, over post-traumatic stress disorder, to development of chronic mental disorders. Defining the sources of oxidative stress in SLS might in the long run provide new therapeutic avenues.