Time-Dependent Effects of Exposure to Physical and Sexual Violence on Psychopathology Symptoms in Late Childhood: In Search of Sensitive Periods in Development

Childhood adversity and psychopathology: the dimensions of timing, type and chronicity in a population-based sample of high-risk adolescents

BACKGROUND

Research on childhood adversity and psychopathology has begun investigating the dimension of timing, however the results have been contradictory depending on the study population, outcome and how adverse life events (ALEs) were operationalized. Additionally, studies so far typically focus only on a narrow range of psychiatric diagnoses or symptoms. The current cross-sectional study aimed to examine the association between timing, type and chronicity of ALEs and adolescent mental health problems.

METHODS

Adolescents from a population-based cohort oversampled on emotional and behavioral problems (mean age 14.8; range 12-17, N = 861) were included in the current analysis. Primary caregivers were interviewed on what ALEs adolescents experienced. ALEs were defined in two ways: (1) broad operationalization, including school difficulties, parental divorce, and family sickness; and (2) physically threatening abuse only, including physical and sexual violence. After looking at lifetime ALEs, we turned to chronicity, timing and sex differences. We focused on overall psychiatric symptoms as well as specific domains of emotional and behavioral problems, assessed using the Youth Self Report (YSR) and psychotic experiences assessed using the Prodromal Questionnaire-16 (PQ-16). A series of linear models adjusted for sociodemographic and parental factors were used.

RESULTS

Lifetime ALEs were associated with all types of psychopathology, with relatively bigger effect sizes for broad than for physical ALEs. The latter associations were found to be more robust to unmeasured confounding. The 9-12 age period of experiencing both broad and physical ALE's was most saliently associated with any psychopathology. Girls were more at risk after experiencing any ALEs, especially if the adversity was chronic or ALEs took place after the age of 12.

CONCLUSIONS

Broad as well as physical ALEs are associated with psychopathology, especially ALEs experienced during the 9-12 age period. Physical ALEs may be more useful in investigating specific etiological factors than broad ALEs. Sex differences may not emerge in lifetime measures of ALEs, but can be important for chronic and later childhood adversity.

Which individual, social, and urban factors in early childhood predict psychopathology in later childhood, adolescence and young adulthood? A systematic review

Background

A comprehensive picture is lacking of the impact of early childhood (age 0-5) risk factors on the subsequent development of mental health symptoms.

Objective

In this systematic review, we investigated which individual, social and urban factors, experienced in early childhood, contribute to the development of later anxiety and depression, behavioural problems, and internalising and externalising symptoms in youth.

Methods

Embase, MEDLINE, Scopus, and PsycInfo were searched on the 5th of January 2022. Three additional databases were retrieved from a mega-systematic review source that focused on the identification of both risk and protective indicators for the onset and maintenance of prospective depressive, anxiety and substance use disorders. A total of 46,450 records were identified and screened in ASReview, an AI-aided systematic review tool. We included studies with experimental, quasi-experimental, prospective and longitudinal study designs, while studies that focused on biological and genetical factors, were excluded.

Results

Twenty studies were included. The majority of studies explored individual-level risk factors (N = 16). Eleven studies also explored social risk factors and three studied urban risk factors. We found evidence for early predictors relating to later psychopathology measures (i.e., anxiety and depression, behavioural problems, and internalising and externalising symptoms) in childhood, adolescence and early adulthood. These were: parental psychopathology, exposure to parental physical and verbal violence and social and neighbourhood disadvantage.

Conclusions

Very young children are exposed to a complex mix of risk factors, which operate at different levels and influence children at different time points. The urban environment appears to have an effect on psychopathology but it is understudied compared to individual-level factors. Moreover, we need more research exploring the interaction between individual, social and urban factors.

A systematic review of the measurement properties of self-report screening tools to detect risk or exposure to child sexual abuse for children under 12

Child sexual abuse (CSA) is a substantial public health issue that is challenging to measure epidemiologically due to the "pact of silence" among those involved. Validated tools could contribute to early recognition or risk detection for CSA. We aimed to systematically assess self-report tools' measurement properties and methodological quality that detect risk or exposure to CSA for children under twelve. The search strategy, selection criteria, data extraction, data analysis, and synthesis followed the COSMIN methodology for systematic reviews (2018). PROSPERO 2021 registration CRD42021278465. MEDLINE, COCHRANE, EMBASE, CINAHL, SCOPUS, and ERIC were searched until August 2021, with an updated search on September 23, 2021, and unlimited by language. The inclusion criteria were: to assess risk or exposure to CSA under twelve years old by objective items and self-report tools; sexual violence risk or exposure in the domestic context; the application context should include health facilities (such as hospital emergency rooms, outpatient clinics, pediatric wards, psychology centers, social services), education (such as schools) and community; no language or date restriction. The exclusion criteria were: non-self-report tools studies, comprehensive articles, comments, editorials, expert opinions, and studies of projective techniques. The COSMIN risk of bias checklist was used to evaluate the methodological quality of the included studies. Feasibility aspects were assessed. This study had no funding source; 29 studies describing eight tools met eligibility criteria. No single instrument reported all nine measurement properties outlined by the COSMIN methodology. The strength of the evidence was moderate to high for six out of eight instruments. ICAST-C and JVQ were the tools that obtained the highest number of rated measurement properties and strength of evidence.

Sexual violence affects adolescents' health and prosocial behaviour beyond other violence exposure

Background: Sexual violence is a public health issue among adolescents globally but remains understudied in Sub-Saharan Africa.Objective: The present study focused on the association of cumulative exposure to different types of sexual violence with mental and physical health problems and prosocial behaviour.Method: We conducted a survey with a regionally representative sample of both in-school and out-of-school adolescents, aged 13-17 years, living in south-western Nigeria. Self-reported exposure to sexual violence, behavioural problems, physical complaints, and prosocial behaviour were assessed.Results: About three quarters of the participants reported the experience of sexual violence (74.6%). Multiple regression models revealed that the more types of sexual violence an individual reported, the more mental and physical health problems, and the fewer prosocial behaviours they reported when controlling for other forms of violence exposure. Latent class analysis revealed three severity classes of sexual violence. Symptoms of mental and physical health indicators were significantly higher as exposure increased by group whereas prosocial behaviours were non-significantly fewer in the opposite direction.Conclusion: This study revealed a consistent and unique relation between sexual violence exposure and negative health outcomes among adolescents. Further research on sexual violence in Sub-Saharan Africa and its associations is needed.

Early Childhood Violence Exposure Patterns in The Drakenstein Child Health Study (DCHS)

Background: Research has highlighted high rates of exposure to violence among South African youth. However, work to date has been largely cross-sectional, focused on violence exposure during the adolescence period, and has been limited to specific types of violence exposure. We examined violence exposure in South African preschool children between 3 and 6 years of age, capturing both direct and indirect forms of violence, and tested for potential sex differences across the several types of exposures. Methods: Lifetime direct and indirect exposure to domestic and community violence was measured by parental report when children were 3.5 years (N = 530), 4.5 years (N = 749) and 6 years of age (N= 417) in a South African birth cohort located in a peri-urban community. Results: There are three main findings. First, a large proportion of children (72%-75%) were reported as having been exposed to some form of direct or indirect violent experience in their homes or communities from a young age. Second, there was significant polyvictimization,  with 49% of the children being exposed to more than one type of violence by age 6. Third, by 4.5 years of age, there was evidence that boys were more likely than girls to be exposed to domestic victimisation (28% vs. 17%) and polyvictimization (38% vs. 28%). Conclusions: These findings highlight the high levels of violence exposure in young South African children, particularly among boys, and the need for prevention at both the community and individual levels.

Early life adversities and lifelong health outcomes: A review of the literature on large, social, long-lived nonhuman mammals

Social nonhuman animals are powerful models for studying underlying factors related to lifelong health outcomes following early life adversities (ELAs). ELAs can be linked to lifelong health outcomes depending on the species, system, sensitive developmental periods, and biological pathways. This review focuses on the literature surrounding ELAs and lifelong health outcomes in large, social, relatively long-lived nonhuman mammals including nonhuman primates, canids, hyenas, elephants, ungulates, and cetaceans. These mammals, like humans but unlike the most-studied rodent models, have longer life histories, complex social structures, larger brains, and comparable stress and reproductive physiology. Collectively, these features make them compelling models for comparative aging research. We review studies of caregiver, social, and ecological ELAs, often in tandem, in these mammals. We consider experimental and observational studies and what each has contributed to our knowledge of health across the lifespan. We demonstrate the continued and expanded need for comparative research to inform about the social determinants of health and aging in both humans and nonhuman animals.

Timing and type of adverse life events: Impact on substance use among high-risk adolescents

A robust association has been reported between childhood adverse life events (ALEs) and risky substance use in adolescence. It remains unclear, however, what the impact of type and timing of these ALEs is. We investigated the association between ALEs and substance use in adolescents. ALEs were operationalized as broad (e.g., moving, parental divorce, family sickness) or physically threatening (physical and/or sexual abuse). First, we examined lifetime ALEs, followed by an investigation into their timing. The sample consisted of 909 adolescents (aged 12-18 years) from a cohort oversampled on high levels of emotional and behavioral problems. The primary caregiver indicated which ALEs each adolescent experienced across their lifetime. Adolescents self-reported on number and frequency of substances used. Poisson and ordinal regression models were used to model the associations. The associations between lifetime ALEs and a substance used were observed only for physical ALEs (incidence rate ratio 1.18 [1.03, 1.35], p = 0.02). When investigating timing, physical ALEs after the age of 12 predicted number of substances used (IRR 1.36 [1.13, 1.63], p < .001). Recent ALEs (occurring after age 12) seem to have considerable impact on substance use. Alcohol and drugs as a coping mechanism were considered a plausible explanation for the results.

Association between childhood maltreatment and callous-unemotional traits in youth: A meta-analysis

Callous-unemotional (CU) traits (i.e., lack of remorse or guilt, callous lack of empathy, deficient concern for the feelings of others) in youth with conduct problems confer risk for a particularly severe and persistent form of antisocial behaviour. Previous research has linked childhood maltreatment as a potential risk factor for CU traits, both primary (i.e., genetically underpinned) and secondary (i.e., environmentally influenced) variants, but findings have been inconsistent, and the association has not yet been tested in a meta-analysis. To address this gap, we conducted a meta-analysis to assess the nature and strength of the associations between childhood maltreatment and its subtypes with CU traits and potential variants (i.e., primary and secondary CU traits). A systematic search identified 29 eligible studies including 9,894 participants (42% female) between the ages of 3 and 18 years (Mage=14.22 years, SD = 1.07). Results revealed a significant moderate positive association between childhood maltreatment and CU traits. All subtypes of maltreatment bar sexual abuse were significantly associated with CU traits. However, it was not possible to compare primary and secondary CU traits directly due to inconsistencies in how they are defined. The limitations posed by current research signal the need for clinical and operational guidelines on how to define primary and secondary CU traits. Additionally, prospective longitudinal, genetically informed research is needed to clarify if maltreatment is a causal risk factor for CU traits.

Association of Child Sexual Abuse Victimization and Murderous Behaviors and the Mediating Role of Psychological Adjustment among College Students in China

A history of child sexual abuse (CSA) is associated with a variety of psychological issues and conduct disorders in adolescents. However, little is known about the association between CSA and its characteristics and murderous behaviors in young adults. The purpose of this study was to examine this relationship and explore the mediating effect of psychological adjustment (PA). A cross-sectional study was conducted with 4034 college students in Anhui Province, China. The participants were invited to complete self-report questionnaires regarding the history of CSA, self-perceived PA and murderous behaviors. PA was evaluated by two of the most important indicators: resilience and emotional release. Mediation analyses were computed via parallel mediation models. Of the participants, 14.1% reported experiencing CSA. After controlling for potential confounders, CSA victimization was robustly and positively associated with murderous ideation (OR: 2.36, 95% CI: 1.77-3.14), murderous plans (OR: 4.02, 95% CI: 2.63-6.12), murderous preparation (OR: 3.87, 95% CI: 2.37-6.31), and murderous attempts (OR: 5.35, 95% CI: 3.11-9.21). CSA victimization that was persistent and of the combined contact or noncontact types greatly increased the risk of murderous behaviors. A dose-response relationship was observed between the duration of experienced CSA and murderous behaviors. Furthermore, the results of the mediation analysis revealed that PA partially mediated the relationship between CSA victimization and murderous behaviors. Therefore, PA protects against the development of murderous behaviors in abused individuals. These findings have important implications for the prevention and intervention of murderous behaviors in adolescents who experienced CSA, highlighting the importance of considering PA as a protective role in this relationship.

A Systematic Review of the Biological Correlates and Consequences of Childhood Maltreatment and Adverse Childhood Experiences

Childhood maltreatment (CM) and adverse childhood experiences (ACEs) are two primary forms of interpersonal victimization that have been associated with a host of deleterious health outcomes. Studies over the past decade have begun to use a range of biologically informed methods to better understand the role biology plays in the relationship between CM, ACEs, and later life outcomes. This line of research has shown that both forms of victimization occur at sensitive periods of development, which can increase the likelihood of "getting under the skin" and influence health and behavior across the life course. This review examines the current state of knowledge on this hypothesis. One hundred and ninety-nine studies are included in this systematic review based on criteria that they be written in English, use a biologically informed method, and be conducted on samples of humans. Results reveal that latent additive genetic influences, biological system functioning captured by biomarkers, polygenic risk scores, and neurobiological factors are commonly associated with exposure and response to CM and ACEs. The implication of these findings for the existing body of research on early life victimization and recommendations for future research and policy are discussed.

Associations Among Age of First Experience of Violence, Type of Victimization, Polyvictimization, and Mental Distress in Nigerian Females

This study explored associations of age of first victimization, sexual violence (SV), physical violence (PV), polyvictimization, and mental distress among females in Nigeria (n = 1,766, 13-24 years old) using the nationally representative 2014 Nigeria Violence Against Children Survey. Multinomial logistic regressions were performed. Nigerian females reporting SV victimization and polyvictimization were more likely to experience higher mental distress. The older the female was at the time of PV victimization, the greater the risk for mental distress. Violence is prevalent in Nigeria and its impact on youth's health is severe. However, evidence-based and data-driven policies and programs can reduce and prevent violence.

Testing Deprivation and Threat: A Preregistered Network Analysis of the Dimensions of Early Adversity

Despite abundant evidence of the detrimental effects of childhood adversity, its nature and underlying mechanisms remain contested. One influential theory, the dimensional model of adversity and psychopathology, proposes deprivation and threat as distinct dimensions of early experience. In this preregistered analysis of data from the Avon Longitudinal Study of Parents and Children (ALSPAC), we used a network and clustering approach to assess the dimensionality of relationships between childhood adversity and adolescent cognition and emotional functioning, and we used recursive partitioning to identify timing effects. We found evidence that deprivation and threat are separate dimensions of adversity and that early experiences of deprivation cluster with later measures of cognition and emotional functioning. This cluster varies by age of exposure; it includes fewer forms of deprivation as children grow from infancy to middle childhood. Our measures did not form a specific cluster linking threat to emotional functioning.

Time Dimension of Childhood Adversities and Externalizing Behavior Among Children of Teen Mothers: Sensitive Period Hypothesis vs. Accumulation Hypothesis

Childhood adversities are associated with compromised behavioral health later in life. However, less attention has been paid to how time contributes to the damaging effects of adversity exposure. In addition, the differential impact of childhood maltreatment and household dysfunction has been understudied. The current study tested (a) the sensitive period hypothesis regarding timing of childhood adversity on externalizing behavior, (b) the accumulation hypothesis regarding the associations between the duration of childhood adversity and externalizing behavior, and (c) the domain-specific impact of childhood adversity on externalizing behavior. Data came from the Young Women and Child Development Study (N = 240). Childhood adversity was measured at seven periods (age range: 5.5-16), which were used to test the sensitive period hypothesis. Childhood adversity at each time period was summed across seven time periods to test the accumulation measure representing the duration of childhood adversity. Least angle and multiple regression analyses were conducted. Results supported the sensitive period hypothesis-the effect of childhood adversity was the most prominent at age 11.5, whereas the accumulation of childhood adversity time periods was not a significant predictor of later externalizing behavior. Probing childhood adversity by subdomains revealed maltreatment primarily accounted for externalizing behavior (p < .05). Findings suggest intervention efforts for children of teen mothers during early adolescence to prevent externalizing behavior in later adolescence. Unpacking childhood adversity may illuminate key areas of vulnerability to externalizing behavior.

Social Relationship as a Factor for the Development of Stress Incubation in Adult Mice

While stress reactions can emerge long after the triggering event, it remains elusive how they emerge after a protracted, seemingly stress-free period during which stress incubates. Here, we study the behavioral development in mice isolated after observing an aggressive encounter inflicted upon their pair-housed partners. We developed a spatially resolved fine-scale behavioral analysis and applied it to standard behavioral tests. It reveals that the seemingly sudden behavioral changes developed gradually. These behavioral changes were not observed if the aggressive encounter happened to a stranger mouse, suggesting that social bonding is a prerequisite for stress incubation in this paradigm. This finding was corroborated by hemisphere-specific morphological changes in cortex regions centering at the anterior cingulate cortex, a cognitive and emotional center. Our non-invasive analytical methods to capture informative behavioral details may have applications beyond laboratory animals.

Age at first exposure to violence and later mental health outcomes: A sex-disaggregated, multi-country analysis in sub-Saharan Africa

BACKGROUND

A growing body of research has begun examining the relationship between a child's age at first exposure to violence and outcomes of mental wellbeing, though no studies have assessed these relationships in the sub-Saharan African (SSA) region.

OBJECTIVE

Given known gender and sex differences in violence exposure and mental health symptomology, this study conducts a multi-country, gender-stratified analysis of the relationship between age at first incident of physical violence and outcomes of wellbeing in SSA.

PARTICIPANTS AND SETTING

This study uses data from the Violence Against Children Surveys on 13-24-year-old males and females in five SSA countries (Kenya (2010), Malawi (2013), Nigeria (2014), Tanzania (2009), and Uganda (2015)).

METHODS

The predictor of interest is a categorical variable indicating whether a respondent's first exposure to physical violence took place from 0 to 5, 6-11, 12 and older, or never. Outcomes of interest include: sadness, anxiety, suicide ideation, smoking, drug use, and alcohol use. Employing both country-specific and pooled data, gender-stratified, multiple logistic regressions are used to estimate the effect of age at first exposure to physical violence on the six outcomes of interest.

RESULTS

Findings show significant variation across countries in age at first exposure to physical violence. For females, findings reveal no association between age at first exposure and outcomes of wellbeing; all periods were equally associated with poor outcomes. For males, results show increased likelihood of anxiety, suicide ideation, and alcohol use when the first violence exposure occurred from 0 to 5 years.

CONCLUSIONS

This study advances the literature on gender and sex differences in mental health symptomology, suggesting that boys and girls may exhibit different symptomology in response to comparable exposures to violence.

Change of pace: How developmental tempo varies to accommodate failed provision of early needs

The interplay of genes and environments (GxE) is a fundamental source of variation in behavioral and developmental outcomes. Although the role of developmental time (T) in the unfolding of such interactions has yet to be fully considered, GxE operates within a temporal frame of reference across multiple timescales and degrees of biological complexity. Here, we consider GxExT interactions to understand adversity-induced developmental acceleration or deceleration whereby environmental conditions hasten or hinder children's development. To date, developmental pace changes have been largely explained through a focus on the individual: for example, how adversity "wears down" aging biological systems or how adversity accelerates or decelerates maturation to optimize reproductive fitness. We broaden such theories by positing shifts in developmental pace in response to the parent-child dyad's capacity or incapacity for meeting children's early, physiological and safety needs. We describe empirical evidence and potential neurobiological mechanisms supporting this new conceptualization of developmental acceleration and deceleration. We conclude with suggestions for future research on the developmental consequences of early adverse exposures.

Association of Maternal Stress and Social Support During Pregnancy With Growth Marks in Children's Primary Tooth Enamel

IMPORTANCE

Exposure to maternal psychosocial stressors during the prenatal and perinatal periods can have major long-term mental health consequences for children. However, valid and inexpensive biomarkers are currently unavailable to identify children who have been exposed to psychosocial stress and the buffers of stress exposure.

OBJECTIVE

To assess whether a growth mark in tooth enamel, the neonatal line, is associated with exposure to prenatal and perinatal maternal psychosocial factors.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study used exfoliated primary canine teeth and epidemiological survey data from 70 children enrolled in the Avon Longitudinal Study of Parents and Children, a birth cohort based in Bristol, England. Exfoliated teeth were collected from children at 5 to 7 years of age. Data were collected from January 1, 1991, to December 31, 1998, and were analyzed from January 1, 2019, to August 10, 2021.

EXPOSURES

Four types of prenatal and perinatal maternal psychosocial factors were studied: stressful life events, psychopathological history, neighborhood disadvantage, and social support. Data were collected from mailed-in questionnaires completed during and shortly after pregnancy.

MAIN OUTCOMES AND MEASURES

Neonatal line width measured within 3 portions of the tooth crown (the cuspal, middle, and innermost third) in exfoliated primary canines.

RESULTS

A total of 70 children (34 of 70 [48.7%] male; 63 of 67 [94.0%] White) were studied. Most children were born full term (57 [83.8%]) and to mothers of typical child-bearing age (60 [88.2%]). Neonatal lines were wider in the canines of children born to mothers who self-reported severe lifetime depression (β = 3.35; 95% CI, 1.48-5.23; P = .001), any lifetime psychiatric problems (β = 2.66; 95% CI, 0.92-4.41; P = .003), or elevated anxiety or depressive symptoms at 32 weeks' gestation (β = 2.29; 95% CI, 0.38-4.20; P = .02). By contrast, neonatal lines were narrower in children born to mothers who self-reported high social support shortly after birth (β = -2.04; 95% CI, -3.70 to -0.38; P = .02). The magnitude of these associations was large, up to 1.2 SD unit differences, and persisted after adjusting for other risk factors.

CONCLUSIONS AND RELEVANCE

In this cohort study, neonatal line width was associated with exposure to maternal perinatal psychosocial factors. Replication and validation of these findings can further evaluate teeth as possible new biomarkers.

Impact of Early Life Stress on Reward Circuit Function and Regulation

Early life stress - including experience of child maltreatment, neglect, separation from or loss of a parent, and other forms of adversity - increases lifetime risk of mood, anxiety, and substance use disorders. A major component of this risk may be early life stress-induced alterations in motivation and reward processing, mediated by changes in the nucleus accumbens (NAc) and ventral tegmental area (VTA). Here, we review evidence of the impact of early life stress on reward circuit structure and function from human and animal models, with a focus on the NAc. We then connect these results to emerging theoretical models about the indirect and direct impacts of early life stress on reward circuit development. Through this review and synthesis, we aim to highlight open research questions and suggest avenues of future study in service of basic science, as well as applied insights. Understanding how early life stress alters reward circuit development, function, and motivated behaviors is a critical first step toward developing the ability to predict, prevent, and treat stress-related psychopathology spanning mood, anxiety, and substance use disorders.

Genome-wide DNA methylation patterns associated with general psychopathology in children

Psychiatric symptoms are interrelated and found to be largely captured by a general psychopathology factor (GPF). Although epigenetic mechanisms, such as DNA methylation (DNAm), have been linked to individual psychiatric outcomes, associations with GPF remain unclear. Using data from 440 children aged 10 years participating in the Generation R Study, we examined the associations of DNAm with both general and specific (internalizing, externalizing) factors of psychopathology. Genome-wide DNAm levels, measured in peripheral blood using the Illumina 450K array, were clustered into wider co-methylation networks ('modules') using a weighted gene co-expression network analysis. One co-methylated module associated with GPF after multiple testing correction, while none associated with the specific factors. This module comprised of 218 CpG probes, of which 198 mapped onto different genes. The CpG most strongly driving the association with GPF was annotated to FZD1, a gene that has been implicated in schizophrenia and wider neurological processes. Associations between the probes contained in the co-methylated module and GPF were supported in an independent sample of children from the Avon Longitudinal Study of Parents and Children (ALSPAC), as evidenced by significant correlations in effect sizes. These findings might contribute to improving our understanding of dynamic molecular processes underlying complex psychiatric phenotypes.

Gene-environment correlations and causal effects of childhood maltreatment on physical and mental health: a genetically informed approach

BACKGROUND

Childhood maltreatment is associated with poor mental and physical health. However, the mechanisms of gene-environment correlations and the potential causal effects of childhood maltreatment on health are unknown. Using genetics, we aimed to delineate the sources of gene-environment correlation for childhood maltreatment and the causal relationship between childhood maltreatment and health.

METHODS

We did a genome-wide association study meta-analysis of childhood maltreatment using data from the UK Biobank (n=143 473), Psychiatric Genomics Consortium (n=26 290), Avon Longitudinal Study of Parents and Children (n=8346), Adolescent Brain Cognitive Development Study (n=5400), and Generation R (n=1905). We included individuals who had phenotypic and genetic data available. We investigated single nucleotide polymorphism heritability and genetic correlations among different subtypes, operationalisations, and reports of childhood maltreatment. Family-based and population-based polygenic score analyses were done to elucidate gene-environment correlation mechanisms. We used genetic correlation and Mendelian randomisation analyses to identify shared genetics and test causal relationships between childhood maltreatment and mental and physical health conditions.

FINDINGS

Our meta-analysis of genome-wide association studies (N=185 414) identified 14 independent loci associated with childhood maltreatment (13 novel). We identified high genetic overlap (genetic correlations 0·24-1·00) among different maltreatment operationalisations, subtypes, and reporting methods. Within-family analyses provided some support for active and reactive gene-environment correlation but did not show the absence of passive gene-environment correlation. Robust Mendelian randomisation suggested a potential causal role of childhood maltreatment in depression (unidirectional), as well as both schizophrenia and ADHD (bidirectional), but not in physical health conditions (coronary artery disease, type 2 diabetes) or inflammation (C-reactive protein concentration).

INTERPRETATION

Childhood maltreatment has a heritable component, with substantial genetic correlations among different operationalisations, subtypes, and retrospective and prospective reports of childhood maltreatment. Family-based analyses point to a role of active and reactive gene-environment correlation, with equivocal support for passive correlation. Mendelian randomisation supports a (primarily bidirectional) causal role of childhood maltreatment on mental health, but not on physical health conditions. Our study identifies research avenues to inform the prevention of childhood maltreatment and its long-term effects.

FUNDING

Wellcome Trust, UK Medical Research Council, Horizon 2020, National Institute of Mental Health, and National Institute for Health Research Biomedical Research Centre.

Future directions in personality pathology development research from a trainee perspective: Suggestions for theory, methodology, and practice

Research on personality disorder (PD) development has received increased attention in the last two decades, spurring reconceptualization in theoretical models of etiology, use of advanced methods, and development of effective treatments. The current manuscript briefly reviews the state of the field and proposes avenues of new research on the development of personality pathology in theoretical, methodological, and clinical veins. We identify the need to adopt a unifying and comprehensive theory to describe PD development across the lifespan, novel statistical methods to complement traditional methods relied on thus far, and the adoption of developmentally sensitive interventions that are disseminated to professionals and trainees alike. These directions for future research aim to augment prevention efforts to reduce the burden of PDs earlier in life.

Exposure to Bullying and General Psychopathology: A Prospective, Longitudinal Study

Although there is mounting evidence that the experience of being bullied associates with both internalizing and externalizing symptoms, it is not known yet whether the identified associations are specific to these symptoms, or shared between them. The primary focus of this study is to assess the prospective associations of bullying exposure with both general and specific (i.e., internalizing, externalizing) factors of psychopathology. This study included data from 6,210 children participating in the Avon Longitudinal Study of Parents and Children (ALSPAC). Child bullying was measured by self-report at ages 8 and 10 years. Child psychopathology symptoms were assessed by parent-interview, using the Development and Well-being Assessment (DAWBA) at ages 7 and 13 years. Bullying exposure significantly associated with the general psychopathology factor in early adolescence. In particular, chronically victimized youth exposed to multiple forms of bullying (i.e., both overt and relational) showed higher levels of general psychopathology. Bullying exposure also associated with both internalizing and externalizing factors from the correlated-factors model. However, the effect estimates for these factors decreased considerably in size and dropped to insignificant for the internalizing factor after extracting the shared variance that belongs to the general factor of psychopathology. Using an integrative longitudinal model, we found that higher levels of general psychopathology at age 7 also associated with bullying exposure at age 8 which, in turn, associated with general psychopathology at age 13 through its two-year continuity. Findings suggest that exposure to bullying is a risk factor for a more general vulnerability to psychopathology.

Why achieving gender equality is of fundamental importance to improve the health and well-being of future generations: a DOHaD perspective

Despite progress in gender equality, women continue to be disadvantaged compared with men. Worldwide, women are more often confronted with poverty, violence, and mental health problems, and they have less access to food and education. All these factors do not only affect women themselves, but also have a negative impact on the child's early environment and impair its early development, thereby reducing the health and well-being of future generations. Framing gender equality as a women's issue fails to highlight the importance of gender equality for the health and well-being of the next generation. As a scientific community investigating early human development and health, we have failed to fully recognize and underscore the importance of gender equality in achieving the best possible start for every child. If women and men had equal rights and opportunities, their children would be more likely to reach their full potential which would improve the health and well-being of future generations. Our studies and interventions have not fully taken into account the complexity of gender inequality and women's disadvantaged positions in society. We need better insight into the complex adaptive interactions between various societal and human factors contributing to gender inequality and find approaches that take this complexity into account. If we want DOHaD science to have societal impact, we should strive beyond gender equality for gender equity and help women achieve equal rights and opportunities. We need to work with public health professionals, human rights activists, and policymakers to gauge the importance of gender equality. After all, gender equality is not only a fundamental human right, but also a necessary foundation for healthier future generations.

Epigenomics of being bullied: changes in DNA methylation following bullying exposure

Bullying among children is ubiquitous and associated with pervasive mental health problems. However, little is known about the biological pathways that change after exposure to bullying. Epigenome-wide changes in DNA methylation in peripheral blood were studied from pre- to post measurement of bullying exposure, in a longitudinal study of the population-based Generation R Study and Avon Longitudinal Study of Parents and Children (combined n = 1,352). Linear mixed-model results were meta-analysed to estimate how DNA methylation changed as a function of exposure to bullying. Sensitivity analyses including co-occurring child characteristics and risks were performed, as well as a Gene Ontology analysis. A candidate follow-up was employed for CpG (cytosine-phosphate-guanine) sites annotated to 5-HTT and NR3C1. One site, cg17312179, showed small changes in DNA methylation associated to bullying exposure (b = -2.67e-03, SE = 4.97e-04, p = 7.17e-08). This site is annotated to RAB14, an oncogene related to Golgi apparatus functioning, and its methylation levels decreased for exposed but increased for non-exposed. This result was consistent across sensitivity analyses. Enriched Gene Ontology pathways for differentially methylated sites included cardiac function and neurodevelopmental processes. Top CpG sites tended to have overall low levels of DNA methylation, decreasing in exposed, increasing in non-exposed individuals. There were no gene-wide corrected findings for 5-HTT and NR3C1. This is the first study to identify changes in DNA methylation associated with bullying exposure at the epigenome-wide significance level. Consistent with other population-based studies, we do not find evidence for strong associations between bullying exposure and DNA methylation.

Observed infant-parent attachment and brain morphology in middle childhood- A population-based study

Poor quality of the early infant-parent bond predicts later child problems. Infant-parent attachment has been suggested to influence brain development, but this association has hardly been examined. In adults, larger amygdala volumes have been described in relation to early attachment disorganization; neuroimaging studies of attachment in children, however, are lacking. We examined the association between infant-parent attachment and brain morphology in 551 children from a population-based cohort in the Netherlands. Infant-parent attachment was observed with the Strange-Situation Procedure at age 14 months and different brain measures were collected with magnetic resonance imaging at mean age 10 years. Children with disorganized infant attachment had larger hippocampal volumes than those with organized attachment patterns. This finding was robust to the adjustment for confounders and consistent across hemispheres. The association was not explained by cognitive or emotional and behavioral problems. Disorganized attachment did not predict any other difference in brain morphology. Moreover, children with insecure organized infant attachment patterns did not differ from those who were securely attached in any brain outcome. Causality cannot be inferred, but our findings in this large population-based study provide novel evidence for a long-term association between the quality of infant-parent attachment and specific brain differences in childhood.

Understanding the Neurobiological Implications of Maltreatment: A Commentary on the Special Issue

A large body of evidence demonstrates the deleterious effects of childhood maltreatment that span across multiple levels of functioning and throughout development. This commentary highlights the important research in this special issue of Child Maltreatment that advances our understanding of the neural and physiological implications of maltreatment. Throughout, the commentary calls attention to critical issues in the study of maltreatment and neurobiological processes for future work in this area.

Frequent Bullying Involvement and Brain Morphology in Children

Background: Over the past few decades, bullying has been recognized as a considerable public health concern. Involvement in bullying is associated with poor long-term social and psychiatric outcomes for both perpetrators and targets of bullying. Despite this concerning prognosis, few studies have investigated possible neurobiological correlates of bullying involvement that may explain the long-term impact of bullying. Cortical thickness is ideally suited for examining deviations in typical brain development, as it has been shown to detect subtle differences in children with psychopathology. We tested associations between bullying involvement and cortical thickness using a large, population-based cohort. Methods: The study sample consisted of 2,602 participants from the Generation R Study. When children were 8 years old, parents and teachers reported on common forms of child bullying involvement (physical, verbal, and relational). Questions ascertained whether a child was involved as a perpetrator (n = 82), a target of bullying (n = 92), as a combined perpetrator and target of bullying (n = 47), or uninvolved in frequent bullying (n = 2,381). High-resolution structural MRI was conducted when children were 10 years of age. Cortical thickness estimates across the cortical mantle were compared among groups. Results: Children classified as frequent targets of bullying showed thicker cortex in the fusiform gyrus compared to those uninvolved in bullying (B = 0.108, p _corrected < 0.001). Results remained consistent when adjusted for socioeconomic factors, general intelligence, and psychiatric symptoms. Children classified as frequent perpetrators showed thinner cortex in the cuneus region; however, this association did not survive stringent correction for multiple testing. Lastly, no differences in cortical thickness were observed in perpetrator-targets. Discussion: Bullying involvement in young children was associated with differential cortical morphology. Specifically, the fusiform gyrus, often involved in facial processing, showed thicker cortex in targets of frequent bullying. Longitudinal data are necessary to demonstrate the temporality of the underlying neurobiology associated with bullying involvement.