Prenatal and childhood exposures to heavy metals and their associations with child cognition, motor skills, behaviour and mental health

Pediatric arterial ischemic stroke involving the basal ganglia and/or thalamus is one of the most common causes of dystonia in children. Dystonia is a movement disorder in which excessive, involuntary muscle contractions result in twisting or repetitive movements, and abnormal posturing. The basal ganglia have been implicated in mood functioning and difficulties in these domains have been noted in adults with dystonia, yet little is currently known about these outcomes in children with dystonia following stroke. The objective of this study was to explore mental health outcomes in children with basal ganglia stroke and to determine whether children with post-stroke dystonia experience additional mental health difficulties. We also examined associations between mental health, cognitive, and motor outcomes. Participants were 75 children with stroke involving the basal ganglia and/or thalamus (dystonia n = 24, no dystonia n = 51). Results supported the presence of greater levels of anxiety and depression symptoms in children with post-stroke dystonia after stroke relative to those with similar patterns of stroke, but no dystonia. There were no significant associations between motor, cognitive, and mental health outcomes in children with post-stroke dystonia aside from depression and behavioral regulation. Motor and cognitive outcome were significantly associated in the stroke only group. These findings suggest maladaptive reorganization after stroke may contribute to motor, cognitive, and mental health outcomes in children with post-stroke dystonia, and that these outcomes are independent from one another.

Background: Air pollution exposure has been associated with adverse cognitive and mental health outcomes in children, adolescents, and adults, although youth may be particularly susceptible given ongoing brain development. However, the neurodevelopmental mechanisms underlying the associations among air pollution, cognition, and mental health remain unclear. We examined the impact of particulate matter (PM2.5) on resting-state functional connectivity (rsFC) of the default mode network (DMN) and three key attention networks: dorsal attention, ventral attention, and cingulo-opercular. Methods: Longitudinal changes in rsFC within/between networks were assessed from baseline (9-10 years) to the 2-year follow-up (11-12 years) in 10,072 youth (M ± SD = 9.93 + 0.63 years; 49% female) from the Adolescent Brain Cognitive Development (ABCD®) study. Annual ambient PM2.5 concentrations from the 2016 calendar year were estimated using hybrid ensemble spatiotemporal models. RsFC was estimated using functional neuroimaging. Linear mixed models were used to test associations between PM2.5 and change in rsFC over time while adjusting for relevant covariates (e.g., age, sex, race/ethnicity, parental education, and family income) and other air pollutants (O3, NO2). Results: A PM2.5 × time interaction was significant for within-network rsFC of the DMN such that higher PM2.5 concentrations were associated with a smaller increase in rsFC over time. Further, significant PM2.5 × time interactions were observed for between-network rsFC of the DMN and all three attention networks, with varied directionality. Conclusion: PM2.5 exposure was associated with alterations in the development and equilibrium of the DMN-a network implicated in self-referential processing-and anticorrelated attention networks, which may impact trajectories of cognitive and mental health symptoms across adolescence.

BackgroundThe increasing prevalence of screen-based activities among children has raised concerns about potential mental health effects. This study investigates the relationship between screen time and mental health outcomes in children aged 6 to 14 years in Saudi Arabia and Bahrain, focusing on emotional symptoms, conduct problems, hyperactivity, peer problems, and depressive symptoms.MethodsA cross-sectional study was conducted with 670 children recruited through stratified random sampling. Data were collected using self-reported questionnaires and parental surveys from January to June 2024. Screen time was assessed across four activities: TV viewing, smartphone usage, computer/tablet use, and video game playing, recorded separately for weekdays and weekends. Mental health was evaluated using the Strengths and Difficulties Questionnaire (SDQ) and the Children’s Depression Inventory (CDI). Descriptive statistics and Pearson correlation coefficients were used to analyze the data.ResultsParticipants reported a mean total screen time of 7.25 ± 2.4 hours on weekdays and 8.4 ± 2.65 hours on weekends. Smartphone usage (2.75 ± 1.3 hours/day) was the most common activity. Emotional symptoms, conduct problems and depressive symptoms were significantly correlated with both weekday and weekend total screen time (weekday r = 0.43, r = 0.31, and r = 0.49, respectively, p < 0.001; weekend r = 0.47, r = 0.33, and r = 0.54, respectively, p < 0.001). Smartphone usage had the strongest association with depressive symptoms (r = 0.46, p < 0.001).ConclusionThis study identifies a significant positive correlation between increased screen time and adverse mental health outcomes in children, particularly emotional symptoms and depressive symptoms. The findings emphasize the need for public health strategies to manage screen time and promote healthier digital habits to mitigate the potential negative effects on children's mental health.

Over 250 million children are developing sub-optimally due to their exposure to early life adversities. While previous studies have examined the independent effects of nutritional status, psychosocial adversities, and environmental pollutants on children's outcomes, little is known about their interaction and cumulative effects. This study aims to investigate the independent, interaction, and cumulative effects of nutritional, psychosocial, and environmental factors on children's cognitive development and mental health in urban and rural India. It also seeks to explain pathways leading to inequities in child outcomes at the individual, household, and neighbourhood levels. A mixed-methods prospective cohort study will be conducted on 1600 caregiver-child dyads (child age 3-10 years) in urban and rural India. Nutritional status, psychosocial adversities, environmental pollutants, and child mental health outcomes will be assessed using parent-report questionnaires. Performance-based measures will be used to assess cognitive outcomes. Venous blood and urine samples will be used to measure nutritional and pesticide biomarkers in 500 children. Indoor air pollution will be monitored in 200 households twice, during two seasons. Multilevel regression, weighted quantile sum regression, and Bayesian kernel machine regression will assess the individual and combined effects of exposures on child outcomes. Thematic analysis of in-depth interviews and focus group discussions will explore pathways to middle-and late childhood development inequities. The data will be used to formulate a Theory of Change (ToC) to explain the biological, psychosocial, and environmental origins of children's cognitive and mental health outcomes across the first decade of life in diverse Indian settings, which can inform interventions targets for promoting children's outcomes beyond the first 1000 days, potentially generalizable to similar under-resourced global settings. The COINCIDE research infrastructure will comprise a valuable global health resource, including prospective cohort data, validated study tools, and stored biological and environmental samples for future studies.

Childhood air pollution exposure is related to cognitive, educational and mental health outcomes in childhood and adolescence: A longitudinal birth cohort study.

Prenatal tobacco exposure, through maternal smoking during pregnancy, has been associated with adverse mental health outcomes in childhood. However, the mechanisms by which prenatal tobacco exposure compromises mental health later in life are unclear. We hypothesized that sensitized reactivity to stressful life events in early childhood mediates the effect of prenatal tobacco exposure on mental health outcomes in middle childhood, after accounting for earlier mental health outcomes. Data were from 12,308 mothers and their children drawn from the Avon Longitudinal Study of Parents and Children, a large prospective population-based study. Mothers' self-reports of smoking during pregnancy, mothers' ratings of their child's reactivity to stressful life events, and teachers' and mothers' ratings of the Strengths and Difficulties Questionnaire assessing 5 domains of mental health outcomes were measured. A positive association was found between prenatal tobacco exposure and stress reactivity between the ages of 2 and 6. In turn, stress reactivity was positively associated with peer (isolation), hyperactivity, conduct, and emotional problems (but not prosocial behaviors) between the ages of 7 and 11, after accounting for the mental health outcome at age 4 and other confounders. Heightened stress reactivity in preschool ages mediated the effect of prenatal tobacco exposure on adverse mental health outcomes between the ages of 7 and 11. Interventions to assist children exposed to tobacco smoke during gestation in coping with stressful life events may help mitigate psychiatric symptoms in this population.

This chapter provides an extensive description of the associations of physical activity and physical fitness with mental health outcomes in youths. Both physical activity and physical fitness have been considered relevant markers of physical health outcomes in children in the last decades. This chapter discusses whether they can also be considered markers of mental health in this population. Although most of the evidence thus far is observational, experimental studies have been conducted in recent years to investigate the cause–effect relation between physical activity and mental health in children. In summary, small- and medium-sized associations have been extensively confirmed in observational studies, while several experimental studies point to a small, yet positive, effect on mental health outcomes in children and adolescents. These associations include numerous psychological well-being and ill-being indicators. As such, these constructs could also be considered markers of mental health in youth. In addition, this chapter also discusses the potential mechanisms that may explain such beneficial effects, including neurobiological, psychosocial, and behavioural factors. All the available evidence and this mechanistic view are considered to propose some practicalities to guide teachers and professionals in the development of physical activity programmes to maximise the effects on mental health outcomes in children. The recommendations, based on the available evidence, include aspects such as the intensity of the physical activity, the duration of the sessions and programmes, and the context for the delivery to preserve a sound mind in children.

IntroductionThere is evidence that maternal perinatal depression is associated with adverse neurodevelopmental and mental health outcomes in children. No study has yet examined the association between maternal depressive symptoms during pregnancy and the postpartum period and the risk of oppositional-defiant disorder (ODD) in children and adolescents.ObjectivesThis study aimed to investigate whether there is an association between perinatal depressive symptoms and the risk of ODD in offspring from age 7 to 15 years.MethodsWe used data from the Avon Longitudinal Study of Parents and Children (ALSPAC), a population-based prospective birth cohort study in the UK. Offspring ODD at the age of 7, 10, 13 and 15 years were assessed by using parental reports the Development and Well-Being Assessment (DAWBA). We applied Generalized Estimating Equation (GEE) modelling to examine associations across the four time points.ResultsMaternal postnatal depressive symptoms were associated with more a two-fold increased risk of ODD overall. Third trimester depressive symptoms (measured at 32 weeks of gestation) increased risk of ODD by 72%. Offspring of mothers who had depressive symptoms both during pregnancy and in the first year of postpartum period have a four-fold increased risk of ODD over time (adjusted OR = 3.59 (1.98-6.52).Conclusions Offspring of mothers with perinatal depressive symptoms are at an increased risk of developing behavioural disorders.

This umbrella review examined the certainty and validity of available meta-analyses for the association between food insecurity (FI) and adverse health outcomes (AHOs) in children and adolescents. A comprehensive systematic search was conducted using three databases: PubMed/MEDLINE, Web of Science, and Scopus, until August 20, 2024. Effect sizes were recalculated using random effects models. The GRADE tool assessed evidence certainty, while AMSTAR-2 and the Newcastle-Ottawa Scale evaluated study quality. Twelve meta-analyses comprising of 108 pooled analyses (557,700 individuals) were included in this umbrella review. Food insecurity was found to be significantly associated with the increased risk of several AHOs in children and adolescents: anemia (OR: 1.50, 95% CI: 1.23 to 1.82; moderate certainty), obesity (OR: 1.16, 95% CI: 1.06 to 1.27; moderate certainty), stunting (OR: 1.12, 95% CI: 1.05 to 1.19; moderate certainty), and dental caries (OR: 1.70, 95% CI: 1.43 to 2.03; low certainty). Regarding mental health in children and adolescents, FI was found to be associated with an increased risk of suicidal ideation (OR: 1.08, 95% CI: 1.01 to 1.16; moderate certainty) and suicide plans (OR: 1.32, 95% CI: 1.14 to 1.54; moderate certainty). Further, there was found to be an increased risk in developmental outcomes (OR: 1.32, 95% CI: 1.10 to 1.59; moderate certainty) and externalizing behaviors (OR: 1.25, 95% CI: 1.08 to 1.44; low certainty). A protective association was observed for cognitive/math development disorders (OR: 0.84, 95% CI: 0.73 to 0.96; low certainty), which may be attributed to methodological limitations, though this finding requires further investigation. Food insecurity was shown to be associated with multiple AHOs in children and adolescents, with moderate to low certainty evidence. Findings should be interpreted cautiously due to substantial heterogeneity and the inclusion of low-quality meta-analyses. The observed heterogeneity and methodological limitations of the included meta-analyses suggest cautious application in designing prevention programs, particularly in designing evidence-informed nutritional and lifestyle interventions.

Schools are ideal settings for physical activity promotion; however, children and adolescents with disability have largely been neglected in school-based health promotion efforts. This review examines the effects of school-based physical activity interventions on academic, cognitive, and mental health outcomes of children and adolescents living with any type of disability (eg,intellectual, physical, behavioral). Six databases (PubMed, PsycINFO, Scopus, MEDLINE, SPORTDiscus, and Embase) were searched from inception to September 2024. Studies were included if they: (1)examined children or adolescents (5-18y) living with disability, (2)included an experimental or quasi-experimental study design, (3)delivered a school-based physical activity intervention, and (4)examined at least one academic, cognitive, or mental health outcome. Multilevel meta-analyses were conducted to examine intervention effects. Prespecified moderators were also examined. Thirty-three studies involving 1454 children and adolescents living with disability were included. Significant effects were found for cognitive (g = 0.42; 95% CI, 0.22 to 0.62) and mental health (g = 0.57; 95% CI, 0.21 to 0.94) outcomes, but not for academic outcomes. Disability classification, intervention length, and physical activity type significantly moderated intervention effects. School-based physical activity programs for children and adolescents with disability can improve measures of cognition and mental health, but not academic performance. Most studies examined children with attention-deficit/hyperactivity disorder, and few were conducted with adolescents which may limit generalizability of study findings. More high-quality research with robust study designs and larger more diverse samples are needed.

Background:Neurodevelopmental and mental health disorders in childhood constitute an emerging global concern, with adverse sequelae which span children’s physical, psychological and social well-being. The aetiology of these disorders is likely complex, multifactorial and polygenic. Polygenic risk scores (PRS), an estimate of an individual’s genetic liability toward a disorder, have been increasingly used in psychiatric research to explore genetic associations with disorders of interest. However, limited work delineates polygenic associations with development and mental health in childhood populations.We aimed to systematically review existing literature on associations between genetic risk (as measured by PRS) and neurodevelopmental and mental health outcomes in childhood and adolescence.Methods:Following the recommended Preferred Reporting Items for Meta-Analyses (PRISMA) guidelines, databases were searched using key search terms. The search commenced in March 2021 and concluded in June 2021. The studies eligible for inclusion were full-text articles investigating polygenic risk associations with neurodevelopmental and/or mental health outcomes in childhood or adolescence.Results:Fourteen studies were eligible for inclusion in this systematic review. The association between higher PRS for attention-deficit/hyperactivity disorder (ADHD) and adverse developmental/mental health outcomes in childhood and adolescence was reported by five studies. Additionally, associations between PRS for bipolar disorder or major depressive disorder and adverse outcomes of interest were also described by two studies; and two studies highlighted associations between schizophrenia PRS and mental health disorders in childhood. The remaining studies highlighted shared polygenic contributions between and within NDDs and mental health disorders in children.Conclusion:The findings of this systematic review suggest that PRS for neurodevelopmental and mental health disorders may associate with adverse neurodevelopmental and mental health outcomes from early childhood to adolescence. In addition, these associations seemed not to be phenotype-specific, suggesting potential shared genetic variation across the phenotypes of interest.

Emerging evidence from both human and preclinical research indicates that cannabis use during pregnancy can influence offspring neurodevelopmental outcomes. Δ9-Tetrahydrocannabinol (THC), the psychoactive compound in cannabis, permeates the placental barrier and modulates the endocannabinoid system, a critical regulator of neurodevelopmental processes. Although converging findings suggest that prenatal cannabis exposure (PCE) is associated with adverse cognitive and mental health outcomes in offspring, the neurobiological mechanisms underlying these associations—particularly in terms of large-scale functional brain network organization—remain poorly understood. In this large-scale cross-sectional study, we leveraged baseline data from the ongoing longitudinal Adolescent Brain Cognitive Development (ABCD) Study, which enrolled 11,875 children across 22 research sites. We examined the effects of PCE, occurring both before and after maternal awareness of pregnancy, on offspring psychopathology and cognitive performance. Resting-state functional MRI data were analyzed using the NeuroMark framework, enabling the identification of individualized intrinsic connectivity networks (ICNs) and estimation of functional network connectivity (FNC) among them. Associations between prenatal exposure, behavioral outcomes, and functional connectivity were assessed using linear mixed-effects models, controlling for a comprehensive set of familial, pregnancy-related, and child-specific covariates. Among 10,836 children (female/male = 5,194/5,642; mean age = 9.96 ± 0.62 years), 754 (6.96%) were prenatally exposed to cannabis. Compared with non-exposed peers, exposed children exhibited higher levels of psychopathology and poorer cognitive performance, except composite fluid cognition (Cohen’s d = − 0.1393 ~ 0.2451, false discovery rate [FDR]–corrected p < .05), consistent with prior reports linking PCE to adverse developmental outcomes. Importantly, prenatal exposure was associated with alterations in FNC that significantly overlapped with neurofunctional correlates of both mental health symptoms (positive correlations between t-statistics, r= 0.0641 ~ 0.5993, FDR-corrected p < .05) and cognitive performance (negative correlations, r = − 0.5438 ~ − 0.6665, FDR-corrected p < .05). These findings provide novel evidence that PCE is associated with altered large-scale brain network connectivity, which in turn relates to both cognitive and mental health outcomes in late childhood. The overlapping neurofunctional correlates of exposure and behavioral outcomes suggest that THC’s interaction with the endocannabinoid system may disrupt the maturation of functional brain networks, providing a potential mechanistic link between prenatal exposure and neurodevelopmental vulnerability.

BackgroundThe mental health of children and adolescents is a key area of health concern internationally. Previous empirical studies suggest that resilience may act as a protective mechanism towards the development of mental health problems. Resilience refers to the ability to employ a collection of protective factors to return to or maintain positive mental health following disadvantage or adversity. Schools represent a potential setting within which protective factors of all children and adolescents may be fostered through resilience-focussed interventions. Despite this potential, limited research has investigated the effectiveness of universal school-based resilience-focussed interventions on mental health outcomes in children and adolescents. The objective of the present review is to assess the effects of universal school-based resilience-focussed interventions, relative to a comparison group, on mental health outcomes in children and adolescents.Methods/designEligible studies will be randomised (including cluster-randomised) controlled trials of universal interventions explicitly described as resilience-focussed or comprising strategies to strengthen a minimum of three internal protective factors, targeting children aged 5 to 18 years, implemented within schools, and reporting a mental health outcome. Screening for studies will be conducted across six electronic databases: MEDLINE, PsycINFO, Educational Resources Information Center (ERIC), Excerpta Medica database (EMBASE), Cumulative Index to Nursing and Allied Health Literature (CINAHL), and the Cochrane Central Register of Controlled Trials (CENTRAL). Two reviewers will retrieve eligible articles, assess risk of bias, and extract data. Where studies are sufficiently homogenous and reported outcomes are amenable for pooled synthesis, meta-analysis will be performed. Narrative description will be used to synthesise trial outcome data where data cannot be combined or heterogeneity exists.DiscussionThis review will aid in building an evidence base for the effectiveness of universal school-based resilience-focussed interventions and in doing so provide an opportunity to better inform the development of interventions to potentially prevent mental health problems in child and adolescent populations.Systematic review registrationPROSPERO CRD42015025908

The main objective is to assess the impact of MBIs on anxiety, depression, and stress in children and adolescents. The secondary objective is to examine the modalities of MBIs used, the duration of interventions, and potential confounding factors, such as age. A comprehensive search of multiple databases was conducted to identify randomized clinical trials (RCTs) evaluating the effects of MBIs on mental health outcomes in children and adolescents. The research was registered in PROSPERO, adhered to PRISMA guidelines, employed the Cochrane Risk of Bias 2 tool, and calculated the effect sizes using mean differences. Thirteen RCTs were included; ten were identified as having some concerns, while three were classified as having a low risk of bias. Mindfulness-Based Stress Reduction (MBSR) demonstrated a small positive effect on depression and anxiety, while non-specific MBIs showed a moderate positive effect both on depression and anxiety. Mindfulness-Based Cognitive Therapy (MBCT) was effective in reducing anxiety, depression (moderate positive effects on both), and stress symptoms. In one study, no significant improvements were seen on both anxiety and depression (for MBCT) and in another study on anxiety (for MBCT/MBSR). The meta-analysis did not identify a significant effect of mindfulness interventions on depression or anxiety. The high heterogeneity suggests varying outcomes, requiring further study of moderating factors. While some studies suggest benefits from MBIs, mainly MBCT's ability to improve mental health outcomes in children and adolescents, their overall efficacy remains uncertain due to the high heterogeneity. The findings underscore the importance of considering the intervention type, duration, and moderating factors, such as age, when implementing MBIs.

Background: Childhood obesity is associated with an increased risk of anxiety and depressive symptoms, representing a growing global mental health concern. Aim: The aim of this review was to examine the impact of physical activity on anxiety and depressive symptoms in children and adolescents with overweight or obesity, with particular emphasis on underlying neurobiological, psychosocial, and behavioral mechanisms. Material and methods: This narrative review synthesizes current evidence on the effects of physical activity on mental health outcomes in children and adolescents with overweight or obesity. A literature search was conducted using PubMed, Scopus, and Web of Science, including studies published between January 2015 and January 2026. Both observational and interventional studies, including randomized controlled trials, systematic reviews, and meta-analyses, were considered. Findings were synthesized narratively. Results: Available evidence indicates that physical activity is associated with small-to-moderate reductions in depressive and anxiety symptoms in youth, with more consistent effects observed for depression. These benefits are mediated through multiple neurobiological, psychosocial, and behavioral pathways. Intervention effectiveness appears to depend on factors such as duration, intensity, supervision, and the inclusion of psychosocial components. However, substantial heterogeneity across studies and limited long-term data remain important limitations. Conclusions: Physical activity represents a promising, accessible, and cost-effective strategy for improving mental health outcomes in children and adolescents with overweight or obesity. To maximize benefits, interventions should be structured, inclusive, and supported by behavioral and motivational strategies. Further research is needed to optimize intervention design and clarify causal mechanisms.