Within-family designs are increasingly used to decompose genotype-trait associations into direct and indirect genetic effects. Many such designs, including trio designs or within-sibship designs, assume an absence of sibling indirect genetic effects. We expand two well-known molecular genetic within-family designs, one variance component (genome-based restricted maximum likelihood) and one trait-based (structural equation modeling with polygenic indices), to estimate sibling indirect genetic effects, along with direct genetic effects. We link the Norwegian Mother, Father, and Child Cohort Study (MoBa) to Norway's national education database to model genetic effects on national standardized testing results at ages 10, 13, and 14, and on parent-rated attention-deficit hyperactivity disorder (ADHD) symptoms at ages 3 and 8 in up to 15,971 genotyped and phenotyped siblings. Estimates of direct and indirect genetic effects from the genome-based restricted maximum likelihood and the structural equation modeling with polygenic indices approaches converge, albeit with the variance component estimates typically an order of magnitude greater than the trait-based estimates. We observe no indirect genetic effects of siblings on educational performance at any age, and only slightly negative indirect genetic effects of siblings on ADHD symptoms at age 3. We argue that the latter effect might reflect parental contrasting ratings. The results suggest that within-family models of educational performance are unlikely to be drastically biased by an assumption of absent sibling indirect genetic effects. Combining trait-based analyses with variance component analyses can benefit understanding of indirect genetic effects, especially when the effects are not specific to a particular mechanism.

Violence exposure is a well-established risk factor for adolescent conduct problems, yet longitudinal research in high-adversity, low- and middle-income countries (LMICs) remains limited. This study investigated whether early adolescent violence exposure predicts concurrent and longer-term conduct problems, and explored potential bidirectional associations and sex differences in a peri-urban South African community with high rates of poverty and violence. Data were drawn from the Thula Sana birth cohort (n = 357; 51.5% female), a longitudinal intervention study in Khayelitsha, South Africa. Adolescents were assessed at early (ages 12-14) and late adolescence (ages 16-19). Violence exposure was measured using adolescent self-report. Conduct problems were measured using adolescent and caregiver report in early adolescence and adolescent self-report in late adolescence. Multiple linear regressions tested cross-sectional associations, and cross-lagged panel models examined longitudinal and bidirectional associations, adjusting for contextual adversity and intervention status. Missing data were addressed using multiple imputation, and findings were confirmed through sensitivity analyses. Violence exposure was associated with higher concurrent conduct problems in early adolescence (β = .15-.19, p < .01) and predicted higher conduct problems in late adolescence (β = .12-.14, p < .05). The reverse pathway, from conduct problems to subsequent violence exposure, was not significant (β = .08-.11, p > .05). Interaction analyses did not provide evidence that associations differed by sex. Violence exposure in early adolescence represents a prospective risk factor for conduct problems in a high-adversity South African setting. Findings highlight the importance of early, contextually grounded violence prevention and the need for further research to test sex-specific pathways and inform the development of gender-responsive intervention strategies.

Domestic violence mechanisms are frequently transmitted across generations, representing a global issue demanding particular attention. This study investigates the intergenerational transmission of intimate partner violence (IPV) and parent-to-child violence (PCV) and whether participating in a multilevel preventive intervention (Fast Track) breaks this transmission. In high-risk elementary schools located in the United States, children considered at high risk for aggressive behavior based on teachers' and parents' screen scores were assigned to either a 10-year intervention or a control group based on their school. The Fast Track trial was registered at clinicaltrials.gov (NCT01653535) and was focused on parenting practices and children's intrapersonal, interpersonal, and academic skills. From the original 891 children, 374 participants with children aged less than 18 years (n = 191 intervention group, n = 183 control group) reported at age 34 their experience with domestic violence and their children's psychological adjustment. The intergenerational mediating pathway from high IPV in the first generation to high PCV in the second generation to greater total mental health difficulties in the third generation was statistically significant in the control group but not in the intervention group. IPV was intergenerationally transmitted by influencing PCV, with a negative effect on the third generation's mental health. Nevertheless, participation in the Fast Track intervention disrupted this cycle. These findings suggest the importance of policies to support preventive childhood interventions.

Parent-child interaction therapy (PCIT) improves parenting and child behavior, yet little is known about how dosage of its two phases, warm relationship building focused child-directed interaction (CDI) sessions and safe, effective discipline skills-focused parent-directed interaction (PDI) sessions, contributes to outcomes, particularly in child welfare-involved families. Understanding these dose-response patterns can clarify the pathways through which PCIT produces change. In a sample of 204 child welfare families with young children, we examined the dose-response relationship between each PCIT phase and key intervention outcomes of positive and negative parenting skills and disruptive child behavior problems. We also used sequential mediation models to test time-ordered intervention dosage effects (i.e., number of CDI sessions completed and subsequent number of PDI sessions completed) on the parent and child outcomes. Sequential mediation models showed that the PCIT intervention exerted significant indirect effects on increased positive parenting skills and decreased negative parenting behaviors and child behavior problems through higher dosage of relationship-enhancing CDI sessions followed by higher dosage of safe discipline-focused PDI sessions. Further, CDI dosage interacted with PDI dosage to predict greater gains in positive parenting skills outcomes. These results contribute new insights into the pathways through which PCIT shapes outcomes in a sample of child welfare-involved families. Findings also highlight the significant unique contribution that limit-setting-oriented PDI, a relatively understudied phase of PCIT, plays in enhancing positive parenting skills and mitigating child behavior problems.

Prospective and retrospective measures of childhood maltreatment often identify different individuals and are differentially associated with psychopathology. This study examines psycho-social factors that may explain discrepancies between these measures. Data were drawn from the Environmental Risk Longitudinal Twin Study, a nationally representative birth cohort of 2,232 children born in 1994-1995 across England and Wales and followed to age 18 (93% retention). Childhood maltreatment was assessed through: (a) prospective assessments from caregivers, researchers, and clinicians at ages 5-12, and (b) retrospective self-reports at age 18 using the Childhood Trauma Questionnaire (for maltreatment occurring up to age 12). For the analyses, we focused on participants identified as maltreated from either measure (n = 290) and an a-priori selected array of potential explanatory variables assessed between ages 5-18. We conducted two sets of analyses: comparing individuals with only prospectively identified maltreatment to those identified by both prospective and retrospective measures to understand why some participants did not retrospectively report or recall maltreatment; and comparing individuals with only retrospective self-reports to those identified by both prospective and retrospective measures to understand why maltreatment had not been detected prospectively. Participants in the prospective-only group reported greater social support over the life course and lower psychopathology at age 18 compared to those identified through both prospective and retrospective measures. Individuals in the retrospective-only group had higher socioeconomic status, higher self-reported adult involvement at age 12, and less exposure to domestic violence compared to those identified through both prospective and retrospective measures. Our findings suggest that perceptions of social support and better mental health may buffer retrospective recall of childhood maltreatment in those with prospective measures. Furthermore, more positive family functioning and socioeconomic factors may hamper prospective detection of childhood maltreatment in those who retrospectively report it.

The issue of suicide among youth with disabilities transitioning into adulthood is a serious public health issue. In navigating this transition, youth with disabilities encounter unique obstacles that require careful consideration and support. This study aims to identify resource profiles among youth with disabilities and their association with suicide attempts in early adulthood. Using data from the National Longitudinal Study of Adolescent Health (Add Health), this study included 1,472 youth with disabilities. A Gaussian finite mixture model (GMM) was employed to identify underlying distinct groups of youth with disabilities based on their available resources. Four latent classes emerged: (1) Socioeconomically Advantaged and Socially Supportive (37%); (2) Socioeconomically Advantaged, but Socially Isolated (28%); (3) Socioeconomically Disadvantaged and Socially Isolated (20%); and (4) Socioeconomically Disadvantaged, but Socially Supportive (15%). Results from the generalized linear mixed model (GLMM) considering a longer transition period into adulthood up to age 32 and relevant time-varying factors found that youth in Socioeconomically Advantaged, but Socially Isolated and Socioeconomically Disadvantaged, but Socially Supportive had a significantly lower likelihood of suicide attempts compared to those in Socioeconomically Advantaged and Socially Supportive. The likelihood of suicide attempts for youth with learning disabilities was significantly lower than for those with physical disabilities, while a history of suicide attempts in adolescence and experience with a death by suicide of family members or friends increased the odds of suicide attempts. The study highlights the heterogeneity of youth with disabilities, demonstrating how demographic characteristics, disability-specific needs, family and school environments and social support systems intersect to influence suicide attempt prevention.

Children often experience both posttraumatic stress (PTS) and depression after potentially traumatic events (PTEs). Latent class analyses (LCAs) identify subgroups with different co-occurring symptoms, but little is known about what predicts transitions between these symptom classes over time. Analyzing these transitions could reveal factors that influence the shift to classes with fewer internalizing symptoms. Using harmonized individual participant data (n = 787) from nine studies (United States, United Kingdom, Australia, and Switzerland) included in the Prospective studies of Acute Child Trauma and Recovery Data Archive (PACT/R), internalizing symptom classes (using PTS and depression items) were identified using LCAs for T1 (0-2 months posttrauma) and T2 (3-15 months posttrauma) separately. Latent transition analysis was used to examine predictors of transitions across symptom classes over time. Included predictors were age, gender, minority status, and trauma type. Five classes were identified at both time points: 'low internalizing' class (T1: 20%; T2: 40%), 'low PTS/moderate-high depression' class (T1: 20%; T2: 27%), 'moderate internalizing' class (T1: 25%; T2: 12%), 'moderate PTS/high depression' class (T1: 17%, T2: 14%), and 'high internalizing' class (T1: 16%, T2: 6%). 'Low internalizing' was the most common and stable response (87% stayed in this class). At both time points, 40% of all children were classified into either a 'low PTS/moderate-high depression' class or a 'moderate PTS/high depression' class. Children belonging to minority groups in their country of residence and children exposed to interpersonal PTEs were less likely to transition from the 'high internalizing' class to lower symptom classes. Most children show low PTS and depression symptoms after PTEs. When symptoms do develop, they usually involve both high depression and PTS, rather than high PTS with low depression. This underscores the importance of assessing both conditions and developing interventions that target multiple disorders. Minority children exposed to interpersonal trauma require special focus in research and treatment.

Strong daily living skills (DLS) are associated with positive outcomes. Prior studies have documented intellectual quotient (IQ)-DLS discrepancies in autistic individuals with average or higher cognitive abilities. Little work in this area includes individuals with co-occurring intellectual disability (ID) or examines IQ-DLS discrepancies at the level of DLS subdomains (i.e., Personal, Domestic, and Community skills). This study examined trajectories of IQ-DLS discrepancies from ages 2-25 in autistic individuals with ID. A total of 127 individuals from a well-characterized longitudinal cohort with verbal IQ < 70 at age 9 were included. IQ-DLS discrepancy scores were calculated by subtracting DLS AEs from nonverbal mental age (NVMA) estimates. Group-based trajectory modeling identified IQ-DLS discrepancy trajectory groups for the DLS domain and Personal, Domestic, and Community subdomains. One-way ANOVA and chi-square analyses were used to compare trajectory groups on demographic and phenotypic characteristics. Two DLS domain discrepancy trajectory groups emerged: IQ > DLS (cognitive abilities exceeded DLS) and IQ < DLS (DLS exceeded cognitive abilities); most participants (78%) were in the IQ > DLS group. An additional group, IQ = DLS (cognitive abilities and DLS were commensurate), emerged in each of the DLS subdomains, for a total of three trajectory groups. Within DLS subdomains, approximately 80% of participants were in either the IQ = DLS or the IQ < DLS trajectory group. In other words, examining scores at the DLS domain-level indicated most participants had cognitive abilities that exceeded DLS, but subdomain scores indicated most participants had DLS that equaled or exceeded cognitive abilities. These results challenge the notion that autism is usually associated with weaknesses in DLS compared to IQ. At the subdomain level, 80% of participants had DLS commensurate with or stronger than their cognitive abilities, indicating domain-level scores may obscure important variability in daily functioning. This work highlights the importance of including autistic individuals with ID in research; patterns observed in samples without ID may not be generalizable.

In a purely meritocratic society, educational outcomes would reflect ability and only ability. Vocabulary size is a common measure of cognitive ability that predicts educational outcomes but is confounded with socioeconomic circumstances (SEC). In preregistered analyses of the nationally representative UK Millennium Cohort Study data (N = 15,576), we used a series of multiple linear and logistic regression analyses to investigate the predictive value of age-5 vocabulary for age-16 educational outcomes and assess whether socioeconomic circumstance moderated this relation. We show that age-5 vocabulary strongly predicted age-16 educational attainment, even after adjusting for both SEC and caregiver vocabulary (OR = 1.62, 95% CIs = [1.52; 1.72]; β = .22, 95% CIs = [0.19; 0.24]). SEC also predicts educational attainment (OR = 2.05, 95% CIs = [1.92; 2.19]), and modifies the association between vocabulary and educational attainment, whereby a larger vocabulary was most advantageous for those in middle SEC groups (interaction term OR = 1.09 [1.03; 1.15]). Early child vocabulary is a strong predictor of children's educational outcomes - even when controlling for proxy measures of the home environment and genetics. Nonetheless, children who enter school with strong vocabulary skills but disadvantaged socioeconomic circumstances still have only about a 50/50 chance of gaining gateway qualifications at age 16.

Conflict and crises have long-lasting and dramatic consequences on the mental health of children. We aimed to investigate the effectiveness of a psychosocial intervention on child mental health in Afghanistan. A two-arm cluster-randomized controlled trial was conducted in 83 rural primary schools within three provinces of Afghanistan. Children in Grades 3-6, their teachers, and one adult family member were enrolled. Schools were randomly assigned (1:1) to one of two groups: a treatment group composed of entire classes receiving a week-long classroom-based teacher-and-child psychosocial training, a one-day family engagement component, and a community-based system dynamics workshop; and a control group. Primary outcomes were anxiety, depression, life skills, self-efficacy, and resilience of the child. Secondary outcomes included reading and mathematical literacy, mathematical problem-solving, and school-based discrimination and stigma. This trial is registered with the International Standard Randomized Controlled Trials Number registry (ISRCTN83632872). In June 2021, 40 schools and n = 2,262 children were randomly assigned to the intervention group and 43 schools and n = 2,277 children to the control group. Preintervention survey started October 2, 2021 (first batch) and April 10th, 2023 (second batch). After a minimum of 4-month intervention, a postintervention survey took place. No treatment effects were found on anxiety, depression, resilience, self-efficacy, life skills, or stigma. Effects were found for academic outcomes and school-based discrimination. Shorter interventions displayed reductions in depression, anxiety, stigma, and discrimination, and an increase in life skills. Additional analyses showed significant effects on several outcomes for boys, on a few outcomes for girls, and in areas where the governmental did not disrupt the process. Classroom-based interventions delivered by trained field-based educational staff can effectively promote child mental health, social-emotional skills, and academic outcomes, and reduce stigma and discrimination among subgroups of children in conflict and crisis settings and have viable potential for scalability.