Higher direct and indirect exposure to bullying has been linked to long-term increases in healthcare costs, worse mental health, and poorer social relationships, as well as a reduction in human capital accumulation and economic productivity. Consequently, preventing and mitigating the long-lasting negative effects of bullying victimization has become a worldwide challenge for school and health policies. This paper reviews the evidence linking early-life bullying victimization to adult socioeconomic outcomes and develops an integrative framework to explain (1) how bullying processes emerge and are sustained during childhood and adolescence; (2) how they affect labor opportunities in adulthood; (3) the mediating roles of skill, social capital, identity, and mental health; and (4) how social structures as well as individual characteristics determined early in life (e.g., innate capacities, vulnerability and susceptibility) may operate as moderators or potential confounders. Our framework draws from theoretical and empirical work in education and labor economics as well as in clinical and developmental psychology. Our integration and synthesis of how the processes relate over time provide researchers, practitioners, and policymakers with concrete directions for future research and support evidence-based arguments for the continued development and improvement of anti-bullying programs by both schools and governments.

OBJECTIVE:Attention-deficit/hyperactivity disorder (ADHD) diagnosed in childhood is associated with adverse socioeconomic outcomes, but questions remain about causality. Prior work is limited by single-timepoint assessments, narrow socioeconomic measurement, and inadequate control for genetic and environmental confounds. METHOD:We used data from the Minnesota Twin Family Study, a multi-decade longitudinal study of 2,764 twins, to examine associations between ADHD and socioeconomic status (SES) across development. Childhood ADHD was defined as meeting diagnostic criteria at baseline (n = 131). SES was measured with parental education and occupation, household income, and neighborhood disadvantage in childhood, and participants' own education, occupation, and income in adulthood. Co-twin control analyses accounted for genetic and shared environmental confounding. We examined apparent adult-onset ADHD (n = 32) as an exploratory comparison. RESULTS:Childhood ADHD was associated with both rearing family SES and adult education. In twin pairs discordant for childhood ADHD, the affected twin showed lower levels of education, indicating that the association is not entirely attributable to the intergenerational transmission of SES and consistent with a causal effect of ADHD. Within-pair differences in adult occupational status and income were not significant, suggesting that these associations reflect shared familial factors. Adult-onset ADHD showed weaker associations overall, with no significant within-pair effects. CONCLUSION:Lower SES in childhood was associated with childhood ADHD, which predicted lower adult SES, particularly for education. Co-twin analyses suggest the childhood ADHD-educational attainment association is not entirely attributable to genetic or familial confounds, whereas adult-onset ADHD showed weaker and less consistent patterns. STUDY REGISTRATION INFORMATION:ADHD and Socioeconomic Status: Approaching Causal Inference in a Longitudinal Study of Twins; https://osf.io/4kufm.

OBJECTIVE:This study examines whether school functioning (academic performance and motivation) and social/behavioral functioning (suspensions and peer affiliations) in high school mediate the association between childhood Attention-Deficit/Hyperactivity Disorder (ADHD) and adult educational attainment. METHOD:Participants were 3,762 twins (1,881 same-sex pairs; 52% female; 96% non-Hispanic White) from the population-based Minnesota Twin Family Study. Childhood ADHD symptoms were assessed via structured diagnostic interviews at intake (age 11 or 17, depending on cohort), mediators were assessed via teacher and self reports at age 17, and educational attainment was assessed in adulthood (mean age = 34.7 years). Mediation path models tested each indirect pathway, and co-twin comparisons were used to better isolate potential causal effects by controlling for familial confounding. RESULTS:At the individual level, all tested indirect paths linking ADHD to educational attainment were significant. However, co-twin control analyses indicated that most associations attenuated when accounting for familial confounding. Only the indirect path through academic motivation persisted after co-twin control, such that twins with greater academic motivation relative to their co-twin also had greater educational attainment, consistent with a potential causal effect. Academic performance and social/behavioral mediators did not show significant mediation after accounting for shared genetic and environmental factors. CONCLUSIONS:Academic motivation emerges as the most robust mediator linking childhood ADHD to reduced educational attainment. Interventions targeting student engagement, self-efficacy, and connection to school may improve long-term educational outcomes in youth with ADHD.

Adverse childhood experiences (ACEs) are strongly associated with increased risk of externalizing problems. Despite their prevalence in military populations, limited research links ACEs to longitudinal externalizing problem trajectories during military service transition. This study aimed to identify distinct trajectories of externalizing problems (deviant behavior, alcohol use, and drug use) in U.S. Army National Guard recruits and examine how baseline ACEs predict membership in higher-risk trajectories during the transition to military service. A longitudinal cohort of 707 Army National Guard recruits was assessed before basic combat training and at four follow-ups over 18 months. Growth mixture modeling was used to identify distinct trajectories for deviant behavior, alcohol use, and drug use, whereas logistic regression analyses were conducted to examine associations between baseline ACEs and trajectory group membership. For each domain, we identified distinct trajectory patterns beyond stable-low: decreasing-increasing and increasing-decreasing deviant behavior trajectories, stable-high and increasing alcohol use trajectories, and a variable drug-users trajectory. Relative to stable-low class membership, higher ACE scores were associated with increased odds of membership in the decreasing-increasing, OR = 1.26, 95% CI [1.12, 1.41], and increasing-decreasing, OR = 1.26, 95% CI [1.15, 1.37], deviant behavior; stable-high alcohol, OR = 1.13, 95% CI [1.03, 1.25]; and drug-users, OR = 1.19, 95% CI [1.11, 1.28], trajectories. Specific ACEs uniquely predicted higher-risk trajectories. These findings suggest that ACEs may have longitudinal effects on the unfolding of externalizing symptom trajectories among military recruits, highlighting the need to address preexisting developmental vulnerabilities when examining pathways to psychopathology during significant life transitions.

Purpose:Cannabis use is associated with increased risk for suicidality. However, the directionality of this association and the role of shared familial influences-such as genetics and environment-remains uncertain. Further, despite higher rates of cannabis use and suicidality endorsement in clinical samples, research in these populations is limited. This study examines cross-sectional and prospective associations between cannabis use and suicidality in a sample characterized by earlier cannabis initiation and heavier use than typically reported, while accounting for shared familial influences. Method:Adolescent sibling groups were recruited from Denver and San Diego (N = 1,261); at least one sibling was recruited from a substance use treatment program, alternative school, or juvenile probation. Participants completed clinical interviews assessing substance use and suicidality at three waves (2001--2019). Cannabis use frequency was examined as a predictor of suicidality using multilevel models accounting for shared familial influences and within-family clustering. Covariates included alcohol, tobacco, other substance use, age, and sex. Reverse associations and exploratory models assessing tobacco as a predictor were also examined. Results:Cannabis use was not associated with suicidality (all p's > 0.05). Exploratory analyses suggested a possible association between tobacco and suicidality (e.g., Wave 1 within-family effect: OR = 1.037, p = 0.016), though these associations were largely reduced to non-significance after accounting for other substance use. Conclusions:Findings in this high-risk clinical sample are inconsistent with literature linking cannabis use to suicidality in community samples. Results underscore the need for further research on the association between general and polysubstance use risk and suicidality.

BackgroundAdverse childhood experiences (ACEs) are associated with mental health problems, but many children who experience ACEs do not develop such difficulties. A warm and supportive adult presence in childhood is associated with a lower likelihood of developing mental health problems after exposure to ACEs. However, it is unclear whether this association is causal, as previous research has not accounted for genetic and environmental confounding.MethodsWe used the twin-difference design to strengthen causal inference about whether a warm and supportive adult presence protects children exposed to ACEs from mental health problems. Participants were from the Environmental Risk (E-Risk) Longitudinal Twin Study, a UK population-representative birth cohort of 2,232 same-sex twins. ACEs were measured prospectively from ages 5 to 12. Maternal warmth was assessed at ages 5 and 10 through maternal speech samples. Adult support was assessed through child reports at age 12. Mental health problems were assessed through interviews at age 12 with parents and teachers and participants at age 18.ResultsAmong children exposed to ACEs, those who experienced greater maternal warmth and adult support had lower levels of mental health problems at ages 12 and 18. In monozygotic twin-difference analyses, the protective effects of maternal warmth and adult support on mental health were attenuated by 70% for maternal warmth and 81% for adult support, compared to phenotypic analyses. Twins who experienced greater maternal warmth and adult support had minimal or no difference in mental health compared to their co-twins, concordant for ACE exposure.ConclusionsThe apparent protective effect of a warm, supportive adult against mental health problems following ACEs is largely explained by genetic and environmental confounding. This suggests that interventions which boost maternal warmth and adult support should be supplemented by components addressing wider family environments and heritable vulnerabilities in children exposed to adversity, to improve mental health.

Background: Cannabis use is associated with outcomes like income, legal problems, and psychopathology. This finding rests largely on correlational research designs, which rely at best on statistical controls for confounding. Here, we control for unmeasured confounders using a longitudinal study of twins. Method: In a sample of 4,078 American adult twins first assessed decades ago, we used cotwin control mixed effects models to evaluate the effect of lifetime average frequency of cannabis consumption measured on substance use, psychiatric, and psychosocial outcomes. Results: On average, participants had a lifetime cannabis frequency of about one to two times per month, across adolescence and adulthood. As expected, in individual-level analyses, cannabis use was significantly associated with almost all outcomes in the expected directions. However, when comparing each twin to their cotwin, which inherently controls for shared genes and environments, we observed within-pair differences consistent with possible causality in three of the 22 assessed outcomes: cannabis use disorder symptoms (beta(W-Pooled) = .15, SE = .02, p = 1.7 x10(-22)), frequency of tobacco use (beta(W-Pooled) = .06, SE = .01, p = 1.2 x10(-5)), and illicit drug involvement (beta(W-Pooled) = .06, SE = .02, p = 1.2 x 10(-4)). Covariate specification curve analyses indicated that within-pair effects on tobacco and illicit drug use, but not cannabis use disorder, attenuated substantially when covarying for lifetime alcohol and tobacco use. Conclusions: The cotwin control results suggest that more frequent cannabis use causes small increases in cannabis use disorder symptoms, approximately 1.3 symptoms when going from a once-a-year use to daily use. For other outcomes, our results are more consistent with familial confounding, at least in this community population of twins.

Psychophysiology can help elucidate the structure and developmental mechanisms of psychopathology, consistent with the Research Domain Criteria initiative. Cross-sectional research using categorical diagnoses indicates that P300 is an electrocortical endophenotype indexing genetic vulnerability to externalizing problems. However, current diagnostic systems' limitations impede a precise understanding of risk. The Hierarchical Taxonomy of Psychopathology (HiTOP) overcomes these limitations by delineating reliable dimensions ranging in specificity from broad spectra to narrow syndromes. The current study used a HiTOP-aligned approach to clarify P300's associations with a higher-order externalizing factor versus syndrome-specific manifestations within externalizing and internalizing spectra during middle and late adolescence. Participants from the Minnesota Twin Family Study's Enrichment Sample contributed psychophysiological and clinical data at age 14 (N = 930) and follow-up clinical data at age 17 (N = 913). Blunted target P300 at age 14 was selectively associated with externalizing as manifested at age 17 at the superspectrum level (rather than specific externalizing syndromes). Unlike in prior work, target P300 amplitude was positively associated with age 17 depressive symptoms (once controlling for standard stimuli). No association was observed with lifetime symptoms of childhood externalizing or depression evident by age 14. The results indicate that blunted target P300 elucidates specific risk for the development of late-adolescent/young-adult expressions of general externalizing, over and above symptoms evident by middle adolescence. Additionally, the findings speak to the synergistic utility of studying HiTOP-aligned dimensions using multiple measurement modalities to build a more comprehensive understanding of the development of psychopathology.

Although observational studies have shown that adolescent cannabis use is associated with impairments in important psychosocial domains, including peer, romantic, and parent–child relationships, educational outcomes, adult socioeconomic status, and legal consequences, mechanisms underlying these associations remain largely unclear. Cannabis use may have a deleterious causal effect on functioning, but it is also possible the association may be due to reverse causation or confounding by shared vulnerability factors that account for both cannabis use in adolescence and concurrent and subsequent psychosocial impairment. Causally informative studies that delineate these possibilities, including research using epidemiologic samples and quasi-experimental designs, are critical to move the field forward.

BACKGROUND:Military services provide a unique opportunity for studying resilience, a dynamic process of successful adaptation (ie, doing well in terms of functioning and symptoms) in response to significant adversity. Despite the tremendous interest in positive adaptation among military service members, little is known about the processes underlying their resilience. Understanding the neurobiological, cognitive, and social mechanisms underlying adaptive functioning following military stressor exposure is essential for enhancing the resilience of military service members. OBJECTIVE:The primary objective of the Advancing Research on Mechanisms of Resilience (ARMOR) longitudinal study is to characterize the trajectories of positive adaptation among young military recruits in response to basic combat training (BCT), a well-defined, uniform, and 10-week period of intense stress (aim 1), and identify promotive and protective processes contributing to individual variations in resilience (aim 2). The secondary objective is to investigate the pathways by which neurobehavioral markers of self-regulation assessed using electroencephalography and magnetic resonance imaging contribute to adaptive trajectories (aim 3). METHODS:ARMOR is an ongoing, prospective longitudinal cohort study of young military recruits who recently joined the National Guard but have not yet shipped out for BCT. Participants (N=1201) are assessed at 5 time points over the initial >2 years of military service beginning before BCT (baseline) and followed up at 2 weeks and 6, 12, and 18 months after BCT. Participants complete web-based questionnaires assessing vulnerability and protective factors, mental health, and socioemotional functioning at each time point and a battery of neurocognitive tests at time 0. A subset of participants also complete structured diagnostic interviews and additional self-report measures and perform neurobehavioral tasks before and after BCT during electroencephalography sessions and before BCT only during magnetic resonance imaging sessions. RESULTS:This UG3/UH3 project was initially funded in August 2017, with the UG3 pilot work completed at the end of 2018. The UH3 phase of the project was funded in March 2019. Study enrollment for the UH3 phase began on April 14, 2019, and ended on October 16, 2021. A total of 1201 participants are enrolled in the study. Follow-up data collection for the UH3 phase is ongoing and projected to continue through February 2024. We will disseminate the findings through conferences, webinars, open access publications, and communications with participants and stakeholders. CONCLUSIONS:The ARMOR study provides a rich data set to identify the predictors and mechanisms of resilient and nonresilient outcomes in the context of military stressors, which are intended to empirically inform the development of prevention and intervention strategies to enhance the resilience of military trainees and potentially other young people facing significant life challenges. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID):DERR1-10.2196/51235.

Although observational studies have shown that adolescent cannabis use is associated with impairments in important psychosocial domains, including peer, romantic, and parent-child relationships, educational outcomes, adult socioeconomic status, and legal consequences, mechanisms underlying these associations remain largely unclear. Cannabis use may have a deleterious causal effect on functioning, but it is also possible the association may be due to reverse causation or confounding by shared vulnerability factors that account for both cannabis use in adolescence and concurrent and subsequent psychosocial impairment. Causally informative studies that delineate these possibilities, including research using epidemiologic samples and quasi-experimental designs, are critical to move the field forward.

Psychopathology and risky behaviors increase during adolescence, and understanding which adolescents are most at risk informs prevention and intervention efforts. Pubertal timing relative to same-sex, same-age peers is a known correlate of adolescent outcomes among both boys and girls. However, it remains unclear whether this relation is better explained by a plausible causal process or unobserved familial liability. We extended previous research by examining associations between pubertal timing in early adolescence (age 14) and outcomes in later adolescence (age 17) in a community sample of 2,510 twins (49% boys, 51% girls). Earlier pubertal timing was associated with more substance use, risk behavior, internalizing and externalizing problems, and peer problems in later adolescence; these effects were small, consistent with previous literature. Follow-up co-twin control analyses indicated that within-twin-pair differences in pubertal timing were not associated with within-twin-pair differences in most adolescent outcomes after accounting for shared familial liability, suggesting that earlier pubertal timing and adolescent outcomes both reflect familial risk factors. Biometric models indicated that associations between earlier pubertal timing and negative adolescent outcomes were largely attributable to shared genetic liability. Although earlier pubertal timing was associated with negative adolescent outcomes, our results suggests that these associations did not appear to be caused by earlier pubertal timing but were likely caused by shared genetic influences.

BackgroundPsychopathology and risky behaviors increase during adolescence, and understanding which adolescents are most at risk informs prevention and intervention efforts. Pubertal timing relative to same-sex, same-age peers is a known correlate of adolescent outcomes among both boys and girls. However, it remains unclear whether this relation is better explained by a plausible causal process or unobserved familial liability. MethodsWe extended previous research by examining associations between pubertal timing in early adolescence (age 14) and outcomes in later adolescence (age 17) in a community sample of 2,510 twins (49% boys, 51% girls). ResultsEarlier pubertal timing was associated with more substance use, risk behavior, internalizing and externalizing problems, and peer problems in later adolescence; these effects were small, consistent with previous literature. Follow-up co-twin control analyses indicated that within-twin-pair differences in pubertal timing were not associated with within-twin-pair differences in most adolescent outcomes after accounting for shared familial liability, suggesting that earlier pubertal timing and adolescent outcomes both reflect familial risk factors. Biometric models indicated that associations between earlier pubertal timing and negative adolescent outcomes were largely attributable to shared genetic liability. ConclusionsAlthough earlier pubertal timing was associated with negative adolescent outcomes, our results suggests that these associations did not appear to be caused by earlier pubertal timing but were likely caused by shared genetic influences.

Background Recent well-powered genome-wide association studies have enhanced prediction of substance use outcomes via polygenic scores (PGSs). Here, we test (1) whether these scores contribute to prediction over-and-above family history, (2) the extent to which PGS prediction reflects inherited genetic variation v. demography (population stratification and assortative mating) and indirect genetic effects of parents (genetic nurture), and (3) whether PGS prediction is mediated by behavioral disinhibition prior to substance use onset. Methods PGSs for alcohol, cannabis, and nicotine use/use disorder were calculated for Minnesota Twin Family Study participants (N = 2483, 1565 monozygotic/918 dizygotic). Twins' parents were assessed for histories of substance use disorder. Twins were assessed for behavioral disinhibition at age 11 and substance use from ages 14 to 24. PGS prediction of substance use was examined using linear mixed-effects, within-twin pair, and structural equation models. Results Nearly all PGS measures were associated with multiple types of substance use independently of family history. However, most within-pair PGS prediction estimates were substantially smaller than the corresponding between-pair estimates, suggesting that prediction is driven in part by demography and indirect genetic effects of parents. Path analyses indicated the effects of both PGSs and family history on substance use were mediated via disinhibition in preadolescence. Conclusions PGSs capturing risk of substance use and use disorder can be combined with family history measures to augment prediction of substance use outcomes. Results highlight indirect sources of genetic associations and preadolescent elevations in behavioral disinhibition as two routes through which these scores may relate to substance use.

Observational studies have linked cannabis use to an array of negative long-term outcomes, including psychiatric symptoms and cognitive impairment. These associations are particularly strong when use occurs in adolescence; however, the causal status of these relationships is unclear.

Variation in the mental health of people who have experienced childhood maltreatment is substantial. One hypothesis is that this variation is attributable, in part, to the timing of maltreatment—specifically, whether maltreatment occurs during sensitive periods in development when the brain is maximally sensitive to particular types of environmental input. To determine whether there is scientific consensus around when periods of peak sensitivity occur, we did a systematic review of human observational studies. Although 89 (75%) of the 118 unique cross-sectional or longitudinal cohort studies we identified reported timing effects, no consistent sensitive periods were identified for any of the most studied outcomes. Thus, observational research on childhood maltreatment has yet to converge on a single period (or set of periods) of increased vulnerability. We identified study characteristics that might contribute to these between-study differences and used observations from our Review to suggest a comprehensive set of recommendations for future research.

Key Points Question Is exposure to outdoor air pollution in childhood and adolescence associated with the development of psychopathology at the transition to adulthood? Findings In this cohort study of 2039 UK-born children followed up for 2 decades, early-life exposure to nitrogen oxides was significantly associated with general psychopathology at 18 years of age, representing greater internalizing, externalizing, and thought disorder symptoms. The associations were not attributable to individual or family-level factors or to disadvantageous neighborhood characteristics. Meaning These findings suggest that exposure to nitrogen oxides in early life may be a nonspecific risk factor for the development of psychopathology as young people begin the transition to adulthood.

Educational success is associated with greater quality of life and depends, in part, on heritable cognitive and non-cognitive traits. We used polygenic scores (PGS) for smoking and educational attainment to examine different genetic influences on facets of academic adjustment in adolescence and educational attainment in adulthood. PGSs were calculated for participants of the Minnesota Twin Family Study (N = 3225) and included as predictors of grades, academic motivation, and discipline problems at ages 11, 14, and 17 years-old, cigarettes per day from ages 14 to 24 years old, and educational attainment in adulthood (mean age 29.4 years). Smoking and educational attainment PGSs had significant incremental associations with each academic variable and cigarettes per day. About half of the adjusted effects of the smoking and education PGSs on educational attainment in adulthood were mediated by the academic variables in adolescence. Cigarettes per day from ages 14 to 24 years old did not account for the effect of the smoking PGS on educational attainment, suggesting the smoking PGS indexes genetic influences related to general behavioral disinhibition. In sum, distinct genetic influences measured by the smoking and educational attainment PGSs contribute to academic adjustment in adolescence and educational attainment in adulthood.

Just how common are "common" mental health problems? For much of the 20 century, psychiatric research and the US health care system seemed to proceed under the assumption that the answer is "not very." It was not until the early 1990s that the United States conducted its first nation-wide survey of mental health problems, the National Comorbidity Survey, which revealed that about half of all adult participants had experienced at least one diagnosable psychiatric disorder in their lifetime, and close to 1 in 3 participants had met criteria for a psychiatric diagnosis in the past 12 months. Subsequent longitudinal studies showed that these estimates-although initially surprising-were still too low, and that, with repeated assessments over long follow-up periods, the proportion of people who report at least 1 diagnosable brush with a psychiatric disorder can exceed 80%..