People's desire to be in nature and how they experience it are partially heritable.

Nature experiences have been linked to mental and physical health. Despite the importance of understanding what determines individual variation in nature experience, the role of genes has been overlooked. Here, using a twin design (TwinsUK, number of individuals = 2,306), we investigate the genetic and environmental contributions to a person's nature orientation, opportunity (living in less urbanized areas), and different dimensions of nature experience (frequency and duration of public nature space visits and frequency and duration of garden visits). We estimate moderate heritability of nature orientation (46%) and nature experiences (48% for frequency of public nature space visits, 34% for frequency of garden visits, and 38% for duration of garden visits) and show their genetic components partially overlap. We also find that the environmental influences on nature experiences are moderated by the level of urbanization of the home district. Our study demonstrates genetic contributions to individuals' nature experiences, opening a new dimension for the study of human-nature interactions.

Attachment and Political Personality are Heritable and Distinct Systems, and Both Share Genetics with Interpersonal Trust and Altruism.

The attachment and caregiving domains maintain proximity and care-giving behavior between parents and offspring, in a way that has been argued to shape people's mental models of how relationships work, resulting in secure, anxious or avoidant interpersonal styles in adulthood. Several theorists have suggested that the attachment system is closely connected to orientations and behaviors in social and political domains, which should be grounded in the same set of familial experiences as are the different attachment styles. We use a sample of Norwegian twins (N = 1987) to assess the genetic and environmental relationship between attachment, trust, altruism, right-wing authoritarianism (RWA), and social dominance orientation (SDO). Results indicate no shared environmental overlap between attachment and ideology, nor even between the attachment styles or between the ideological traits, challenging conventional wisdom in developmental, social, and political psychology. Rather, evidence supports two functionally distinct systems, one for navigating intimate relationships (attachment) and one for navigating social hierarchies (RWA/SDO), with genetic overlap between traits within each system, and two distinct genetic linkages to trust and altruism. This is counter-posed to theoretical perspectives that link attachment, ideology, and interpersonal orientations through early relational experiences.

Two babies, two bonds: Frequency and correlates of differential maternal-infant bonding in mothers of twins.

We assessed prevalence and correlates of differential maternal-infant bonding (i.e., experiencing a stronger bond with one baby vs. the other) in mothers of twins, focusing on aspects of maternal mental health, well-being, and pregnancy/birth that have been previously linked with maternal-infant bonding. Participants (N = 108 American women, 88.89% White, 82.41% non-Hispanic, aged 18-45, who gave birth to twins in the past 6-24 weeks) were recruited from postpartum support websites. Participants completed a Qualtrics survey assessing pregnancy/birth history, symptoms of depression and anxiety, sleep, stress, romantic relationship satisfaction, and postpartum bonding. Twenty-six participants (24.07%) reported a bonding discrepancy. These participants endorsed higher symptoms of depression and anxiety, lower relationship satisfaction, lower average postpartum bonding, higher general and parenting stress, and longer pregnancy (all ps > .05). Greater degree of bonding discrepancy correlated with more depression, higher parenting stress, longer pregnancy, and lower relationship satisfaction (all ps > .05). Mothers of twins may benefit from postpartum mental health support, stress management strategies, and interventions to improve bonding. Future work should assess the role of breastfeeding difficulties, delivery method, birth-related trauma, infant regulatory capacity, and temperament. Longitudinal studies will help test cause and effect and potential long-term repercussions of maternal-infant bonding discrepancies.

Evaluamos la prevalencia y factores correlacionados del apego afectivo diferencial materno­infantil (v.g. experimentar un apego más fuerte con un bebé vs. el otro) en madres de gemelos, enfocándonos en aspectos de salud mental materna, bienestar, así como el embarazo/parto que previamente han sido relacionadas con la afectividad materno­infantil. A las participantes (N = 108 mujeres estadounidenses, 88.89% blancas, 82.41% no hispanas, de 18­45 años, que dieron a luz gemelos en las pasadas 6­24 semanas) se les reclutó de los sitios de apoyo posterior al parto en la red. Las participantes completaron una encuesta Qualtrics para evaluar el historial de embarazo/parto, los síntomas de depresión y ansiedad, el sueño, el estrés, la satisfacción con la relación romántica, así como la afectividad posterior al parto. Veintiséis participantes (24.07%) reportaron discrepancia en el apego afectivo. Estas participantes confirmaron síntomas más altos de depresión y ansiedad, más baja satisfacción en la relación, más bajo promedio de apego afectivo posterior al parto, más alto estrés general y de crianza, así como un más largo embarazo (todos los ps > .05). Un mayor grado de discrepancia en el apego afectivo se relacionó con más depresión, un más alto estrés de crianza, un más largo embarazo, así como una más baja satisfacción en la relación (todos los ps > .05). Las madres de gemelos pudieran beneficiarse de un apoyo de salud mental posterior al parto, estrategias de cómo arreglárselas con el estrés e intervenciones para mejorar el apego afectivo. El trabajo futuro debe evaluar el papel de las dificultades de amamantar, el método usado para dar a luz, el trauma relacionado con el nacimiento, la capacidad regulatoria del infante y el temperamento. Estudios longitudinales ayudarán a poner a prueba la causa y el efecto las potenciales repercusiones a largo plazo de las discrepancias en el apego afectivo materno­infantil.

Nous avons évalué la prévalence et les corrélats du lien maternel­bébé différentiel (c'est­à­dire qui font l'expérience d'un lien plus fort avec un bébé par rapport à l'autre) chez les mères de jumeaux ou jumelles, en mettant l'accent sur les aspects de la santé mentale maternelle, le bien­être et la grossesse/naissance ayant précédemment été liés au lien maternel­bébé. Les participantes (N = 108 femmes américaines, 88,89% blanches, 82,41% non­latinas, âgées de 18­45 ans, ayant donné naissance à des jumeaux ou jumelles dans les 6­24 semaines précédentes) ont été recrutées à partir de sites internet de soutien postpartum. Les participantes ont rempli un questionnaire Qualtrics évaluant la grossesse/l'histoire de la naissance, les symptômes de dépression et d'anxiété, le sommeil, le stress, la satisfaction de la relation amoureuse et le lien postpartum. Vingt­six participantes (24,07%) ont fait état d'un écart du lien. Ces participantes ont fait état de plus de symptômes de dépression et d'anxiété, d'une satisfaction avec la relation plus basse, d'un lien postpartum plus bas en moyenne, d'un stress général et parental plus élevé, et d'une grossesse plus longue (tout ps >,05). Un degré plus élevé d'écart du lien a correspondu à plus de dépression, un stress de parentage plus élevé, une grossesse plus longue et une satisfaction de la relation plus basse tous ps > ,05). Les mères de jumeaux ou jumelles peut tirer profit d'un soutien en santé mentale postpartum, de stratégies de gestion du stress, et d'interventions pour améliorer le lien. Dans le futur des recherches devraient évaluer le rôle de difficultés de l'allaitement, la méthode d'accouchement, le trauma lié à la naissance, la capacité régulatoire du bébé et son tempérament. Des études longitudinales permettront de tester la cause et l'effet et les répercussions à long terme potentielle pour les écarts dans le lien maternel­bébé.

Adolescents' perceptions of family social status correlate with health and life chances: A twin difference longitudinal cohort study.

Children from lower-income households are at increased risk for poor health, educational failure, and behavioral problems. This social gradient is one of the most reproduced findings in health and social science. How people view their position in social hierarchies also signals poor health. However, when adolescents' views of their social position begin to independently relate to well-being is currently unknown. A cotwin design was leveraged to test whether adolescents with identical family backgrounds, but who viewed their family's social status as higher than their same-aged and sex sibling, experienced better well-being in early and late adolescence. Participants were members of the Environmental Risk Longitudinal Twin Study, a representative cohort of British twins (n = 2,232) followed across the first 2 decades of life. By late adolescence, perceptions of subjective family social status (SFSS) robustly correlated with multiple indicators of health and well-being, including depression; anxiety; conduct problems; marijuana use; optimism; not in education, employment, or training (NEET) status; and crime. Findings held controlling for objective socioeconomic status both statistically and by cotwin design after accounting for measures of childhood intelligence (IQ), negative affect, and prior mental health risk and when self-report, informant report, and administrative data were used. Little support was found for the biological embedding of adolescents' perceptions of familial social status as indexed by inflammatory biomarkers or cognitive tests in late adolescence or for SFSS in early adolescence as a robust correlate of well-being or predictor of future problems. Future experimental studies are required to test whether altering adolescents' subjective social status will lead to improved well-being and social mobility.

A Representational Similarity Analysis of Cognitive Control during Color-Word Stroop.

Progress in understanding the neural bases of cognitive control has been supported by the paradigmatic color-word Stroop task, in which a target response (color name) must be selected over a more automatic, yet potentially incongruent, distractor response (word). For this paradigm, models have postulated complementary coding schemes: dorsomedial frontal cortex (DMFC) is proposed to evaluate the demand for control via incongruency-related coding, whereas dorsolateral PFC (DLPFC) is proposed to implement control via goal and target-related coding. Yet, mapping these theorized schemes to measured neural activity within this task has been challenging. Here, we tested for these coding schemes relatively directly, by decomposing an event-related color-word Stroop task via representational similarity analysis. Three neural coding models were fit to the similarity structure of multivoxel patterns of human fMRI activity, acquired from 65 healthy, young-adult males and females. Incongruency coding was predominant in DMFC, whereas both target and incongruency coding were present with indistinguishable strength in DLPFC. In contrast, distractor information was strongly encoded within early visual cortex. Further, these coding schemes were differentially related to behavior: individuals with stronger DLPFC (and lateral posterior parietal cortex) target coding, but weaker DMFC incongruency coding, exhibited less behavioral Stroop interference. These results highlight the utility of the representational similarity analysis framework for investigating neural mechanisms of cognitive control and point to several promising directions to extend the Stroop paradigm.SIGNIFICANCE STATEMENT How the human brain enables cognitive control - the ability to override behavioral habits to pursue internal goals - has been a major focus of neuroscience research. This ability has been frequently investigated by using the Stroop color-word naming task. With the Stroop as a test-bed, many theories have proposed specific neuroanatomical dissociations, in which medial and lateral frontal brain regions underlie cognitive control by encoding distinct types of information. Yet providing a direct confirmation of these claims has been challenging. Here, we demonstrate that representational similarity analysis, which estimates and models the similarity structure of brain activity patterns, can successfully establish the hypothesized functional dissociations within the Stroop task. Representational similarity analysis may provide a useful approach for investigating cognitive control mechanisms.

Childhood maltreatment and disordered gambling in adulthood: disentangling causal and familial influences.

BACKGROUND: Despite abundant research on the potential causal influence of childhood maltreatment (CM) on psychological maladaptation in adulthood, almost none has implemented the discordant twin design as a means of examining the role of such experiences in later disordered gambling (DG) while accounting for genetic and family environmental confounds. The present study implemented such an approach to disentangle the potential causal and familial factors that may account for the association between CM and DG. METHODS: Participants were 3750 twins from the Australian Twin Registry [Mage = 37.60 (s.d. = 2.31); 58% female]. CM and DG were assessed separately via two semi-structured telephone interviews. Random-intercept generalized linear mixed models were fit to the data; zygosity, sex, educational attainment, childhood psychiatric disorder, adult antisocial behavior, and alcohol use disorder (AUD) were included as covariates. RESULTS: Neither quasi-causal nor familial effects of CM predicted DG after adjusting for covariates. Educational attainment appeared to reduce the risk of DG while AUD appeared to increase risk; evidence also emerged for familial effects of antisocial behavior on DG. Post-hoc analyses revealed a familial effect of CM on antisocial behavior, indicating that the association between CM and DG identified in unadjusted models and in prior studies may be accounted for by genetic and shared family environmental effects of antisociality. CONCLUSIONS: These findings add to the meager literature showing that CM does not exert a causal effect on DG, and present novel evidence that familial effects of antisocial behavior may account for the association between CM and DG identified in extant non-twin research.

Parental criticism and adolescent internalising symptoms: using a Children-of-Twins design with power calculations to account for genetic influence.

BACKGROUND: Parental criticism is correlated with internalising symptoms in adolescent offspring. This correlation could in part reflect their genetic relatedness, if the same genes influence behaviours in both parents and offspring. We use a Children-of-Twins design to assess whether parent-reported criticism and offspring internalising symptoms remain associated after controlling for shared genes. To aid interpretation of our results and those of previous Children-of-Twins studies, we examine statistical power for the detection of genetic effects and explore the direction of possible causal effects between generations. METHODS: Data were drawn from two Swedish twin samples, comprising 876 adult twin pairs with adolescent offspring and 1,030 adolescent twin pairs with parents. Parent reports of criticism towards their offspring were collected concurrently with parent and offspring reports of adolescent internalising symptoms. Children-of-Twins structural equation models were used to control for genetic influence on the intergenerational association between parental criticism and adolescent internalising. RESULTS: Parental criticism was associated with adolescent internalising symptoms after controlling for genetic influence. No significant role was found for shared genes influencing phenotypes in both generations, although power analyses suggested that some genetic effects may have gone undetected. Models could not distinguish directionality for nongenetic, causal effects between generations. CONCLUSIONS: Parental criticism may be involved in psychosocial family processes in the context of adolescent internalising. Future studies should seek to identify these processes and provide clarity on the direction of potential causal effects.

Are there positive effects of having a sibling with special needs? Empathy and prosociality of twins of children with non-typical development.

This study examined whether typically developing (TD) twins of non-TD children demonstrate enhanced empathy and prosociality. Of 778 Hebrew-speaking Israeli families who participated in a twin study, 63 were identified to have a non-TD child with a TD twin, and 404 as having both twins TD. TD twins of non-TD children (27% males) were compared to the rest of the cohort of TD children (46% males) on measures of empathy and prosociality. Participants were 11 years old. TD twins of non-TD children scored significantly higher than TD twins of TD children in a measure of cognitive empathy (d = .43). No differences were found in emotional empathy and prosociality. The specificity of the positive effect on cognitive empathy is discussed.

General Cognitive Abilities and Psychosocial Development in Children and Adolescents Having a Co-Twin with Down Syndrome.

OBJECTIVE: To examine the general cognitive and psychosocial development in children and adolescents having a co-twin with Down syndrome. STUDY DESIGN: A case control study with an individually matched control group was conducted. Participants included families with twins discordant for Down syndrome as well as with typically developing twins. The group of unaffected co-twins aged 4-16 years was compared with a control group of typically developing twins in terms of general cognitive abilities, behavioral problems, and prosocial behavior. The age and sex and the sex composition of the twins were individually matched. The Sijnders-Oomen nonverbal intelligence test was applied to assess children's IQ, and parents completed the Strength and Difficulties Questionnaire. RESULTS: The unaffected co-twins did not differ from typically developing twins with respect to their IQ. Concerning the psychosocial development, significantly heightened values in unaffected co-twins twins were only obtained for the conduct problems scale (P = .01; r = 0.45), neither for the total difficulties score nor for the other behavioral problem scales significant differences were found. CONCLUSIONS: The general cognitive development of the unaffected co-twin of children with Down syndrome is not affected by the presence of their Down syndrome twin. Unaffected co-twins showed increased conduct problems, which is most pronounced in the younger children.

The causal nature of the association between resting pulse in late adolescence and risk for internalizing and externalizing disorders: a co-relative analysis in a national male Swedish sample.

BACKGROUND: Resting pulse is robustly and inversely associated with the risk for externalizing disorders and may be positively associated with internalizing disorders. We know little about the causal nature of these associations. METHODS: We examined resting pulse at conscription examination in 369 301 males born 1960-80 with a mean (s.d.) follow-up of 29.1 (7.7) years. From pulse rates, we predicted, using Cox models, the risk for criminal behavior (CB), drug abuse (DA), alcohol use disorder (AUD), major depression (MD), and anxiety disorders (AD), assessed from medical, criminal, and pharmacy registries. Co-relative analyses were conducted on the general population, cousin, half-sibling, full-sibling, and monozygotic pairs discordant for the outcome. Twin/sibling modeling for pulse was performed using OpenMX. RESULTS: Familial resemblance for pulse resulted entirely from genetic factors. In the general population, the risk for externalizing disorders (CB, DA, and AUD) and internalizing disorders (MD and AD) were, respectively, significantly associated with low and high resting pulse rate. For CB, DA, and AUD, co-relative analyses showed that the inverse association with pulse resulted entirely from familial common causes (aka 'confounders'). By contrast, co-relative analyses found that the association between higher pulse and MD and AD resulted from direct causal effects. CONCLUSIONS: Resting pulse has a negative and positive association with, respectively, the risk for externalizing and for internalizing disorders. Co-relative analyses indicate that the nature of these associations differ, suggesting that elevated pulse appears to directly increase the risk for internalizing disorders while the reduced pulse is a risk index for underlying traits that predispose to externalizing disorders.

Familial coaggregation of major psychiatric disorders among first-degree relatives of patients with obsessive-compulsive disorder: a nationwide study.

BACKGROUND: Whether the first-degree relatives (FDRs) of patients with obsessive-compulsive disorder (OCD) have an increased risk of the major psychiatric disorders, namely schizophrenia, bipolar disorder, OCD, major depressive disorder (MDD), autism spectrum disorder (ASD), and attention deficit hyperactivity disorder (ADHD), remains unclear. METHODS: Using the Taiwan National Health Insurance Research Database with the whole population sample size (n = 23 258 175), 89 500 FDRs, including parents, offspring, siblings, and twins, of patients with OCD were identified in our study. The relative risks (RRs) of major psychiatric disorders were assessed among FDRs of patients with OCD. RESULTS: FDRs of patients with OCD had higher RRs of major psychiatric disorders, namely OCD (RR 8.11, 95% confidence interval (CI) 7.68-8.57), bipolar disorder (RR 2.85, 95% CI 2.68-3.04), MDD (RR 2.67, 95% CI 2.58-2.76), ASD (RR 2.38, 95% CI 2.10-2.71), ADHD (RR 2.19, 95% CI 2.07-2.32), and schizophrenia (RR 1.97, 95% CI 1.86-2.09), compared with the total population. Different familial kinships of FDRs, such as parents, offspring, siblings, and twins consistently had increased risks for these disorders. In addition, a dose-dependent relationship was found between the numbers of OCD probands and the risk of each major psychiatric disorder. CONCLUSIONS: The FDRs, including parents, offspring, siblings, and twins, of patients with OCD have a higher risk of OCD, schizophrenia, bipolar disorder, MDD, ADHD, and ASD. The familial co-aggregation of OCD with OCD and other major psychiatric disorders was existent in a dose-dependent manner. Given the increased risks of psychiatric disorders, medical practitioners should closely monitor the mental health of the FDRs of patients with OCD.

Adolescent Decision-Making Under Risk: Neural Correlates and Sex Differences.

An increased propensity for risk taking is a hallmark of adolescent behavior with significant health and social consequences. Here, we elucidated cortical and subcortical regions associated with risky and risk-averse decisions and outcome evaluation using the Balloon Analog Risk Task in a large sample of adolescents (n = 256, 56% female, age 14 ± 0.6), including the level of risk as a parametric modulator. We also identified sex differences in neural activity. Risky decisions engaged regions that are parts of the salience, dorsal attention, and frontoparietal networks, but only the insula was sensitive to increasing risks in parametric analyses. During risk-averse decisions, the same networks covaried with parametric levels of risk. The dorsal striatum was engaged by both risky and risk-averse decisions, but was not sensitive to escalating risk. Negative-outcome processing showed greater activations than positive-outcome processing. Insula, lateral orbitofrontal cortex, middle, rostral, and superior frontal areas, rostral and caudal anterior cingulate cortex were activated only by negative outcomes, with a subset of regions associated with negative outcomes showing greater activation in females. Taken together, these results suggest that safe decisions are predicted by more accurate neural representation of increasing risk levels, whereas reward-related processes play a relatively minor role.

Exploring the Associations Between Delayed School Entry and Achievement in Primary and Secondary School.

This research investigated whether delayed school entry was associated with higher achievement in national tests of reading and numeracy in Grades 3, 5, 7, and 9 (n = 2,823). Delayed entry was related to advantages in reading (0.14 SD) and numeracy (0.08 SD) at Grade 3, although little variance was explained (1%-2%). This slight advantage persisted for both domains in Grades 5 and 7, albeit with smaller effects. In Grade 9 there was no association between delayed entry and either reading or numeracy. Exploratory analyses with subsamples in each grade (n = 424-667) revealed no associations between delayed entry and achievement after controlling for inattention and hyperactivity, and negative associations between inattention and achievement in all grades in both domains (-0.33, -0.49 SD).

Residential green space and child intelligence and behavior across urban, suburban, and rural areas in Belgium: A longitudinal birth cohort study of twins.

BACKGROUND: Exposure to green space has beneficial effects on several cognitive and behavioral aspects. However, to our knowledge, no study addressed intelligence as outcome. We investigated whether the level of urbanicity can modify the association of residential green space with intelligence and behavior in children. METHODS AND FINDINGS: This study includes 620 children and is part of the East Flanders Prospective Twin Survey (EFPTS), a registry of multiple births in the province of East Flanders, Belgium. Intelligence was assessed with the Wechsler Intelligence Scale for Children-Revised (WISC-R) in 620 children (310 twin pairs) between 7 and 15 years old. From a subset of 442 children, behavior was determined based on the Achenbach Child Behavior Checklist (CBCL). Prenatal and childhood residential addresses were geocoded and used to assign green space indicators. Mixed modeling was performed to investigate green space in association with intelligence and behavior while adjusting for potential confounding factors including sex, age, parental education, neighborhood household income, year of assessment, and zygosity and chorionicity. We found that residential green space in association with both intelligence and behavior in children was modified by the degree of urbanicity (p < 0.001). In children living in an urban environment, multivariable adjusted mixed modeling analysis revealed that an IQR increment of residential green space (3,000-m radius) was associated with a 2.6 points (95% CI 1.4-3.9; p < 0.001) higher total intelligence quotient (IQ) and 2.0 points (95% CI -3.5 to -0.4; p = 0.017) lower externalizing behavioral score. In children residing in a rural or suburban environment, no association was found. A limitation of this study is that no information was available on school location and the potential for unmeasured confounding (e.g., time spend outdoors). CONCLUSIONS: Our results indicate that residential green space may be beneficial for the intellectual and the behavioral development of children living in urban areas. These findings are relevant for policy makers and urban planners to create an optimal environment for children to develop their full potential.

Do neighborhood social processes moderate the etiology of youth conduct problems?

BACKGROUND: Prior work has robustly suggested that social processes in the neighborhood (i.e. informal social control, social cohesion, norms) influence child conduct problems (CP) and related outcomes, but has yet to consider how these community-level influences interact with individual-level genetic risk for CP. The current study sought to do just this, evaluating neighborhood-level social processes as etiologic moderators of child CP for the first time. METHODS: We made use of two nested samples of child and adolescent twins within the Michigan State University Twin Registry (MSUTR): 5649 families who participated in in the Michigan Twins Project (MTP) and 1013 families who participated in the Twin Study of Behavioral and Emotional Development (TBED-C). The neighborhood social processes of informal social control, social cohesion, and norms were assessed using neighborhood sampling techniques, in which residents of each twin family's neighborhood reported on the social processes in their neighborhood. Standard biometric GxE analyses evaluated the extent to which they moderated the etiology of CP. RESULTS: The 'no moderation' model provided the best fit to the data in nearly all cases, arguing against neighborhood social processes as etiologic moderators of youth CP. CONCLUSIONS: The neighborhood social processes evaluated here do not appear to exert their effects on child CP via etiologic moderation. The documented links between neighborhood social processes and child CP are thus likely to reflect a different etiologic process. Possibilities include environmental main effects of neighborhood social processes on child CP, or genotype-environment correlations.

Using discordant twin methods to investigate an environmentally mediated pathway between social support and the reduced likelihood of adolescent psychotic experiences.

BACKGROUND: Social support has been shown to be associated with a reduced likelihood of developing psychotic experiences in the general population and even amongst those at high risk due to exposure to multiple forms of victimisation (poly-victimised). However, it is unclear whether this association is merely due to the confounding effects of shared environmental and genetic influences, or reverse causality. Therefore, we investigated whether social support has a unique environmentally mediated effect on adolescent psychotic experiences after accounting for familial factors, including genetic factors, and also prior psychopathology. METHODS: Participants were from the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally-representative cohort of 2232 UK-born twins. Adolescents were interviewed at age 18 about psychotic experiences and victimisation exposure since age 12, and their perceptions of social support. Prior childhood mental health problems and psychotic symptoms were assessed at age 12. The discordant twin method was used to disentangle the relative family-wide and unique-environmental effects of social support on psychotic experiences in the general population and among poly-victimised adolescents. RESULTS: Perceived social support, particularly from friends, was found to have a unique environmentally mediated buffering effect on adolescent psychotic experiences in the whole sample and in the high-risk poly-victimised group. CONCLUSIONS: The protective effects of social support on adolescent psychotic experiences cannot be accounted for by shared environmental or genetic factors, nor by earlier psychopathology. Our findings suggest that early intervention programmes focused on increasing perceptions of social support have the potential to prevent the emergence of psychotic experiences amongst adolescents.

Are changes in ADHD course reflected in differences in IQ and executive functioning from childhood to young adulthood?

BACKGROUND: Attention-deficit hyperactivity disorder (ADHD) is associated with poorer cognitive functioning. We used a developmental, genetically-sensitive approach to examine intelligence quotient (IQ) from early childhood to young adulthood among those with different ADHD courses to investigate whether changes in ADHD were reflected in differences in IQ. We also examined executive functioning in childhood and young adulthood among different ADHD courses. METHODS: Study participants were part of the Environmental Risk (E-Risk) Longitudinal Twin Study, a population-based birth cohort of 2232 twins. We assessed ADHD in childhood (ages 5, 7, 10 and 12) and young adulthood (age 18). We examined ADHD course as reflected by remission, persistence and late-onset. IQ was evaluated at ages 5, 12 and 18, and executive functioning at ages 5 and 18. RESULTS: ADHD groups showed deficits in IQ across development compared to controls; those with persistent ADHD showed the greatest deficit, followed by remitted and late-onset. ADHD groups did not differ from controls in developmental trajectory of IQ, suggesting changes in ADHD were not reflected in IQ. All ADHD groups performed more poorly on executive functioning tasks at ages 5 and 18; persisters and remitters differed only on an inhibitory control task at age 18. CONCLUSIONS: Differences in ADHD course - persistence, remission and late-onset - were not directly reflected in changes in IQ. Instead, having ADHD at any point across development was associated with lower average IQ and poorer executive functioning. Our finding that individuals with persistent ADHD have poorer response inhibition than those who remitted requires replication.

Internalizing and externalizing psychopathology in middle age: genetic and environmental architecture and stability of symptoms over 15 to 20 years.

BACKGROUND: Internalizing and externalizing psychopathology factors explain much of the covariance among psychiatric conditions, especially at the level of genetic risk. However, few studies have examined internalizing and externalizing factors in middle-aged samples, especially their ability to predict later symptoms across midlife. The goals of the current study were (i) to quantify the genetic and environmental influences on internalizing and externalizing psychopathology in individuals in their early 40s, and (ii) examine the extent to which these genetic and environmental influences predict self-reported measures of internalizing and externalizing symptoms 15-20 years later. METHOD: 1484 male twins completed diagnostic interviews of psychopathology at mean age 41 and self-reported measures of anxiety, depression, substance use, and related variables at up to two time-points in late middle age (mean ages 56 and 62). RESULTS: Structural equation modeling of the diagnostic interviews confirmed that internalizing and externalizing factors accounted for most of the genetic variance in individual disorders, with substantial genetic (ra = 0.70) and environmental (re = 0.77) correlations between the factors. Internalizing psychopathology at age 41 was correlated with latent factors capturing anxiety, depression, and/or post-traumatic stress symptoms at ages 56 (r = 0.51) and 62 (r = 0.43). Externalizing psychopathology at age 41 was correlated r = 0.67 with a latent factor capturing aggression, tobacco use, and alcohol use at age 56. Stability of both factors was driven by genetic influences. CONCLUSIONS: These findings demonstrate the considerable stability of internalizing and externalizing psychopathology symptoms across middle age, especially their genetic influences. Diagnostic interviews effectively predict self-reported symptoms and behaviors 15-20 years later.

Marriage and reductions in men's alcohol, tobacco, and cannabis use.

BACKGROUND: Psychoactive substance use is lower among married compared to divorced or unmarried men; yet, the nature of this effect remains unclear because becoming and staying married is potentially confounded with substance-related background familial and individual factors, like parental divorce and personality. The authors investigated the associations between marital status and substance use; how substance use changed across the transition to marriage; and whether marriage effects were likely to be causal. METHOD: The sample included 1790 adults from male-male twin pairs from a population-based registry. Measures of marital status and alcohol, tobacco, and cannabis use came from Life History Calendars. Data were analyzed using regression, co-twin comparison, and within-person models. The latter models are tools for quasi-causal inference that control for familial and individual-level confounders. RESULTS: Married men used less alcohol, tobacco, and cannabis than men who were divorced/separated or single. In analyses of substance use across the transition to marriage, men reduced their alcohol and cannabis use both before and after marriage, but their tobacco use only after marriage. These effects were largely robust in co-twin and within-person analyses. CONCLUSIONS: Marriage was associated with substantial reductions in substance use compared to being divorced/separated or single, and these reductions began prior to marriage. The co-twin comparison and within-person models ruled out the alternative explanation that marriage effects were due to confounding background familial and individual factors. These results provide strong evidence that the social role expectations associated with marriage reduce psychoactive substance use.

Midlife Study of the Louisville Twins: Connecting Cognitive Development to Biological and Cognitive Aging.

The Louisville Twin Study (LTS) began in 1958 and became a premier longitudinal twin study of cognitive development. The LTS continuously collected data from twins through 2000 after which the study closed indefinitely due to lack of funding. Now that the majority of the sample is age 40 or older (61.36%, N = 1770), the LTS childhood data can be linked to midlife cognitive functioning, among other physical, biological, social, and psychiatric outcomes. We report results from two pilot studies in anticipation of beginning the midlife phase of the LTS. The first pilot study was a participant tracking study, in which we showed that approximately 90% of the Louisville families randomly sampled (N = 203) for the study could be found. The second pilot study consisted of 40 in-person interviews in which twins completed cognitive, memory, biometric, and functional ability measures. The main purpose of the second study was to correlate midlife measures of cognitive functioning to a measure of biological age, which is an alternative index to chronological age that quantifies age as a function of the breakdown of structural and functional physiological systems, and then to relate both of these measures to twins' cognitive developmental trajectories. Midlife IQ was uncorrelated with biological age (- .01) while better scores on episodic memory more strongly correlated with lower biological age (- .19 to - .31). As expected, midlife IQ positively correlated with IQ measures collected throughout childhood and adolescence. Additionally, positive linear rates of change in FSIQ scores in childhood significantly correlated with biological age (- .68), physical functioning (.71), and functional ability (- .55), suggesting that cognitive development predicts lower biological age, better physical functioning, and better functional ability. In sum, the Louisville twins can be relocated to investigate whether and how early and midlife cognitive and physical health factors contribute to cognitive aging.