The aim of the study was to examine associations between life events and self-assessed loneliness in adolescence. We used data from a Norwegian population-based twin sample including seven birth cohorts (N = 2,879, 56% females). The participants completed self-report questionnaires three times throughout adolescence, with 2 years in between (i.e.,…

Future orientation tends to prevent engagement in risk behaviours and results in good academic performance among adolescents. Our study aimed to establish whether genetic factors contributed to future orientation among Chinese adolescents. We recruited 988 pairs of twins from Beijing. By constructing a high-order A (additive genetic variance) C…

The interplay of genetic and environmental factors behind cognitive development has preoccupied multiple fields of science and sparked heated debates over the decades. Here we tested the hypothesis that developmental genes rely heavily on cognitive challenges - as opposed to natural maturation. Starting with a polygenic score (cogPGS) that…

This research examines how the human genome and SES jointly and interactively shape verbal ability among youth in the U.S. The youth are aged 12-18 when the study starts. The research draws on findings from the latest GWAS as well as a rich set of longitudinal SES measures at individual, family and neighborhood levels from Add Health (N = 7194).…

Virtuous character development in children is correlated with parenting behavior, but the role of genetic influences in this association has not been examined. Using a longitudinal twin/sibling study (N = 720; Time 1 (T1) M[subscript age] = 12-14 years, Time 3 (T3) M[subscript age] = 25-27 years), the current report examines associations among…

Background: Confounding introduced by gene-environment correlation (rGE) may prevent one from observing a true gene-environment interaction (G × E) effect on psychopathology. The present study investigated the interacting effect of the BDNF Val66Met polymorphism and stressful life events (SLEs) on adolescent depression while controlling for the…

Recognition of the interplay between nature and nurture is decades old in fields such as psychiatry, but other fields in the social sciences continue to be hampered by the idea that social and biological variables compete for explanatory relevance. In a recent study of the adolescent brain and risk taking, Males critiqued biologically oriented…

Objective: To explain the differential course of anxiety and depression in individuals from childhood to adulthood by examining age-related changes in the genetic and environmental etiology of anxious and depressive symptoms. Method: A sample of 1470, 1839, and 2023 Dutch twins aged 12, 14, and 16 years reported on symptoms of anxious depression…

This "Monograph" reports theoretically relevant behavioral, biological, and self-report assessments of a sample of 14-17-year-olds who had been classified into one of four temperamental groups at 4 months of age. The infant temperamental categories were based on observed behavior to a battery of unfamiliar stimuli. The infants classified as high…

Examined family influences on vocational interest development. Hypothesized that parents with similar interests were more likely to have adolescents who also developed those interests than were parents whose interests were very divergent. To "unconfound" genetic and environmental influences, parent-child interest difference scores were compared…

Data from 236 pairs of black twins and white twins aged 13-17 years were used to examine genetic and environmental factors influencing cranial size, an indirect estimate of brain volume. Genetic factors are required to account for the phenotypic variance in cranial capacity. (SLD)

Examined relative contributions of genetic and environmental influences to the covariation between sibling relationships and mother/adolescent relationships in 719 same-sex sibling pairs of varying degrees of genetic relatedness. Found that the overlapping effects of shared environment on the two relationship subsystems explained most of the…

The mother, father, and adolescent siblings from 675 families were observed interacting in problem-solving sessions. Siblings were monozygotic twins, dyzygotic twins, or full siblings in nondivorced families and full, half, and unrelated siblings in stepfamilies. Results suggested a greater genetic component to adolescent behavior than to parent…

Parents of Swedish twin pairs ages 7 to 9 years and of British twin pairs ages 8 to 16 years completed the Child Behavior Checklist. Found that genetic factors influenced aggressive antisocial behavior to a greater extent than nonaggressive antisocial behavior, which was also significantly influenced by the shared environment. There was a…

Studied continuity and change in general cognitive ability from infancy to adolescence in adoptees (107 children), biological siblings (87 pairs), and twins (224 monozygotic and 189 dyzygotic pairs). Findings generally support previous findings about genetic and environmental factors, with the exception that in the transition to adolescence,…