Persistence and innovation effects in genetic and environmental factors in negative emotionality during infancy: A twin study

Abstract

BackgroundDifficult temperament in infancy is a risk factor for forms of later internalizing and externalizing psychopathology, including depression and anxiety. A better understanding of the roots of difficult temperament requires assessment of its early development with a genetically informative design. The goal of this study was to estimate genetic and environmental contributions to individual differences in infant negative emotionality, their persistence over time and their influences on stability between 5 and 18 months of age.MethodParticipants were 244 monozygotic and 394 dizygotic twin pairs (49.7% male) recruited from birth. Mothers rated their twins for negative emotionality at 5 and 18 months. Longitudinal analysis of stability and innovation between the two time points was performed in Mplus.ResultsThere were substantial and similar heritability (approximately 31%) and shared environmental (57.3%) contributions to negative emotionality at both 5 and 18 months. The trait’s interindividual stability across time was both genetically- and environmentally- mediated. Evidence of innovative effects (i.e., variance at 18 months independent from variance at 5 months) indicated that negative emotionality is developmentally dynamic and affected by persistent and new genetic and environmental factors at 18 months.ConclusionsIn the first two years of life, ongoing genetic and environmental influences support temperamental negative emotionality but new genetic and environmental factors also indicate dynamic change of those factors across time. A better understanding of the source and timing of factors on temperament in early development, and role of sex, could improve efforts to prevent related psychopathology.

Heritability of Psychological Traits and Developmental Milestones in Infancy

“…We identified 5047 publications (4675 publications in databases and 372 publications in references). After duplicate removal and screening, 139 publications were included, containing data on 79 044 twin pairs (31 053 MZ and 47 991 DZ twins), 52 twin cohorts, 21 countries, and 6 continents between 1972 and 2020. The sample included 66 407 twin pairs from Western, educated, industrialized, rich, and democratic countries (in Europe, North America, and Oceania; 84.01%) and 12 637 twin pairs from Africa, Asia, and South America (15.99%) (eResults, eFigures 2 and 3, and eTable 4 in the Supplement).…”

“…Quality assessment results are displayed in eFigure 19 in the Supplement. The mean (SD) score for the 106 publications included in the meta-analysis was 75.58% (13.83%).…”

Birth weight is associated with adolescent brain development: A multimodal imaging study in monozygotic twins

“…Previous research has indicated the importance of developmental timing in determining genetic or environmental contributions on the brain and on emotional behaviors (Lacourse et al, 2014; Schumann et al, 2017). At the behavioral level, longitudinal research in twins has shown that that the relative contributions of genetics and environment to aggression and negative affect (behaviors known to be modulated by limbic circuits) are age dependent (Lacourse et al, 2014; Schumann et al, 2017). Longitudinal studies in large twin samples, with repeated brain measures throughout development, may help to further clarify these age‐specific genetic and environmental contributions to brain structure and function.…”

Gender Differences in Depression: Evidence From Genetics

“…some new genetic factors emerge in depressive symptoms (Lau and Eley, 2006) or symptoms of anxiety and depression (Nivard et al, 2015) in adolescence. Compared with the 5-month-old baby, the negative emotionality of an 18-month-old baby was affected by persistent and new genetic factors (Schumann et al, 2017). So, it is necessary to use a longitudinal cohort design to investigate the gender differences in the genetic basis of depression at different ages and their developmental changes.…”