Parental criticism and adolescent internalising symptoms: Associations remain after accounting for shared genetic effects

ObjectiveParental criticism is associated with internalising symptoms in adolescent offspring. It is unclear whether these behaviours cause one another, and/or whether they are influenced by shared genes in related parent-offspring pairs. We use an Extended 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 psychosocial influences between generations.MethodData were drawn from two Swedish twin samples, comprising 876 adult twin pairs with adolescent offspring and 1030 adolescent twin pairs with parents. Parents reported on criticism towards their offspring, concurrently with parent and offspring reports of adolescent internalising symptoms. Extended Children of Twins structural equation models were used to examine intergenerational social and genetic mechanisms.ResultsParental criticism was associated with adolescent internalising symptoms after controlling for genetic relatedness. No significant role was found for shared genes influencing phenotypes in both generations. Power analyses confirmed that any undetected genetic effects were small. Models could not distinguish the causal direction of possible psychosocial effects between generations.ConclusionThe association between parent-reported criticism and adolescent internalising symptoms is not attributable to genetic confounding in this sample. As such, 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.

Parental Prenatal Symptoms of Depression and Offspring Symptoms of ADHD: A Genetically Informed Intergenerational Study

Objective: The primary aim of the present study was to separate the direct effect of maternal prenatal depression on offspring ADHD from the passive transmission of genetic liability. Method: A children-of-twins and siblings design including 17,070 extended-family units participating in the Norwegian Mother and Child Cohort Study was used. Self-ratings were obtained from parents using the Symptom Checklist during pregnancy. Maternal ratings using Conner’s Parent Rating Scale were obtained when the children were 5 years of age. Results: Genetic influences were important for explaining similarity between parents and offspring. There was also evidence for a maternal effect after accounting for genetic transmission ( m = 0.06, 95% confidence interval [CI] = [0.02, 0.09]). Conclusion: Our results were consistent with hypotheses suggesting that maternal prenatal depression influences symptoms of ADHD in offspring. However, the effect was weak and a substantial portion of the association could be accounted for by shared genetic influences.

Nicholas (Nick) G. Martin and the Extended Twin Model

The extended twin model is a unique design in the genetic epidemiology toolbox that allows to simultaneously estimate multiple causes of variation such as genetic and cultural transmission, genotype–environment covariance and assortative mating, among others. Nick Martin has played a key role in the conception of the model, the collection of substantially large data sets to test the model, the application of the model to a range of phenotypes, the publication of the results including cross-cultural comparisons, the evaluation of bias and power of the design and the further elaborations of the model, such as the children-of-twins design.

Minnesota Center for Twin and Family Research

The Minnesota Center for Twin and Family Research (MCTFR) comprises multiple longitudinal, community-representative investigations of twin and adoptive families that focus on psychological adjustment, personality, cognitive ability and brain function, with a special emphasis on substance use and related psychopathology. The MCTFR includes the Minnesota Twin Registry (MTR), a cohort of twins who have completed assessments in middle and older adulthood; the Minnesota Twin Family Study (MTFS) of twins assessed from childhood and adolescence into middle adulthood; the Enrichment Study (ES) of twins oversampled for high risk for substance-use disorders assessed from childhood into young adulthood; the Adolescent Brain (AdBrain) study, a neuroimaging study of adolescent twins; and the Siblings Interaction and Behavior Study (SIBS), a study of adoptive and nonadoptive families assessed from adolescence into young adulthood. Here we provide a brief overview of key features of these established studies and describe new MCTFR investigations that follow up and expand upon existing studies or recruit and assess new samples, including the MTR Study of Relationships, Personality, and Health (MTR-RPH); the Colorado-Minnesota (COMN) Marijuana Study; the Adolescent Brain Cognitive Development (ABCD) study; the Colorado Online Twins (CoTwins) study and the Children of Twins (CoT) study.

The Mid-Atlantic Twin Registry of Virginia Commonwealth University

The Mid-Atlantic Twin Registry (MATR) is a population-based registry of more than 60,000 twins primarily born or living in Virginia, North Carolina and South Carolina. Researchers may utilize the MATR for administration of research services, including study recruitment, data or sample (e.g., DNA) collection, archival dataset creation, as well as data collection through mailed, phone or online surveys. In addition, the MATR houses the MATR Repository, with over 1700 DNA samples primarily from whole blood available for researchers interested in DNA genotyping. For over 40 years MATR twins have participated in research studies with investigators from a range of scientific disciplines and institutions. These studies, which have resulted in numerous publications, explored diverse topics, including substance use, smoking behaviors, developmental psychopathology, bullying, children’s health, cardiovascular disease, cancer, the human microbiome, epigenetics of aging, children of twins and sleep homeostasis. Researchers interested in utilizing twins are encouraged to contact the MATR to discuss potential research opportunities.

The Study of Personality Architecture and Dynamics (SPeADy): A Longitudinal and Extended Twin Family Study

The Study of Personality Architecture and Dynamics (SPeADy) is a German research project that aims to investigate the sources of interindividual differences in intraindividual personality development. The main focus lies in the dynamic interplay between more stable core characteristics and more environmentally malleable surface characteristics, as well as between personality and life experiences over time. SPeADy includes a twin family study encompassing data from 1962 individuals (age: 14–94) of 682 families, including 570 complete twin pairs (plus 1 triplet set), 327 parents, 236 spouses and 145 children of twins. Data collection started in 2016 and data from the first wave are currently obtainable as open source. Available data comprise a broad range of personality variables, such as personality trait constructs, motives, interests, values, moral foundations, religiosity and self-related concepts. For the currently ongoing second wave of data collection, we added retrospective reports on major life events. Special features of this genetically informative study are the extended twin family data and its longitudinal design. Three assessment waves in 2 years’ intervals are planned until 2022. In this article, we briefly describe the design and contents of the SPeADy twin family study as well as some recent findings, future plans and open science issues.

Children of the Twins Early Development Study (CoTEDS): A Children-of-Twins Study

The Children of the Twins Early Development Study (CoTEDS) is a new prospective children-of-twins study in the UK, designed to investigate intergenerational associations across child developmental stages. CoTEDS will enable research on genetic and environmental factors that underpin parent–child associations, with a focus on mental health and cognitive-related traits. Through CoTEDS, we will have a new lens to examine the roles that parents play in influencing child development, as well as the genetic and environmental factors that shape parenting behavior and experiences. Recruitment is ongoing from the sample of approximately 20,000 contactable adult twins who have been enrolled in the Twins Early Development Study (TEDS) since infancy. TEDS twins are invited to register all offspring to CoTEDS at birth, with 554 children registered as of May 2019. By recruiting the second generation of TEDS participants, CoTEDS will include information on adult twins and their offspring from infancy. Parent questionnaire-based data collection is now underway for 1- and 2-year-old CoTEDS infants, with further waves of data collection planned. Current data collection includes the following primary constructs: child mental health, temperament, language and cognitive development; parent mental health and social relationships; parenting behaviors and feelings; and other socioecological factors. Measurement tools have been selected with reference to existing genetically informative cohort studies to ensure overlap in phenotypes measured at corresponding stages of development. This built-in study overlap is intended to enable replication and triangulation of future analyses across samples and research designs. Here, we summarize study protocols and measurement procedures and describe future plans.

Children of the Twins Early Development Study (CoTEDS): A Children-of-Twins Study

The Children of the Twins Early Development Study (CoTEDS) is a new prospective children-of-twins study in the UK, designed to investigate intergenerational associations across child developmental stages. CoTEDS will enable research on genetic and environmental factors that underpin parent-child associations, with a focus on mental-health and cognitive related traits. Through CoTEDS we will have a new lens to examine the roles that parents play in influencing child development, as well as the genetic and environmental factors that shape parenting behaviour and experiences. Recruitment is ongoing from the sample of approximately 20,000 contactable adult twins who have been enrolled in the Twins Early Development Study (TEDS) since infancy. TEDS twins are invited to register all offspring to CoTEDS at birth, with 550 children registered as of May 2019. By recruiting the second generation of TEDS participants, CoTEDS will include information on adult twins and their offspring from infancy. Parent questionnaire-based data collection is now underway for one- and two-year-old CoTEDS infants, with further waves of data collection planned. Current data collection includes the following primary constructs: child mental-health, temperament, language and cognitive development; parent mental-health and social relationships; parenting behaviours and feelings; and other socio-ecological factors. Measurement tools have been selected with reference to existing genetically-informative cohort studies, to ensure overlap in phenotypes measured at corresponding stages of development. This built-in study overlap is intended to enable replication and triangulation of future analyses across samples and research designs. Here, we summarise study protocol and measurement procedures and describe future plans.