Joakim Ebeltoft

• Eilertsen, Espen Moen; Eftedal, Nikolai Haahjem; Cheesman, Rosa Catherine Gillespie; Ayorech, Ziada; Ebeltoft, Joakim Coleman & Sunde, Hans Fredrik [Show all 9 contributors for this article] (2026). Multivariate maternal effects across the internalizing–externalizing spectrum in childhood: results from the Norwegian mother, father, and child cohort study. Journal of Child Psychology and Psychiatry. ISSN 0021-9630. p. 1–13. doi: 10.1111/jcpp.70111. Full text in Research Archive Show summary

  Background From a functionalist perspective, parenting behaviors have adaptive functions and are partly expressions of genetic variation. Maternal genes that have effects on children are often referred to as indirect maternal genetic effects. Indirect genetic effects provide a means for measuring the role of parenting without the need for specifying the relevant parental behaviors. We studied indirect maternal genetic effects to address both the importance and commonality of parenting across the internalizing–externalizing spectrum of behavior problems in childhood. We further addressed how indirect genetic effects impact our understanding of direct genetic effects if not accounted for. Methods Utilizing data from the Norwegian Mother, Father, and Child Cohort Study (MoBa), our analyses involved 42,423 children and their mothers. Both pedigree and genotype data were used to infer genetic relationships. We applied multivariate latent variable models to distinguish indirect maternal genetic effects and direct offspring genetic effects on seven measures of internalizing–externalizing behaviors. Results Our findings indicate significant maternal genetic influences, explaining 7%–18% of the variance across internalizing–externalizing behaviors. A general maternal effect common across behaviors could adequately account for most of the variability. The analyses further indicate that direct child genetic effects appear smaller and more complex when indirect maternal genetic effects are modeled simultaneously. Conclusions By summarizing the effects of parenting with indirect maternal genetic effects, we show a substantial contribution of parents with respect to internalizing–externalizing behaviors in childhood. Although parenting is multifaceted, the effects of parenting are general and can succinctly be described as a single common dimension. Further, our study demonstrates that direct genetic effects appear smaller and more complex when maternal genetic effects are accounted for, highlighting the confounding potential of parental effects in understanding the role of genetic differences in child psychopathology.

• Ebeltoft, Joakim Coleman; Ystrøm, Eivind; Ayorech, Ziada & Eilertsen, Espen Moen (2026). Parental wealth and mental disorders in Norway (2006–2023): a nationwide registry-based study of 1.4 million young people. The Lancet Regional Health - Europe. 62. doi: 10.1016/j.lanepe.2025.101567. Full text in Research Archive Show summary

  Background Young people from families with low socioeconomic position have higher rates of mental disorders. However, wealth is underexamined despite large wealth inequity worldwide. Here, we aim to investigate the relationship between early life parental wealth and mental disorders in young Norwegians. Methods We conducted a population study of associations between early-life parental wealth and 17 diagnostic categories of mental disorders in 1.4 M children (7–12), adolescents (13–18), and young adults (19–24) observed 2006–2023. Ranked parental socioeconomic indicators at age 0–6 (wealth, income, occupation, and education) and mental disorder diagnoses (ICD-10 and ICPC-2) were obtained from Norwegian Tax, Employment, Education, and Control and Payment of Health Reimbursements registries. Estimates were derived from mean prevalences, generalised estimating equations, and sibling comparison designs. Findings Parental wealth represents a gradient in young people’s mental disorders across age, sex, diagnostic categories, and cohorts. The lowest wealth quintile demonstrated 87% [95% CI = 78–96%] higher 1-year prevalence than the highest quintile. In multivariable analyses, parental wealth was the strongest predictor of mental disorders relative risk in adolescents (1.83 [1.76–1.9]) and young adults (1.92 [1.8–2.04]), while wealth (1.53 [1.46–1.6]) and education (1.52 [1.45–1.6]) were the strongest predictors in children. Parental wealth has a significant within-family association with mental disorders (relative risks: children 1.57 [1.44–1.71], adolescents 1.34 [1.26–1.42], young adults 1.42 [1.31–1.54]). Interpretation Our study serves as a point of reference for understanding the relationship between parental wealth and mental health. Our findings establish early life parental wealth as a fundamental social gradient in young people’s mental disorders.

• Tamnes, Christian K.; Bekkhus, Mona; Eilertsen, Maja; Nes, Ragnhild Bang; Prydz, Monica Beer & Ystrom, Eivind [Show all 63 contributors for this article] (2025). The nature of the relation between mental well-being and ill-being. Nature Human Behaviour. 9(12), p. 2431–2440. doi: 10.1038/s41562-025-02319-x. Full text in Research Archive
• Ebeltoft, Joakim Coleman; Eilertsen, Espen Moen; Cheesman, Rosa Catherine Gillespie; Ayorech, Ziada; Hootegem, Arno Van & Lyngstad, Torkild Hovde [Show all 7 contributors for this article] (2025). The genetic and environmental composition of socioeconomic status in Norway. Nature Communications. 16(1). doi: 10.1038/s41467-025-58961-6. Full text in Research Archive Show summary

  Estimating the contributions of genetic and environmental factors is key to understanding differences in socioeconomic status (SES). However, the heritability of SES varies by measure, method, and context. Here, we estimate genetic and environmental sources of variance and commonality in the ‘big four’ SES indicators. We use high-quality administrative data on educational attainment, occupational prestige, income, and wealth, and employ four family-based and unrelated genotype-based heritability methods, all drawn from the same population-wide cohort of >170,000 Norwegians aged 35-45. By drawing subsamples from a consistent sample and using registry-based data, we reduce differences in estimates due to population characteristics and measurement error. Our results show that genetic variation consistently explains more for educational attainment and occupational prestige. Family-shared environmental contributions explained more for educational attainment and wealth. Our results highlight considerable common influences on the four SES indicators among genetic and shared environmental factors, but not among non-shared environmental factors. Overall, we show how the relative importance of genetic and environmental factors to SES differences in Norway varies by method and type of socioeconomic attainment. This study is a reliable source for comparing heritability methods, and for comparing SES indicators and their genetic and environmental commonality in a social-democratic welfare state.

• Cheesman, Rosa Catherine Gillespie; Anapaz, Ville; Alten, Sjoerd van; Abdellaoui, Abdel; Porneso, Ralph Pascual Ortiz & Ebeltoft, Joakim Coleman [Show all 16 contributors for this article] (2025). Genetic associations with educational fields. Nature Genetics. ISSN 1061-4036. 57, p. 2997–3006. doi: 10.1038/s41588-025-02391-z. Full text in Research Archive Show summary

  Educational field choices shape careers, wellbeing and the societal skill distribution, yet genetic influences on what people study remain poorly understood. Here we show that genetic factors are associated with educational field specializations using genome-wide association studies (GWASs) across 463,134 individuals from Finland, Norway and the Netherlands (effective n between 40,072 and 317,209). We identified 17 independent genome-wide significant variants linked to 7 of 10 educational fields, with average heritability of 7%. The genetic signal is specific to field choice rather than educational level, persisting after controlling for years of schooling and confounding factors. By examining genetic clustering across specializations, we uncovered two key dimensions: technical versus social and practical versus abstract. We performed GWASs of these components and demonstrated distinct genetic correlations with personality, behavior and socioeconomic status. Our findings demonstrate that genomic research can illuminate ‘horizontal’ stratification, revealing insights into vocational interests and social sorting beyond traditional attainment measures.

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• Ofstad, Sverre Berg; Peng, Qiyuan; Ebeltoft, Joakim; Bjørndal, Ludvig Daae; Rayner, Christopher & Ayorech, Ziada [Show all 10 contributors for this article] (2026). PGI-by-Environment interactions: practical guidelines for robust research. Full text in Research Archive
• Eilertsen, Espen Moen; Eftedal, Nikolai Haahjem; Cheesman, Rosa Catherine Gillespie; Ayorech, Ziada; Ebeltoft, Joakim Coleman & Sunde, Hans Fredrik [Show all 9 contributors for this article] (2024). Multivariate parental effects across the internalizing-externalizing spectrum in childhood: results from the Norwegian Mother, Father, and Child Cohort Study. Full text in Research Archive
• Ebeltoft, Joakim Coleman; Eilertsen, Espen Moen; Cheesman, Rosa Catherine Gillespie; Ayorech, Ziada; Hootegem, Arno Van & Lyngstad, Torkild Hovde [Show all 7 contributors for this article] (2024). Triangulating Approaches to Evaluate the Genetic and Environmental Composition of Socioeconomic Status. Full text in Research Archive
• Ystrøm, Eivind; Cheesman, Rosa Catherine Gillespie; Hootegem, Arno Van; Ghirardi, Gaia; Ofstad, Sverre Berg & Ebeltoft, Joakim Coleman (2024). Roads less traveled in social science genetics. Full text in Research Archive
• Cheesman, Rosa Catherine Gillespie; Anapaz, Ville; Alten, Sjoerd van; Abdellaoui, Abdel; Ebeltoft, Joakim Coleman & Porneso, Ralph Pascual Ortiz [Show all 16 contributors for this article] (2024). The Genetics of Educational Fields. Full text in Research Archive
• Ebeltoft, Joakim Coleman; Eilertsen, Espen Moen; Cheesman, Rosa Catherine Gillespie; Ayorech, Ziada; Hootegem, Arno Van & Lyngstad, Torkild Hovde [Show all 7 contributors for this article] (2024). Parent SES and young people's mental health: Doctoral project. Full text in Research Archive
• Ebeltoft, Joakim Coleman; Eilertsen, Espen Moen; Cheesman, Rosa Catherine Gillespie; Ayorech, Ziada; Hootegem, Arno Van & Lyngstad, Torkild Hovde [Show all 7 contributors for this article] (2024). Triangulating Approaches to Evaluate the Genetic and Environmental Composition of Socioeconomic Status: Multi-method study. Full text in Research Archive
• Ebeltoft, Joakim Coleman; Eilertsen, Espen Moen; Cheesman, Rosa Catherine Gillespie; Ayorech, Ziada; Hootegem, Arno Van & Lyngstad, Torkild Hovde [Show all 7 contributors for this article] (2024). Genetic and environmental composition of SES. Full text in Research Archive
• Ebeltoft, Joakim Coleman; Eilertsen, Espen Moen; Cheesman, Rosa Catherine Gillespie; Ayorech, Ziada; Hootegem, Arno Van & Lyngstad, Torkild Hovde [Show all 7 contributors for this article] (2024). Doctoral project: Socioeconomic status and young people's mental health. Full text in Research Archive
• Ebeltoft, Joakim Coleman; Eilertsen, Espen Moen; Cheesman, Rosa Catherine Gillespie; Ayorech, Ziada; Qin, Qi & Ystrøm, Eivind (2023). The inheritance of inequality: Comparing heritability estimates of socioeconomic status. Full text in Research Archive
• Qin, Qi; Cheesman, Rosa Catherine Gillespie; Eilertsen, Espen Moen; Ebeltoft, Joakim Coleman; Ayorech, Ziada & Ystrøm, Eivind (2023). School and geographical differences in the effect of heritable emotional and behavioral traits on educational performance. Full text in Research Archive
• Qin, Qi; Cheesman, Rosa Catherine Gillespie; Eilertsen, Espen Moen; Ebeltoft, Joakim Coleman; Ayorech, Ziada & Ystrøm, Eivind (2023). School and geographical differences in the effect of heritable emotional and behavioural traits on educational performance. Full text in Research Archive
• Eilertsen, Espen Moen; Eftedal, Nikolai Haahjem; Cheesman, Rosa Catherine Gillespie; Ebeltoft, Joakim Coleman; Sunde, Hans Fredrik & Tandberg, Anneli Desire [Show all 8 contributors for this article] (2023). Multivariate parental effects across the internalizing-externalizing spectrum in childhood: results from the Norwegian Mother, Father, and Child Cohort Study. Full text in Research Archive
• Ebeltoft, Joakim Coleman; Eilertsen, Espen Moen; Cheesman, Rosa Catherine Gillespie; Ayorech, Ziada; Qin, Qi & Ystrøm, Eivind (2023). Inheritance of inequality: Comparing heritability estimates. Full text in Research Archive
• Ebeltoft, Joakim Coleman; Eilertsen, Espen Moen; Cheesman, Rosa Catherine Gillespie; Ayorech, Ziada; Qin, Qi & Ystrøm, Eivind (2023). Inheritance of inequality. Full text in Research Archive
• Ebeltoft, Joakim; Ystrom, Eivind; Eilertsen, Espen Moen & Ayorech, Ziada (2026). Dissecting intergenerational patterns of socioeconomic status and mental disorders in Norway. Universitetet i Oslo. Full text in Research Archive Show summary

  Socioeconomic status (SES) and mental disorders run in families—representing intergenerational persistence of advantages and disadvantages. Through three original research studies, this thesis investigates intergenerational patterns of socioeconomic status and mental disorders in Norway using genetically informed designs. First, in paper 1, I explore the coarse-grained etiology of the “big four” SES indicators —education, income, occupation, and wealth. By triangulating four advanced genetic methods, I demonstrate common and unique genetic and environmental sources of variance in parent SES. The substantial common variation across the “big four” is linked to genetic and shared environmental influences, while the considerable unique variance is explained by non-shared environment variation. Second, in paper 2, I assess the risk of mental disorders in young people given their parents’ SES—wealth in particular. In multivariable models including the “big four,” parental wealth is the strongest predictor of most mental disorder diagnoses in children, adolescents, and young adults. Significant associations between parent wealth and risk of mental disorders in young people persist after controlling for sibling-shared genetic and environmental factors. Third, in paper 3, I investigate the effects of children’s genetic differences on parents’ economic outcomes from 3 years before birth to 15 years after birth. By controlling for parent genetic factors, child genetic effects were identified using two methods. We found no conclusive evidence of child genetic effects on parent income, wealth, and government transfers. Three broad causal models can explain SES and mental disorder outcome correlations between parents (X) and their children (Y): A) third factors causing correlated observations (X←Z→Y), B) parent factors causing child outcomes (X→Y), and C) child factors causing parent outcomes (X←Y). Paper 1 provides evidence of model A, showing how common genetic and environmental factors explain large shares of the variance between the “big four” SES indicators. Paper 2 provides evidence of both model A and B, indicating that both shared genetic and environmental factors and parental wealth influence mental disorder risk in their children. Paper 3 provides inconclusive evidence of model C child genetic effects on their parents’ economic outcomes. This thesis argues that genetically informed designs are valuable for dissecting at least three important conceptual angles with regard to intergenerational patterns of SES and mental disorders: (i) genetic architecture as the focus—estimating the relative magnitude genetic contributions to phenotypes, and genetic correlations between phenotypes (paper 1); (ii) genetics as a confounder—estimating social effects while accounting for genetic similarity in families (papers 2 and 3), (iii) genetics as a proxy for a social effect—estimating socially-mediated genetic influences on another person’s phenotype (paper 3).

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