Child Development and Mental Health

In this doctoral thesis, Dr. Hekmat Alrouh investigates the interplay of genetic, environmental, and intergenerational factors that shape child development, physical health, and mental wellbeing across childhood and adolescence. Spanning multiple empirical studies, the work addresses themes such as enduring mental health (EMH), intergenerational transmission of body mass index (BMI), educational attainment, and the unique impact of the COVID-19 pandemic on youth wellbeing. Data are drawn primarily from large twin and family samples, leveraging genetically informative designs to disentangle the relative contributions of genes and environments. Early chapters introduce the concept of EMH, which is defined as a state in which individuals display no clinically significant mental health problems across key developmental stages. The thesis presents evidence that EMH occurs in only a minority of children and adolescents, emphasizing that experiencing at least some degree of mental health difficulty is more common than previously assumed. These chapters also highlight the crucial roles that parental education, child academic performance, and subjective wellbeing (as measured by life satisfaction scales) play in fostering positive mental health trajectories. Mid-thesis chapters explore how BMI and educational attainment transmit across generations. By analyzing parent-offspring data, the thesis shows that parental BMI is the strongest predictor of a child’s BMI—both in childhood and adolescence—and that higher parental education correlates with children’s scholastic success. Yet, the work clarifies that the association between parental education and offspring BMI can often be explained by parents’ own BMI, cautioning against oversimplified claims that lower parental education, in itself, causes childhood obesity. Later chapters assess the effects of the COVID-19 pandemic and lockdowns on children’s mental health and wellbeing. Employing a multi-cohort and multi-informant approach, the author observes that the pandemic had heterogeneous impacts, with some youth experiencing exacerbated behavioral or emotional problems. This disruption also enabled the study of how environmental stress interacts with genetic predispositions for mental health, providing insights into gene–environment interplay during a global crisis. Furthermore, the thesis highlights how survey framing—for example, mentioning COVID-19 before asking about wellbeing—can subtly shift parental reports of a child’s mental state, underlining the importance of measurement context when interpreting mental health data. Overall, the dissertation underscores that child mental health is shaped by a dynamic, complex set of influences that span genetic vulnerabilities, parental characteristics, and contextual stressors such as the pandemic. The research ultimately advocates a more integrated, preventative approach to youth mental health, stressing that early identification of risk and resilience factors—such as parental BMI and education—can inform strategies to support child development and psychological wellbeing.