Direct and Indirect Genetic Effects of Parental Liabilities to Mental Health Conditions and Related Traits on Children's Behavioural Difficulties: A Multi-Cohort Study
This multi-cohort study of over 33,000 families found that while child externalising difficulties are primarily driven by direct genetic transmission (such as ADHD risk), internalising difficulties are significantly influenced by indirect genetic effects, particularly through maternal neuropsychiatric liabilities.