Population Studies of the Heritable Influences on the Mind and Brain

Decades of prior genetic research using twin modelling designs has shown that differences in human behavior are strongly influenced by differences in our DNA. Through advances in DNA genotyping it has become feasible to study the genetic factors that contribute to human variation by large-scale genome-wide association studies (GWAS).
In this thesis, our aim was to study the genetic variants, genes and genetic pathways that explain variation in a broad diversity of behavioral outcomes making use of big data analyses in large population cohorts. By integrating GWAS results and GWAS-derived polygenic risk scores with gene-expression data, functional gene-sets and MRI imaging of the brain, this thesis provides a step forward in understanding the association between genetic variation and health-related phenotypes, including intelligence, neuroticism and depression, and insomnia, and the pathways and cell-types in the brain through which these genetic factors act.