As an infrastructural resource the department maintains the Netherlands Twin Register (NTR) and the Biobank associated with the NTR.
Individual differences in behaviour and health are studied in four interconnected research themes:
Research on the genetic architecture, in children, adolescents and adults of cognitive abilities, attention and memory processes. Individual differences in the longitudinal development of mental functioning are studied from a behavioural (e.g. what is the heritability? what is the genetic correlation across the lifespan?) and a molecular genetic perspective (candidate gene and whole-genome based gene finding). In addition to measuring endpoints we assess intermediate phenotypes or “endophenotypes” such as electrophysiological indices of brain development, brain structure as assessed with MRI (both in random and selected twin samples), and performance measures.
Research on cardiovascular functioning under laboratory and real life situations in relation to psychosocial stress, lifestyle, and genetic predisposition. Classical cardiovascular risk factors (e.g. lipid levels, BMI, smoking, hypertension) are studied as well as behavioural and psychosocial risk factors, particularly smoking behaviour, physical exercise, work stress, and the hostility/depression cluster. An important asset in this regard is the locally developed Vrije Universiteit Ambulatory Monitoring System (VU-AMS), which allows continuous 24-hour registration of sympathovagal and hemodynamic cardiovascular regulation in large (twin) samples.
Research on the genetic and environmental factors, as well as their interaction, that influence 1) the risk for anxiety and depression and comorbid phenotypes (addiction, migraine) in adults and 2) the development of behavioural and emotional problems (e.g. attention problems, aggression and anxiety) in children. Large-size longitudinal survey studies focus on the development of psychopathology and on the genetic influences across the life-span in children and adults. In adults, informative families for gene hunting studies have been selected and genome-wide linkage and association scans are carried out to characterize the genes responsible for individual differences in liability to anxiety, depression, personality disorders, and nicotine and alcohol dependence.
Causes and consequences of Twinning
A longstanding series of research projects is the genetics of twinning. In addition, we look at the mental and physical health implications of twinning, for example in relation to school performance.
For these four research themes, a genetic epidemiological approach on survey data in very large (>50000) samples is combined with experimental studies in selected subsamples that are informative for environmental (discordant monozygotic twins) or (epi)genetic (e.g. (epi)genotypes at candidate genes) risk factors.