Neural correlates of gene-environment interactions in ADHD
The way we respond to our environment partly depends on our genes. So-called gene-environment interactions (GxE) may explain why some children develop attention-deficit/hyperactivity disorder (ADHD) when exposed to a stressful environment, whereas others do not. Knowledge of GxE may therefore not only contribute to a better understanding of this disorder, but also help in the development of prevention or treatment strategies that are tailored to the individual.
In this PhD project, Dennis investigated the relation between genes, stress, and ADHD.
Results
We found that genes regulating the activity of the brain’s stress response pathway explain differences between people in their sensitivity to stress. People with specific variants of the serotonin transporter (5-HTT) and the glucocorticoid receptor (NR3C1) genes showed a stronger relation between long-term exposure to stress and symptoms of ADHD. They also had lower brain volume and activity in brain areas important for the ability to control behavior, which are also relevant for ADHD. He further found that statistical methods that are able to take into account interactions between many genes and stressful experiences simultaneously are particularly well-suited to predict ADHD severity.
What do these results mean for practice?
In conclusion, the GxE approach is valuable for developing a more nuanced understanding of the influence of genetic and environmental risk factors on ADHD and the brain. His pattern of results illustrates that the biological systems underlying behavior are made up of many parts that influence each other, parts that should not be studied in isolation if we wish to truly understand how they work.
The research study
Using data from NeuroIMAGE, research is being conducted to further investigate the genetics, environmental risk factors (also in interplay with genetics) and the function and structure of the brain in ADHD and related behavioral disorders.
A range of current methods and technologies are being used for the research related to NeuroIMAGE.
These include genome-wide association studies (GWAS) and functional and structural MR imaging (MRI).
Collaboration
We conducted this research in collaboration with the University of Groningen (RUG) and the University Medical Center Groningen (UMCG) and the Donders Institute for Brain, Cognition and Behavior (Radboud University Nijmegen).