The mechanisms underlying associations between risk factors and ADHD: a large scale genetically informative study
Attention-Deficit/Hyperactivity Disorder (ADHD) is an early-onset, highly prevalent neuropsychiatric disorder that persistent into adolescence and adulthood in a sizable number of affected children of both genders.
Comorbidity is a distinct clinical feature of both childhood and adult ADHD. Several important exposures to environmental risks have been identified, but it is unclear whether these risks really are causal or whether the associations are due to confounding from familial effects.
The overarching context of this project is to identify and describe novel environmental risks for ADHD and to delineate the genetic and environmental processes underlying these associations. The project will use data from (1) the Swedish Prescribed Drug Register, which identifies over 35.000 individuals with a diagnosis of ADHD that are treated with stimulant medication and (2) three unique, population-based twin studies, which contains detailed assessments of environmental risks, ADHD symptoms and associated condition from more than 40.000 twins. A record linkage with the multi-generation registry and several other population registries is proposed to enrich these four ADHD cohorts with detailed information regarding environmental risks. The use of twin data combined with information form the multi-generation registry allows for quasi-experimental analyses, which provide highly informative tests of a causal environmental hypothesis. As DNA is available from almost 20.000 twins, this project is also set up to follow up novel environmental risk exposures with molecular genetic analyses of gene-environmental interplay.
The specific aims of this project are to:
- Identify and describe environmental risk factors for ADHD.
- Examine genetic and environmental confounds underlying the observed ADHD-risk factor associations.
- Study the interplay of measured candidate genes and environments for ADHD.
