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Trial Lecture – time and place
See Trial Lecture.
Adjudication committee
- First opponent: Professor Esben Agerbo, Aarhus University, Denmark
- Second opponent: Professor Maj-Britt Posserud, University of Bergen,
- Third member and chair of the evaluation committee: Professor II Theresa Wilberg, University of Oslo
Chair of the Defence
Professor II Anners Lerdal, University of Oslo
Principal Supervisor
Associate Professor Alexandra Havdahl, University of Oslo
Summary
Although disorders such as ADHD, autism spectrum disorder (autism), schizophrenia and bipolar disorder are highly heritable, knowledge is lacking on how genetic risk manifests in developmental traits in the first years of life.
The aim of this thesis was to increase our understanding of childhood manifestations of genetic risk for neurodevelopmental traits. We investigated dimensional trait measures as outcomes, moving beyond categorical diagnoses.
The polygenic risk score for ADHD was associated with hyperactivity and inattention before the age of 2 with increasing strength up to 8 years, and with language difficulties at age 5 and 8. The autism polygenic risk score was associated with language difficulties at 18 months, motor difficulties at 3 years, and hyperactivity and inattention at 8 years. Polygenic risk for bipolar disorder was associated with conduct and oppositional defiant difficulties at 8 years. We did not identify robust associations for the schizophrenia polygenic risk score. For most of the associations we did not identify any sex differences. An exception was the association between polygenic risk for ADHD and hyperactivity at 18 months, which was stronger in boys. We performed genome-wide association studies on several traits related to restricted repetitive behavior and social communication and identified four genome-wide significant loci. The positive genetic correlation found between restricted and repetitive behavior and autism and the negative genetic correlation between social reciprocity and autism, but none of the other measures, could imply that these trait factors are, in fact, distinct.
Taken together, the studies included in this thesis contribute to strengthening our understanding of how genetic factors are involved in the development of childhood neurodevelopmental traits. More research is needed to understand the multidimensionality of neurodevelopmental traits, their etiology, and how they overlap with other traits.
Additional information
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