PhD defence D. (Dogukan) Koc

Below is a brief summary of the dissertation:

How does a child’s brain develop under the combined influence of early-life experiences and biological vulnerability? This thesis examines that question by focusing on two closely related issues during the perinatal period: maternal depressive symptoms and antidepressant use during pregnancy. It also investigates how neurotransmitter-related genetic and neurobiological factors may shape brain development during adolescence. Using large-scale longitudinal neuroimaging data from population-based cohorts, this work studies brain structure, white matter, and functional connectivity from childhood into adolescence.

The findings show that prenatal exposure to selective serotonin reuptake inhibitors (SSRIs) and maternal depressive symptoms are both associated with subtle differences in offspring brain development, although the patterns are not identical. Some alterations appear to persist, whereas others attenuate over time, suggesting developmental plasticity. These results underline the importance of carefully separating the effects of maternal mental health from those of medication exposure in observational research.

In addition, this thesis shows that neurotransmitter-related genetic liability and serotonin-informed brain organization are associated with variation in adolescent brain morphology and behavioral problems. Together, the findings contribute to a better understanding of how perinatal mental health, antidepressant exposure, and underlying neurobiology jointly shape the developing brain. This knowledge may help inform future research and support more personalized and evidence-based care for families during pregnancy and early life.