How is ADHD associated with comorbidities and health related outcomes? : The role of familial factors and ADHD during pregnancy

Abstract: Background: Attention-Deficit/Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder characterized by impaired attention and hyperactivity/impulsivity. ADHD is associated with several comorbidities and health-related outcomes. However, it is uncertain whether ADHD is more strongly associated with certain disorder domains, and whether ADHD-related comorbidities and health-related outcomes is important to consider during pregnancy. Aims: To expand the knowledge regarding the genetic overlap between ADHD and other psychiatric disorder symptoms, and to increase the awareness and understanding related to ADHD in women, with a focus on adverse health behaviors, mental health problems, and pregnancy outcomes. Methods: The present thesis includes one systematic review and metaanalysis (Study I), and three studies based on population-based register data from Sweden (Study II, III, and IV), and Norway (Study II).Results: Individuals with ADHD have an increased liability to meet criteria for externalizing, internalizing and neurodevelopmental disordersymptoms, and these co-occurrences are partly due to shared genetic risks. Further, ADHD is an important risk factor to consider before, during and after pregnancy, as ADHD increases the risk of smoking during pregnancy, mental health problems postpartum, and adverse pregnancy outcomes.Conclusions: The genetic overlaps between ADHD and other psychiatric disorder symptoms were similar across disorder dimensions. Further, results demonstrated that ADHD is an important risk factor to consider in women surrounding pregnancy. These findings point towards the importance of recognizing that women diagnosed with ADHD need to be prioritized and allowed more attention and support by the healthcare system, specifically during their fertile years.