Högskolan i Skövde

Developmental Dyslexia (DD), Attention Deficit Hyperactivity Disorder (ADHD), and Educational Attainment (EA) are highly prevalent conditions that have a significant impacton individuals' academic and social functioning. These conditions have a complex genetic basis and are often comorbid. To assess the polygenic architecture of these traits, psychiatric genetics researchers utilize a sophisticated tool known as polygenic scores (PGS). By combining numerous genes of individually modest effects, PGS summarizes an individual's genetic risk as a single score. In this study, we aimed to examine the association between PGS for ADHD and EA with typical DD traits. Using a meta-analytic approach, we analyzed data from earlier studies and found that PGS-ADHD accounts for 1.2% of the variance in DD, with a pooled effect size of r = -0.11 (95% CI = [-0.171, -0.050]). Similarly, PGS-EA accounted for 3.2% of the variance in DD, with a pooled effect size of r = 0.18 (95% CI = [0.070, 0.288]). Although these effect sizes are relatively small, it is important to note that PGS are not typically strong predictors on their own, but rather capture a small portion of the genetic variation that contributes to a trait or outcome. My findings suggest that PGS for ADHD and EA are associated with DD, indicating that DD has a complex genetic basis. However, these findings also raise questions about the impact of PGS on psychiatric research moving forward. To address these questions, I provide recommendations for future researchdirections.