Genome-Wide Association Studies of Delay Discounting and Impulsive Personality Traits in Children From the Adolescent...

Impulsivity, often operationalized as delay discounting (DD) and as impulsive personality traits via the UPPS-P scales, is a key transdiagnostic construct across psychiatric disorders. Recent genome-wide association studies (GWAS) have studied the genetic basis of impulsivity in adults, but it remains unclear how similar the genetic architecture of DD is in children. The present study conducted GWAS of DD and impulsivity traits in 5548 children (ages 9-10 years old) of genetically inferred European ancestry from the Adolescent Brain Cognitive Development (ABCD) Study. Heritability estimates for DD (h² = 0.20, S.E. = 0.10) and UPPS-P subscales (h² = 0.08-0.11 S.E. = 0.05) were comparable to adult estimates. Genetic correlations between adult and child impulsivity were modest (r_g = 0.28-0.46), with positive urgency showing the strongest correlation (r_g = 0.83). While no genome-wide significant associations were identified, the top associated variants were mapped to genes previously linked to smoking initiation (rs3820908; p = 6.5 × 10^-8) and UPPS-P Lack of Premeditation (rs17292179; p = 4.2 × 10^-7). Polygenic score (PGS) associations were used to compare the genetic signals in children with those reported in adults. Adult PGSs for DD and positive and negative urgency indicators explained small but significant variance in the respective child impulsivity phenotypes (0.36%-0.44%, p < 7.5 × 10^-4). Additionally, UPPS-P indices were broadly associated with PGSs derived from adult externalizing (0.42%-1.02%) and ADHD (0.23%-0.79%). This first GWAS of impulsivity in children offers a developmentally informed comparison of genetic influences, revealing both similarities and differences by developmental stage.