Family history of ADHD associates with stronger problem-solving skills amongst 2- to 3-year-olds.

Background: Attention-Deficit/Hyperactivity Disorder (ADHD) is linked to strengths in creative problem-solving amongst school-aged children and adults. In contrast, autism (which frequently co-occurs with ADHD) is associated with lower generativity, and perseverative responses during problem-solving. Little is known about how ADHD and autism traits-or broader heritable autism and ADHD phenotypes-associate with problem-solving skills in early childhood. Methods: 129 UK 2- and 3-year-olds (exploratory dataset) and 74 Swedish 3-year-olds (confirmatory dataset) with and without a family history (FH) of ADHD and autism, completed a problem-solving task. Parents reported on their 3-year-olds' ADHD and autism traits using the Child Behaviour Checklist and Social Responsiveness Scale-2. FH group differences in problem-solving performance were tested using ANOVA (exploratory dataset, FH-autism and FH-ADHD as fixed factors) and t-test (confirmatory and combined datasets split by FH-ADHD). Linear regressions of problem-solving success on autism/ADHD traits were run in both samples. Results: Compared with peers with no FH-ADHD, children with FH-ADHD showed higher problem-solving success at 2 (partial ω 2 = 0.106) and 3 years (partial ω 2 = 0.045) in the exploratory dataset. In the confirmatory dataset, a FH-ADHD-and-autism group trended towards higher success scores compared with a no-FH-ADHD group (comprising FH-autism-only and no-FH ADHD-or-autism sub-groups) but scores were only significantly higher for children with FH-ADHD-and-autism when compared with children with no FH-ADHD-or-autism (g s  = 0.977). ADHD (but not autism) traits were positively associated with problem-solving performance in the exploratory (β = 0.212, p = 0.031) and combined samples (β = 0.173, p = 0.024). Effects were a consistent direction and magnitude, but not significant, in the confirmatory sample alone (β = 0.201, p = 0.103). Conclusions: Considering a child's family history alongside their neurodivergent traits may help to identify their likely strengths, and how to access them: Children with ADHD traits and/or a family history of ADHD are likely to have an aptitude for generative problem-solving when presented with highly motivating, ecologically valid challenges.