Blurred lines: Investigating functional profiles in autism and ADHD across key developmental domains

While Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) present distinct symptoms and developmental trajectories, they also share overlapping characteristics across different domains. This exploratory study investigated differences between ASD, ADHD and non-diagnosed (ND) peers across theory of mind, pragmatic language, inattention, impulsivity, social skills, and behavioral problems. A data-driven approach was further applied to explore whether distinct functional profiles emerged across these domains and whether such profiles aligned with traditional diagnostic categories. The sample included 204 participants aged 8-16: 51 with ASD, 64 with ADHD, and 89 ND, matched for age, sex, and intelligence quotient. Results highlight that both clinical groups performed worse than ND peers, with no differences between ASD and ADHD. Latent profile analysis identified four distinct profiles: 1 ("Inattentive with pragmatic difficulties"; n = 20), 2 ("Social deficits with behavioral dysregulation"; n = 63), 3 ("Highly impulsive"; n = 24), and 4 ("Minimal impairments"; n = 97). The first three were predominantly composed of autistic and ADHD participants, while the fourth was distinctive of ND. Notably, 50 % of both autistic and ADHD participants were grouped into Profile 2, characterized primarily by parental reports, alongside weaknesses performing tests. Our findings suggest that ASD and ADHD share difficulties across key developmental domains, with functional profiles extending beyond traditional diagnostic boundaries. Given the exploratory nature of the study and the relatively limited sample size, these findings should be considered preliminary and warrant replication in larger and more diverse samples. Despite this, our results support a dimensional view of neurodevelopmental conditions, while highlighting the need to integrate informant reports, psychometric data, and clinical judgment to ensure meaningful interpretations of a child's functional profile.