Neurocognitive endophenotypes in neurodevelopmental disorders: social cognition and executive functions in children with Autism Spectrum Disorder Level 1 and Attention-Deficit/Hyperactivity Disorder

Introduction: Executive Functions (EF) and Social Cognition (SC) show strong interdependence, yet it remains unclear whether social difficulties in neurodevelopmental disorders, such as Autism Spectrum Disorder Level 1 (ASD1) and Attention Deficit/Hyperactivity Disorder (ADHD), arise from shared EF related mechanisms or reflect disorder specific neurocognitive architectures. Comparative studies integrating both ecological and performance based measures remain scarce. This study aims to analyze the relationship between executive functions and Social Cognition skills across three matched developmental groups: Autism Spectrum Disorder Level 1 (ASD1), Attention-Deficit/Hyperactivity Disorder (ADHD), and Typical Development (TD). Methods: A total of 123 children aged 6–11 years participated in the study: ASD1 (N = 42), ADHD (N = 43), and TD (N = 38). Participants were evaluated using the WISC-IV, BRIEF-2, and selected subtests of the NEPSY-II. Non-parametric group comparisons and multiple linear regression models within the clinical groups were performed. Results: Both clinical groups showed widespread EF and SC impairments compared to TD peers, but with distinct profiles. ADHD exhibited pronounced deficits in inhibition and attentional control (Inhibition, Auditory/Visual Attention), whereas ASD1 showed greater impairment in SC (ToM, AR), cognitive flexibility (Shift), and rule-guided tasks (Response Set, Design Fluency). Regression models revealed disorder-specific EF–SC relationships: in ADHD, SC performance was strongly scaffolded by EF (Inhibition, Auditory Attention, Design Fluency; ToM model R² = 0.72). In ASD1, ToM was predicted primarily by AR and Response Set (R² = 0.55), indicating relative independence from basic inhibitory and attentional resources. Conclusions: Despite superficially similar social difficulties, ASD1 and ADHD display distinct patterns of association between EF and SC: executive-regulatory deficits in ADHD versus primary mentalizing and shifting impairments in ASD1. These findings support the need for transdiagnostic profiling to optimize early screening and to guide targeted, domain-specific rehabilitative and psychoeducational interventions for each diagnostic profile.