Differentiating pure cognitive disengagement syndrome and attention-deficit/hyperactivity disorder-restrictive inattentive presentation with respect to depressive symptoms, autistic traits, and neurocognitive profiles

This study aimed to differentiate "pure" cognitive disengagement syndrome (CDS) from attention-deficit/hyperactivity disorder-restrictive inattentive presentation (ADHD-RI) by examining their neurocognitive profiles and associations with autistic traits (ATs) and depressive symptoms. A cross-sectional study was conducted involving three groups: pure CDS (<i>n</i> = 24), ADHD-RI (<i>n</i> = 32), and controls (<i>n</i> = 31). Participants underwent neuropsychological assessments using Computerized Neurocognitive Assessment Software (CNS) Vital Signs, alongside evaluations for ATs with the Autism Spectrum Screening Questionnaire, depressive symptoms with the Children's Depression Inventory, and CDS symptoms with the Barkley Child Attention Scale. A semi-structured interview was also conducted with all participants and their parents to ensure the diagnostic validity of the groups. Findings indicated no dimensional symptomatological distinctions between CDS and ADHD-RI, except for CDS symptoms, and demonstrated no significant differences in neurocognitive test profiles between CDS and ADHD-RI, except for the neurocognition index and reaction time. ATs and depressive symptoms did not significantly differ between the pure CDS and ADHD-RI groups but were significantly elevated in both groups compared to controls. The ADHD-RI group exhibited significantly worse performance than CDS concerning the neurocognition index and reaction time, and worse than controls regarding the neurocognition index, reaction time, psychomotor speed, and complex attention. This study elucidates that ADHD-RI and "pure" CDS have substantially overlapping neurocognitive and phenotypic profiles despite certain minor differences, which is detrimental to subjects with ADHD-RI in terms of overall neurocognition and reaction time. It can be argued that, compared to "pure" CDS, executive dysfunction might be slightly more specific to ADHD-RI, while depressive symptoms and ATs are common in both psychological constructs.