Phenotypic evaluation of attention deficit hyperactivity disorder (Adhd): Existence of a continuum of severity in children

Abstract

Background: Within the study of the structure of ADHD there is an ongoing debate as to whether phenotypic differences are due to differences in the severity of symptoms of inattention, hyperactivity, and impulsivity along an underlying continuum or whether the differences reflect are qualitatively distinct subtypes with unique etiologies. Objective: To analyze whether the behaviors of inattention, hyperactivity and impulsivity in children reflect qualitatively different presentations within ADHD, variations along a single continuum of severity or different levels of severity within the representations. Method: A study was carried out through confirmatory factor analysis (CFA), latent class analysis (LCA) and factor mixture models (FMM) of the ADHD phenotype according to the data collected through the Child and Adolescent Behavior Inventory (CABI) of 632 participants (M = 10.46 years; SD = 2.35) from the city of Talca (Chile) in general population. Results: For the 16 models analyzed, it was inferred that the MFM of three factors (IN, HI and IM) and four classes, a majority with a low score (unaffected) and a minority with a high score (affected), with two very similar intermediate categories, showed the best fit. Conclusions: The FMM showed that ADHD would vary along a continuum of severity, within symptoms of the disorder from mild, to moderate, or severe, rather than existing as discrete diagnostic categories.