ABSTRACT
Abstract Background Parents and teachers can be valuable sources of information for characterizing children's ADHD-related impairments in different environments. However, evidence indicated that those categories of informants often provide conflicting responses in formal assessment scales, which may challenge diagnostic decisions regarding the condition. Objective: We aimed to investigate reliability rates between parents and teachers of children and adolescents with and without ADHD using SNAP IV. Methods 199 children and adolescents aged 6 to 17 years were evaluated for ADHD symptoms using parent-rated and teacher-rated SNAP IV scales. Intraclass correlation coefficients were analyzed for ADHD domains (inattention and hyperactivity/impulsivity), as well as for defiant-oppositional behavior. Results Reports from parents and teachers showed low reliability for all ADHD domains. Parents' scores on the SNAP IV were higher than those of teachers. Parents and teachers provided highly discrepant responses concerning to the presence and severity of ADHD in children and adolescents, which might result from intrinsic aspects related to their daily functioning in different settings. Discussion Clinicians should consider those trends in parental and teachers' responses when interpreting results from informant-based instruments for detecting ADHD.