Perplexities in Discrimination of Attention Deficit Hyperactivity Disorder (ADHD): Specific Behaviors that may hold some Answers

Attention deficit hyperactivity disorder (ADHD) is a source of diagnostic and intervention confusion and uncertainty for practitioners and parents. Questions creating some of the confusion were answered in a series of three studies. The sample was parent and teacher behavioral ratings for 389 children and 502 adolescents with ADHD and 3131 children and 3161 adolescents without ADHD in public and private schools and mental health clinics in forty states. In the first study, data was derived from participant T-scores on the Behavior Assessment System for Children (2nd ed.) to evaluate the construct validity using first and second order factor analyses. Sufficient construct validity was established. In the second study, descriptive discriminant analyses (DDA) and item level ANOVAs were used to investigate whether behaviors that discriminate between the target (i.e., ADHD) and comparison groups were associated with the primary symptoms, comorbid conditions, functional impairment, or some combination of the three. Analyses were completed using subscale T-scores and individual item scores from the target and comparison groups. Results were compared to determine if the behaviors that discriminated between the groups were consistent across developmental stages and between parents and teachers as raters. Primary symptoms, comorbid conditions, and functional impairment explained the variance as rated by parents and teachers. Primary symptoms were found to be the strongest discriminators of children and adolescents as rated by parents. Atypicality explained the largest variance (72.25%) between children and learning problems explained the largest variance (64.32%) between adolescents when rated by teachers. The third study was a literature review of intervention studies to increase the academic performance of youth with ADHD in light of the statistical significance controversy. Fifty-one single subject and group design studies of academic, behavioral, multimodal and parent training were found. Both sides of the statistical significance controversy were summarized. The method of result reporting for 23 group design studies was investigated. Seventy-seven percent of the studies reported results as ?significant? with 26% reporting effect sizes. Researchers are encouraged to report effect sizes and explicitly compare results to previous studies in order to establish replicability for ease of educator interpretation.