ADHD and giftedness: a neurocognitive consideration of twice exceptionality.

Current models of cognition and behavioral diagnosis emphasize categorical classification over continuous considerations of function and promote the "differential diagnosis" of various conditions according to observational criteria. However, an overemphasis on a purely behavioral, categorical approach to understanding human function fails to address the comorbidity of different disorders and does not include a consideration of overlapping levels of function, from "pathological" through "normal," to "gifted" or exceptional. The frequent co-occurrence of "gifted" and "pathological" function is thus difficult to understand from a corticocentric and purely behavioral and observational point of view. This article reviews "giftedness" in relation to the diagnosis of attention-deficit hyperactivity disorder, coexistence of which is termed "twice exceptional." It additionally considers problems in assessing these functions using current neuropsychological tests and methodologies that are presumably based upon a corticocentric model of cognition.