When the cognitive paradigm became dominant, inattention became the focus of ADHD, and disorder was renamed attention deficit disorder (ADD). Two subtypes would later appear in the literature, which correspond to ADD with or without hyperactivity. The diagnostic nomenclature reflects the notion that the primary problem was an attentional (and thus, cognitive) one and not primarily behavioral. The attentional problems had to do with the ability to shift attention from one stimulus to another (something that Jonah Lehrer has called an attention-allocation disorder, since it isn’t really a deficit of attention). The hyperactivity symptoms were also reformulated as cognitive: connected with an executive processing deficit termed “freedom from distractibility.”

Here is a solid article that describes the arc of knowledge development that surrounds ADHD interventions, and brings the cognitive paradigm to the forefront in a very thoughtful manor.

The second to last paragraph points to current cerebellar studies which is of course our area of focus.

When the cognitive paradigm became dominant, inattention became the focus of ADHD, and disorder was renamed attention deficit disorder (ADD). Two subtypes would later appear in the literature, which correspond to ADD with or without hyperactivity. The diagnostic nomenclature reflects the notion that the primary problem was an attentional (and thus, cognitive) one and not primarily behavioral. The attentional problems had to do with the ability to shift attention from one stimulus to another (something that Jonah Lehrer has called an attention-allocation disorder, since it isn’t really a deficit of attention). The hyperactivity symptoms were also reformulated as cognitive: connected with an executive processing deficit termed “freedom from distractibility.”

In DSM-IV, published in 1994, the subtypes were made standard and there wasn’t much change in the diagnostic criteria per se, but there were changes in the name of the disorder, which reflected changes in the literature in terms of the understanding of the etiology of the disorder. The term ADD did not hold up, and the disorder became known as ADHD, with three subtypes: ADHD with hyperactivity/impulsiveness, ADHD with inattention, and a combined subtype in which patients have both hyperactive and attention-related symptoms. Due to improved neuroimaging technology, these subtypes seem to reflect structural and functional abnormalities found in the frontal lobe, and in its connections with the basal ganglia and cerebellum.

The set of the symptoms associated with ADHD seem not to have changed much in the last one hundred years. However, paradigm shifts within the field of psychopathology have changed the way in which researchers understand the underlying causal factors, as well as which of the symptoms are thought to be primary.

via What is ADHD? Paradigm Shifts in Psychopathology | Child's Play.