described a single disorder of attention resembling the hyperactive-impulsive subtype of ADHD, Crichton postulates an additional attention disorder, described as a "morbid diminution of its power or energy", and further explores possible "corporeal" and "mental" causes for the disorder (including "irregularities in diet, excessive evacuations, and the abuse of corporeal desires"). However, he does not further describe any symptoms of the disorder, making this an early but certainly non-specific reference to an SCT-like syndrome. One example from fictional literature is Heinrich Hoffmann's character of "Johnny Head-in-Air" (Hanns Guck-in-die-Luft), in Struwwelpeter (1845). (Some researchers see several characters in this book as showing signs of child psychiatric disorders). The Canadian pediatrician Guy Falardeau, besides working with hyperactive children, also wrote about very dreamy, quiet and well-behaved children that he encountered in his practice. First research efforts In more modern times, research surrounding attention disorders has traditionally focused on hyperactive symptoms, but began to newly address inattentive symptoms in the 1970s. Influenced by this research, the DSM-III (1980) allowed for the first time a diagnosis of an ADD subtype that presented without hyperactivity. Researchers exploring this subtype created rating scales for children which included questions regarding symptoms such as short attention span, distractibility, drowsiness, and passivity. In the mid-1980s, it was proposed that as opposed to the then accepted dichotomy of ADD with or without hyperactivity (ADD/H, ADD/noH), instead a three-factor model of ADD was more appropriate, consisting of hyperactivity-impulsivity, inattention-disorganization, and slow tempo subtypes. In the 1990s, Weinberg and Brumback proposed a new disorder: "primary disorder of vigilance" (PVD). Characteristic symptoms of it were difficulty sustaining alertness and arousal, daydreaming, difficulty focusing attention, losing one's place in activities and conversation, slow completion of tasks and a kind personality. The most detailed case report in their article looks like a prototypical representation of SCT. The authors acknowledged an overlap of PVD and ADHD but argued in favor of considering PVD to be distinct in its unique cognitive impairments. Problematic with the paper is that it dismissed ADHD as a nonexistent disorder (despite it having several thousand research studies by then) and preferred the term PVD for this SCT-like symptom complex. A further difficulty with the PVD diagnosis is that not only is it based merely on 6 cases instead of the far larger samples of SCT children used in other studies but the very term implies that science has established the underlying cognitive