In 1798, Scottish physician Sir Alexander Crichton published a series of books in which he provided case studies of mental illnesses and disorders. One chapter was devoted to what he called “attention” and “its diseases.” He described how a person’s attention had a normal range, and that being distracted was not always abnormal. Attention deficits occurred, he wrote, when a person struggled with “sustaining attention in tasks or play activities” and was easily sidetracked.
Crichton wasn't the only one to try to reckon with attention deficits. Over a century later, in the early 1900s, a physician in London described the inability to focus as a lack of “moral control” and warned it could lead to criminality later in life. In the 1920s., research in the U.S. took another dark turn when physicians studied children who contracted encephalitis during the 1918 outbreak and later displayed inattention or hyperactivity. Scientists began associating attention deficits with brain damage.
Although scientists would later disprove it, the brain-damage theory persisted well into the 1960s, as scientists questioned whether a kinetic imbalance caused inattention and hyperactivity in children. The second edition of the Diagnostic Statistical Manual of Mental Disorders (DSM) in 1968 even took it a step further, describing it as a “hyperkinetic reaction of childhood.”
