Abstract

Tested were two theoretical models, the polygenetic multiple-threshold model and the constitutional variability model, which were both developed to explain the male predominance of attention deficit hyperactivity disorder (ADHD). The differential correlates to ADHD predicted by these models were tested in a clinic-referred sample of 13 girls and 67 boys who were reliably diagnosed with ADHD using a multi-informant procedure. Our data were not consistent with the predictions made by the two models, including the shared assumption that girls with ADHD would show a more severe form of the disorder. However, boys with ADHD were more likely to have fathers with a childhood history of ADHD, which may provide the basis for alternative theories of the male predominance. In addition, girls with ADHD were younger at the time of referral than boys with ADHD, despite the fact that their parents reported the onset of symptoms no earlier in girls with ADHD, than in boys with ADHD.