A group of 25 children diagnosed as now hyperactive by DSM III criteria is compared on primary personality factors with 50 controls, 14 additional hyperactives under medication and 11 ordinary behavior difficulty cases, on the hypothesis that they true hyperactives will show a high score on Factor D, the factorof excitability from the 16 Personality Factor Questionnaire (16PF). New items made up from DSM III description fit the D factor, as a factor, excellently. But the school-diagnosed DSM III's differed from controls principally in having low intelligence. It is suggested that low intelligence in a classroom situation creates a state syndrome superficially resembling the D scale and DSM III diagnoses of hyperactivity.