HYPERACTIVITY in childhood has received a good deal of research and clinical attention in recent years (see Campbell, 1976;Sroufe, 1975;Wender, 1971). Research has focused on the comparison of school-age hyperactive and normal samples using cognitive, attentional, and psychophysiological measures and on the effects of stimulant medication on hyperactive symptomatology (Campbell, Douglas and Morgenstern, 1971;Cohen, Douglas and Morgenstern, 1971). However, the early antecedents and course of hyperactivity remain a subject of speculation. What few longitudinal studies exist have followed school-age samples into adolescence (Weiss, Minde, Werry, Douglas and Nemeth, 1971), while information about hyperactivity in infancy and early childhood is scant. Descriptions have been based largely on clinical impression (Wender, 1971) or on extrapolation from studies using either normal samples (Halverson and Waldrop, 1976) or somewhat differently defined clinical samples (Thomas, Chess and Birch, 1968).A recent study (Schleifer, Weiss, Cohen, Elman, Cvejic and Kruger, 1975) attempted to fill this gap by recruiting a sample of preschool hyperactive children from pediatricians in private practice and studying them in a research nursery. Behavioural observations of hyperactive and normal control subjects indicated that hyperactives got out of their seats and left the table more frequently during structured, teacher-directed activities than controls. They were also more aggressive toward peers. However, "blind" ratings by the nursery school teachers indicated that only one-third of the hyperactive sample was perceived as more than moderately active. Based on these teacher ratings, Schleifer et al. (1975) dubbed the moderately active children as "situational" hyperactives since their high activity was apparently situation-specific, that is observed only at home. The very active children were seen as "true" hyperactives since their high activity was crosssituational. "True" hyperactives differed from both "situationals" and controls on observational and cognitive style measures. They tended to be more aggressive and to leave the table more often than "situational" hyperactives and controls. Furthermore, they seemed more typical of the children who usually appear at a clinic when they reach school age because teachers complain of their inattentive and disruptive behaviour in the classroom.In our work at the Montreal Children's Hospital, our definition of hyperactivity has included behavioural problems both at home and school. However, because many of the preschool subjects were not yet in any formal school setting, this •Requests for reprints to Dr. S. B. Campbell, who is now at The
