The low stability of behavior problems between toddlerhood
and later childhood has implications for using the term “disorder”
in referring to these problems in very early childhood
(Campbell, 2002; Egger & Angold, 2006). It may be somewhat
less problematic in the preschool range. There is currently much
debate about the appropriateness of using traditional diagnostic
categories, particularly for infants and toddlers. Rapid developmental
change within the period 0–5 makes it particularly
hard to distinguish normal from abnormal behavior, and to
set age-appropriate criteria for classification systems. Thus,
having six temper tantrums a day might be bothersome but
normal at 22 months, but could contribute to a diagnosis of
oppositional defiant disorder (ODD) in a 4-year-old.