Aggressive behavioral patterns span different diagnoses
in preschoolers. In a referred clinic sample of 79 preschoolers
ranging in age from 2 1⁄2 to 5 1⁄2 years old; 59.5% met criteria
for oppositional defiant disorder, 41.8% met criteria for conduct
disorder and 59.5% met criteria for one of the three subtypes
of ADHD (Keenan and Wakschlag, 2000). Similarly, the 0-3
Diagnostic Classification recognizes newly emerging aggression
toward peers, adults and animals, and restricted affect range as
a symptom of posttraumatic stress in infants (National Center
for Clinical Infant Programs, 1994). Behavioral aggression in
preschoolers can also present as part of other established neuropsychiatric disorders where a prefrontal dysfunction model is
suggested (Raine, 1998). This is also reported in children with
autism spectrum disorders, and Tourette’s disorder.