are most effective with specific subtypes of youth will
assist mental health professionals in reducing CD
symptoms and the concomitant costs to society.Definition and Subtypes
According to the Diagnostic and Statistical Manual of
Mental Disorders(fourth edition, text revision; DSM-
IV-TR), CD is a repetitive and persistent pattern of
behavior that violates others’ rights or age-appropriate
norms and causes clinically significant impairments in
various domains of functioning. For example, symp-
toms of CD may include aggression, damaging prop-
erty, and lying. For a diagnosis of CD, the youth must
have evidenced 3 of the 15 symptoms within the past
12 months, with at least 1 symptom being present for
the past 6 months.
Because youths with CD are a heterogeneous group,
various attempts have been made to identify subtypes
of CD for informing etiology and intervention
strategies. Earlier versions of the DSMdifferentiated
between socialized versus undersocialized and aggres-
sive versus nonaggressive dimensions. The socialized
subtype was characterized by covert and overt antiso-
cial behavior committed within the context of groups,
whereas the undersocialized subtype was characterized
by assaultive behavior that was carried out alone.
The current version of the DSMin part incorporates
Terrie Moffitt’s taxonomy and differentiates subtypes
based on the age of onset: The childhood-onset and
adolescence-onset subtypes are defined by characteris-
tics of the disorder being present before and after the
age of 10, respectively. This classification is intended
to distinguish the life-course-persistent antisocial
youth from the adolescence-limited antisocial youth, a
potentially less serious subtype of CD. In support of
this distinction, research by Paul Frick and Jeffrey
Burke and colleagues has found that childhood-onset
CD is associated with temperament and family dys-
function, whereas adolescence-onset CD is associated
with delinquent peer affiliation. Furthermore, early
onset is associated with the persistence of CD and an
increased likelihood of violent and criminal behavior.
Two other classification systems include differenti-
ating CD into overt and covert subtypes and on the
basis of two common co-occurring disorders, attention
deficit hyperactivity disorder (ADHD) and anxiety.
Research by Jeffrey Burke and colleagues and Paul
Frick and colleagues suggests that there is some evi-
dence for the utility of these distinctions. The presence
of covert symptoms is associated with the persistenceof CD, and youths with both CD and ADHD engage in
a greater variety of delinquent behaviors and are more
violent. In contrast, youths with both CD and anxiety
display fewer impairments in peer relationships and
have fewer police contacts.Prevalence and Impact
According to the DSM-IV-TR, the prevalence of CD
ranges from 1% to more than 10% in the general pop-
ulation. Large-scale population studies report preva-
lence rates ranging from 3% to 10% in nonclinical
samples. Prevalence rates by gender are reported to
range from 2% to 16% in boys and 1% to 9% in girls.
The differences in prevalence rates are likely due to
differences in the age of the youths sampled, CD cri-
teria, time frame, and method of assessment.
The negative consequences associated with CD
affect a variety of domains, including education (e.g.,
poor academic performance), employment (e.g.,
increased likelihood of the need for financial assis-
tance), relationships (e.g., peer rejection), mental
health (e.g., substance abuse), and criminality. Second,
a diagnosis of CD can increase one’s risk for other
psychiatric and emotional disorders. The most well-
established outcome is the link between CD and anti-
social personality disorder (APD) in adulthood, on the
assumption that there is a developmental progression
between the disorders. Research by Lee Robins sug-
gests that between 25% and 40% of children with CD
will meet the diagnostic criteria for APD.
Finally, CD is one of the most costly diagnoses in
terms of involvement with mental health services and
the criminal justice system. Youths with CD use a vari-
ety of services, including additional school resources,
social services, general health services, inpatient and
outpatient mental health services, and juvenile justice
services. Research by Michael Foster and Damon Jones
indicates that the cost of services used by the average
youth with CD exceeds $14,000 per youth by the end
of adolescence and the cost of total expenditures across
adolescence is approximately $70,000 more than for
youths without any behavioral disorders. Research by
Stephen Scott and colleagues indicates, in more general
terms, that children with CD cost 10 times more than
those without CD.Conduct Disorder and Psychopathy
Research by Paul Frick and Donald Lynam sug-
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