Childhood Disorders 651
Adolescent-Onset Type
For people with adolescent-onset type, the symptoms of conduct disorder emerge
with or after—but not before—puberty. The disruptive behaviors are not likely to
be violent and typically include minor theft, public drunkenness, and property of-
fenses, rather than violence against people and robbery, which are more likely with
childhood-onset type (Moffi t et al., 2002). The behaviors associated with adoles-
cent-onset type of conduct disorder can be thought of as exaggerations of normal
adolescent behaviors (Moffi tt & Caspi, 2001). With this type, the disruptive behav-
iors are usually transient, and adolescents with this disorder are able to maintain re-
lationships with peers (who may behave disruptively along with them). This type of
conduct disorder has been found to have a small sex difference; the male to female
ratio is 1.5 to 1 (Moffi tt & Caspi, 2001).
Childhood-Onset Type
DSM-IV-TR distinguishes only two types of conduct disorder based on the time of
onset—adolescence or childhood. But researchers have further identifi ed two variants
of childhood-onset conduct disorder, each with different features and pathways to
the disorder (Frick & Muñoz, 2006): Some people with childhood-onset type exhibit
callous and unemotional traits (Caputo, Frick, & Brodsky, 1999; Frick, Bodin, &
Barry, 2000), which are features of psychopathy (discussed in Chapter 13), and
others with childhood-onset type do not possess these traits.
Childhood-Onset Type With Callous and Unemotional Traits
Children and teenagers with callous and unemotional traits are likely to be more ag-
gressive, both when responding to real or perceived provocations and when exhib-
iting disruptive behavior for some type of gain, such as premeditated theft (Kruh,
Frick, & Clements, 2005). This variant of conduct disorder has the highest herita-
bility (Viding et al., 2005). Like adults with psychopathy, these young people seek
out exciting and dangerous activities, are relatively insensitive to threat of punish-
ment (Frick et al., 2003), and are strongly oriented toward the possibility of reward
(Pardini, Lochman, & Frick, 2003). Moreover, they are less reactive to threatening
or distressing stimuli (Frick et al., 2003; Loney et al., 2003).
Researchers propose that the decreased sensitivity to punishment—associ-ated with low levels of fear—underlies the unique constellation of callousness
and increased aggression (Frick, 2006; Pardini, Obradovic, & Loeber, 2006).
Individuals with this variant of conduct disorder are not concerned about the
negative consequences of their violent behaviors. And lacking fear and the
bodily arousal that goes along with it, they don’t learn to refrain from certain
behaviors and thereby fail to internalize social norms or develop a conscience
or empathy for others (Frick & Morris, 2004; Pardini, 2006; Pardini, Loch-
man, & Frick, 2003). In fact, those with conduct disorder with callous and
unemotional traits are less likely to recognize emotional expressions of sadness
(Blair et al., 2001).
Childhood-Onset Type Without Callous and Unemotional Traits
Some individuals with conduct disorder that arises before puberty do not possess
callous or unemotional traits. These people are less likely to be aggressive in general.
When they are aggressive, it is usually as a reaction to a perceived or real threat; it
is not premeditated (Frick et al., 2003). People with this variant of childhood- onset
conduct disorder have diffi culty regulating their negative emotions: They have high
levels of emotional distress (Frick & Morris, 2004; Frick et al., 2003), and they
react more strongly to other people’s distress (Pardini, Lochman, & Frick, 2003)
and to negative emotional stimuli generally (Loney et al., 2003). In addition, they
process social cues less accurately, and so are more likely to misperceive such cues
and respond aggressively when (mis)perceiving threats (Dodge & Pettit, 2003).
Because of their problems in regulating negative emotions, they are more likely to