Conduct Disorder

Definition and Subtypes

According to the Diagnostic and Statistical Manual of Mental Disorders (fourth edition, text revision; DSMIV-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, symptoms of CD may include aggression, damaging property, 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 DSM differentiated between socialized versus undersocialized and aggressive versus nonaggressive dimensions. The socialized subtype was characterized by covert and overt antisocial 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 DSM in 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 characteristics 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 differentiating 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 evidence for the utility of these distinctions. The presence of covert symptoms is associated with the persistence of 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.

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