Adolescents with conduct disorder have a repetitive and persistent pattern of behavior in which they violate the rights of others, or violate norms and rules that are appropriate to their age. The DSM-IV outlines two subtypes of Conduct Disorder based on:

• Their nature of the presenting problems
• The course of their development:

1. Childhood-onset type appears in children before the age of 10, and is the most common type. These children (usually male) frequently display physical aggression and have disturbed peer relationships. These children are more likely to have persistent conduct disorders and are more likely to develop adult antisocial personality disorder than those with the adolescent-onset type (American Psychiatric Association, 1994). 

2. Adolescent-onset type is defined by the absence of conduct disorder prior to age 10. These adolescents are less likely to display aggression and are more likely to have normal peer relationships. They are also less likely to have persistent conduct disorders or to develop adult antisocial personality disorder (American Psychiatric Association, 1994).