Factors that influence the development of conduct disorder include biological factors (including genetic factors), brain trauma, child abuse and other childhood traumas, failure in school, and psychosocial components. Children of a parent who has antisocial personality disorder have an increased risk of developing conduct disorder. Siblings of individuals with conduct disorder also have an increased risk of developing the disorder.

Studies of the neurobiology of the disorder have linked it to underarousal of the autonomic nervous system and impaired functioning of the nonadrenergic system. Researchers have demonstrated that the brains of patients with severe conduct disorder and who demonstrate callous behavior show less activity in the amygdala region—an area of the brain that typically responds to situations that would elicit empathy. Social risk factors that may predispose a child to conduct disorder include socioeconomic deprivation; harsh, punitive parenting with verbal or physical aggression; separation from parents; early institutionalization; family neglect, parental psychiatric illness, substance abuse, or marital discord; and large family size, crowding, and divorce with persistent hostility between the parents. Roughly 30% to 50% of clinical populations with conduct disorder also have attention deficit hyperactivity disorder (ADHD).

The prevalence of conduct disorder among people ages 9 to 17 is about 1% to 4%. An estimated 6% to 16% of boys and 2% to 9% of girls younger than age 18 have the disorder. Studies of youths show that up to 40% of those detained in juvenile detention centers have disruptive behavior disorders. The prognosis is worse in children with an earlier onset; these children are more likely to develop antisocial personality disorder as adults.

The individual with conduct disorder may exhibit:

• aggressive behavior with family members and peers

• cruelty to animals

• sexually abusive behavior

• sexually precocious behavior and prostitution

• lying

• cheating in school

• truancy

• substance abuse

• criminal behavior such as property destruction or stealing.

• Poor performance in school

• Societal costs caused by delinquency and crime

• Occupational difficulties

• Legal problems

• Physical injuries from fighting

• Sexually transmitted diseases

• Unplanned pregnancy

• Higher incidence of other psychosocial disorders, such as ADHD, oppositional-defiance disorder, mood disorders, anxiety disorders, depression, and learning disabilities

Medical and psychiatric evaluations, feedback from parents, a school consultant’s recommendations, case manager plan, and reports from a probation officer can assist in a team approach to diagnosis. Some of the assessment tools include:

• Rating of Aggression Against People and/or Property Scale

• Nisonger Child Behavior Rating Form

• Conners Parent Rating Scale.

The diagnosis is made when the patient meets the criteria in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision. (See Diagnosing conduct disorder.)

Treatment focuses on coordinating the child’s psychological, physiologic, and educational needs. Studies have shown that multifaceted psychosocial treatments coupled with early intervention have demonstrated the most effectiveness. A structured living environment with consistent rules and consequences can help reduce many symptoms. Parents need to be taught consistent parenting and how to deal with the child’s demands, and to set realistic goals for his behavior. Juvenile justice interventions may also be necessary to monitor and help control the individual’s behavior.