Serious and persistent patterns of disturbed conduct and antisocial behaviour predominantly affect boys and comprise the largest group of childhood psychiatric disorders. Conduct disturbance may begin early in childhood, manifesting as oppositional, aggressive and defiant behaviour becoming established during the primary school years and amplifying after puberty. The presence of other psychological disorders is common in these children, with about 30% showing ADHD and learning problems. Clinical depression is also found in about 20% of young people with conduct disorder, and, although controversial, a prospective study suggests that this emotional disturbance is secondary to the conduct disorder.
The clinical features are shown in Box 5. This group of childhood disorders requires vigorous early intervention, assessment and management because, although about a third make a reasonable adjustment, there is evidence that at least half of the young people with serious conduct disorder will continue to experience mental health and psychosocial problems in adult life, such as personality disorder, criminality and alcoholism, and about 5% develop schizophrenia.