Disruptive Behaviour 73such as low cholesterol. There are also abnormal arousal patterns with
failure to calm down after frustration. However, the only reliably repli-
cable findings are that some children and adolescents with disruptive
behavioural disorders have lower heart rates, and are more generally
under-aroused. Infants with temperaments classified as ‘difficult’ are
more likely to be referred for aggressive problems later on. MRI scans are
beginning to show differences in brain activation patterns in individuals
with disruptive behavioural disorders during a range of neurocognitive
tests but no consistent pattern is yet apparent. Children and adolescents
with neurodevelopmental disorders such as cerebral palsy and epilepsy
are more likely to have problems with irritability and defiance, but
are no more likely than other children to engage in severe antisocial
behaviour.
2 Psychological processes. Significant cognitive attributional bias has been
shown in aggressive children and adolescents, whereby they are more
likely to perceive neutral acts by others as hostile. As the individual
gets more disliked and rejected by his or her peers, the opportunity
for seeing things this way increases. Social skills are lacking. Emotional
processes in individuals with disruptive behavioural disorders have been
little studied, although self-esteem is often low and co-existent misery
common. The role of academic achievement is discussed above.
Immediate environment
1 Parental psychiatric disorder. This is an important influence but is mainly
mediated through marital discord and child-rearing practices and is not
specific to any particular psychiatric condition in the parents.
2 Parental criminality. Similar environmental considerations apply, altho-
ugh an irritable or callous temperament may be passed on genetically.
3 Child-rearing practices. Disruptive behavioural disorders are strongly asso-
ciated with discord between parents, hostility directed at the child, lack
of warmth, and lack of involvement with their child. While these factors
may partly be a reaction to the individual’s disruptive behaviour, follow-
up and intervention studies show they have a causal role in initiating
and maintaining that behaviour. Lack of supervision and inconsistent
discipline are also clearly associated with disruptive behavioural disor-
ders, perhaps because the individual is not given the opportunity to
experience and learn predictable social rules. Harsh discipline is also
associated with disruptive behavioural disorders.
4 Parent–child interaction patterns. Fine-grained analysis has shown that
disruptive behaviour escalates if this enables children and adolescents
to get more attention, avoid unpleasant demands or get their own way
more often. By responding in ways that reward disruptive behaviour,
and by failing to encourage socially acceptable behaviour, parents are
inadvertently training their children to behave antisocially. Interven-
tions to break this cycle have been shown to be effective.
5 Sexual abusecan lead to the emergence of disruptive behaviour in girls
or boys who were previously free of such problems.