Brain Disorders 241these are often marked enough to warrant a diagnosis of oppositional-
defiant disorder, it is relatively unusual for these individuals to develop
the more seriously antisocial behaviours that are characteristic of severe
conduct disorder. Anxiety as well as irritability may sometimes contribute
to outbursts when individuals with brain disorders are faced with demands
they have difficulty meeting. Episodic outbursts are far more likely to be
behavioural than epileptic, although the latter possibility may need to
be considered, particularly if the episodes are completely unprovoked or
accompanied by other pointers to epilepsy, such as altered consciousness
or a subsequent need to sleep.
Specific neurological disorders may be associated with especially high
risks for particular psychiatric problems, for example, Sydenham chorea
has been linked to an unexpectedly high rate of obsessive-compulsive
disorder (see Chapter 14). Some of the behavioural consequences of child-
hood brain disorders only become apparent in adulthood, for example, the
high rate of adult-onset schizophrenia in individuals with developmental
abnormalities of the temporal lobes. The current evidence suggests that
there are few differences in the psychiatric consequences of left- and
right-sided brain lesions. Studies of early-acquired head injuries have not
revealed consistent effects of locus or timing of injury on rate or type of
psychiatric problem.
Interaction with other risk factors
Having a brain disorder does not generally render children immune to the
adverse effects of ‘ordinary’ psychiatric risk factors, such as exposure to
marital friction. There is continuing controversy as to whether children
with brain disorders are more vulnerable to ordinary risk factors or simply
as vulnerable.
Mediating links
There are many possible mediating links between brain and behavioural
disorders, though the relative importance of different links remains to be
established. In some cases, the link may be relatively direct, for example,
autistic impairments may simply reflect damage to the brain systems
involved in communication and social interaction. In other cases, psy-
chosocial factors, such as poor self-image, unrealistic family expectations,
or peer rejection play an important part too. Specific learning problems
and below-average IQ are common consequences of brain abnormalities.
When present, these problems add to the stresses on the child, particularly
if their special educational needs are unrecognised or unmet (as is all too
often the case). Treatments for the physical disorder may also contribute
to the psychiatric problems. Anti-epileptic medication can have adverse
psychiatric consequences; regular physiotherapy can lead to considerable