Autistic Spectrum Disorders 49however, concentration is poor for all activities. Perhaps surprisingly, since
individuals with autism can appear indifferent to people, a quarter or more
suffer from social anxiety disorder – they get very fearful and avoidant of
contact with other people, which is not the same as indifference. Severe
and frequent temper tantrums are common and may be triggered by their
inability to communicate needs, or by someone interfering with their
rituals and routines. Interference by others may also unleash aggressive
outbursts. Children and adolescents with autism and intellectual disability
are particularly prone to self-injurious behaviours, such as head banging,
eye poking or hand biting. Extreme food fads represent one particular
form of ritualistic behaviour. Intense fears may lead to phobic avoidance.
Some of these phobias are exaggerations of common childhood fears (for
example, of large dogs) while others are idiosyncratic (for example, fear of
petrol pumps). Hallucinations and delusions are not generally associated
with autism. Sleep difficulties are very common and may exacerbate
psychiatric problems.
Assessment
A thorough history and examination should be carried out looking for
the core features and associated conditions as described above. There are
standardised interviews such as the Autism Diagnostic Interview (ADI)
that help clarify the diagnosis through algorithms that take into account
severity on each of the three featured dimensions. However, a history
is not enough and more subtle abnormalities of social interaction and
communication may be helpfully assessed using standardised observa-
tional tests, such as the Autism Diagnostic Observation Schedule (ADOS).
Because such assessments are time-consuming, it can help to use one of a
number of screening questionnaires (for example, the Social Communica-
tion Questionnaire, SCQ) that have reasonable psychometric properties.
Differential diagnosis
Developmental or acquired language disorders
Unlike individuals with autism, children and adolescents with ‘pure’
phonological-syntactic language disorders (see Chapter 30) can com-
municate successfully by gesture and have a good capacity for social
interaction. However, there are ‘overlap’ cases involving a severe
phonological-syntactic language problems with a lesser degree ofpragmatic
language impairment, resulting in language difficulties that do affect social
interaction, sometimes combined with other mild or patchy features of
autism that are too mild to warrant the diagnosis of an ASD (see Chap-
ter 30). In future classifications, such children and adolescents may be
classified as having aSocial Communication Disorder. Acquired aphasia with
epilepsy (Landau-Kleffner syndrome, see Chapter 30) may also involve