New Zealand Autism Spectrum Disorder Guideline - Ministry of Health

Part 1: Diagnosis and initial assessment of ASD
Part 1
These disorders may also occur in association
with ASD. Other conditions occur more
commonly in association with ASD than in
the general population. When two different
conditions or disorders occur together in the same
individual they are called co-morbidities 80 81 .
They include:
• attention deficit hyperactivity disorder
• anxiety disorders (including obsessivecompulsive
disorder)
• Tourette syndrome
• depression
• developmental dyspraxia/developmental
coordination disorder
• epilepsy
• nutritional deficiencies secondary to
restricted diet
• specific learning disability or intellectual
disability.
If a co-morbidity is suspected, then an
appropriate evaluation should be carried
out and a treatment plan put in place
(Recommendation 1.3.2).
An increasing number of specific medical
conditions have been described as being
associated with autistic symptomatology.
These include:
• degenerative neurological or metabolic
condition
• Down syndrome
• fetal alcohol spectrum disorder
• fragile X
• Rett syndrome
• tuberose sclerosis.
Every child with a developmental problem
for which no cause is obvious should have
a paediatric evaluation and an appropriate
focused investigation, depending on the findings
from that evaluation (Recommendation 1.3.3).
All children with a language delay or difficulty
should have an audiology hearing assessment as
part of their evaluation.
Any child in whom there is a history of possible
developmental regression should have the
possibility of neurodegenerative disease or
metabolic disorder considered and appropriately
investigated. This should involve consultation
with a paediatric neurologist or metabolic
specialist, as appropriate.
In children where there is doubt about diagnosis
and who have a history of abuse or disrupted
early attachment, an opinion from a child
psychiatrist or psychologist is necessary to
consider possibilities such as:
• attachment disorders
• other psychiatric disorders, including
schizophrenia and schizoid personality
disorder in older children, adolescents and
adults.
Management of epilepsy will not be addressed
in this guideline. Children with uncomplicated
epilepsy should be managed by a paediatrician.
Children with complicated or refractory epilepsy
should have an evaluation by a paediatric
neurologist.
Pharmacotherapy in ASD and for other comorbidities
in association with ASD is discussed
in section 4.4.
1.3.b Young people and adults
Careful differential diagnosis is extremely
important for young people and adults
(Recommendation 1.3.1). ASD can be
misdiagnosed, for any number of psychiatric
conditions can coexist with or be superimposed
on ASD 19 33 38 46 . Common differential diagnoses
and/or coexisting conditions include
schizophrenia, intellectual disability, catatonia,
depression, anxiety disorders, obsessivecompulsive
disorders, attention disorders,
language disorders, disorders of impulse
control, and substance abuse 33 34 51 82 .
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New Zealand Autism Spectrum Disorder Guideline