Scimex: Less than three per cent of Australian children diagnosed with autism spectrum disorder (ASD) are being identified by the age of two, the earliest age ASD can be reliably diagnosed, an Australian study has found. The researchers also reported that the incidence of ASD in Australia has been steadily rising.
Researchers from La Trobe University found that the average age of
diagnosis for the 15 074 children agedunder 7 registered with the
Helping Children with Autism Package (HCWAP) between 30 June 2010 and
30 June 2012 was 4 years and 1 month.
The researchers, Ms Catherine Bent, a PhD candidate at La Trobe working under the supervision of Prof.
Cheryl Dissanayake and Dr Josephie Barbaro, wrote that "this finding represents a possible average delay
[in diagnosis] of 2 years (and common delays of up to 4 years)".
Children registered with the HCWAP in Western Australia and New South Wales were diagnosed earlier
(median age at diagnosis of 3 years and 10 months, and 3 years and 11 months, respectively) than in other
Girls registered with HCWAP were diagnosed an average of 1 month earlier than boys.
There was no significant difference in diagnosis age between Indigenous children and non-Indigenous
children, although children from a culturally and linguistically diverse background were diagnosed 5 months
earlier than other children.
The most frequent age of diagnosis found in the study was 5 years and 11 months.
increase in frequency of ASD diagnoses at 6 years of age may be
attributable to children's ASD beingidentified when they enter school,
aged about 5 years, and the associated delay for diagnostic
assessments", the authors wrote.
"The end of the eligibility period for funding through the HCWAP (at age 7) may also contribute to the
increase in diagnoses at 6 years of age.
"Further, there may be a subgroup of children who are diagnosed later because of factors in their clinical
presentation, such as comorbid conditions or the presentation being less severe."
The researchers report that the incidence of ASD in Australia has been steadily rising. In 1999–2000 the
incidence of ASD in 0–4-year-olds was 5.1 per 10 000 in NSW and 8.0 per 10 000 in WA, whereas from
2003 to 2005 the national prevalence in 0–5-year-olds was estimated to increase from 16.1 to 22.0 per 10
However, their study reports that more than three times this number are currently diagnosed with ASD and
registered with the HCWAP. Several factors may be contributing to this, such as increased awareness and
changes to the diagnostic criteria.