Fewer than 3% of Australian children diagnosed with autism are being identified by the age of two, the earliest age it can be reliably identified, according to a study in the Medical Journal of Australia.
Researchers from La Trobe University found the average age of diagnosis for the 15,074 children aged under seven registered with the Helping Children with Autism Package between June 2010 and June 2012 was four years and one month.
The researchers, Catherine Bent, a PhD candidate at La Trobe working under the supervision of Professor Cheryl Dissanayake and Dr Josephie Barbaro, wrote that “this finding represents a possible average delay (in diagnosis) of two years (and common delays of up to four years)”.
Children 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 states.
Girls registered were diagnosed an average of 1 month earlier than boys.
The most frequent age of diagnosis found in the study was 5 years and 11 months.
The researchers report the incidence of autism spectrum disorder (ASD) in Australia has been steadily rising.
In 1999–2000 the incidence in under four year olds was 5.1 per 10,000 in NSW and 8 per 10,000 in WA. From 2003 to 2005 the national prevalence in under five year olds was estimated to increase from 16.1 to 22.0 per 10,000.
However, their study reports that more than three times this number are currently diagnosed and registered. Several factors may be contributing to this, such as increased awareness and changes to the diagnostic criteria.
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