Factors Affecting Age at Autism Spectrum Disorder Diagnosis in UK

Early intervention programmes can help children with autism spectrum disorder (ASD) but the older the child, the less impact they tend to have. A number of initiatives have attempted to increase early diagnosis of ASD, including the National Autism Plan for Children published in 2003, and guidelines from the National Institute for Health and Care Excellence published in 2011. Researchers from Newcastle University wanted to find out whether children were in fact being diagnosed earlier.

Authors Denise Brett, Frances Warnell, Helen McConachie, Jeremy Parr
Published by Journal of Autism and Development Disorders, March 2016

SUMMARY
The research team analysed data on 2,134 children with ASD from two large family databases, making it the biggest study undertaken in the UK of children with ASD. In all, 83 per cent of the children were male and 17 per cent were female. The median age at which children were diagnosed was 55 months, or four years and seven months. This figure is in line with a 2014 US study but lower than previous smaller-scale UK studies. The researchers tracked data on the age of diagnosis from 2004 to 2014 and found no significant difference in mean or median figures over that time. The full title of their paper is Factors Affecting Age at Autism Spectrum Disorder Diagnosis in UK: No Evidence That Diagnosis Age Has Decreased Between 2004 and 2014.

Children with additional diagnoses were found to have been diagnosed with ASD later than children without other diagnoses. Children with attention deficit hyperactivity disorder (ADHD), dyslexia and dyspraxia were diagnosed with ASD much later than children who did not have these conditions. Children who received a diagnosis of ASD before the age of 60 months tended to come from less deprived areas than those who were diagnosed later on. Boys tended to have an earlier age of diagnosis than girls.

The researchers also looked at whether the type of disorder had an impact on the age of diagnosis and found children with a diagnosis of autism were diagnosed earlier than those with a diagnosis of ASD. Meanwhile those with Apserger's syndrome were diagnosed later. Non-verbal children and children who could only say a few words or echo the words of others, were diagnosed earlier than verbal children. Children whose parents reported needing "very substantial support" received an earlier diagnosis. The researchers expected to find having a sibling with ASD would lead to an earlier age of diagnosis as parents might recognise ASD-like behaviour, but this was not the case. They suggest this may be because ASD can present differently in different children or because health professionals may dismiss concerns thinking the second child is copying the behaviour of the first.