Developing better tools to diagnose autism in adulthood is among the key aims of a new study by Flinders University PhD candidate Clare Holmes.
The School of Psychology graduate has just begun a four-year thesis to improve understanding of autism characteristics later in life, and how these behaviours differ from childhood, with the wider aim of developing new adult-specific diagnostic tools.
While autism is predominantly diagnosed in early childhood, Ms Holmes said anecdotal evidence showed a growing number of people were being diagnosed in adulthood.
"Some people get diagnosed as adults because they're going through the diagnostic process with their child and recognise some of the same characteristics in themselves," Ms Holmes said.
"Others might not have necessarily needed a diagnosis until adulthood because they had a lot of support as a child but pressures in adulthood like the breakdown of a relationship might lead them to seek help," she said.
"Milder forms of autism, such as Asperger's, weren't introduced into the diagnostic manual until the mid-90s so some adults who met these criteria may have been overlooked before these milder forms of autism were added to the diagnostic guidelines."
Ms Holmes said while there were many successful diagnostic tools to identify autism in childhood, adult diagnostic protocols often relied on information that was difficult for adults to obtain.
"Further, a lot of behavioural observation tools are aimed at children and include things like watching the child play, which is of course inappropriate for adults," she said.
"Usually the health professional will ask for early developmental information which can be hard to obtain if you're a person in your 40s, and while there are various self-report tools available for adults, due to the nature of autism they might lack insight into their impairments."
Ms Holmes said the study also aimed to develop a more comprehensive understanding of "what autism looks like" in adulthood.
"Children and adults with an autism spectrum disorder will usually show the same broad social impairments and restricted, repetitive behaviours but these traits won't look the same.
Some of the communication difficulties in childhood, for example, will be totally different for adults.
"That's why I want to develop diagnostic tools that reflect how autism presents in adulthood so we can ensure adults don't become the hidden face of autism.
"For the adults who are diagnosed later in life, many say it's a relief because they finally have a better understanding of the difficulties they've been experiencing for so many years."