How to tell if you, your child or your loved one has autism or ADHD

Parents wonder if their child is high-energy or hyperactive, while teenagers worry - am I disorganised or is my brain actually different from everyone else's?

The Canberra Times asked Head of the Autism Research Team at Telethon Kids Institute, Professor Andrew Whitehouse, and Chair of Developmental Mental Health at the University of Melbourne, Professor Dave Coghill, about the symptoms of autism and ADHD.

There is no easy way to identify symptoms of autism, Dr Whitehouse said.

"It depends on the age, it depends on the person," he said.

Very young children with autism might have less eye contact than other children, or a reduced response to their name.

"We also see a sort of tendency to not engage in social interaction or engagement," Dr Whitehouse said.

There is a lot of variability between children with autism, he said.

"Some children will have lots of language, other children will really struggle to develop much verbal language at all," Dr Whitehouse said.

Autism and ADHD is often not be picked up until children go to school.

"They may develop verbal language and have an ability to interact and socially engage, but when the demands of school are placed upon them, that's when we start to understand some of the true challenges that they're experiencing," Dr Whitehouse said.

Autism presents in varying ways in adults, but there is one consistency - the symptoms have a significant impact on someone's daily life, Dr Whitehouse said.

The core symptoms of autism are difficulties with social communication, having rigid and fixed routines and particular special interests, Dr Coghill said.

"Those interests can change throughout their lives," he said.

"But they need to have both the social communication difficulties [and] those particular interests."

Unlike autism, ADHD is very hard to diagnose in young children, Dr Coghill said.

"There's such a big natural variability in young children's ability to focus and concentrate," he said.

"In a lot of kids before the age of five or six, [it is] often better to watch and to wait and to put in supportive strategies."

For older children and adults who suspect they have ADHD, it is also important they look out for core symptoms, Dr Coghill said.

These include inattention like difficulties with attention, concentration, distractibility, organisation and forgetfulness.

Some people also have symptoms of hyperactivity, such as fidgetiness, restlessness, and difficulty sitting still.

"People with ADHD tend to be impulsive, they tend to interrupt, to butt in, but also to not take enough time making good decisions," Dr Coghill.

Like autism, a diagnosis of ADHD requires more than just checking symptoms off a list. They have to impact your everyday functioning and have been consistent throughout your life.

Four in five people with autism in 2015 were male, according to Australian Bureau of Statistics data.

And ADHD is diagnosed two to three times more often in males than females, the Australian Psychological Society told a federal Senate inquiry.

While there is no such thing as "girl" autism or ADHD, females can present differently because they are better at masking, or camouflaging, their symptoms, Dr Coghill said.

"Girls and boys, males and females, are different in the way that they socialise, in the way that they interact," he said.

"But there isn't a special gender or sex-specific ADHD or autism."

Girls and women with ADHD can fail to be diagnosed because they are not as hyperactive or impulsive, Dr Coghill said.

"Because they're not causing problems in a classroom or in social situations ... people will often call them the dreamer in the class, when in actual fact, they're trying very hard to contribute, but can't," he said.

While many people fall through the cracks, Dr Whitehouse does not believe that autistic women and girls are underdiagnosed.

"Over the last 20 years, there's been a huge advocacy effort to provide that information to the public [that] actually autism is also found in females," he said.

Autism and ADHD often co-occur, meaning people often have both.

If you think you or your child is neurodivergent, it is best to first contact a general practitioner, psychologist or paediatrician. You can also call the national autism helpline on 1300 308 699 or ADHD Help on 1300 39 39 19.