The current rates of autism suggest boys are four times more likely to be diagnosed with ASD than girls. Almost everything we know about autism comes from studying boys, so what does ASD look like in girls and how is it different from boys with autism?
At first glance, girls seem less likely than boys to develop ASD
Research suggests girls with autism may be hiding in plain sight
Differences in autism rates for boys and girls may have more to do with diagnosis criteria than biological differences
The ratio of boys with ASD compared to girls
It is generally accepted that for every four boys with autism there is one girl. This ratio rises to around 10:1 in high functioning autism, and is considered even higher in some parts of the world. Overall, researchers find more males than females with autism no matter where the data comes from.
However, a growing body of research suggests girls with autism may be hiding in plain sight. Some studies show that girls have less severe symptoms than boys and are better able to mask their behaviours at school. This means girls with milder forms of autism are often diagnosed later in life, possibly delaying intervention.
Are girls better at ‘masking’ symptoms of ASD?
There are countless stories online of autistic women not receiving a diagnosis until adulthood. There are also reports from families of girls with autism who have shared their frustration on how difficult it was to receive a proper diagnosis. It seems that being female protects the brain from some developmental disabilities, such as autism. Recent studies also show girls need more genetic errors or mutations to develop autism when compared to boys.
However, there is increasing evidence that autism presents differently in females, suggesting the lower rates in girls may also be due to the way it’s diagnosed. Girls with autism appear to be better at ‘camouflaging’ their symptoms to fit in and are more likely to mimic others in social situations. Also, as ASD diagnosis criteria is largely based on how autism presents, it can be misdiagnosed or go unrecognised in girls.
What factors affect this difference?
The criteria for diagnosing autism isn’t different for boys compared to girls, but research suggests ASD may look quite different, making it harder to diagnose. One main difficulty researchers face is girls with autism appear to act in ways that are considered ‘acceptable’ for girls compared to boys.
For instance, girls with autism may appear passive, withdrawn, dependent or even depressed. In boys these behaviours are raised as being unusual whereas they are much more accepted in girls. Girls may be obsessively interested in specific areas but may not be drawn to “geeky” subjects like math or science. They may have less repetitive and restricted behaviours compared to boys but could also just have behaviours that go unrecognised. In Western culture, girls who show these traits are more likely to be ignored or misunderstood rather than diagnosed and treated.
What does autism in girls look like?
Although every child with autism is different, there are some common traits in girls with autism. These include:
A strong imagination (might escape into worlds of fiction or nature)
A special interest in music, art, animals and literature
A desire to organise and arrange objects
Not wanting to play with other girls
A tendency to impersonate others in social situations to blend in
Able to hold their emotions in at school but meltdown at home
Strong sensory feelings, especially to sounds and touch
While these symptoms may seem obvious, the more severe symptoms noticed in boys likely means more males are referred for diagnosis and treatment earlier in development than girls, resulting in them being diagnosed more often.
How does this differ from boys with autism?
The list of common autistic behaviours – which experts describe as “repetitive and restricted behaviours” – come from mainly studying boys with autism. With growing research comes a greater understanding, and recent studies are starting to better define ways girls with autism appear to present differently from boys with autism. These differences include:
Girls with autism are less repetitive and have wider areas of play
Girls with autism are more focussed and harder to distract
Girls may be able to better manage social communication in early childhood compared to boys
Girls with autism are more likely than boys to also suffer from anxiety and/or depression
Girls with autism are more likely to choose interests that appear more typical than boys repetitive interests in schedules, statistics, or transportation
Girls with autism are less likely to be aggressive and more likely to be withdrawn or passive
If biases were removed, would diagnosis be even?
Although these differences are becoming easier to notice and researchers better understand how ASD shows in girls compared to boys, it still seems like ASD is less common in girls. Researchers have found a 3-to-1 ratio even when following children from infancy and continually screening them for autism. Girls also seem to need a bigger genetic mutation than boys to develop ASD.
Girls who come close to autism criteria when they are young should be re-evaluated when they approach adolescence. One of the reasons there's a higher male-to-female ratio is because some females never come to the attention of ASD services.
As we learn more about autism in girls and the differences they have compared to boys, we learn to appreciate how important early diagnosis and support can be. If you’re concerned your child may be showing signs of autism, contact your child and family health nurse or GP.
Do we need to expand the diagnosis criteria for autism? Let us know why you think girls are diagnosed with autism at lower rates than boys in the comments below.