Historically, autism has been viewed as a condition that affects men and boys more often than women and girls. But a new large-scale study, based on data from millions of people, suggests that’s not actually the case, at least in Sweden.
Although boys are diagnosed with the condition at higher rates during childhood, in adulthood the ratio is approximately 1:1, suggesting that it is not a case of fewer women having autism: they just aren’t diagnosed until later in life.
Diagnosis rates for autism spectrum disorders (ASD) have been increasing since the 1990s, but diagnoses are not equal between men and women.
O DSM-5which defines mental health conditions and recommended treatments, states that for every four men diagnosed with autism, only one woman receives the diagnosis.
But the recent study, in the journal The BMJ, led by epidemiologist Caroline Fyfefrom the Karolinska Institute in Sweden, paints a very different picture, adding to a growing body of research that suggests that autistic women and girls are being harmed by current diagnosis and treatment systems.
Autism is a neurodevelopmental disorder characterized by difficulties in social interactions and communication, intense and specific interests in certain topics or activities, repetitive behaviors and a strong preference for routine.
Treatment of autism involves controlling symptoms. It is a spectrum disorder, which means that some people need extra support — for example, if they are unable to speak, earn money, or live independently — while others can live independently and they may be able to control their symptoms with therapy, workplace accommodations, and treating specific symptoms and other health problems that often occur together.
Diagnosis in childhood is often based on the opinions of caregivers and health professionals about whether the child’s behaviors fit the DSM-5 description.
“More recent research, as well as common experiences reported by autistic women, suggest that the true proportion is less skewed and that current practices are not recognizing autism in many women until later in life, if at all,” explains the patient and autism advocate. Anne Cary.
This evidence appears to support the argument that systemic biases in diagnosisrather than a true gap in incidence, are based on the common.
Fyfe’s team analyzed the medical records of more than 2.7 million Swedes born between 1985 e 2020 to track how the prevalence and proportions of clinical diagnosis of ASD changed from birth to 37 years of age.
Although men were typically diagnosed with autism at much higher rates than women during childhood, this sex ratio has stabilized at almost the same at around 20 years old of age.
This discovery suggests that the Autism is not actually a predominantly male condition: It just takes longer for girls and women to be diagnosed. The reason for this is still unclear.
“This male to female ratio may therefore be substantially lower than previously thought, to the point that in Sweden it may no longer be distinguishable in adulthood,” report Fyfe and his team.
“These observations highlight the need to investigate why female groups receive diagnoses later than males.”
As Cary points out, it is possible that the data can be explained by a delay in the appearance of autistic traits in women. “If that is the case, it may not be reasonable to assume that autism is being ignored in girls,” he says.
But she also cites some good reasons why missed diagnosis is a serious possibility.
“Firstly, there are likely to be differences between sexes in the presentation of autistic traitsespecially in childhood. Second, informants (e.g., parents, teachers) and diagnosticians may expect that women are less likely to be autistic and develop a prejudice against the recognition of autistic traits in girls», she explains.
However, according to , the study’s many years of data, coming from such a large sample, make the conclusions quite robust, but some limitations need to be taken into account.
On the one hand, the data is from a group entirely born in Sweden, so it may not represent what is happening in the rest of the world. The effects of conditions that normally occur together with autism spectrum disorder, such as ADHD, intellectual disability, depression and anxiety, were not considered. It also did not delve into other demographic factors, such as race or socioeconomic status.
There was also a lack of data prior to 2001, which meant that the age at diagnosis of ASD was generally later for the older study groups, which may mean that the difference in age at diagnosis between men and women may actually be underestimated.
“Future research should focus on phenotypic differences in the manifestation of ASD by sex and the implications for screening and diagnostic practices,” conclude Fyfe and his team.
Teresa Oliveira Campos, ZAP //
