A new study suggests autism diagnosis rates are “more or less equal for men and women,” significantly challenging long-held assumptions about gender disparities.
Previous understanding often cited a four-to-one ratio of men or boys to women or girls, a figure a 2017 study had already narrowed to three to one.
An international team, led by experts at Sweden’s Karolinska Institutet, meticulously tracked over 2.7 million individuals.
Their research examined all people born in Sweden between 1985 and 2000, following their diagnostic journeys up to 2022.
During this period, some 2.8 per cent of the population received an autism spectrum disorder diagnosis.
They found that the male-to-female ratio of diagnosis decreased over time to the extent that it “may no longer be distinguishable by adulthood”.
“Findings indicate that the male to female ratio for autism spectrum disorder has decreased over time and with increasing age at diagnosis,” the authors wrote in The BMJ.
“This male to female ratio may therefore be substantially lower than previously thought, to the extent that, in Sweden, it may no longer be distinguishable by adulthood.”
Lead author Dr Caroline Fyfe, who now works at the University of Edinburgh, told the Press Association: “ASD (autism spectrum disorder) has traditionally been seen as a condition that disproportionately affects males.
“Our study found that whilst this sex difference was still visible amongst children under 10 years – with roughly three to four boys diagnosed for each girl diagnosed, there was a rapid increase in diagnoses of ASD among girls during adolescence.
“This produced a female catch-up effect, such that by the age of 20 years – rates of ASD were more or less equal for men and women.
“We think this is important because it suggests late or underdiagnosis of ASD in females rather than there being an actual sex difference.”
A linked editorial, written by a patient and patient advocate, adds: “Studies like (this) are essential to changing the assumption that autism is more prevalent in the male sex than in the female sex.
“As autistic girls and women await proper diagnosis, they are likely to be (mis)diagnosed with psychiatric conditions, especially mood and personality disorders, and they are forced to self-advocate to be seen and treated appropriately: as autistic patients, just as autistic as their male counterparts.”
Commenting on the study, Dr Judith Brown, from the National Autistic Society, said: “The results of this study highlight the fact that gender should never be a barrier to receiving an autism diagnosis and access to the right support.
“Historically, it was wrongly assumed that autistic people were mostly men and boys, but we now know that women and girls are more likely to ‘mask’ what is traditionally thought of as signs of autism, making it harder to identify the challenges they face.
“Misdiagnosed autistic women can develop co-existing mental health difficulties, such as anxiety and depression, as a result of a lack of support and the exhaustion of masking.
“This is why it’s so vital that the experiences of autistic women and girls are not overlooked, and outdated stereotypes and incorrect assumptions are finally put to rest.”
Dr Steven Kapp, senior lecturer in psychology at the University of Portsmouth, added: “Autistic women and girls have often been missed because of subtler behaviours from trends towards more imitation and masking, including more eye contact than male counterparts.
“Research has revealed that clinical biases contribute to under-recognition of women and girls, which we in the autistic community have long critiqued.
“Lack of self-understanding may amplify lack of self-acceptance, such as the over-representation of autistic females among anorexic people. Greater gender parity in autism diagnosis promotes more safety, wellbeing and positive relationships for autistic women and girls.”
