Females as Likely to Be Autistic as Males, but Diagnosis Disparity Persists in Childhood
Patient advocates argue that new research underscores systemic biases in the understanding and diagnosis of autism, challenging long-held assumptions about gender prevalence. A comprehensive study led by the Karolinska Institutet in Sweden has found that females may be just as likely to be autistic as males, yet boys are significantly more likely to receive a diagnosis during childhood.
Study Reveals Shifting Diagnosis Patterns Over Time
The research, published in the BMJ, analysed diagnosis rates for individuals born in Sweden between 1985 and 2020, tracking 2.7 million people. Of this group, 2.8% were diagnosed with autism between the ages of two and 37. The findings indicate that by the age of 20, diagnosis rates for men and women become almost equal, suggesting that the gender discrepancy in autism prevalence is much lower than previously believed.
Dr Caroline Fyfe, the lead author, explained, "Our findings suggest that the gender difference in autism prevalence is much lower than previously thought, due to women and girls being underdiagnosed or diagnosed late." The study calculated that in childhood, boys were diagnosed on average nearly three years earlier than girls, with a median age of 13.1 for boys compared to 15.9 for girls. Overall, boys were three to four times more likely than girls to be diagnosed with autism under the age of 10.
Adolescence Sees Rapid Increase in Female Diagnoses
However, the research observed that girls "catch up" by the time they reach 20, owing to a rapid increase in autism diagnoses during adolescence. The authors conclude, "These observations highlight the need to investigate why female individuals receive diagnoses later than male individuals." Over the last three decades, gender disparities in diagnosis rates have remained consistent for children under 10 but decreased rapidly for all other age groups.
The study notes, "Findings indicate that the male to female ratio for autism spectrum disorder has decreased over time and with increasing age at diagnosis. 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."
Systemic Biases and Masking Factors Under Scrutiny
In a linked editorial, patient advocate Anne Cary emphasised that the research supports arguments that systemic biases in diagnosis, rather than a true gap in incidence, are behind the discrepancy. She pointed out that while delayed onset of symptoms and masking play roles, the methods and tools used to diagnose autism may be biased and require refinement. "These biases have meant that a girl who would ultimately have a diagnosis of autism would have a less than third of a chance of receiving a diagnosis before the age of 10 years," Cary added.
She further warned that undiagnosed autistic girls and women are often misdiagnosed with psychiatric conditions such as mood and personality disorders, forcing them to self-advocate for appropriate recognition and treatment.
Charities Call for Action on Gender Stereotypes
Autism charities have responded to the findings by urging greater efforts to tackle gender stereotypes. Dr Judith Brown, head of evidence and research at the National Autistic Society, stated, "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 are traditionally thought of as signs of autism."
She highlighted the risks of misdiagnosis, noting that autistic women can develop coexisting mental health difficulties like anxiety and depression due to 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," she emphasised.
Jolanta Lasota, chief executive of Ambitious about Autism, echoed these concerns, saying, "Autistic girls have different experiences to autistic boys and have slipped under the radar for far too long." She added that by having their needs misunderstood, they miss out on vital support, sometimes reaching crisis points with their mental health.
Clinical Perspectives on Diagnosis and Support
Dr Conor Davidson, former Royal College of Psychiatrists' autism champion and clinical lead for the Leeds autism diagnostic service, commented on the clinical implications. "Autism in girls is more likely to go undetected during childhood and signs of the condition might only surface during adolescence or even early adulthood," he said. He noted that adult neurodevelopmental clinics in the UK are seeing higher numbers of women than men in recent years, but long waiting lists for assessments remain a significant barrier.
"There are many autistic women who have not received a diagnosis, and it is vital that they are able to access a timely assessment and care if they need it," Dr Davidson stressed. He also urged psychiatrists to consider autism when assessing patients with mental health problems, particularly for women whose condition may have been overlooked in childhood.
The study calls for ongoing research and adaptation in diagnostic services to better understand and support the diverse presentations of autism in girls and women, ensuring that increasing numbers of individuals receive the recognition and assistance they require.
