New research from Sweden suggests that while boys are diagnosed with autism at higher rates in childhood, the gap largely closes by adulthood. This finding raises questions about underdiagnosis in girls and the potential for delayed care. The study, published in the BMJ, followed 2.7 million people born between 1985 and 2020, revealing a significant “catch-up” effect as the cohort aged.
The Early Disparity
For years, statistics from institutions like the U.S. Centers for Disease Control and Prevention have shown boys being diagnosed with autism roughly three times more often than girls. Theories to explain this imbalance have ranged from biological differences in brain development to genetic predispositions. However, the new study suggests that these early diagnostic patterns might not reflect the true prevalence of autism in females.
The “Catch-Up” Effect
Researchers found that in early childhood, boys were indeed much more likely to receive an autism diagnosis (around 2.8% of the cohort were diagnosed by 2022). But as the group entered adulthood, that disparity diminished significantly. By age 20, women were almost equally likely to be diagnosed with autism as men. This suggests that girls may be underdiagnosed early in life, with their condition going unrecognized until later years.
Why the Delay?
Experts point to several potential reasons for the diagnostic gap. One possibility is systemic biases in how autism is evaluated, with clinicians possibly missing subtle presentations of the condition in girls. Another factor could be masking, where individuals consciously or unconsciously suppress autistic traits to fit in socially. This can delay recognition of the condition, leaving people without the support they need.
Consequences of Late Diagnosis
Delayed or missed diagnoses have real-world consequences. Autistic individuals without proper support may struggle more to access appropriate treatment and may be misdiagnosed with other conditions like anxiety or ADHD in the meantime. This can lead to unnecessary suffering and hinder their ability to thrive.
A Step Toward Correction
The study is described by experts as “well done” and “powerful,” using extensive and reliable data. Researchers hope the findings will encourage more accurate diagnoses, particularly for women. As professor Gina Rippon puts it, if this study brings more attention to the underdiagnosis of autistic women, that alone will be a significant step forward.
The study’s long-term data collection and large sample size make its conclusions highly credible, suggesting a pressing need to reevaluate diagnostic practices and ensure equitable care for all autistic individuals.
