A new study published in the Journal of the American Academy of Child & Adolescent Psychiatry explores the differences in diagnostic characteristics of autism between boys and girls, suggesting a gender bias in which girls with "high-functioning" autism are underdiagnosed.
Autism spectrum disorders (ASD) are typically more prevalent in males, rather than females, with estimates of a 4:1 ratio of males to females, for reasons unknown up until this point. Deficits of ASD include, but are not limited to, delays in language development, difficulties in reciprocal social interaction and communication, repetitive behaviors and narrow interests.
The researchers compared data from 363 girls and boys aged between ten and twelve years of age, 189 of whom were diagnosed with ASD and 174 of whom did not meet the diagnostic criteria for ASD, but still received high scores on empirical measures of ASD traits. Behavioral and intellectual deficits were also examined.
After comparing this data, the researchers found that the girls, rather than the boys, who met the criteria for ASD had a significantly higher prevalence of low intellectual levels and behavioral difficulties. This suggests that in lieu of behavioral and intellectual deficits, girls are less likely to be diagnosed with ASD than boys. This may be due to the fact that girls who meet some of the criteria for a diagnosis of "high-functioning" autism (those who did not demonstrate low intellectual levels or behavioral deficits) may possess better adaptive or compensatory skills, leading to the gender bias in diagnosis.
Whether girls acquire such adaptive skills developmentally, or if this is a shortcoming of the diagnostic measures used for ASD, is unclear. However, if a gender bias does exist, and girls are being underdiagnosed in comparison to boys, this may mean that the current rates of autism diagnosis, currently at 1 in 88, is also biased as a result.
