Boys are more likely than girls to be diagnosed with autism spectrum disorder (ASD) but new research suggests that more girls may have the condition than previously thought but may have not been diagnosed because they are better than boys at covering up some of the signs.

Researchers from University College London used a series of tests to analyse emotional reactions in more than 3,500 participants in Children of the 90s.

In one test, participants were asked to identify photographs of people as happy, sad, angry or scared. In another, they were asked to attribute one of the same four emotions to an animated triangle and circle moving around a screen.

Both boys and girls previously identified as having attributes of autism, based on a questionnaire about social communication completed by their parents, were more likely to make mistakes when identifying sad and scared faces and were more likely to wrongly identify faces as happy.

When looked at separately, girls with autistic traits were better at recognising emotions in the photographs but fared less well with the triangle cartoons. This suggests that girls may be better at masking the signs of autism in typical social situations but are less able to do so in unfamiliar situations. This has important implications for how girls are clinically assessed for ASD. Many may not be diagnosed and could be missing out on the treatment they need. 

When asked to assess whether children have ASD, teachers are six times more likely to identify boys over girls, suggesting an assumption that boys are more likely to have the condition than girls are. Parents, one the other hand, are only twice as likely to identify a boy rather than a girl.

Speaking about the findings, lead author, Dr Radha Kothari, said:

‘The lack of association between social communication difficulties and facial emotion recognition in girls suggests girls might learn to compensate for facial emotion recognition difficulties. This has important implications for current assessment of clinical ASD in girls. Gender-specific assessment of ASD traits and characteristics might be important in order to understand the causes of ASD, and individual treatment needs across gender.’