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Attenuation of typical sex differences in 800 adults with autism vs. 3,900 controls.



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Cassidy, Sarah 
Auyeung, Bonnie 
Achoukhi, Maryam 


Sex differences have been reported in autistic traits and systemizing (male advantage), and empathizing (female advantage) among typically developing individuals. In individuals with autism, these cognitive-behavioural profiles correspond to predictions from the "extreme male brain" (EMB) theory of autism (extreme scores on autistic traits and systemizing, below average on empathizing). Sex differences within autism, however, have been under-investigated. Here we show in 811 adults (454 females) with autism and 3,906 age-matched typical control adults (2,562 females) who completed the Empathy Quotient (EQ), the Systemizing Quotient-Revised (SQ-R), and the Autism Spectrum Quotient (AQ), that typical females on average scored higher on the EQ, typical males scored higher on the SQ-R and AQ, and both males and females with autism showed a shift toward the extreme of the "male profile" on these measures and in the distribution of "brain types" (the discrepancy between standardized EQ and SQ-R scores). Further, normative sex differences are attenuated but not abolished in adults with autism. The findings provide strong support for the EMB theory of autism, and highlight differences between males and females with autism.



Adolescent, Adult, Aged, Autistic Disorder, Case-Control Studies, Cognition, Empathy, Female, Humans, Male, Middle Aged, Sex Characteristics, Young Adult

Journal Title

PLoS One

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Public Library of Science (PLoS)
Medical Research Council (G0600977)
This study received funding from the UK Medical Research Council, the Wellcome Trust, and the Autism Research Trust. Meng-Chuan Lai was supported by the William Binks Autism Neuroscience Fellowship, the European Autism Interventions - A Multicentre Study for Developing New Medications (EU-AIMS), and Wolfson College, Cambridge.