International Meeting for Autism Research: Sex Differences In Behavior In Adults with High Functioning Autism Spectrum Conditions

Sex Differences In Behavior In Adults with High Functioning Autism Spectrum Conditions

Friday, May 13, 2011: 2:30 PM
Elizabeth Ballroom GH (Manchester Grand Hyatt)
1:15 PM
M. C. Lai1, M. V. Lombardo2, G. Pasco3, A. Ruigrok1, S. J. Wheelwright4, S. A. Sadek1, B. Chakrabarti2,5 and S. Baron-Cohen2, (1)Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom, (2)Autism Research Centre, University of Cambridge, Cambridge, United Kingdom, (3)Centre for Research in Autism and Education, Institute of Education, London, United Kingdom, (4)Autism Research Centre, University of Cambridge, Cambridge, (5)Centre for Integrative Neuroscience and Neurodynamics, University of Reading, Reading, United Kingdom
Background:  It is uncertain if there are phenotypic sex differences in autism spectrum conditions (ASC). Understanding behavioral sex differences (and similarities) in ASC is important not only for clinical assessment and sub-grouping, but also has implications for theories of psychological sex differences and of autism.

Objectives:  To investigate sex differences and similarities, at both behavioral and cognitive levels, in age- and IQ-matched adults with ASC with above-average IQ.

Methods:  Eighty-three (45 males and 38 females) adults with clinical diagnoses of ASC (high-functioning autism or Asperger syndrome) were recruited for behavioral assessment. Sixty-two of them (33 males and 29 females) who met the Autism Diagnostic Interview-Revised (ADI-R) cutoff for autism were subsequently analyzed. All participants were assessed using the ADI-R, Autism Diagnostic Observation Schedule (ADOS), Autism Spectrum Quotient (AQ), Empathy Quotient (EQ), Systemizing Quotient (SQ), Reading the Mind in the Eyes Test (Eyes), Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI), and Obsessive-Compulsive Inventory-Revised (OCI-R).

Results:  Male and female adults with ASC showed comparable severity of childhood autistic symptoms on the ADI-R on the three core dimensions. However, females with ASC showed significantly more lifetime sensory symptoms (p = 0.034), as assessed by three sensory-related items on the ADI-R. Moreover, females showed significantly fewer current autistic socio-communicative characteristics (p = 0.001), as assessed by the module 4 of ADOS. ASC females with developmental language delay showed lower performance IQ than those without (p < 0.001), but this was not evident for males. However, both sexes with ASC reported similar levels of autistic traits on the AQ, EQ and SQ, and co-occurring symptoms (anxiety, depression and obsessive-compulsive traits) on the BAI, BDI, and OCI-R, and performed comparably on an advanced mentalizing (Eyes) task.

Conclusions:  The present study profiles both phenotypic sex differences and similarities in adults with ASC. This underscores the importance of investigating the developmental history in assessing women with ASC, whose autistic nature can sometimes be masked by their apparently typical social-communication when interacting with people. Sensory issues and correlation between language delay and intellectual ability are more prominent in females than males, which may be informative for sub-grouping of ASC. The absence of some sexually dimorphic cognitive features (e.g. autistic traits and empathizing-systemizing profiles) in ASC compared to typical controls may also be etiologically relevant. Both sex differences and similarities in the behavioral presentation of ASC should be taken into consideration in future research and in clinical settings.

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