Gender Differences in Children and Adolescents with High-Functioning Autism Spectrum Disorders

Background: It has been proposed that there is a distinct female phenotype for Autism Spectrum Disorders (ASD) which leads to a number of females on the spectrum being diagnosed later than males or missed completely (Lai et al. 2015). This hypothesised phenotype states that: (1) females are more likely to adopt camouflage strategies to mask or compensate for their autism; (2) females are more socially motivated and consequently make more effort to establish friendships; (3) females are more likely to have internalising difficulties (anxiety, depression) which go unnoticed; (4) that females are more likely to have restricted and repetitive interests that are “relational” in nature, i.e., involve developing and maintaining relationships with others. These “others” could be animals; they could be real people including celebrities; they could be imaginary friends or fictional characters (Attwood, 2006).

Historically the development of gold-standard ASD assessment measures has relied upon predominantly male samples, causing them to have a male-centric understanding of how ASD presents. As such, current assessment measures for ASD, such as the Autism Diagnostic Schedule Observation (ADOS), are thought to fail to capture the hypothesised female ASD phenotype.

Objectives: To develop and pilot a coding frame, the Gendered Autism Behaviour Scale (GABS), which can measure the female ASD phenotype from videoed ADOS sessions.

Methods: 18 GABS items were developed based on current understanding of the female phenotype for ASD using a combination of research evidence and expert-clinician experience. ADOS Module 3 and 4 assessment recordings were then coded using the GABS to compare males (n=22) and females (n=22) with ASD aged between 9 and 15 years. Inter-rater reliability was evaluated using the Kappa statistic, and two-tailed Fisher’s exact tests were carried out to compare GABS item scores for males and females.

Results: The GABS had acceptable inter-rater reliability with an average Cohen’s kappa of .65. The reporting of camouflaging in ADOS interviews was very low across the genders with only 3/22 males and 5/22 females showing evidence of camouflaging and no significant differences were found. Whilst there was no difference between females and males in terms of the intensity of their focus interests, there was a gender difference in the nature of these interests: females were more likely to talk about relational interests, in particular, animals, whereas males described more non-social interests (p<.001). Females also reported higher degrees of internalising difficulties (p<.05) and being more affected by social acceptance and rejection than males (p<.05).

Conclusions: Preliminary findings indicate that the GABS is a reliable instrument for assessing gender differences in standard ADOS Module 3 and 4 assessments. It revealed significant differences in how males and females with ASD present, especially in terms of the nature of their restricted and repetitive interests and their social motivation. ASD measures should cover areas such as camouflaging and relational interests so as to improve early and accurate diagnosis and support for females with ASD.