Sex Similarities and Differences in Autism Presentation in Adulthood

Background: Previous research regarding the clinical autism phenotype across males and females reveals mixed findings. For instance, some studies indicate that females with ASD display more severe social and communication difficulties but fewer restricted and repetitive behaviors than males with ASD. Furthermore, research to date has focused on examining gender differences within the ASD group only. This is problematic given that many aspects of social functioning in typically-developing (TD) individuals are known to vary as a function of sex. Lastly, there is limited research examining self-perception and sex differences in adults with ASD.

Objectives: Examination of sex-differential cognitive and behavioral presentations of adults with ASD.

Methods: Collected as part of a larger study, the sample consists of 46 adults with ASD (34 males; Mean age=24.2) and 49 TD adults (31 males; Mean age=25.8). To examine cognitive profiles the Wechsler Abbreviated Scale of Intelligence, 2^nd Edition (WASI-II) was used. Subjective perception of social functioning was assessed using the Social Responsiveness Scale, Second Edition (SRS-2)–Adult Self-Report and the Autism Quotient Form (AQ). Clinician-rated levels of social functioning were measured using the ADOS-2, Module 4.

Results:

Individuals with ASD demonstrated significantly lower verbal reasoning abilities (WASI-II, Similarities) and overall verbal skills (WASI-II, VCI) than the TD group [F(1,87)=3.74, p=.056; F(1,87)=4.22, p=.043, respectively]. There were no significant sex differences in cognitive profiles within or across diagnostic groups.

The AQ total scores were significantly higher in the ASD group compared to TD group [F(1,90)=57.89, p<.001]. Furthermore, there was a significant interaction between sex and diagnosis [F(1,90)=6.17, p=.015], reflecting that sex differences were larger in the ASD group. A subsequent T-test showed that ASD females self-reported more autism-related traits than ASD males [t(44)=2.16, p=.036; Female (M=29.1, SD=8.1) and Male (M=23.5, SD=7.5)]. Likewise, the SRS-2 Total T-score and all subscale T-scores were significantly higher in the ASD group compared to TD group. Again, sex differences were significantly different by diagnostic group. In the ASD group, females reported significantly more deficits in Social Cognition [t(41)=2.57, p=.014], Social Communication [t(43)=2.55, p=.014], Social Motivation [t(43)=2.68, p=.011], and Restricted Interests and Repetitive Behaviors [t(43)=2.94, p=.005]. In the TD group, an opposite pattern was found with males reporting significantly more deficits than females with regard to Social Awareness [t(45)=-4.35, p<.001] and Social Communication [t(45)=-2.18, p=.034].

The ADOS-2 subdomains total scores (i.e., Communication, Social Interaction, and Stereotyped Behaviors and Restricted Interests) were all significantly higher for the ASD group compared to the TD group. Significant sex differences were found in the ASD group, but not the TD group. Specifically, ASD males scored significantly higher than ASD females in the Communication domain [t(43)=-3.31, p=.001]. There were no significant sex differences in Social Interaction or Stereotyped Behaviors and Restricted Interests Total scores.

Conclusions: While women and men with ASD show many similarities, there also appear to be distinct differences in their clinical presentations. Notably, females with ASD self-reported higher levels of social-communicative difficulties, despite receiving lower clinical ratings of communicative impairment. Self-perception of individuals with ASD offers important insight and directions for further investigations.