Sex differences in scores on standardized measures of autism symptoms: a multisite integrative data analysis

Abstract

Background: Concerns have been raised that scores on standard measures of autism spectrum disorder (ASD) symptoms may differ as a function of sex. However, these findings are hindered by small female samples studied thus far. The current study evaluated if, after accounting for age, IQ, and language level, sex affects ASD severity estimates from diagnostic measures among children with ASD. Methods: Data were obtained from eight sources comprising 27 sites. Linear mixed-effects models, including a random effect for site, were fit for 10 outcomes (Autism Diagnostic Observation Schedule [ADOS] domain-level calibrated severity scores, Autism Diagnostic Interview-Revised [ADI-R] raw scores by age-based algorithm, and raw scores from the two indices on the Social Responsiveness Scale [SRS]). Sex was added to the models after controlling for age, NVIQ, and an indicator for language level. Results: Sex significantly improved model fit for half of the outcomes, but least square mean differences were generally negligible (effect sizes [ES] < 0.20), increasing to small to moderate in adolescence (ES < 0.40). Boys received more severe RRB scores than girls on both the ADOS and ADI-R (age 4 + algorithm), and girls received more severe scores than boys on both SRS indices, which emerged in adolescence. Conclusions: This study combined several available databases to create the largest sample of girls with ASD diagnoses. We found minimal differences due to sex beyond other known influences on ASD severity indicators. This may suggest that, among children who ultimately receive a clinical ASD diagnosis, severity estimates do not systematically differ to such an extent that sex-specific scoring procedures would be necessary. However, given the limitations inherent in clinically ascertained samples, future research must address questions about systematic sex differences among children or adults who do not receive clinical diagnoses of ASD. Moreover, while the current study helps resolve questions about widely used diagnostic instruments, we could not address sex differences in phenotypic aspects outside of these scores.

Polish Adaptation of the Social Communication Questionnaire (SCQ) and Female Autism Phenotype: An Investigation of Potentially Sex-Biased Items in the Screening Assessment and Their Impact on Scores

“…The study showed that the ASD females in our group were phenotypically similar to ASD males. The results cohere with those of a recent large-scale and multi-site analysis by Kaat and colleagues [ 35 ], wherein no differences were found between autistic males and females assessed via the ADI-R, and consequently via the SCQ, the latter of which is based on the former. The results are also in line with those of Park and colleagues [ 36 ], who found that normative sex differences may be absent in children with ASD.…”

“…The results are also in line with those of Park and colleagues [ 36 ], who found that normative sex differences may be absent in children with ASD. Much like the patients in Kaat’s [ 35 ] or Park’s [ 36 ] analyses, all the individuals in our study had clinical ASD diagnoses as well. Furthermore, we hypothesize that narrow constructs and a wide range of behavioral exemplars might elucidate more subtle sex differences among the individuals already diagnosed with ASD.…”

Camouflaging in Autism: Examining Sex‐Based and Compensatory Models in Social Cognition and Communication

“…The male‐centric perspective and lack of sex‐based norms on the ADOS‐2 and most diagnostic measures [McPartland et al, 2016] limit the generalizability of this finding and thus, future research is warranted. Recently, based on the largest collected dataset on females already diagnosed with ASD ( n = 1,463), Kaat et al [2020] reported that sex differences on most diagnostic measures were small and may not have clinical relevance. However, if a male‐centric measure is used to identify sex‐based differences, then conclusions from it are inherently biased.…”

Research Review: A systematic review and meta‐analysis of sex/gender differences in social interaction and communication in autistic and nonautistic children and adolescents

“…Indeed, a recent large-scale and multisite analysis found no social interaction and communication differences between autistic males and females based upon the ADOS and ADI-R (Kaat Sex/gender differences in social interaction/communication et al, 2020), providing some evidence that sex/ gender dependent cut-off scores are unnecessary. Kaat et al (2020) acknowledged, however, that a major limitation of their analysis was the inclusion of only individuals who already had clinical diagnoses of ASD. Specifically, the authors recognized that they were unable to evaluate sensitivity and specificity of these diagnostic instruments, particularly for those individuals who have milder ASD and/or differing behavioural presentations, which could include females.…”