Parent-Endorsed Sex Differences in Toddlers with and Without ASD: Utilizing the M-CHAT

J Autism Dev Disord (2017) 47:126–134 DOI 10.1007/s10803-016-2945-8 ORIGINAL PApER Parent-Endorsed Sex Differences in Toddlers with and Without ASD: Utilizing the M-CHAT Roald A. Øien1,2 · Logan Hart1,2 · Synnve Schjølberg3 · Carla A. Wall2 · Elizabeth S. Kim4 · Anders Nordahl-Hansen5 · Martin R. Eisemann1 · Katarzyna Chawarska2 · Fred R. Volkmar2 · Frederick Shic2 Published online: 18 October 2016 © Springer Science+Business Media New York 2016 Abstract Sex differences in typical development can provide context for understanding ASD. Baron-Cohen (Trends Cogn Sci 6(6):248–254, 2002) suggested ASD could be considered an extreme expression of normal male, compared to female, phenotypic profiles. In this paper, sexspecific M-CHAT scores from N = 53,728 18-month-old toddlers, including n = 185 (32 females) with ASD, were examined. Results suggest a nuanced view of the “extreme male brain theory of autism”. At an item level, almost every male versus female disadvantage in the broader population was consistent with M-CHAT vulnerabilities in ASD. However, controlling for total M-CHAT failures, this male disadvantage was more equivocal and many classically ASD-associated features were found more common in nonASD. Within ASD, females showed relative strengths in joint attention, but impairments in imitation. Electronic supplementary material The online version of this article (doi:10.1007/s10803-016-2945-8) contains supplementary material, which is available to authorized users. Roald A. Øien ; 1 Department of Psychology, UiT - The Arctic University of Norway, PB 6050, N-9037, Tromsø, Norway 2 Child Study Center, Yale School of Medicine, Yale University, New Haven, CT, USA 3 Mental Health, Norwegian Institute of Public Health, Oslo, Norway 4 Center for Autism Research, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA 5 Department of Special Needs Education, University of Oslo, Oslo, Norway 123 Keywords Sex differences · Gender differences · Behavior · Autistic traits · m-Chat · Identification Introduction Studies examining gender differences in typically developing infants and toddlers show sex-specific patterns in behavior and development. Differences include higher activity level in males, while social orienting, reciprocity, eye-contact and language development tend to represent areas of strength for females (Bouchard et al. 2009; Connellan et al. 2000; Hittelman and Dickes 1979; Lutchmaya and Baron-Cohen 2002; Maccoby and Jacklin 1974; Reilly et al. 2009; Riddoch et al. 2007; Trouton et al. 2002; Zambrana et al. 2012). One study found that infants as young as 1-day of age showed sex-specific looking preferences, with males preferring mechanical objects while females showed a greater degree of interest in faces (Connellan et al. 2000). These findings are consistent with several studies suggesting that females in the general population outperform males in a variety of skills typically perceived as being deficits within ASD, e.g. sensitivity to facial expressions (McClure 2000; Montagne et al. 2005), performance on questionnaires measuring empathy (Davis 1994), age when reaching developmental milestones e.g. theory of mind (Happé 1995), and language development (Halpern 1997; Zahn-Waxler et al. 2006). Sex differences in autism-related symptoms among children with ASD is an emerging but under-researched area. The most frequently reported sex difference in ASD is the disproportionally higher male to female prevalence, consistently reported since the seminal studies by Kanner (1943) and Asperger (1944). Fombonne (2003, 2005, 2007) reported across studies male to female prevalence ratios J Autism Dev Disord (2017) 47:126–134 ranging from 4.3:1, with 5.5:1 in groups within the normal IQ range. For moderate to severe intellectual disability male to female ratios of 1.33:1 (McCarthy et al. 1984) and 1.95:1 (Fombonne 2005, 2007) have been reported. While numerous theories have been forwarded to explain the causal mechanisms of this predominantly high male–female ratio in ASD, the topic remains widely debated in the current literature. For example, the positive correlation between intellectual disability and severity of symptoms (Carter et al. 2007; Kopp and Gillberg 2011; Lai et al. 2012; Mayes and Calhoun 2011), combined with the fact that males are more prone to developmental delay have led some to hypothesize that the higher prevalence of autism in males stems from a greater risk of developmental disability (Boyle et al. 2011). The exact nature of this relationship is unclear, and studies have found evidence that sex differences in cognitive performance, adaptive abilities and repetitive behaviors do not appear to be ASD specific, but instead bear a closer resemblance to those found in typically developing children (Messinger et al. 2015; Zweigenbaum et al. 2012). However, other viewpoints stress specific biological factors related to autism, e.g. as illustrated by findings which note that higher genetic risk for autism may occur in females with idiopathic autism (Gilman et al. 2011; Levy et al. 2011; Robinson et al. 2013; Skuse 1997, 2000). While the specific behavioral influences of sex differences in ASD presents as unclear within current literature. Some have posited that these behavioral differences could, in part, influence the observed asymmetry in sex prevalence if they contribute to the risk that subtle cases of ASD in females may go unrecognized (Dworzynski et al. 2012). This research suggests that this may be particularly true for females falling into the average range of IQ and who, as a group, typically tend to display fewer disruptive behavioral outbursts than their male peers (Dworzynski et al. 2012). Less disruptive behavior and outbursts might be related to the fact that females score higher on internalizing behavior and lower on externalizing behaviors compared to males (Bölte et al. 2011; Mandy et al. 2012; Solomon et al. 2012; Szatmari et al. 2012), an area of work which has achieved a somewhat greater degree of consensus than the existing literature on more specific sex difference in ASD. On the other hand Baron-Cohen and colleagues, have turned to the general population and suggest that he “systemizing cognitive profile” typically found in males within the general population is reflected in gender differences in autism (Auyeung et al. 2013; Baron-Cohen 2002; Baron-Cohen and Benenson 2003; Baron-Cohen et al. 2005; Bölte et al. 2011; Hattier et al. 2011; Mandy et al. 2012; Szatmari et al. 2012). In line with these studies, which widen the context by which behavioral manifestations of autism are considered by considering population-based phenomena, the present 127 study further extends continuum-based perspectives of ASD-related behaviors in a large population based sample of children between 17 and 30 months. This perspective is consistent with the Research Domain Criteria (RDoC: Insel et al. 2010). The behavior rated on the (...truncated)