Female Autism Phenotypes Investigated at Different Levels of Language and Developmental Abilities

Females evaluated for autism: characteristics and co-occurring and differential DSM-5 diagnoses

Objective: While sex differences in autism spectrum disorder (ASD) have been identified in areas such as neurocognitive functioning, behavior patterns, and diagnostic criteria, less work has focused on differences within females referred for ASD evaluation, including those who did not go on to receive a diagnosis. This study examined psychological and behavioral characteristics and co-occurring and differential DSM-5 diagnoses between pediatric female participants who received an ASD diagnosis (ASD+) and those who did not (ASD-). Method: Data on cognitive functioning, adaptive functioning, internalizing symptoms, externalizing symptoms, and ADOS-2 scores were analyzed among 137 3- to 20-year-old patients. The sample was divided into two age groups (ages 3-8 and ages 9-20) for analyses of between-group differences (ASD+ vs. ASD-) and predictors of group membership. Results: Females in the ASD+ group were significantly younger, had lower cognitive scores, lower internalizing and externalizing symptoms, and had higher Autism Diagnostic Observation Schedule-2 (ADOS-2) scores than those in the ASD- group. ADOS-2 scores were also the only significant predictor of ASD group membership across age groups. The ASD+ group had a higher percentage of intellectual disability while the ASD- group had higher percentages of anxiety disorder, attention-deficit/hyperactivity disorder, and disruptive behavior disorders. Conclusions: Psychological and behavioral presentations among females referred for ASD evaluation varied with age and ASD diagnostic groups. These results highlight potential female differences in ASD referrals and identification of ASD and the need to improve care for females in consideration of demographic factors.

Characterizing individual differences in children and adolescents with autism spectrum disorder: a descriptive study

Introduction

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by a higher prevalence in male than in female participants. Recent studies have hypothesized the presence of different phenotypes in male and female participants with ASD. The present study aims to assess possible sex differences in cognitive and adaptive functioning, symptomatology of ASD, and psychopathological comorbidities in a large sample of children and adolescents with ASD.

Methods

The study included a total of 2,146 children and adolescents diagnosed with ASD, comprising 1785 boys (mean age 7.12 ± 3.69 years) and 361 girls (mean age 6.25 ± 3.30 years). The age of the participants ranged from 1.35 to 19.05 years (mean age 9.98 ± 3.64). The study sought to include all children and adolescents diagnosed with Autism or ASD.

Results

Present results showed that girls with ASD had lower IQs than boys but similar adaptive functioning. The severity of symptoms of ASD was greater in boys than in girls, as were scores on psychopathological measures. With increasing age, boys with ASD showed greater impairment in social communication skills than girls and increased psychopathological comorbidities. Older girls showed fewer restricted and repetitive behaviors.

Discussion

Exploring phenotypic differences in children and adolescents with ASD fosters an understanding of subtle diagnostic facets that may go unrecognized, allowing for increasingly individualized and tailored interventions.

Towards a comprehensive approach to mentalization-based treatment for children with autism: integrating attachment, neurosciences, and mentalizing

Autism spectrum disorder (ASD) is diagnosed based on socio-communicative difficulties, which are believed to result from deficits in mentalizing, mainly evidenced by alterations in recognizing and responding to the mental states of others. In recent years, efforts have been made to develop mentalization-based treatment (MBT) models for this population. These models focus on enhancing individuals' ability to understand and reflect on their own mental states, as well as those of others. However, MBT approaches for people with ASD are limited by their existing theoretical background, which lacks a strong foundation grounded in neuroscience-based evidence properly integrated with attachment, and mentalizing. These are crucial aspects for understanding psychological processes in autism, and as such, they play a pivotal role in shaping the development of tailored and effective therapeutic strategies for this specific population. In this paper we review evidence related to the neurobiological, interpersonal, and psychological dimensions of autism and their implications for mentalizing processes. We also review previous mentalization-based frameworks on the psychosis continuum to provide a comprehensive understanding of attachment, neurobiology, and mentalization domains in therapeutic approaches for autism. After presenting a synthesis of the literature, we offer a set of clinical strategies for the work with children with autism. Finally, we provide recommendations to advance the field towards more robust models that can serve as a basis for evidence-based therapeutic strategies.

Barriers to an Autistic Identity: How RRBs may Contribute to the Underdiagnosis of Females

Background

Autistic females are frequently underdiagnosed, misdiagnosed, and/or diagnosed later in life. Restricted and Repetitive Behaviors (RRBs) are increasingly critical for diagnosis and yet are commonly rated lower in females. Whether this reflects genuinely lower levels of these traits, or if female-typical RRBs have a different phenotypic presentation that may not register on current quantitative measurement tools is unclear.

Methods

Twenty-one autistic females and 21 autistic males matched on chronological age and FSIQ completed the AQ, ADOS-2, and ADI-R. Items from the ADOS-2 and ADI-R were selected that were relevant to the four areas of restricted and repetitive behavior in the DSM-5 diagnostic criteria of autism. Using a mixed-methods analytical approach, scores and comments on these measures were compared between sexes to better characterize RRBs in autistic females.

Results

There were no sex differences on the AQ, which broadly assesses autistic traits. When analyzed by the four DSM-5 RRB criteria, there were no sex differences on the ADI-R when using traditional algorithm scoring that narrows questions down to those that are more sensitive and specific in capturing autism in research samples with a high proportion of males. When incorporating additional items relevant to the DSM-5 to identify sex changes in a broader pool of items, females scored higher on stereotyped movements and speech. Females also engaged in more sensory behaviors during the ADOS-2. Qualitative analyses indicated that females were more likely to engage in stereotyped body rocking and spinning, stereotyped behaviors when anxious, to show major reactions to changes, repetitive language including listing and counting, and sensory behaviors, especially in the tactile domain.

Conclusion

Exploratory findings highlight sex differences in RRBs that may help enhance diagnostic clarity for females. Higher tactile sensory behaviors in females suggests there may be increased diagnostic sensitivity for females with the updated DSM-5 that now includes sensory components as part of the diagnostic criteria.

Sex difference contributes to phenotypic diversity in individuals with neurodevelopmental disorders

Objective

Gain a better understanding of sex-specific differences in individuals with global developmental delay (GDD), with a focus on phenotypes and genotypes.

Methods

Using the Deciphering Developmental Disorders (DDD) dataset, we extracted phenotypic information from 6,588 individuals with GDD and then identified statistically significant variations in phenotypes and genotypes based on sex. We compared genes with pathogenic variants between sex and then performed gene network and molecular function enrichment analysis and gene expression profiling between sex. Finally, we contrasted individuals with autism as an associated condition.

Results

We identified significantly differentially expressed phenotypes in males vs. females individuals with GDD. Autism and macrocephaly were significantly more common in males whereas microcephaly and stereotypies were more common in females. Importantly, 66% of GDD genes with pathogenic variants overlapped between both sexes. In the cohort, males presented with only slightly increased X-linked genes (9% vs. 8%, respectively). Individuals from both sexes harbored a similar number of pathogenic variants overall (3) but females presented with a significantly higher load for GDD genes with high intolerance to loss of function. Sex difference in gene expression correlated with genes identified in a sex specific manner. While we identified sex-specific GDD gene mutations, their pathways overlapped. Interestingly, individuals with GDD but also co-morbid autism phenotypes, we observed distinct mutation load, pathways and phenotypic presentation.

Conclusion

Our study shows for the first time that males and females with GDD present with significantly different phenotypes. Moreover, while most GDD genes overlapped, some genes were found uniquely in each sex. Surprisingly they shared similar molecular functions. Sorting genes by predicted tolerance to loss of function (pLI) led to identifying an increased mutation load in females with GDD, suggesting potentially a tolerance to GDD genes of higher pLI compared to overall GDD genes. Finally, we show that considering associated conditions (for instance autism) may influence the genomic underpinning found in individuals with GDD and highlight the importance of comprehensive phenotyping.

Sex Differences in the Developmental Trajectories of Autism Spectrum Disorder

Purpose of Review

Females and males are disproportionately diagnosed with autism, a sex difference that has historically represented this neurodevelopmental condition. The current review examines lifespan developmental trajectories of autism based on sex to elucidate behavioral phenotypic differences that may contribute to differential rates of diagnosis.

Recent Findings

We review sex differences in diagnostic criteria: social communication and restricted interests/repetitive behaviors (RRBs). Results suggest RRBs are more indicative of a diagnosis in males, whereas social differences are more indicative of a diagnosis in females. Factors contributing to a later diagnosis in females include social strengths (camouflaging) and diagnostic overshadowing.

Summary

Sex differences in diagnostic criteria may contribute to differential rates of identification in males and females. Sex differences are most pronounced when assessing naturalistic social communication instead of reliance on standardized measure. Numerous future directions are identified including increasing samples of sub-threshold autistic females and evaluating longitudinal sex differences.

Sex differences matter: Males and females are equal but not the same

Sex differences between males and females can be detected early in life. They are present also later even to a much greater extent affecting our life in adulthood and a wide spectrum of physical, psychological, cognitive, and behavioral characteristics. Moreover, sex differences matter also in individual's health and disease. In this article, we reviewed at first the sex differences in brain organization and function with respect to the underlying biological mechanisms. Since the individual functional differences in the brain, in turn, shape the behavior, sex-specific psychological/behavioral differences that can be observed in infants but also adults are consequently addressed. Finally, we briefly mention sex-dependent variations in susceptibility to selected disorders as well as their pathophysiology, diagnosis, and response to therapy. The understanding of biologically determined variability between males and females can have important implications, especially in gender-specific health care. We have the impression that it is very important to emphasize that sex matters. Males and females are differently programmed by nature, and it must be respected. Even though we as males and females are not the same, we would like to emphasize that we are still equal and together form a worthy colorful continuum.

Intellectual disabilities moderate sex/gender differences in autism spectrum disorder: a systematic review and meta-analysis

BACKGROUND

Girls/women with autism spectrum disorder (ASD) are suggested to exhibit different symptom profiles than boys/men with ASD. Accumulating evidence suggests that intellectual disability (ID) may affect sex/gender differences in ASD. However, a systematic review and meta-analysis on this topic is missing.

METHODS

Two databases (MEDLINE and PsycINFO) were used to search for studies reporting sex/gender differences (girls/women versus boys/men) in social communication and interaction, restrictive and repetitive behaviour and interests (RRBIs), sensory processing, and linguistic and motor abilities in ASD. The final sample consisted of 79 studies. The meta-analysis was performed with Review Manager using a random-effects model. Participants with ASD without and with ID were analysed as separate subgroups, and the effects in these two subgroups were also compared with each other.

RESULTS

Girls/women with ASD without ID displayed fewer RRBIs, more sensory symptoms and less problems in linguistic abilities than their boys/men counterparts. In contrast, girls/women with ASD with ID displayed more social difficulties and RRBIs, poorer linguistic abilities and more motor problems than boys/men with ASD with ID. Comparisons of groups of participants with ASD without ID versus participants with ASD with ID confirmed differences in sex/gender effects on social difficulties, sensory processing, linguistic abilities and motor abilities.

CONCLUSIONS

Our results clearly suggest that the female phenotype of ASD is moderated by ID. Among individuals with ASD with ID, girls/women seem to be more severely affected than boys/men, whereas among individuals with ASD without ID, girls/women with ASD may have less symptoms than boys/men. Such phenotypic differences could be a potential cause of underrecognition of girls/women with ASD, and it is also possible that observed phenotypic differences may reflect underdiagnosing of girls/women with ASD.

Wechsler Intelligence Scale for Adults - Fourth Edition profiles of adults with autism spectrum disorder

AIM

In this study, we have compared 229 Wechsler Adults Intelligence Scale - Fourth Edition (WAIS-IV) cognitive profiles of different severity adults with autism spectrum disorder to verify the impact of several variables including sex, age, level of education and autism severity level in an Italian sample. Moreover, we wanted to find out the optimal cut points for the major intelligence quotients in order to discriminate autism severity levels.

METHODS

Participants were recruited from two National Health System Center in two different Italian regions and were assessed with gold-standard instruments as a part of their clinical evaluation. According to DSM-5, cognitive domains were also measured with multi-componential tests. We used the Italian adaptation of WAIS-IV. We checked our hypotheses using linear regression models and receiver operating characteristics (ROC) curves.

RESULTS

Our results showed that age and level of education have a strong impact on Verbal Comprehension (VCI) and Working Memory Indexes (WMI). Gender differences are relevant when considering the VCI and Processing Speed index (PSI) in which women obtained the best performance. These differences are still relevant when considering cut points of ROC because 69 resulted to be the optimal cut point for women, 65 for men.

CONCLUSIONS

Few conclusions can be assumed only examining Full Scale Intelligence Quotient (FSIQ) scores as it includes many different information about broader cognitive abilities. Looking deeper at main indexes and their subtests findings are consistent with previous research on the disorder (moderate correlations of FSIQ, Perceptual Reasoning index, WMI and PSI with the participants' age), while other results are unforeseen (no effect of sex found on FSIQ score) or novel (significant effect of education on VCI and WMI). Using an algorithm predicting optimal cut point for discriminating through autism severity levels can help clinicians to better label and quantify the required help a person may need, a test cannot replace diagnostic and clinical evaluation by experienced clinicians.

Clinical and demographic differences by sex in autistic Venezuelan children: A cross-sectional study

BACKGROUND

Sex differences in symptom severity and adaptive function in children with ASD have been historically inconsistent and studies are predominantly from American- and European-residing populations. Alike, there is limited information on the complex interplay between sex, intelligence, adaptive function, and autism symptom severity; this is crucial to identify given their predictive value for health outcomes in autism AIM: This study aimed to identify sex differences in autism symptom severity and adaptive function in a sample of Venezuelan children.

METHOD

One-hundred-and-three Venezuelan children ages 3-7 completed a comprehensive assessment for symptom severity, adaptive functioning, and intelligence.

RESULTS

Sex differences were not present in any autism diagnostic domain or adaptive function.Symptom severity was not a significant predictor for adaptive function, which contrasts with studies sampling American children.

CONCLUSION

This study corroborates other findings based on non-American children, where symptom severity was not a function of adaptive function. Awareness of the interplay of culture, sex-related standards, and autism symptomatology will result in better identification and diagnosis of autism regardless of sex or cultural background. What this paper adds? This paper aids the current literature on sex difference on both autism symptom severity and adaptive function. It also provides a snapshot of the relationship between symptom severity, adaptive function, and other psychological variables that influence the outcome of children with ASD.

Sex Differences in Autism Spectrum Disorder: Diagnostic, Neurobiological, and Behavioral Features

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder with a worldwide prevalence of about 1%, characterized by impairments in social interaction, communication, repetitive patterns of behaviors, and can be associated with hyper- or hypo-reactivity of sensory stimulation and cognitive disability. ASD comorbid features include internalizing and externalizing symptoms such as anxiety, depression, hyperactivity, and attention problems. The precise etiology of ASD is still unknown and it is undoubted that the disorder is linked to some extent to both genetic and environmental factors. It is also well-documented and known that one of the most striking and consistent finding in ASD is the higher prevalence in males compared to females, with around 70% of ASD cases described being males. The present review looked into the most significant studies that attempted to investigate differences in ASD males and females thus trying to shade some light on the peculiar characteristics of this prevalence in terms of diagnosis, imaging, major autistic-like behavior and sex-dependent uniqueness. The study also discussed sex differences found in animal models of ASD, to provide a possible explanation of the neurological mechanisms underpinning the different presentation of autistic symptoms in males and females.

Behavioral gender differences across Pre-School Children with Autism Spectrum Disorders: a cross-sectional study

There is increasing literature showing that the presentation of Autism Spectrum Disorder (ASD) could be different according to the sex of the patient. Through the analysis of the Autism Diagnostic Interview Revised interview results of a study group consisting of 56 preschool children diagnosed with ASD potential differences in the presentation of ASD were searched. Variables investigated were verbal abilities, the presence/absence of unusual sensory interests, as well as of echolalia. The results showed significant differences between gender in restricted and repetitive behavior (p < 0.01), in particular for those children who have no unusual sensory interest (p < 0.05) and with minimal verbal ability (p < 0.05). The findings contribute providing evidences on phenotypical differences in preschool children with a diagnosis of Autism Spectrum Disorder.

Sex/gender differences in children with autism spectrum disorder: A brief overview on epidemiology, symptom profile, and neuroanatomy

Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental conditions whose shared core features are impairments in social interaction and communication as well as restricted patterns of behavior, interests, and activities. The significant and consistent male preponderance in ASD prevalence has historically affected the scientific knowledge of autism in females as regards, inter alia, the clinical presentation, the genetic architecture, and the structural brain underpinnings. Indeed, females with ASD are under-investigated as samples recruited for clinical research typically reflect the strong male bias of the disorder. In the last years, the study of the various aspects of sex/gender (s/g) differences in ASD is gaining increased clinical and research interest resulting in a growing number of investigations on this topic. Here, I review and discuss evidence emerged from epidemiological, clinical, and neuroimaging studies in the last decade focusing on s/g differences in children with ASD. These studies are the prerequisites for the development of assessment and treatment practices which take into consideration s/g differences in ASD. Ultimately, a better understanding of s/g differences aims at improving healthcare for both ASD males and females.

The Impact of Birth Order on Language Development in Autistic Children from Simplex Families

The current study investigated the impact of birth order on vocabulary and social language development in 1338 first-born and 1049 s-born autistic youth (M age = 9.03 years, SD = 3.57; 86.4% male) from the Simons Simplex Collection. Frequentist and Bayesian analyses revealed mixed findings in language development. There were no differences in vocabulary or social language between first-born and second-born children. However, birth order and income together predicted expressive vocabulary and inappropriate speech such that birth order had a greater impact on language in lower-income families. This is the first study to investigate the impact of birth order on language outcomes in autistic youth and has implications for early intervention in lower-resourced communities.

An Exploration of Physical and Phenotypic Characteristics of Bangladeshi Children with Autism Spectrum Disorder

This study explored the physical and clinical phenotype of Bangladeshi children with autism spectrum disorder (ASD). A totally of 283 children who were referred for screening and administered Module 1 of the Autism Diagnostic Observation Schedule (ADOS) were included. Overall, 209 met the ADOS algorithmic cutoff for ASD. A trend for greater weight and head circumference was observed in children with ASD versus non-ASD. Head circumference was significantly (p < 0.03) larger in ASD males compared with non-ASD males. A trend was also observed for symptom severity, higher in females than males (p = 0.068), with further analyses demonstrating that social reciprocity (p < 0.014) and functional play (p < 0.03) were significantly more impaired in ASD females than males. The findings help understand sex differences in ASD.

Psychotropic Polypharmacy Among Children and Youth with Autism: A Systematic Review

Objectives: Majority of youth with autism are taking two or more medications (psychotropic or nonpsychotropic) simultaneously, also known as polypharmacy. Yet the efficacy and the potential outcomes of polypharmacy in this population are widely unknown. This systematic literature review described the trends of polypharmacy among autistic youth, and identified factors associated with polypharmacy. Methods: Sixteen studies were included, encompassing over 300,000 youth with autism. Results: Rates of polypharmacy varied quite substantially across studies, ranging from 6.8% to 87% of autistic youth. Having psychiatric comorbidities, self-injurious behaviors, and physical aggression, as well as being male and older, were associated with higher rates of polypharmacy. Conclusion: Findings emphasize the importance of further research to determine appropriate practices related to the monitoring of adverse side effects, and the long-term impact of polypharmacy among autistic youth.

Sex Differences in Autism Spectrum Disorder: Repetitive Behaviors and Adaptive Functioning

Sex differences in restricted and repetitive behaviors (RRBs) in individuals with Autism Spectrum Disorder (ASD) have been explored with mixed findings. We aimed to investigate sex differences in RRBs through a specific measure—i.e., the Repetitive Behavior Scale Revised (RBS-R)—in a sample of preschool-age and school-age children with ASD. Additionally, we evaluated if RRBs were differently related to adaptive functioning within the male and the female age groups. A sample of 210 ASD individuals (3–18 years; 145 males, 65 females) underwent an in-depth assessment including a cognitive, adaptive functioning evaluation (i.e., the Adaptive Behavior Assessment System, Second Edition (ABAS-II)) and RRBs assessment (i.e., RBS-R). No significant sex differences on the RBS-R total score or any RBS-R subscale emerged. Within the group of older participants, RRBs were negatively associated with all adaptive skill domains independently from sex and age. Our results suggest a lack of sex differences in RRBs in our sample. Additionally, our findings highlight the possible negative impact of RRBs on adaptive skills in older individuals with autism, emphasizing the need for autistic individuals of both sexes to undergo an early intervention targeting RRBs, in order to improve their adaptive skills.

Prenatal, perinatal, and postnatal factors associated with autism spectrum disorder cases in Xuzhou, China

BACKGROUND

The aim of the present study was to explore the prenatal, perinatal, and postnatal risk factors in children with autism spectrum disorder (ASD) from Xuzhou, China by comparing them with healthy children.

METHODS

Children with ASD who received rehabilitation training at special education schools and rehabilitation institutions in Xuzhou were selected as the ASD group, and healthy children during the same period were selected as the healthy non-ASD group. A questionnaire based on the possible causes and susceptibility factors of ASD in children was issued and given to all children in this study.

RESULTS

The findings of the present study revealed a higher prevalence of prenatal, perinatal, and postnatal factors in children with ASD compared with healthy children. There were significantly more males than females in the ASD group, and the proportion of boys to girls was 5.81:1 (P<0.05). Logistic regression analysis suggested that the risk factors of male children developing ASD were feeding difficulties, poor living environment during pregnancy, maternal exposure to cigarette smoking during pregnancy, and perinatal hypoxia. Factors associated with ASD risk among were identified, such as living environment during pregnancy, delivery method, feeding difficulties, and epilepsy (P<0.05). Feeding difficulties and living in the countryside during pregnancy might be risk factors for ASD in girls according to the logistic regression analysis.

CONCLUSIONS

This survey confirmed the high prevalence of prenatal, perinatal, and postnatal factors in children with ASD. Some of these factors may be effective entry points for the prevention and treatment of ASD.

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

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.

Social Communication and Structural Language of Girls With High-Functioning Autism Spectrum Disorder

Purpose The purpose of this study was to characterize social communication and structural language of school-age girls with high-functioning autism spectrum disorder (HF-ASD) compared to a matched group of girls who are typically developing (TD). Method Participants were 37 girls between 7;5 and 15;2 (years;months)-18 HF-ASD and 19 TD. Children completed the Test of Pragmatic Language-Second Edition (TOPL-2) and Clinical Evaluation of Language Fundamentals-Fifth Edition. Parents completed the Children's Communication Checklist-2 United States Edition (CCC-2) and Receptive and Expressive Communication subdomains of the Vineland Adaptive Behavior Scales-Second Edition. Results In the area of social communication, girls with HF-ASD earned significantly lower scores and were more often classified as having an impairment on the TOPL-2 and the CCC-2. However, 28% and 33% earned average scores on the TOPL-2 and the CCC-2, respectively. In the area of structural language, no significant differences were found between groups on Clinical Evaluation of Language Fundamentals-Fifth Edition indexes. In contrast, girls with HF-ASD earned significantly lower scores and were more often classified as having an impairment on the Vineland Adaptive Behavior Scales-Second Edition. Sixty-one percent and 83% scored below average on the Receptive and Expressive Communication subdomains, respectively. Conclusions It has been argued that girls with HF-ASD, when compared to boys with HF-ASD, may have advantages for social communication and structural language that mask their impairments. However, when compared to girls who are TD, girls with HF-ASD demonstrated impaired social communication and structural language. Clinicians should include and carefully examine multiple sources of information when assessing girls with HF-ASD.

No Sex Differences in Cognitive Ability in Young Children with Autism Spectrum Disorder

Inconsistent findings regarding sex differences in cognition have been found in people with autism spectrum disorder (ASD). This study evaluated sex differences in cognitive-developmental functioning in a large clinical sample of young children diagnosed with ASD. The sample included children 18-68 months of age who received the Mullen Scales of Early Learning (MSEL) through Autism Treatment Network (ATN) sites from 2007 to 2013 (N = 1587, 16.7% female). In this large clinically referred sample of young children with ASD in the United States, no significant differences were found between the sexes for the MSEL Early Learning Composite (ELC) standard score, domain T Scores or age equivalents. These findings persisted when examining different age ranges, cognitive levels and domain profiles.

Motor delay - An early and more common "red flag" in girls rather than boys with autism spectrum disorder

BACKGROUND

Autism and intellectual disability may coincide and be preceded by global developmental delay or by motor delay.

HYPOTHESIS

Motor delay in the context of global developmental delay is an initial "red flag" for ASD, with added risk in girls.

OBJECTIVE

To assess early developmental milestones in girls with ASD as compared to diagnosed boys, considering prematurity risk.

METHOD

Developmental milestones in a cohort of 467 children with ASD - diagnosed at mean age of 3.4 years (SD = 2.2) - were analyzed according to gender and prematurity risk.

RESULTS

111 girls (24 %), 356 boys (76 %), presented with motor milestones acquisition grossly within the normal range. However, there was a shift towards acquisition of walking being at the later end of the norm range, with this shift being more prominent in girls. 60 % of girls and 47 % of boys with ASD had motor delay and 49 % of girls and 36 % of boys had global developmental delay. The extent of the delays was greater in the prematurity subgroup.

CONCLUSION

Global delay of early milestones occurred in half of children with ASD and in 60 % of girls with ASD. Delayed acquisition of independent walking is relatively more common in girls subsequently diagnosed with ASD.

DAS-II Cognitive Profiles Are Not Diagnostically Meaningful For Autism: A ROC Analysis

Intelligence assessment is an integral part of a comprehensive autism evaluation. Many past studies have described a cognitive profile of autistic individuals characterized by higher nonverbal than verbal IQ scores. The diagnostic utility of this profile, however, remains unknown. We leveraged receiver operating characteristic methods to determine the sensitivity, specificity, and area under the curve (AUC) of three different IQ profiles in a large sample of children who have an autism spectrum disorder diagnosis (N = 1,228, Simons Simplex Collection) who completed the Differential Ability Scales-Second Edition (DAS-II), School Age compared to the normative sample provided by the DAS-II publisher (N = 2,200). The frequently discussed nonverbal > verbal IQ profile performed near chance at distinguishing ASD from normative individuals (AUC: 0.54, 95% CI [0.52-0.56]), and performed significantly worse for females than males (AUC: females: 0.46 [0.41-0.52]; males: 0.55 [0.53-0.58]). All cognitive profiles showed AUC < 0.56. We conclude that while significant differences between verbal and nonverbal IQ scores exist at the group level, these differences are small in an absolute sense and not meaningful at an individual level. We do not recommend using cognitive profiles to aid in autism diagnostic decision-making. LAY SUMMARY: Some researchers and clinicians have reported an "autistic cognitive profile" of higher nonverbal intelligence than verbal intelligence. In an analysis of over 1,000 autistic children, we found that the group's average nonverbal intelligence is usually higher than their verbal intelligence. However, this pattern should not be used by clinicians to make an individual diagnosis of autism because our results show it is not helpful nor accurate.

Differences in Developmental Functioning Profiles Between Male and Female Preschoolers Children With Autism Spectrum Disorder

This study investigated differences in clinical symptoms and developmental functioning profiles as well as sex-specific correlations of clinical characteristics and communication abilities, motor skills, and maladaptive behaviors in male and female preschoolers with autism spectrum disorder (ASD). Fifty-two females (mean age 4.5 ± 2.16 years old) and 62 males (mean age 4.2 ± 1.17 years old) with ASD were enrolled and assessed by measures including the Autism Diagnostic Observation Schedule-Second Edition (ADOS-2) and Psychoeducational Profile-Third Edition (PEP-3). We found intellectual disability in 91.2% of the children. While preschoolers with ASD showed comparable severity of restricted and repetitive behaviors (P = 0.17), females with ASD were less severely affected than age and intelligence quotient-matched males with ASD in the ADOS-2 social affect domain (P value = 0.001) and calibrated severity scores (P = 0.002). Interestingly, sex-specific linear regressions revealed that fine motor skills were predictive of impaired social affect in males but not in females. Specifically, motor skills might be the core feature for sex differences in ASD. Although preliminary, this finding suggests the need for more sex-specific diagnostic and intervention strategies in order to improve early identification efforts and specific intervention targets. LAY SUMMARY: Little is known about differences in developmental and functional profiles in males and females with autism spectrum disorder (ASD). We found important similarities and differences in the core ASD symptoms between male and female preschoolers. In addition, fine motor skills seem to predict social affect impairment and ASD symptom severity in males with ASD. Autism Res 2020, 13: 1537-1547. © 2020 International Society for Autism Research, Wiley Periodicals, Inc.

Sex and gender impacts on the behavioural presentation and recognition of autism

PURPOSE OF REVIEW

With increasing awareness of potential differences of autism presentation in nonmale versus male individuals, this review summarizes the rapidly evolving literature on sex and gender impacts on autism across nosology, behavioural presentation, developmental change and contextual recognition biases.

RECENT FINDINGS

Most studies have not differentiated sex versus gender impacts. Regarding behavioural presentation, measurement invariance across sex/gender was found in several standard measures. On this basis, diagnosed females overall showed lower restricted/repetitive behaviour/interests/activities (RRBI) than males, with small and variable effects depending on age, developmental level and kinds of RRBI. Differences insufficiently captured by standard measures may include autistic females displaying female-gender-typical narrow interests, higher social attention, linguistic abilities, motivation for friendship and more camouflaging than autistic males. Regarding developmental change, diagnosed young girls were more likely to have better cognitive development, less intense autistic symptoms and reduction of symptoms over time. Difficulties in adaptive functioning and social challenges, however, may emerge more for females in adolescence. Regarding diagnosis, general expectancy biases and gender-stereotypes may impede timely recognition of autism in females.

SUMMARY

Appreciating the multilevel sex and gender impacts on presentation, development, and diagnosis is key to sex-equitable and gender-equitable care for autistic individuals. A holistic approach to understanding the person in the contexts of sex and gender is essential for timely and accurate diagnosis and support.

Relations between Everyday Executive Functioning and Language in Youth with Down Syndrome and Youth with Autism Spectrum Disorder

Language and executive functioning are major impairments in many neurodevelopmental disorders, but little is known about the relations between these constructs, particularly using parent-report. Thus, the current research sought to examine relations between executive function and language in two groups - Down syndrome (DS; n=41; Mage = 11.2) and autism spectrum disorder (ASD; n=91; Mage = 7.7). Results were as follows: in DS, executive function predicted pragmatic, but not structural language after covarying for age, sex, and social functioning; in ASD, executive function predicted both. Findings highlight the interrelatedness of language and executive functioning and may have implications for intervention development.

Sex/gender differences in neurology and psychiatry: Autism

Autism is a heterogenous set of early-onset neurodevelopmental conditions that are more prevalent in males than in females. Due to the high phenotypic, neurobiological, developmental, and etiological heterogeneity in the autism spectrum, recent research programs are increasingly exploring whether sex- and gender-related factors could be helpful markers to clarify the heterogeneity in autism and work toward a personalized approach to intervention and support. In this chapter, we summarize recent clinical and neuroscientific research addressing sex/gender influences in autism and explore how sex/gender-based investigations shed light on similar or different underlying neurodevelopmental mechanisms of autism by sex/gender. We review evidence that may help to explain some of the underlying sex-related biological mechanisms associated with autism, including genetics and the effects of sex steroid hormones in the prenatal environment. We conclude that current research points toward coexisting quantitative and, perhaps more evidently, qualitative sex/gender-modulation effects in autism across multiple neurobiological aspects. However, converging findings of specific neurobiological presentations and sex/gender-informed mechanisms cutting across the many subgroups within the autism spectrum are still lacking. Future research should use big data approaches and new stratification methods to decompose sex/gender-related heterogeneity in autism and work toward personalized, sex/gender-informed intervention and support for autistic people.

The sex-specific association between autistic traits and eating behavior in childhood: An exploratory study in the general population

Children with Autism Spectrum Disorder (ASD) often exhibit problematic eating behaviors, an observation mostly based on male dominated, clinical ASD study samples. It is, however, important to evaluate both children with an ASD diagnosis and children with subclinical autistic traits as both often experience difficulties. Moreover, considering the suggestion of a possible girl-specific ASD phenotype, there is a need to determine whether autistic traits are related with problematic eating behaviors in girls as well. This study explores the sex-specific association between autism (both autistic traits and diagnosed ASD) and eating behavior in middle childhood in Generation R, a prospective population-based cohort from fetal life onwards. We collected parental reports of autistic traits at six years (Social Responsiveness Scale) and of eating behavior at ten years (Children's Eating Behaviour Questionnaire). In this cohort of 3559 children, autistic traits at six years were associated with more Picky Eating, Emotional Eating and Food Responsiveness in later childhood (e.g. adjusted B for Picky Eating = 0.07; 95% CI: 0.03, 0.11). Stratified analyses showed that in girls, autistic traits were associated with more Emotional Overeating and Emotional Undereating (e.g. adjusted B for Emotional Undereating = 0.12; 95% CI: 0.04, 0.20), while no associations were found for boys. Results comparing children with and without an ASD diagnosis in the cohort largely confirm these associations (e.g. in girls, adjusted B for Emotional Undereating = 0.72; 95% CI: 0.01, 1.42). Our results point to a sex-specific association between autism and eating behavior in middle childhood. Also, our study is the first study to show that autistic traits are associated with emotionally based eating problems in girls and possibly represent part of a girl-specific ASD phenotype.

What About the Girls? Sex-Based Differences in Autistic Traits and Adaptive Skills

There is growing evidence of a camouflaging effect among females with autism spectrum disorder (ASD), particularly among those without intellectual disability, which may affect performance on gold-standard diagnostic measures. This study utilized an age- and IQ-matched sample of school-aged youth (n = 228) diagnosed with ASD to assess sex differences on the ADOS and ADI-R, parent-reported autistic traits, and adaptive skills. Although females and males were rated similarly on gold-standard diagnostic measures overall, females with higher IQs were less likely to meet criteria on the ADI-R. Females were also found to be significantly more impaired on parent reported autistic traits and adaptive skills. Overall, the findings suggest that some autistic females may be missed by current diagnostic procedures.

White Matter Tract-Cognitive Relationships in Children with High-Functioning Autism Spectrum Disorder

OBJECTIVE

The purpose of the present study was to clarify the relationship between white matter tracts and cognitive symptoms in children with high-functioning autism spectrum disorder (ASD).

METHODS

We examined the cognitive functions of 17 children with high-functioning ASD and 18 typically developing (TD) controls and performed diffusion tensor imaging (DTI) tractography. We compared the results between the groups and investigated the correlations between the cognitive scores and DTI parameters within each group.

RESULTS

The Comprehension scores in the ASD group exhibited a positive correlation with mean diffusivity (MD) in the forceps minor (F minor). In the TD group, the Comprehension scores were positively correlated with fractional anisotropy (FA) in the right inferior fronto-occipital fasciculus (IFO) and left anterior thalamic radiation (ATR), and negatively correlated with MD in the left ATR, radial diffusivity (RD) in the right IFO, and RD in the left ATR. Additionally, a positive correlation was observed between the Matching Numbers scores and MD in the left uncinate fasciculus and F minor, and RD in the F minor. Furthermore, the Sentence Questions scores exhibited a positive correlation with RD in the right inferior longitudinal fasciculus. Relative to TD controls, the specific tract showing a strong correlation with the cognitive scores was reduced in the ASD group.

CONCLUSION

Our findings indicate that white matter tracts connecting specific brain areas may exhibit a weaker relationship with cognitive functions in children with ASD, resulting in less efficient cognitive pathways than those observed in TD children.

Evaluating Sex and Age Differences in ADI-R and ADOS Scores in a Large European Multi-site Sample of Individuals with Autism Spectrum Disorder

Research on sex-related differences in Autism Spectrum Disorder (ASD) has been impeded by small samples. We pooled 28 datasets from 18 sites across nine European countries to examine sex differences in the ASD phenotype on the ADI-R (376 females, 1763 males) and ADOS (233 females, 1187 males). On the ADI-R, early childhood restricted and repetitive behaviours were lower in females than males, alongside comparable levels of social interaction and communication difficulties in females and males. Current ADI-R and ADOS scores showed no sex differences for ASD severity. There were lower socio-communicative symptoms in older compared to younger individuals. This large European ASD sample adds to the literature on sex and age variations of ASD symptomatology.

Sex Differences in Autism Spectrum Disorder: a Review

PURPOSE OF REVIEW

Neurodevelopmental disorders disproportionately affect males. The mechanisms underlying male vulnerability or female protection are not known and remain understudied. Determining the processes involved is crucial to understanding the etiology and advancing treatment of neurodevelopmental disorders. Here, we review current findings and theories that contribute to male preponderance of neurodevelopmental disorders, with a focus on autism.

RECENT FINDINGS

Recent work on the biological basis of the male preponderance of autism and other neurodevelopmental disorders includes discussion of a higher genetic burden in females and sex-specific gene mutations or epigenetic changes that differentially confer risk to males or protection to females. Other mechanisms discussed are sex chromosome and sex hormone involvement. Specifically, fetal testosterone is involved in many aspects of development and may interact with neurotransmitter, neuropeptide, or immune pathways to contribute to male vulnerability. Finally, the possibilities of female underdiagnosis and a multi-hit hypothesis are discussed. This review highlights current theories of male bias in developmental disorders. Topics include environmental, genetic, and epigenetic mechanisms; theories of sex chromosomes, hormones, neuroendocrine, and immune function; underdiagnosis of females; and a multi-hit hypothesis.

Issues in Identification and Assessment of Children with Autism and a Proposed Resource Toolkit for Speech-Language Pathologists

BACKGROUND

The prevalence of autism spectrum disorder (ASD) has increased significantly in the last decade as have treatment choices. Nonetheless, the vastly diverse autism topic includes issues related to naming, description, iden-tification, assessment, and differentiation from other neu-rodevelopmental conditions. ASD issues directly impact speech-language pathologists (SLPs) who often see these children as the second contact, after pediatric medical practitioners. Because of shared symptomology, differentiation among neurodevelopmental disorders is crucial as it impacts treatment, educational choices, and the performance trajectory of affected children.

OBJECTIVES

To highlight issues in: identification and differentiation of ASD from other communication and language challenges, the prevalence differences between ASD gender phenotypes, and the insufficient consideration of cultural factors in evaluating ASD in children. A second objective was to propose a tool to assist SLPs in the management of autism in children.

SUMMARY

A universal resource toolkit development project for SLP communities at large is proposed. The resource is comprised of research-based observation and screening tools for caregivers and educators, as well as parent questionnaires for portraying the children's function in the family, cultural com-munity, and educational setting.

Trait and Ability Emotional Intelligence in Adolescents With and Without Autism Spectrum Disorder

Social-emotional impairments are considered core symptoms of Autism Spectrum Disorder (ASD). Although numerous interventions have been developed to remediate the social deficits in children with ASD, few have been designed to meet the needs of youth. Given research demonstrating relations between emotional intelligence (EI) and social outcomes in adults with Asperger Syndrome (AS), the current study examined both trait and ability EI to elucidate the nature of the EI strengths and impairments in youth with and without ASD. Twenty-five adolescents with ASD and 25 adolescents without ASD aged 13 to 17 years completed measures of ability and trait EI. Findings suggest that aspects of both trait and ability EI were significantly weaker in adolescents with ASD compared with typically developing adolescents. Implications, limitations, and future research are discussed.

Evaluation of behavioral change after adenotonsillectomy for obstructive sleep apnea in children with autism spectrum disorder

BACKGROUND AND OBJECTIVE

Obstructive sleep apnea (OSA) may affect daily cognitive functioning in children. The aims of our study were two-fold. The first aim was to detect, using the Child Behavior Checklist (CBCL), whether adenotonsillectomy (AT) for the treatment of OSA improved the behavior of children with autism spectrum disorder (ASD). The second aim was to identify characteristics for behavioral improvement following the treatment of OSA in these children with ASD.

METHODS

The behaviors of ASD children aged 5-14 years diagnosed as having OSA (n=30) were evaluated using CBCL before and after AT. CBCL evaluation of ASD children without OSA at two time points with the same interval served as a control (n=24). We statistically examined the two groups. In addition, we conducted a paired t-test to assess changes in CBCL Tscores between the improved group and unchanged/deteriorated group to identify characteristics that may affect behavioral changes following OSA treatment.

RESULTS

After AT, T-scores of the CBCL scales were significantly improved in the OSA group, but no change was observed in the control. A paired t-test revealed that the improved group had significantly higher scores on the CBCL pre-AT than the unchanged/deteriorated group in ASD children with OSA after OSA treatment.

CONCLUSIONS

Behavioral problems were significantly improved following AT in ASD children with OSA. Early detection and treatment of children with OSA is essential to prevent behavioral problems and to support mental development.

Sex differences in parent-reported executive functioning and adaptive behavior in children and young adults with autism spectrum disorder

This study is the largest to date examining executive function and adaptive skills in females with autism spectrum disorder (ASD). Its primary aim was to utilize parent ratings of real-world executive functioning and adaptive behavior to better understand whether females with ASD differ from males with ASD in these areas of everyday functioning. We compared 79 females with ASD to 158 males with ASD (ages 7-18) who were statistically matched on age, IQ, and level of ADHD or ASD traits. All participants were assessed using the Behavior Rating Inventory of Executive Function (BRIEF) and a subset (56 females and 130 males) also received the Vineland Adaptive Behavior Scales (VABS). Females were rated by parents as having greater problems with executive function on the BRIEF. Parents also rated females as exhibiting more difficulties than males on the Daily Living Skills domain of the VABS. There was a correlation between increased global EF difficulty and decreased adaptive ability in both males and females. Our results indicate relative weaknesses for females compared to males diagnosed with ASD on executive function and daily living skills. These differences occur in the absence of sex differences in our sample in age, IQ, clinician ratings of core ASD symptomatology, parent ratings of ADHD symptoms, and parent-reported social and communication adaptive skills on the VABS. These findings indicate specific liabilities in real world EF and daily living skills for females with ASD and have important implications for targeting their treatments. Autism Res 2017, 10: 1653-1662. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

The clinician perspective on sex differences in autism spectrum disorders

Research studies using existing samples of individuals with autism spectrum disorders have identified differences in symptoms between males and females. Differences are typically reported in school age and adolescence, with similarities in symptom presentation at earlier ages. However, existing studies on sex differences are significantly limited, making it challenging to discern if, how, and at what point in development females with autism spectrum disorder actually exhibit a different behavioral presentation than males. The purpose of this study was to gather impressions from a large group of clinicians to isolate specific areas for future study of sex differences. Clinicians were surveyed about their opinions and perceptions of symptom severity in females, as compared to males, at different points during development. They were also asked to provide open-ended responses about female symptom presentation. Consistent with previous literature, clinicians noted more sex-related differences in restricted and repetitive behaviors and fewer differences for social communication features. Differences were most commonly observed in school age and adolescence, suggesting this time period as a critical and particularly vulnerable window for females with autism spectrum disorder. The results are discussed in the context of other male/female differences across development so that more targeted investigations of autism spectrum disorder sex differences across development.

Sex Differences in Diagnosis and Clinical Phenotypes of Chinese Children with Autism Spectrum Disorder

The aim of this study was to explore the differences between boys and girls in the diagnosis and clinical phenotypes of autism spectrum disorder (ASD) in China's mainland. Children diagnosed with ASD (n = 1064, 228 females) were retrospectively included in the analysis. All children were assessed using the Autism Diagnostic Interview-Revised (ADI-R) and Autism Diagnostic Observation Schedule (ADOS). The results showed that girls scored significantly higher in ADI-R socio-emotional reciprocity than boys, and also scored lower in ADI-R and ADOS restricted and repetitive behaviors (RRBs). Meanwhile, the proportions of girls who satisfied the diagnostic cut-off scores in the ADI-R RRBs domain were lower than in boys (P < 0.05). Our results indicated that girls with ASD show greater socio-emotional reciprocity than boys. Girls also tended to show fewer RRBs than boys, and the type of RRBs in girls differ from those in boys. The ADI-R was found to be less sensitive in girls, particularly for assessment in the RRBs domain.

Are males and females with autism spectrum disorder more similar than we thought?

Differences in behavioral and cognitive profiles have been suggested to potentially impact the presentation of social and communication symptoms in females with autism spectrum disorder. This study examined gender differences in age of diagnosis, cognitive profiles, social communication symptomatology, and autism spectrum disorder symptom severity in a community-based sample of 566 males and 113 females with autism spectrum disorder ranging in age from 1 year, 9 months to 56 years, 4 months. Results suggest either very small or no gender differences in age at diagnosis, intelligence quotient, cognitive profiles, or autism spectrum disorder symptom severity. This is a departure from clinical lore that females with autism spectrum disorder are more likely to have lower intelligence quotient and more severe impairments. There is a slight difference in symptom severity with females having higher average total Childhood Autism Rating Scale scores, but this difference is likely of minimal clinical significance. In contrast, on the Autism Diagnostic Observation Schedule-Generic, females were found to receive lower scores than males particularly on modules 2 and 3. Across males and females, individuals with stronger verbal problem-solving skills were found to receive lower Autism Diagnostic Observation Schedule-Generic module 3 scores. Given the language demands of this module, additional attention may be warranted when evaluating older children and adolescents for autism spectrum disorder.

Sex differences in the association between infant markers and later autistic traits

Background

Although it is well established that the prevalence of autism spectrum disorder (ASD) is higher in males than females, there is relatively little understanding of the underlying mechanisms and their developmental time course. Sex-specific protective or risk factors have often been invoked to explain these differences, but such factors are yet to be identified.

Methods

We take a developmental approach, using a prospective sample of 104 infants at high and low familial risk for ASD, to characterise sex differences in infant markers known to predict emerging autism symptoms. We examine three markers previously shown to be associated with later autistic social-communication symptoms: the Autism Observation Scale for Infants (AOSI) total score, attention disengagement speed and gaze following behaviour. Our aim was to test whether sex differences were already present in these markers at 1 year of age, which would suggest sex-specific mechanisms of risk or protection.

Results

While no sex differences were found in any of the three markers investigated, we found sex differences in their relationship to 3-year autism traits; all three markers significantly predicted later autism traits only in the boys.

Conclusions

Previously identified ‘early autism markers’ were associated with later autism symptoms only in boys. This suggests that there may be additional moderating risk or protective factors which remain to be identified. Our findings have important implications for prospective studies in terms of directly testing for the moderating effect of sex on emerging autistic traits.

Electronic supplementary material

The online version of this article (doi:10.1186/s13229-016-0081-0) contains supplementary material, which is available to authorized users.

Does sex influence the diagnostic evaluation of autism spectrum disorder in adults?

It is unknown whether sex influences the diagnostic evaluation of autism spectrum disorder, or whether male and female adults within the spectrum have different symptom profiles. This study reports sex differences in clinical outcomes for 1244 adults (935 males and 309 females) referred for autism spectrum disorder assessment. Significantly, more males (72%) than females (66%) were diagnosed with an autism spectrum disorder of any subtype (x(2) = 4.09; p = 0.04). In high-functioning autism spectrum disorder adults (IQ > 70; N = 827), there were no significant sex differences in severity of socio-communicative domain symptoms. Males had significantly more repetitive behaviours/restricted interests than females (p = 0.001, d = 0.3). A multivariate analysis of variance indicated a significant interaction between autism spectrum disorder subtype (full-autism spectrum disorder/partial-autism spectrum disorder) and sex: in full-autism spectrum disorder, males had more severe socio-communicative symptoms than females; for partial-autism spectrum disorder, the reverse was true. There were no sex differences in prevalence of co-morbid psychopathologies. Sex influenced diagnostic evaluation in a clinical sample of adults with suspected autism spectrum disorder. The sexes may present with different manifestations of the autism spectrum disorder phenotype and differences vary by diagnostic subtype. Understanding and awareness of adult female repetitive behaviours/restricted interests warrant attention and sex-specific diagnostic assessment tools may need to be considered.