The development of autistic social traits across childhood and adolescence in males and females

Altered prefrontal and cerebellar parvalbumin neuron counts are associated with cognitive changes in male rats

Exposure to valproic acid (VPA), a common anti-seizure medication, in utero is a risk factor for autism spectrum disorder (ASD). People with ASD often display changes in the cerebellum, including volume changes, altered circuitry, and changes in Purkinje cell populations. ASD is also characterized by changes in the medial prefrontal cortex (mPFC), where excitatory/inhibitory balance is often altered. This study exposed rats to a high dose of VPA during gestation and assessed cognition and anxiety-like behaviors during young adulthood using a set-shifting task and the elevated plus maze. Inhibitory parvalbumin-expressing (PV +) neuron counts were assessed in the mPFC and cerebellar lobules VI and VII (Purkinje cell layers), which are known to modulate cognition. VPA males had increased PV + counts in crus I and II of lobule VII. VPA males also had decreased parvalbumin-expressing neuron counts in the mPFC. It was also found that VPA-exposed rats, regardless of sex, had increased parvalbumin-expressing Purkinje cell counts in lobule VI. In males, this was associated with impaired intra-dimensional shifting on a set-shifting task. Purkinje cell over proliferation may be contributing to the previously observed increase in volume of Lobule VI. These findings suggest that altered inhibitory signaling in cerebellar-frontal circuits may contribute to the cognitive deficits that occur within ASD.

Age effects on autism heritability and etiological stability of autistic traits

BACKGROUND

Autism and autistic traits onset in childhood but persist into adulthood. Little is known about how genetic and environmental factors influence autism and autistic traits into adulthood. We aimed to determine age effects on the heritability of clinically diagnosed autism and the etiological stability of autistic traits from childhood to adulthood using twin methods.

METHODS

From 23,849 twin pairs in the Swedish Twin Register born between 1959 and 2010, we identified 485 individuals (1.01%, 31.5% female) with a clinical autism diagnosis. We estimated and compared the relative contribution of genetic, shared, and nonshared environmental influences to autism in childhood and adulthood. We further used multivariate twin analysis with four measurement points among 1,348 twin pairs in the longitudinal Twin Study of Child and Adolescent Development to assess the phenotypic and etiological stability of autistic traits - measured with three scales from the Child Behavior Checklist - from childhood to adulthood.

RESULTS

Autism heritability was comparable from childhood, (96% [95% CI, 76-99%]) to adulthood (87% [67-96%]). Autistic traits were moderately stable (phenotypic correlation = 0.35-0.61) from childhood to adulthood, and their heritability varied between 52 and 71%. We observed stable as well as newly emerging genetic influences on autistic traits from ages 8-9 to 19-20, and unique nonshared environmental influences at each age.

CONCLUSIONS

Genetic factors are important for autism and autistic traits in adulthood and separate genetic studies in adults are warranted.

Take a Closer Look: Considerations for Autism Spectrum Disorder Assessment in Female Children and Adolescents

Assessment for autism spectrum disorder (ASD) in the pediatric female population entails unique diagnostic complexities. Females are often misdiagnosed, undiagnosed, or receive an ASD diagnosis at a later age than males. Male bias in ASD, masking behaviors, cultural norms, and overlapping neurodevelopmental comorbidities (such as attention deficit/hyperactivity disorder and intellectual disability) contribute to this phenomenon. The authors present two clinical cases evaluated in an interdisciplinary developmental behavioral pediatrics (DBP) team to highlight these considerations. Cases describe adolescent and school aged females with medical complexity who did not initially appear to have ASD symptoms but later were diagnosed with ASD. Patient anonymity is preserved. Best practice recommendations are discussed. Shared decision making, intentional history taking, thorough observation of behavior and restrictive/repetitive/sensory interests in multiple settings, and attention to social communication in the context of cognitive capacity are essential for ASD assessment in pediatric females.

Potential mechanisms underlying the association between feeding and eating disorders and autism

There is a reliable association between autism and Feeding and Eating Disorders. Concerningly, where these two conditions co-occur, clinical outcomes of Feeding and Eating Disorders are significantly worse, and treatment less effective, than when the Feeding and Eating Disorders occur in neurotypical individuals. Problematically, the reason for the association between autism and Feeding and Eating Disorders is poorly understood, which constrains advances in clinical care. This paper outlines several possible mechanisms that may underlie the observed association and suggests ways in which they may be empirically tested. Mechanisms are split into those producing an artefactual association, and those reflecting a genuine link between conditions. Artefactual associations may be due to conceptual overlap in both diagnostic criteria and measurement, Feeding and Eating Disorders causing transient autistic traits, or the association being non-specific in nature. A genuine association between autism and Feeding and Eating Disorders may be due to common causal factors, autism directly or indirectly causing Feeding and Eating Disorders, and Feeding and Eating Disorders being a female manifestation of autism.

A comparison of the presentations of males and females with autism spectrum disorder and those narrowly below the diagnostic threshold

LAY ABSTRACT

Most research about autism spectrum disorder (ASD) in females has looked at autistic features in people who have already received diagnoses. Because our understanding of ASD has been shaped by the difficulties of males, females may experience different difficulties and may not meet the criteria for diagnosis because of a skewed concept of ASD. We extracted detailed information from the assessment reports of 222 children who were either diagnosed with ASD (156 children) or not diagnosed despite many ASD traits (78 children). Females were less likely to have restricted interests, especially females who did not receive an ASD diagnosis. Females who did not receive an ASD diagnosis tended to show more ability in social and emotional reciprocity than what would qualify them for a diagnosis. We also found sex-/gender-specific profiles of body use and speech mannerisms. Many behaviours were more closely linked with an ASD diagnosis for males and others for females, suggesting that behaviours may be interpreted differently depending on the child's sex/gender. We discuss implications for assessing females for ASD in the context of this evidence.

Prevalence of Autism Spectrum Disorder and Co-Morbidities in Children and Adolescents: A Systematic Literature Review

Objective

Individuals with autism spectrum disorder often present somatic and/or psychiatric co-morbid disorders. The DSM-5 allows for consideration of additional diagnoses besides ASD and may have impacted the prevalence of co-morbidities as well as being limited in capturing the true differences in prevalence observed between males and females. We describe the prevalence of ASD and frequently observed co-morbidities in children and adolescents (<18 years) in the United States and five European countries.

Methods

Two systematic literature reviews were conducted in PubMed and Embase for the period 2014-2019 and focusing on the prevalence of ASD and nine co-morbidities of interest based on their frequency and/or severity: Attention Deficit Hyperactivity Disorder (ADHD), anxiety, depressive disorders, epilepsy, intellectual disability (ID), sleep disorders, sight/hearing impairment/loss, and gastro-intestinal syndromes (GI).

Results

Thirteen studies on prevalence of ASD and 33 on prevalence of co-morbidities were included. Prevalence of ASD was 1.70 and 1.85% in U.S children aged 4 and 8 years respectively, while prevalence in Europe ranged between 0.38 and 1.55%. Additionally, current evidence is supportive of a global increase in ASD prevalence over the past years. Substantial heterogeneity in prevalence of co-morbidities was observed: ADHD (0.00-86.00%), anxiety (0.00-82.20%), depressive disorders (0.00-74.80%), epilepsy (2.80-77.50%), ID (0.00-91.70%), sleep disorders (2.08-72.50%), sight/hearing impairment/loss (0.00-14.90%/0.00-4.90%), and GI syndromes (0.00-67.80%). Studies were heterogeneous in terms of design and method to estimate prevalence. Gender appears to represent a risk factor for co-morbid ADHD (higher in males) and epilepsy/seizure (higher in females) while age is also associated with ADHD and anxiety (increasing until adolescence).

Conclusion

Our results provide a descriptive review of the prevalence of ASD and its co-morbidities in children and adolescents. These insights can be valuable for clinicians and parents/guardians of autistic children. Prevalence of ASD has increased over time while co-morbidities bring additional heterogeneity to the clinical presentation, which further advocates for personalized approaches to treatment and support. Having a clear understanding of the prevalence of ASD and its co-morbidities is important to raise awareness among stakeholders.Appeared originally in Front Psychiatry 2021; 12:744709.

Improving Diagnostic Procedures in Autism for Girls and Women: A Narrative Review

Biases exist in the diagnostic process for autism spectrum disorder (henceforth "autism"), which result in some girls and women being diagnosed later or missed entirely. Current diagnostic tools may not capture the full range of behavioural presentations of autism, leading to under-identification. This review explores why these biases may occur, and how diagnostic procedures could be adapted to better identify autistic girls and women. We recommend that diagnostic assessments are adjusted to capture a broader range of behavioural exemplars of autism; that camouflaging of autistic traits is taken into account; and that care is taken to ensure co-occurring mental health conditions do not overshadow autism diagnosis. We offer recommendations, building on gold-standard diagnostic guidelines, for how diagnostic procedures can be improved for girls and women.

Does camouflaging predict age at autism diagnosis? A comparison of autistic men and women

It is frequently reported that females are likely to receive an autism diagnosis at a later age than their male counterparts, despite similar levels of autistic traits. It has been suggested that this delay in diagnosis may in part reflect the propensity of females, more than males, to engage in camouflaging behaviors that reduce the appearance of autism-related traits. This article presents two studies which examined the relationship between gender/sex, camouflaging, and age at diagnosis in two samples of (cis-gender) autistic adults. Study 1 included data from three online samples including 242 autistic men and 570 autistic women aged 18-75 years. Study 2 included data from a longitudinal population-based sample including 24 autistic men and 35 autistic women aged 20-24 years. Camouflaging was measured with the self-report Camouflaging Autistic Traits Questionnaire (CAT-Q). Overall, the results showed that, on average, females were diagnosed later than males. There was a stronger relationship between camouflaging and age at autism diagnosis (AaD) for females, compared with males. Within sample one, there was a significant camouflaging-by-sex interaction; high-camouflaging females had a later AaD. The role of autistic traits and changes in attitudes towards female autism and camouflaging need further exploration. These findings highlight the need for greater clinician and key stakeholder awareness and understanding of camouflaging behavior, particularly for females, during the diagnostic process.

Improving autism identification and support for individuals assigned female at birth: clinical suggestions and research priorities

Emerging evidence suggests that the higher prevalence of autism in individuals who are assigned male than assigned female at birth results from both biological factors and identification biases. Autistic individuals who are assigned female at birth (AFAB) and those who are gender diverse experience health disparities and clinical inequity, including late or missed diagnosis and inadequate support. In this Viewpoint, an international panel of clinicians, scientists, and community members with lived experiences of autism reviewed the challenges in identifying autism in individuals who are AFAB and proposed clinical and research directions to promote the health, development, and wellbeing of autistic AFAB individuals. The recognition challenges stem from the interplay between cognitive differences and nuanced or different presentations of autism in some AFAB individuals; expectancy, gender-related, and autism-related biases held by clinicians; and social determinants. We recommend that professional development for clinicians be supported by health-care systems, professional societies, and governing bodies to improve equitable access to assessment and earlier identification of autism in AFAB individuals. Autistic AFAB individuals should receive tailored support in education, identity development, health care, and social and professional sense of belonging.

Sex Differences on the ADOS-2

The sex difference in the prevalence of autism spectrum disorder (ASD) may be magnified by sex differences on diagnostic measures. The current study compared autistic males and females on items on the gold-standard diagnostic measure, the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2). In a sample of 8-to-17-year old autistic individuals from research (n = 229) and clinical settings (n = 238), females were less likely to show atypicalities on most items related to social-communication behaviors and on total and subscale scores. When controlling for overall intensity of symptomatology, no sex differences survived statistical corrections. Diagnostic criteria and/or gold-standard assessments may be less sensitive to female presentations of ASD and/or autistic females may exhibit fewer or less intense behaviors characteristic of ASD.

Autism trends in a medium size coastal town of England

Autism spectrum disorder (ASD) is a complex set of neurodevelopmental conditions which affects just under 1% of the global population. This study aims to investigate the trends in ASD diagnoses in a typical English deprived coastal community over the last two decades. ASD information for patients registered at Fleetwood GP practices were provided for the period between July 1952 to March 2022. The incidence and prevalence were calculated and Poisson regression modelling was employed to estimate the effects of age and sex on the number of ASD diagnoses over time. The study shows that there has been an upward trend in the number of ASD diagnoses over the past two decades. Model's results showed that sex differences in ASD diagnoses are less pronounced when accounting for time trends. The study findings show that Fleetwood has experienced a similar rise in ASD cases as the rest of the UK, most likely due to increased awareness that may explain the time effects over gender differences. However, due to the small sample size of the study, confirmation of the gender results and identification of the factors determining the temporal trends are needed in order to determine the gender effects in ASD diagnosis.

Girls With Social and/or Attention Deficit Re-Examined in Young Adulthood: Prospective Study of Diagnostic Stability, Daily Life Functioning and Social Situation

OBJECTIVE

Investigate diagnostic stability, daily life functioning and social situation in women diagnosed with ADHD and/or ASD in childhood.

METHODS

Prospective 17 to 20-year follow-up study of 100 girls of whom 92 diagnosed in childhood with main DSM-IV ADHD or ASD, and 60 comparison girls. Ninety and 54 of these women were examined (M = 27, 4 years old) with semi-structured interviews and questionnaires, close relatives were interviewed.

RESULTS

At follow-up, 89% of women with ADHD or ASD in childhood still met the criteria for either of these diagnoses. Very few women were "in remission." In 34% the main diagnosis shifted from ADHD to ASD. Women with ADHD and ASD had significantly more disability and unfavorable social situation than comparison women.

CONCLUSION

Women with ADHD and/or ASD in childhood had impairing problems 17 to 20 years later. Early ADHD changed to ASD in adulthood in some cases. Nearly all with ASD met criteria for ADHD as adults.

Sex differences in neurodevelopmental trajectories in children with different levels of autistic traits

AIM

Little is known about early manifestations of autism spectrum disorders (ASD) in females, including those who may be overlooked by the current diagnostic criteria. We longitudinally explored sex differences in the trajectories of cognitive and motor functions and adaptive behaviors in children with different levels of autistic traits.

METHODS

The participants were 824 children from the Hamamatsu Birth Cohort for Mothers and Children (HBC Study), Japan, who were classified into three autistic trait groups-low, moderate, and high-based on the Social Responsiveness Scale-Second Edition. Cognitive and motor functions were measured at seven time-points from 0.5 to 3.5 years of age using the Mullen Scales of Early Learning. Adaptive behaviors were measured at five time-points from 2.7 to 9 years of age using the Vineland Adaptive Behavior Scales-Second Edition. Trajectories were depicted using latent growth curve modeling.

RESULTS

Sex-specific trajectories were observed in the high-autistic-trait group, with only males showing a temporary decline in expressive language around the age of 2 years and a slight improvement thereafter. They also showed a slight improvement around 3 years in the adaptive behavior communication domain but a gradual downward trend later. Females in the high-autistic-trait group showed no distinct manifestation before the age of 3 years but showed a downward trend after 3.5 years in the adaptive behavior communication domain.

CONCLUSION

Females and males with higher autistic traits than their same-sex peers, independent of clinical diagnosis, may have different phenotypes in certain neurodevelopmental domains during infancy and early childhood.

Developmental trajectories of autistic social traits in the general population

BACKGROUND

Autistic people show diverse trajectories of autistic traits over time, a phenomenon labelled 'chronogeneity'. For example, some show a decrease in symptoms, whilst others experience an intensification of difficulties. Autism spectrum disorder (ASD) is a dimensional condition, representing one end of a trait continuum that extends throughout the population. To date, no studies have investigated chronogeneity across the full range of autistic traits. We investigated the nature and clinical significance of autism trait chronogeneity in a large, general population sample.

METHODS

Autistic social/communication traits (ASTs) were measured in the Avon Longitudinal Study of Parents and Children using the Social and Communication Disorders Checklist (SCDC) at ages 7, 10, 13 and 16 (N = 9744). We used Growth Mixture Modelling (GMM) to identify groups defined by their AST trajectories. Measures of ASD diagnosis, sex, IQ and mental health (internalising and externalising) were used to investigate external validity of the derived trajectory groups.

RESULTS

The selected GMM model identified four AST trajectory groups: (i) Persistent High (2.3% of sample), (ii) Persistent Low (83.5%), (iii) Increasing (7.3%) and (iv) Decreasing (6.9%) trajectories. The Increasing group, in which females were a slight majority (53.2%), showed dramatic increases in SCDC scores during adolescence, accompanied by escalating internalising and externalising difficulties. Two-thirds (63.6%) of the Decreasing group were male.

CONCLUSIONS

Clinicians should note that for some young people autism-trait-like social difficulties first emerge during adolescence accompanied by problems with mood, anxiety, conduct and attention. A converse, majority-male group shows decreasing social difficulties during adolescence.

Sex differences in the course of autistic and co-occurring psychopathological symptoms in adolescents with and without autism spectrum disorder

LAY ABSTRACT

There is an ongoing debate as to whether autism spectrum disorder (ASD) is expressed differently in women than men. Studies on sex differences in autistic symptoms and symptoms of other psychiatric problems present in individuals with autism generally do not include a general population comparison group, making it unclear whether differences are specific to autism or merely reflecting development in the general population. In this study, we compared sex differences in the course of autistic and at the same time present symptoms of other psychiatric problems in adolescents with milder forms of ASD to those in a group of the general population with an equal intelligence quotient (IQ) and socioeconomic status. Data of five assessment moments from ages 11 to 22 years were analyzed using a statistic procedure that allowed us to determine which factors affect the course of symptoms over time. We found that in adolescence, sex differences in the course of psychopathological symptoms specific for autism are confined to the repetitive stereotyped domains. Males had higher scores on the sensory/stereotypic and resistance to change domains, the latter difference disappeared during the course of adolescence due to an increase of these problems in autistic females. Other sex differences, among which an increase over time in mood and anxiety problems in females was the most outstanding, were also observed in females without autism. These sex-specific differences have relevance in the clinical care of autistic men and women, although they are subtle compared to differences between individuals with and without autism.

Interrelated development of autism spectrum disorder symptoms and eating problems in childhood: a population-based cohort

Eating problems, such as food selectivity or picky eating, are thought to be an epiphenomenon of autism spectrum disorders (ASD). Yet eating problems are also common in the general pediatric population and overlap with ASD symptoms. However, the temporal association between ASD symptoms and eating problems is poorly understood. This study examines the bidirectional association between ASD symptoms and eating problems across child development, and investigates whether these associations differ by child sex. Participants (N = 4,930) were from the population-based Generation R Study. Parents reported their child's ASD symptoms and eating problems using the Child Behavior Checklist at 5 assessments from toddlerhood to adolescence (1.5 to 14 years, 50% girls). A Random Intercept Cross-Lagged Panel Model was used to examine the lagged associations between ASD symptoms and eating problems at the within-person level, controlling for stable, trait-like differences at the between-person level. At the between-person level, there was a strong correlation between ASD symptoms and eating problems (β = .48, 95% CI: 0.38 to 0.57). Controlling for these between-person effects, there was limited evidence for consistent, predictive effects of ASD symptoms and eating problems at the within-person level. Associations did not differ by child sex. Findings suggest that ASD symptoms and eating problems may represent a cluster of traits that are highly stable from early childhood to adolescence, which have a minimal reciprocal effect at the individual-level. Future research could focus on these trait-like qualities to inform the development of supportive, family-focused interventions.

The association between autistic traits and excessive smartphone use in Chinese college students: The chain mediating roles of social interaction anxiety and loneliness

This study draws upon a large sample of Chinese college students to examine the chain mediating roles of social interaction anxiety and loneliness in the relation between autistic traits and excessive smartphone use. To test our hypothesis that social interaction anxiety and loneliness mediate the relation between autistic traits and excessive smartphone use, we recruited a sample of 1103 college students and asked them to complete an assessment that measured the degrees of autistic traits, social interaction anxiety, loneliness, and excessive smartphone use. The results showed significant correlations among these variables. More autistic traits, which are correlated with higher levels of social interaction anxiety and higher levels of loneliness, were found to be associated with excessive smartphone use. In conclusion, this study highlights the need for screening for excessive smartphone use among college students who demonstrate autistic traits. Social interaction anxiety and loneliness show great potential in screening for excessive smartphone use among college students with high levels of autistic traits. We discuss the practical implications of the findings and directions for future study.

Mental health and social difficulties of late-diagnosed autistic children, across childhood and adolescence

BACKGROUND

Autism can be diagnosed from 2 years of age, although most autistic people receive their diagnosis later than this after they have started education. Research is required to understand why some autistic children are diagnosed late, and the level and nature of unmet need prior to diagnosis for late-diagnosed children.

METHODS

We examined trajectories of emotional, behavioural and social difficulties (EBSDs) across childhood and adolescence, comparing 'earlier-diagnosed' (diagnosed 7 years or younger) with 'late-diagnosed' (diagnosed between 8 and 14 years) autistic children. Data were from the Millennium Cohort Study, a population-based UK birth cohort. EBSDs were measured using the parent-report Strengths and Difficulties Questionnaire, at 3, 5, 7, 11 and 14 years. We used Growth Curve Modelling to investigate levels and rates of change in these difficulties, and to compare earlier- (n = 146) and late-diagnosed (n = 284) autistic children.

RESULTS

Aged 5, earlier-diagnosed autistic children had more emotional (i.e., internalising), conduct, hyperactivity and social difficulties; although clinical difficulties in these areas were nevertheless common in late-diagnosed children. There was a faster annual increase in scores for all domains for late-diagnosed children, and by age 14 years, they had higher levels of EBSDs. These results persisted when we ran adjusted models, to account for the late-diagnosed group having higher rates of late-diagnosed attention deficit/hyperactivity disorder, higher IQ, a higher proportion of females and older and more educated mothers.

CONCLUSIONS

Emotional, behavioural and social difficulties are associated with, and may influence, the timing of autism diagnosis. Late-diagnosed autistic children often have high levels of mental health and social difficulties prior to their autism diagnosis, and tend to develop even more severe problems as they enter adolescence.

Early neurodevelopmental problems and risk for avoidant/restrictive food intake disorder (ARFID) in 4-7-year-old children: A Japanese birth cohort study

Background

An overrepresentation of neurodevelopmental problems (NDPs) has been observed in individuals with avoidant/restrictive food intake disorder (ARFID). Previous studies on the association between ARFID and NDPs have been limited by cross-sectional data from clinical samples of small size. This study aimed to extend previous research by using prospectively collected data in a non-clinical child cohort. We examined the occurrence of early NDPs in 4-7-year-old children with suspected ARFID and how predictive early NDPs are of ARFID.

Methods

Data were collected via parent-report a sub-sample of the Japan Environment and Children's Study (JECS) including 3728 children born 2011-2014 in Kochi prefecture. NDPs were assessed biannually between 0.5 and 3 years of age with the Ages and Stages Questionnaire-3, at age 2.5 years with the ESSENCE-Q, and at age 1 and 3 years via parent-reported clinical diagnoses. ARFID was identified cross-sectionally (at age 4-7 years) using a newly developed screening tool. Logistic regressions were used to test association of (1) a composite early NDP risk score, (2) specific early NDPs, and (3) neurodevelopmental trajectories over time with ARFID.

Results

Children in the highest risk percentiles of the NDP risk score had roughly three times higher odds of having suspected ARFID; the absolute risk of later ARFID for children above the 90th percentile was 3.1%. Early NDPs (excluding early feeding problems) were more predictive of later ARFID than were early feeding problems. Specific NDPs predictive of ARFID were problems with general development, communication/language, attention/concentration, social interaction, and sleep. Neurodevelopmental trajectories of children with and without suspected ARFID started to divert after age 1 year.

Conclusions

The results mirror the previously observed overrepresentation of NDPs in ARFID populations. In this non-clinical child cohort, early feeding problems were common and rarely developed into ARFID; however, our findings imply that they should be monitored closely in children with high NDP risk to prevent ARFID.

Measuring autism in males and females with a differential item functioning approach: Results from a nation-wide population-based study

Existing screening instruments for Autism Spectrum Disorder (ASD) might be prone to detect a male manifestation of ASD. Here, we examined the 17 items from the ASD domain in the Autism-Tics, ADHD and other Comorbidities inventory (A-TAC) for Differential Item Functioning (DIF). Data were obtained from the Child and Adolescent Twin Study in Sweden (CATSS) in which parents have responded to the A-TAC. Information regarding a registered diagnosis of ASD were retrieved from the National Patient Register. The cohort was divided into a developmental sample for evaluation of DIF, and a validation sample for examination of the diagnostic accuracy of the total ASD domain, and a novel male and female short form. Our main finding included the identification of DIF for six items, three favouring males and three favouring females. The full, 17 item, ASD domain and the male and female short form showed excellent ability to capture ASD diagnoses in both males and females up to the age of nine years. The full ASD domain in A-TAC is psychometrically largely equivalent across sex and the limited differences between males and females diminish the need for a sex-specific scoring when utilizing the 17 item total score.

Towards equitable diagnoses for autism and attention-deficit/hyperactivity disorder across sexes and genders

PURPOSE OF REVIEW

Sex/gender-related factors contribute to contextual issues influencing the recognition of autism and attention-deficit/hyperactivity disorder (ADHD), and modulate how neurodevelopmental characteristics are manifested. This review summarizes the empirical literature to provide directions for improving clinical diagnostic practices.

RECENT FINDINGS

Timing of autism and/or ADHD diagnosis, particularly in girls/women, is related to the individual's developmental characteristics and co-occurring diagnoses, and expectancy, alongside gender stereotype biases, of referral sources and clinicians. This is further compounded by sex and gender modulations of behavioural presentations. The emerging 'female autism phenotype' concept may serve as a helpful illustration of nuanced autism phenotypes, but should not be viewed as essential features of autism in a particular sex or gender. These nuanced phenotypes that can present across sexes and genders include heightened attention to socially salient stimuli, friendship and social groups, richness in language expression, and more reciprocal behaviours. The nuanced female-predominant ADHD phenotypes are characterized by subtle expressions in hyperactivity-impulsivity (e.g., hyper-verbal behaviours). Optimizing neurodevelopmental diagnoses across sexes and genders also requires an understanding of sex-related and gender-related variations in developmental trajectories, including compensation/masking efforts, and the influences of co-occurring conditions on clinical presentations.

SUMMARY

Equitable diagnoses across sexes and genders for autism and ADHD require understanding of the nuanced presentations and the Gestalt clinical-developmental profiles, and addressing contextual biases that influence diagnostic practices.

Childhood diagnoses in individuals identified as autistics in adulthood

Background

Autism is a developmental condition, where symptoms are expected to occur in childhood, but a significant number of individuals are diagnosed with autism for the first time in adulthood. Here, we examine diagnoses given in childhood among individuals that are diagnosed with autism in adulthood, to investigate whether the late autism diagnosis might be explained by misdiagnosis in childhood or diagnostic overshadowing.

Methods

Through the Danish National Patient Registry, we identified individuals diagnosed with autism in adulthood (N = 2199), as well as a control sample with no records of an autism diagnosis (N = 460,798) and calculated how many had received different psychiatric or neurological diagnoses in childhood.

Results

We found that most childhood diagnoses were overrepresented in those with an adult autism diagnosis, and attention-deficit hyperactivity disorder, affective disorders, anxiety, and stress disorders were the most prevalent childhood conditions in this group. However, 69% of males and 61% of females with adult autism diagnoses were not found to have received any of the investigated diagnoses before 18 years of age, and most childhood diagnoses were given after the age of 12.

Limitations

Milder to moderate cases of psychiatric conditions that have been solely treated by family physicians or school psychologists may not be fully included in our dataset. The study is based on data from the Danish health care system, and further research is needed to assess whether the findings can be generalized to other countries.

Conclusion

A majority of those with an adult autism diagnosis had no records of having received any of the investigated diagnoses in childhood. In these cases, the late autism diagnosis is therefore unlikely to be explained by either misdiagnosis or overshadowing. This result is at odds with the prevailing notion that autistic symptoms tend to diminish with age. Therefore, further research is warranted to examine how and if early signs of autism may have manifested among these individuals, and how similar they are to autistic people diagnosed earlier in their development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13229-021-00478-y.

Barriers to Autism Spectrum Disorder Diagnosis for Young Women and Girls: a Systematic Review

There is increased recognition that women and girls with autism spectrum disorders (ASD) are underserved by the clinical criteria and processes required to receive a diagnosis. This mixed-methods systematic review aimed to identify key barriers to obtaining an ASD diagnosis in girls and young women under 21 years. Six themes were identified that focused on perceived gendered symptoms, namely behavioural problems, social and communication abilities, language, relationships, additional diagnoses/difficulties and restricted and repetitive behaviours and interests. Five themes were identified as (parental) perceived barriers to diagnosis, namely compensatory behaviours, parental concerns, others’ perceptions, lack of information/resources and clinician bias. This review highlights the importance of enhancing widespread understanding and recognition of ASD presentation in females across development. PROSPERO Centre for Reviews and Dissemination (ID 2018 CRD42018087235)

Association of phthalate exposure with autistic traits in children

BACKGROUND

Phthalates are synthetic chemicals with endocrine-disrupting properties. They are reportedly associated with various neurotoxic outcomes. Studies on exposure to phthalates and children's autistic traits have shown inconsistent results with respect to sex and susceptible time periods. We investigated the association of phthalate exposure during the prenatal period and childhood with autistic traits over time using a birth cohort in South Korea.

METHODS

Five phthalate metabolites were measured during mid-term pregnancy and children's follow-up at ages of 4, 6, and 8 years among a total of 547 mother-child pairs. The social communication questionnaire (SCQ) was used to assess autistic traits of children at each time point. The relationship between phthalate metabolites and SCQ scores were analyzed by exposure windows and sex.

RESULTS

A 2.7 fold increase in di-(2-ethylhexyl) phthalate metabolite levels, mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) during pregnancy was associated with increased SCQ scores at 4 years by 8.5% (95% confidence intervals [CI]: 1.9%, 15.5%) and 7.4% (95% CI: 0.3%, 15.0%), respectively, but not at the age of 6 or 8 years. Moreover, MEHHP levels at ages of 4 and 8 years were associated with increased SCQ scores at 8 years by 9.9% (95% CI: 1.8%, 18.6%) and 9.6% (95% CI: 1.3%, 18.6%), respectively. Boys showed stronger associations between phthalate exposure and SCQ scores than girls.

CONCLUSION

The study suggested different susceptible time windows of phthalate exposure: exposure during pregnancy is associated with autistic traits in young children, whereas exposure during early childhood years leads to autistic traits in school-aged children, particularly boys.

Influences of student race/ethnicity and gender on autism special education classification considerations

LAY ABSTRACT

Autism prevalence has continued to rise in recent years. However, females and children from Black, Latinx, and Asian backgrounds are often misidentified or identified less often than White males. These identification disparities make it difficult for children to receive appropriate special education and school intervention services. In this study, school psychologists read a vignette featuring a student with possible autism symptoms. The vignette varied by student race/ethnicity and gender. Afterward, participants rated the likelihood that they would classify the student with autism and their confidence in this rating. Student race/ethnicity and gender influenced both classification likelihood and confidence. These results suggest that school psychologists are influenced by implicit bias and do not fully consider cultural factors in school autism evaluations. This may contribute to identification disparities.

Variable Emergence of Autism Spectrum Disorder Symptoms From Childhood to Early Adulthood

OBJECTIVE

Autism spectrum disorder (ASD) is currently considered an early-onset neurodevelopmental condition. Follow-up studies of clinic-ascertained autism suggest that autistic symptoms typically decline with age, although symptom improvement is limited for some. To date there have been no population-based prospective studies investigating the natural history of autistic symptoms from childhood to adulthood. The aim of this study was to characterize the development and heterogeneity of autistic symptoms in a population-based cohort from childhood to age 25.

METHODS

Data were analyzed in a prospective U.K. population-based cohort (ALSPAC). Trajectories were derived using five assessments of the parent-rated Social and Communication Disorders Checklist (SCDC) spanning ages 7-25. Additional measures were used to validate symptom trajectories.

RESULTS

Three distinct SCDC symptom trajectory classes were identified: low (88.5%), declining (5.0%), and late-emerging (6.5%). Both the declining and late-emerging trajectory classes were associated with child and adult ASD measures, low IQ, communication problems, peer problems, and worse adult functioning compared with the low trajectory class. Male sex was associated with a higher likelihood of being in the declining trajectory class (odds ratio=2.84, 95% CI=2.19, 3.69). This sex difference was not observed in the late-emerging class (odds ratio=1.00, 95% CI=0.80, 1.24) compared with the low trajectory class.

CONCLUSIONS

ASD symptom levels that emerged early tended to decline across development, although impairment was still present in adulthood for some. For others, autistic symptoms emerged across adolescence and adulthood. This challenges our current understanding that ASD symptoms inevitably first manifest early in development.

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

BACKGROUND

Evidence increasingly suggests that ASD manifests differently in females than males. Previous reviews investigating sex/gender differences in social interaction and social communication have focused at the level of broad constructs (e.g. comparing algorithm scores from pre-existing diagnostic instruments) and have typically reported no significant differences between males and females. However, a number of individual studies have found sex/gender differences in narrow construct domains.

METHODS

We conducted a systematic review and random effects model meta-analyses (in January 2019 and updated January 2020) that investigated sex/gender differences in narrow construct measures of social communication and interaction in autistic and nonautistic children and adolescents, and adults. Study quality was appraised using the Appraisal Tool for Cross-Sectional Studies (AXIS, BMJ Open, 6, 2016, 1).

RESULTS

Across 16 studies (including 2,730 participants), the analysis found that female (vs. male) individuals with ASD had significantly better social interaction and social communication skills (SMD = 0.39, p < .001), which was reflective of a similar sex/gender profile in nonautistic individuals (SMD = 0.35, p < .001). Nonautistic males had significantly better social interaction and communication than males with ASD (SMD = 0.77, p < .001). Nonautistic females also had significantly better social interaction and communication than females with ASD (SMD = 0.72, p  <.001). Nonautistic males had better social interaction and communication than females with ASD, though this difference was not significant (SMD = 0.30, p = .07).

CONCLUSIONS

This systematic review and meta-analysis highlighted important sex/gender differences in social interaction and communication for individuals with ASD, likely not captured by pre-existing diagnostic instruments, which potentially contribute to the under recognition of autism in females, and may need to be reflected in the diagnostic process.

Autism spectrum disorder: An examination of sex differences in neuropsychological and self-report measures of executive and non-executive cognitive function

LAY ABSTRACT

Research comparing females and males with a diagnosis of autism suggests that there are sex differences in some characteristics such as behaviour regulation. One area not studied in detail is whether females and males with autism perform differently in tests of cognitive ability. The results of previous research are quite mixed. One explanation may be that some research comparing females and males with autism did not include a neurotypical control group for comparison. As a result, it is not clear whether the sex differences in cognitive ability observed in people with autism are similar to differences between neurotypical males and females. To better understand whether there are unique differences between males and females with autism, it is important to also compare them with neurotypical males and females. In our research, we included a neurotypical group and compared males and females with and without a diagnosis of autism. We found that the sex differences in autism are similar to what we observe in males and females without autism. Our study showed that compared with males, females (with and without autism) do better in assessments of processing speed, cognitive flexibility, verbal learning and memory and semantic fluency. Our results suggest that although females show different cognitive performance to males, these sex differences were not specific to the group with a diagnosis of autism.

Gender differences between adolescents with autism in emergency psychiatry

LAY ABSTRACT

Among adolescents seen for psychiatric emergency consultation, the percentage of adolescents with autism is increasing over the years. This applies even more to girls than to boys. We collected data of 1378 adolescents aged 12-18 years who were seen for urgent consultation by mobile psychiatric emergency services in the Netherlands. Among these, there were 64 autistic girls and 125 autistic boys. We wanted to know more about differences in problems between autistic and typical developing adolescents in crisis, both to prevent crisis and to improve services. The percentage of adolescents with autism increased over the years studied. Autistic adolescents experienced more severe impairment in functioning compared to typically developing adolescents. Compared to other adolescents, both boys and girls on the autism spectrum were diagnosed less frequently with mood disorders, behavioral disorders, relational problems, and abuse. Autistic girls had a higher suicide risk and suffered more often from anxiety disorders than autistic boys, while autistic boys had a longer history of problems. Outpatient care for children with autism should include easy access to specialized professionals who aim to reduce anxiety and help young people with autism to cope with the challenges of adolescence. Because possibly signs were missed during the emergency consultation, we recommend that as part of the routine procedure in crisis situations adolescents with autism are asked about mood and behavioral problems explicitly, as well as about negative life events.

Anorexia nervosa and autism: a prospective twin cohort study

BACKGROUND

Anorexia nervosa (AN) and autism spectrum disorder (ASD) may be phenotypically and etiologically linked. However, due to the absence of prospective studies, it remains unclear whether the elevation of autistic traits in AN is evident in early childhood. Here, we prospectively investigated autistic traits before and after the first diagnosis of AN.

METHODS

In a population-based sample of 5,987 individuals (52.4% female) from the Child and Adolescent Twin Study in Sweden, parents reported autistic traits at ages 9 and 18. AN and ASD diagnoses were retrieved from the Swedish National Patient Register. In addition, AN diagnoses were ascertained by parent-reported treatment for AN. We compared whether individuals with and without AN differed in autistic traits before the first diagnosis of AN (age 9) and after the first diagnosis of AN (age 18).

RESULTS

We did not find evidence for elevated autistic traits in 9-year-old children later diagnosed with AN. At age 18, however, there was a marked elevation in restricted/repetitive behavior and interests, but only in the subgroup of individuals with acute AN. A less pronounced elevation was observed for social communication problems.

CONCLUSIONS

Coping strategies in individuals with ASD and the somewhat different female ASD phenotype may explain why we did not find elevated autistic traits in children who later developed AN. Alternatively, it is possible that elevated autistic traits were not present prior to the onset of AN, thus questioning the previously reported elevated prevalence of ASD in AN. Future studies should use tailored measurements in order to investigate whether autistic traits in individuals with AN are best conceptualized as an epiphenomenon of the acute AN phase or whether these symptoms indeed represent ASD as a clinically verifiable neurodevelopmental disorder.

A Conceptual Analysis of Autistic Masking: Understanding the Narrative of Stigma and the Illusion of Choice

Autistic masking is an emerging research area that focuses on understanding the conscious or unconscious suppression of natural autistic responses and adoption of alternatives across a range of domains. It is suggested that masking may relate to negative outcomes for autistic people, including late/missed diagnosis, mental health issues, burnout, and suicidality. This makes it essential to understand what masking is, and why it occurs. In this conceptual analysis, we suggest that masking is an unsurprising response to the deficit narrative and accompanying stigma that has developed around autism. We outline how classical social theory (i.e., social identity theory) can help us to understand how and why people mask by situating masking in the social context in which it develops. We draw upon the literature on stigma and marginalization to examine how masking might intersect with different aspects of identity (e.g., gender). We argue that although masking might contribute toward disparities in diagnosis, it is important that we do not impose gender norms and stereotypes by associating masking with a "female autism phenotype." Finally we provide recommendations for future research, stressing the need for increased understanding of the different ways that autism may present in different people (e.g., internalizing and externalizing) and intersectionality. We suggest that masking is examined through a sociodevelopmental lens, taking into account factors that contribute toward the initial development of the mask and that drive its maintenance.

Lay summary

Why is this topic important?: Autistic masking is a complicated topic. We currently think that masking includes things such as making eye contact even if it makes you feel uncomfortable, or not talking about your interests too much for fear of being labeled "weird." There is a lot about masking that we do not know yet, but it is important to understand masking as we think that it might have a negative effect on autistic people.What was the purpose of this article?: The purpose of this article was to look at current explanations of masking, and try to figure out what is missing.What do the authors conclude?: We conclude that work on masking needs to think about autistic people in a different way. Autistic people grow up in a social world and experience a lot of negative views about autism and autistic people. We argue that we need to understand how this social world and the trauma that can come from being part of it contributes toward masking. We also argue against the idea that masking is a "female" thing that occurs as a result of there being a "female-specific" subtype of autism, because this might make it harder for some people to get a diagnosis (e.g., nonbinary people, and men and women who do not fit with any of the current criteria). Instead we argue that people need to recognize that autism does not look like one "type" of person, and try to separate ideas about masking from ideas about a person not fitting a stereotype.What do the authors recommend for future research on this topic?: Though masking is called a "social strategy," there has not been a lot of social theory applied to masking research. We recommend that researchers use theories about how people try to fit in, and theories about how people exclude and hurt people who are different. This can help us to understand why autistic people mask. We also stress the need to understand that masking is not necessarily a choice, and that there are many unconscious aspects. We argue that researchers should try to find out when masking starts to happen (e.g., in childhood) and what makes people feel like they need to keep up the mask. We also recommend lot more research into autistic identity, and how different parts of identity (including things such as gender, race, and co-occurring conditions) might mean that someone has to mask more (or less), or in different ways.How will this analysis help autistic adults now and in the future?: We hope that this analysis will help researchers to understand that some aspects of masking might be unique to autistic people, but some aspects might be like other kinds of "pretending to be normal" that other people who are socially excluded use to try and fit in. We hope that our suggestions can help to improve our understanding of masking, and lead to research that makes life better for autistic people.

The factor structure of the macaque social responsiveness scale-revised predicts social behavior and personality dimensions

Most primate species are highly social. Yet, within species, pronounced individual differences in social functioning are evident. In humans, the Social Responsiveness Scale (SRS) measures variation in social functioning. The SRS provides a quantitative measure of social functioning in natural social settings and can be used as a screening tool for autistic traits. The SRS was previously adapted for use in chimpanzees and recently refined for rhesus macaques, resulting in the macaque Social Responsiveness Scale-Revised (mSRS-R). Here, we performed an exploratory factor analysis on the mSRS-R in a large sample of male rhesus macaques (N = 233). We investigated the relationships of the resulting mSRS-R factors to quantitative social behavior (alone, proximity, contact, groom, and play) and to previously-established personality dimensions (Sociability, Confidence, Irritability, and Equability). Factor analysis yielded three mSRS-R factors: Poor Social Motivation, Poor Social Attractiveness, and Inappropriate Behavior. mSRS-R factors mapped closely to social behavior and personality dimensions in rhesus macaques, providing support for this instrument's convergent and discriminant validity. Animals with higher Poor Social Motivation were more likely to be observed alone and less likely to be observed in contact and grooming with conspecifics. Animals with higher Poor Social Attractiveness were less likely to be observed playing but more likely to be observed grooming with conspecifics. Inappropriate Behavior did not predict any behavioral measure. Finally, animals with higher Poor Social Motivation and higher Poor Social Attractiveness had less sociable personalities, whereas animals with more Inappropriate Behavior were more confident and more irritable. These findings suggest that the mSRS-R is a promising, psychometrically robust tool that can be deployed to better understand the psychological factors contributing to individual differences in macaque social functioning and, with relevant species-specific modification, the SRS may hold promise for investigating variation in social functioning across diverse primate taxa.

Trajectories of autistic social traits in childhood and adolescence and disordered eating behaviours at age 14 years: A UK general population cohort study

BACKGROUND

Some people with eating disorders have difficulties with social communication. However, no longitudinal evidence regarding the direction of this association exists. We investigated trajectories of autistic social traits across childhood and adolescence in adolescents with and without disordered eating behaviours in early adolescence.

METHODS

We used data from the Avon Longitudinal Study of Parents and Children. Our disordered eating measure indicated presence of any, monthly and weekly disordered eating (fasting, purging, dieting, binge eating) at age 14 years. Autistic social traits were reported by mothers using the Social and Communication Disorders Checklist (SCDC) at age seven, 11, 14 and 16 years. We modelled SCDC score trajectories using multilevel negative binomial models adjusting for a number of child- and maternal-level confounders.

RESULTS

Of the 5,381 adolescents included in our sample, 421 (7.8%) experienced one or more disordered eating behaviours, and 148 (2.8%) weekly episodes. Adolescents with disordered eating had a 20% increase in SCDC scores (relative risk (RR) 1.23, 95% confidence interval (CI):1.14, 1.32) compared to those without disordered eating. This association was particularly apparent for those reporting weekly (RR 1.43, 95%CI: 1.27, 1.61) as opposed to monthly disordered eating (RR 1.12, 95%CI: 1.01, 1.22).

CONCLUSIONS

Greater autistic social traits in childhood could represent a risk factor for the development of disordered eating in adolescence. Although mechanisms of this association need to be elucidated, clinicians should be aware that autistic social traits could have predated the eating disorder when managing people with these conditions.

Trajectories of Autism Symptom Severity Change During Early Childhood

Autism symptom severity change was evaluated during early childhood in 125 children diagnosed with autism spectrum disorder (ASD). Children were assessed at approximately 3 and 6 years of age for autism symptom severity, IQ and adaptive functioning. Each child was assigned a change score, representing the difference between ADOS Calibrated Severity Scores (CSS) at the two ages. A Decreased Severity Group (28.8%) decreased by 2 or more points; a Stable Severity Group (54.4%) changed by 1 point or less; and an Increased Severity Group (16.8%) increased by 2 or more points. Girls tended to decrease in severity more than boys and increase in severity less than boys. There was no clear relationship between intervention history and membership in the groups.

Prevalence of Autism Spectrum Disorder and Co-morbidities in Children and Adolescents: A Systematic Literature Review

Objective: Individuals with autism spectrum disorder often present somatic and/or psychiatric co-morbid disorders. The DSM-5 allows for consideration of additional diagnoses besides ASD and may have impacted the prevalence of co-morbidities as well as being limited in capturing the true differences in prevalence observed between males and females. We describe the prevalence of ASD and frequently observed co-morbidities in children and adolescents (<18 years) in the United States and five European countries. Methods: Two systematic literature reviews were conducted in PubMed and Embase for the period 2014-2019 and focusing on the prevalence of ASD and nine co-morbidities of interest based on their frequency and/or severity: Attention Deficit Hyperactivity Disorder (ADHD), anxiety, depressive disorders, epilepsy, intellectual disability (ID), sleep disorders, sight/hearing impairment/loss, and gastro-intestinal syndromes (GI). Results: Thirteen studies on prevalence of ASD and 33 on prevalence of co-morbidities were included. Prevalence of ASD was 1.70 and 1.85% in US children aged 4 and 8 years respectively, while prevalence in Europe ranged between 0.38 and 1.55%. Additionally, current evidence is supportive of a global increase in ASD prevalence over the past years. Substantial heterogeneity in prevalence of co-morbidities was observed: ADHD (0.00-86.00%), anxiety (0.00-82.20%), depressive disorders (0.00-74.80%), epilepsy (2.80-77.50%), ID (0.00-91.70%), sleep disorders (2.08-72.50%), sight/hearing impairment/loss (0.00-14.90%/0.00-4.90%), and GI syndromes (0.00-67.80%). Studies were heterogeneous in terms of design and method to estimate prevalence. Gender appears to represent a risk factor for co-morbid ADHD (higher in males) and epilepsy/seizure (higher in females) while age is also associated with ADHD and anxiety (increasing until adolescence). Conclusion: Our results provide a descriptive review of the prevalence of ASD and its co-morbidities in children and adolescents. These insights can be valuable for clinicians and parents/guardians of autistic children. Prevalence of ASD has increased over time while co-morbidities bring additional heterogeneity to the clinical presentation, which further advocates for personalized approaches to treatment and support. Having a clear understanding of the prevalence of ASD and its co-morbidities is important to raise awareness among stakeholders.

The influence of choline treatment on behavioral and neurochemical autistic-like phenotype in Mthfr-deficient mice

Imbalanced one carbon metabolism and aberrant autophagy is robustly reported in patients with autism. Polymorphism in the gene methylenetetrahydrofolate reductase (Mthfr), encoding for a key enzyme in this pathway is associated with an increased risk for autistic-spectrum-disorders (ASDs). Autistic-like core and associated behaviors have been described, with contribution of both maternal and offspring Mthfr^+/- genotype to the different domains of behavior. Preconception and prenatal supplementation with methyl donor rich diet to human subjects and mice reduced the risk for developing autism and autistic-like behavior, respectively. Here we tested the potential of choline supplementation to Mthfr-deficient mice at young-adulthood to reduce behavioral and neurochemical changes reminiscent of autism characteristics. We show that offspring of Mthfr^+/- mothers, whether wildtype or heterozygote, exhibit autistic-like behavior, altered brain p62 protein levels and LC3-II/LC3-I levels ratio, both, autophagy markers. Choline supplementation to adult offspring of Mthfr^+/- mothers for 14 days counteracted characteristics related to repetitive behavior and anxiety both in males and in females and improved social behavior solely in male mice. Choline treatment also normalized deviant cortical levels of the autophagy markers measured in male mice. The results demonstrate that choline supplementation even at adulthood, not tested previously, to offspring of Mthfr-deficient mothers, attenuates the autistic-like phenotype. If this proof of concept is replicated it might promote translation of these results to treatment recommendation for children with ASDs bearing similar genetic/metabolic make-up.

Age of First Walking and Associations with Symptom Severity in Children with Suspected or Diagnosed Autism Spectrum Disorder

Age of first walking (AOW) is reported to be later in autism spectrum disorder (ASD) compared with typical development. However, the relationship between AOW and variations in ASD symptoms across different neurodevelopmental disorders is largely unknown. This study investigated AOW and its association with autism symptom severity in a large sample of children (N = 490, 23% females) clinically evaluated for suspected ASD, differentiated into ASD (n = 376) and non-ASD (n = 114) diagnoses. Children with ASD achieved independent walking significantly later than children with non-ASD diagnoses. AOW was significantly associated with ASD symptom severity, and females had a non-significant later AOW. The current findings suggest that in cases with delayed AOW, ASD should be considered as an actual differential diagnosis, perhaps particularly in girls.

Patterns of autism symptoms: hidden structure in the ADOS and ADI-R instruments

We simultaneously revisited the Autism Diagnostic Interview-Revised (ADI-R) and Autism Diagnostic Observation Schedule (ADOS) with a comprehensive data-analytics strategy. Here, the combination of pattern-analysis algorithms and extensive data resources (n = 266 patients aged 7-49 years) allowed identifying coherent clinical constellations in and across ADI-R and ADOS assessments widespread in clinical practice. Our clustering approach revealed low- and high-severity patient groups, as well as a group scoring high only in the ADI-R domains, providing quantitative contours for the widely assumed autism subtypes. Sparse regression approaches uncovered the most clinically predictive questionnaire domains. The social and communication domains of the ADI-R showed convincing performance to predict the patients' symptom severity. Finally, we explored the relative importance of each of the ADI-R and ADOS domains conditioning on age, sex, and fluid IQ in our sample. The collective results suggest that (i) identifying autism subtypes and severity for a given individual may be most manifested in the ADI-R social and communication domains, (ii) the ADI-R might be a more appropriate tool to accurately capture symptom severity, and (iii) the ADOS domains were more relevant than the ADI-R domains to capture sex differences.

Determinants of an autism spectrum disorder diagnosis in childhood and adolescence: Evidence from the UK Millennium Cohort Study

This study aimed to identify determinants of a late autism spectrum disorder diagnosis, including diagnoses made 'very late' (i.e., in adolescence), using the Millennium Cohort Study, a nationally representative population-based cohort in the United Kingdom. Children diagnosed with autism spectrum disorder by age 14 (N = 581) were included and grouped by the parent-reported timing of diagnosis: before school (up to age 5), during primary school (age 5-11) and during secondary school (age 11-14). Predictors of diagnostic timing, at the child, family and school levels, were investigated using multinomial logistic regression. Most (79%) children with autism spectrum disorder were diagnosed after school entry, and 28% were not diagnosed until secondary school. Among those not diagnosed until secondary school, 75% had been identified at age 5 years by a parent and/or teacher as having socio-behavioural difficulties. Being diagnosed after starting school was predicted by living in poverty (adjusted relative risk ratio: primary = 1.90, 95% confidence interval: 1.03-3.53; secondary = 2.15, 1.05-4.42) and/or having no initial parental concerns (primary = 0.32, 0.15-0.70; secondary = 0.19, 0.09-0.43). Having typical-range intelligence also predicted diagnosis during secondary school. The result indicates that those without cognitive delays and poorer children were at risk of 'very late' (i.e. adolescent) diagnosis. Strategies to promote earlier identification, targeting age at primary school entry, could help those more likely to be diagnosed late.Lay abstractDespite policy emphasis on early identification, many children with autism spectrum disorder are diagnosed late, with some being diagnosed as late as in adolescence. However, evidence on what determines the timing of autism spectrum disorder diagnosis including children diagnosed in adolescence is lacking. Understanding these determinants, particularly in those diagnosed later than is ideal, can inform the development of effective strategies to improve earlier identification of autism spectrum disorder. This study used a nationally representative population-based cohort in the United Kingdom to explore child, family and school level predictors of timing of autism spectrum disorder diagnosis. In the United Kingdom, 79% of the children with autism spectrum disorder were diagnosed after entering primary school and 28% during secondary school. Among those not diagnosed until secondary school, 75% had shown social difficulties noticed by parents and/or teachers at age 5 years. The results suggest that healthcare providers should be aware that, even for universal systems of care, those living in poverty and having higher intelligence are most likely to miss out on a timely diagnosis. Strategies to promote earlier identification among school-aged children, including targeting primary school entry age (i.e. around age 5) and that encouraging referrals for a formal assessment at the first report of concerns over the child's social development may benefit those children who would otherwise be diagnosed later.

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.

The Female Autism Phenotype and Camouflaging: a Narrative Review

Autism is more commonly diagnosed in males than females. One explanation is the ‘female protective effect’: there is something inherent in being female which reduces the likelihood of developing autism. However, evidence suggests that the condition is underdiagnosed in females, perhaps because females express their autism in ways which do not meet current diagnostic criteria. This review explores evidence for a female-typical autism presentation, the Female Autism Phenotype (FAP) and the component of camouflaging (compensating for and masking autistic characteristics) in particular. The evidence so far supports the existence of a female-typical autism presentation, although further examination of the characteristics and their impact across all genders and ages is needed.

Polygenic Risk Scores for Developmental Disorders, Neuromotor Functioning During Infancy, and Autistic Traits in Childhood

BACKGROUND

Impaired neuromotor development is often one of the earliest observations in children with autism spectrum disorder (ASD). We investigated whether a genetic predisposition to developmental disorders was associated with nonoptimal neuromotor development during infancy and examined the genetic correlation between nonoptimal neuromotor development and autistic traits in the general population.

METHODS

In a population-based cohort in The Netherlands (2002-2006), we calculated polygenic risk scores (PRSs) for ASD and attention-deficit/hyperactivity disorder (ADHD) using genome-wide association study summary statistics. In 1921 children with genetic data, parents rated autistic traits at 6 years of age. Among them, 1174 children (61.1%) underwent neuromotor examinations (tone, responses, senses, and other observations) during infancy (9-20 weeks of age). We used linear regressions to examine associations of PRSs with neuromotor scores and autistic traits. We performed a bivariate genome-based restricted maximum likelihood analysis to explore whether genetic susceptibility underlies the association between neuromotor development and autistic traits.

RESULTS

Higher PRSs for ASD were associated with less optimal overall infant neuromotor development, in particular low muscle tone. Higher PRSs for ADHD were associated with less optimal senses. PRSs for ASD and those for ADHD both were associated with autistic traits. The single nucleotide polymorphism-based heritability of overall motor development was 20% (SE = .21) and of autistic traits was 68% (SE = .26). The genetic correlation between overall motor development and autistic traits was .35 (SE = .21, p < .001).

CONCLUSIONS

We found that genetic liabilities for ASD and ADHD covary with neuromotor development during infancy. Shared genetic liability might partly explain the association between nonoptimal neuromotor development during infancy and autistic traits in childhood.

The Relationship Between Social Communication and Social Functioning in Pediatric TBI: A Pilot Study

Objective: Social communication presents a significant difficulty for children with traumatic brain injury (TBI). Although several measures are used to examine social communication, there is no gold-standard assessment tool. The present pilot study examined the ability of the Social Communication Disorders Checklist (SCDC) to detect social communication difficulties in pediatric TBI. Further, we examined the relationship between social communication and social functioning as assessed by parental ratings of behavior and objective measures of social cognition.

Methods: Sixteen children with pediatric TBI and 20 age, education and sex matched healthy controls (HCs) participated. All participants participated in a neuropsychological evaluation and parents filled out questionnaires. Parents rated their children's social communication abilities using the SCDC, as well as the Behavior Assessment System for Children, Second Edition (BASC-2). The pediatric subjects completed a task of social cognition, specifically Theory of Mind (ToM).

Results: The pediatric TBI group had significantly lower scores on the SCDC compared to the HCs (p = 0.001). In the pediatric group, SCDC scores correlated significantly with scores on the BASC-2, as well as performance on the ToM task, indicating that children with lower parent-rated social communication abilities also had lower scores on the objective measure of social cognition.

Conclusions: These data provide preliminary evidence that children with TBI have difficulties with social communication, as evidenced by lower scores on the SCDC, and that SCDC scores correlate with subjective and objective measures of social cognition and behavior in pediatric TBI.

Differences in the expression of restricted repetitive behaviors in female and male BTBR T + tf/J mice

Autism spectrum disorder (ASD) is characterized by the expression of restricted repetitive behaviors (RRBs) and impairments in social recognition and communication. Epidemiological studies demonstrate males are three times more likely than females to be affected. Although this is the case, more recent studies suggest females may be underrepresented in these numbers due to standard clinical measures of RRBs and social behaviors. In addition, many studies examining mouse models of ASD exclude females due to the sex disparity in diagnoses. The present study examined how female and male BTBR T + Itpr3tf /J (BTBR) compare to control C57BL/6J mice on tests of RRBs (probabilistic reversal learning, repetitive grooming, spontaneous alternation, and marble burying) and social behaviors (three chambered social approach task). Utilizing a spatial reversal learning test with 80/20 probabilistic feedback, in which ASD individuals have exhibited deficits, we find that female BTBR mice do not show the same impairment found in male BTBR mice. Interestingly, control female C57BL/6J mice required more trials to reach criterion. Female BTBR mice expressed comparable rates of repetitive grooming, marble burying and spontaneous alternation compared to female C57BL/6J mice. Male BTBR mice expressed higher rates of grooming behavior and locomotor activity compared to male C57BL/6J mice, as found in previous studies. Similarly, male BTBR mice showed a reduction in both measures of social approach compared to controls. Both male and female BTBR mice showed a reduction in sniff time for the stranger mouse compared to controls. Together these findings demonstrate how female BTBR mice do not display the RRB profile expressed by male BTBR mice. Testing of repetitive behaviors in ASD needs to better reflect the sex differences in how RRBs manifest in females compared to their extensively researched male counterparts.

The role of gender in the perception of autism symptom severity and future behavioral development

Background

Increasing attention is being paid to the higher prevalence of boys with Autism Spectrum Disorder (ASD) and to the implications of this ratio discrepancy on our understanding of autism in girls. One recent avenue of research has focused on caregiver's concern, suggesting that autism might present differently in boys and girls. One unexplored factor related to concerns on child development is whether socio-cultural factors such as gender-related expectations influence the evaluation of symptom severity and predictions about future behavioral development.

Methods

The latter concerns were the focus of the present study and were explored by investigating laypeople's judgment of the severity of autism symptoms using an online parent role-playing paradigm, in which participants were asked to rate vignettes depicting the behaviors of a child in different everyday life scenarios. The child's gender and the severity of ASD symptoms were manipulated to examine the effect of gender on the perception of symptom severity.

Results

Results suggest that there are no gender differences in perceived symptom severity and associated degree of concern for 5-year-old boys and girls but that there is a gender difference in perceived future atypicality at 15 years old, with boys being rated as more likely to be perceived as atypical by their peers at that age than girls.

Conclusions

Investigating parent's cognition about their child's future behavioral development can provide additional information regarding delayed diagnosis of autistic girls.

Stability of Autistic Traits from 5 to 8 Years of Age Among Children in the General Population

Little is known about the across time stability of autistic traits during the transition period from preschool to school age in the general population. The current study compared autistic traits assessed by a mother-reported quantitative measure, the Social Responsiveness Scale, at age 5 and 8 years and examined the intraclass correlation coefficients of scores across the period for 168 Japanese community-based children. Results showed that total and two subdomain-related autistic trait scores remained primarily stable in males and females. This stability was observed for both children with higher and lower autistic traits scores with a possible sex-specific pattern. Our findings suggest that autistic traits in the general population can be reliably assessed using quantitative measures for this age period.

Psychometric properties of the chinese version of autism spectrum quotient-children's version: A sex-specific analysis

A Simplified Chinese translation of the Autism Spectrum Quotient-Children's Version (AQ-C) is needed for research in mainland China. Autism Spectrum Disorder (ASD) is a condition that differs in presentation and prevalence by sex. Thus, evaluating the psychometric validity of the AQ-C in males and females is an important step in its validation. The present study aims to develop a Chinese translation of the parent-report AQ-C, and test its psychometric properties among Mandarin Chinese speaking boys and girls. A total of 1,020 non-clinical children and 134 children with ASD were assessed. Factor analyses were performed for the whole sample, as well as for girls and boys separately. A 30-item, 5-factor model (the Chinese AQ-C) showed adequate goodness of fit (root mean square error of approximation [RMSEA] = 0.037; comparative fit index [CFI] = 0.907; Tucker-Lewis index [TLI] = 0.901) for the whole sample. According to parents' reports, non-clinical boys had significantly higher scores than non-clinical girls on the Chinese AQ-C. Sex-specific factor structures were identified resulting in a 4-factor model with 32 items for girls (the Chinese AQ-Girls), and a 4-factor model with 34 items for boys (the Chinese AQ-Boys). The cut-off scores of the Chinese AQ-C, AQ-Girls, and AQ-Boys were 44.5, 42.5, and 46.5, respectively. These three Chinese versions of the AQ-C all showed satisfactory internal consistency (α = 0.786-0.840) and concurrent validity with the Social Responsiveness Scale (r = 0.789-0.814) for the total scale. Differences have been found in the sex-specific factor structures of the AQ-C which would be more reliable to use for future research when measuring autistic traits in the general population. Autism Res 2019, 12: 303-315 © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: This study developed Chinese versions of the Autism Spectrum Quotient-Children's Version (AQ-C) in Chinese boys and girls together and separately. The AQ-C showed good psychometric properties in boys and girls together and separately. There were differences in sex-specific factor structures of the AQ-C. These results suggest that the sex-specific Chinese versions of the AQ-C provide reliable and valid measurement of autistic traits.