Review of factor analytic studies examining symptoms of autism spectrum disorders

Should We Continue to Tell Autistic People that Their Brains are Different?

Autism is often considered to reflect categorically 'different brains'. Neuropsychological research on autism spectrum disorder (ASD) however, has struggled to define this difference, or derive clear-cut boundaries between autism and non-autism. Consequently, restructuring or disbanding the ASD diagnosis is becoming increasingly advocated within research. Nonetheless, autism now exists as a salient social construction, of which 'difference' is a key facet. Clinical and educational professionals must influence this cautiously, as changes to autism's social construction may counterproductively affect the quality of life of autistic people. This paper therefore reviews ASD's value as both neuropsychological and social constructs. Although lacking neuropsychological validity, the autism label may be beneficial for autistic self-identity, reduction of stigma, and administering support. Whilst a shift away from case-control ASD research is warranted, lay notions of 'different brains' may be preserved.

Early Language, Social Communication, and Autism Characteristics of Young Toddlers at Elevated Likelihood for Autism Identified by the First Years Inventory-Lite

PURPOSE

The purposes of this article were (a) to compare the developmental skills of toddlers whose scores on the First Years Inventory-Lite (FYI-Lite), an early screening tool, indicated an elevated likelihood of a later diagnosis of autism (ELA) to the developmental skills of toddlers at a lower likelihood of a later diagnosis of autism (LLA) and (b) to examine how autism characteristics are correlated with communication measures in toddlers at an ELA.

METHOD

We assessed the language, social communication (SC) skills, and characteristics of autism demonstrated by 45 toddlers at an ELA and 37 toddlers at an LLA between the ages of 11 and 18 months and compared group scores on these measures. We also examined the correlations between the characteristics of autism and language measures within the ELA group.

RESULTS

Toddlers at an ELA demonstrated lower scores on measures of global expressive and receptive language, receptive vocabulary, gestures, and response to joint attention bids as well as SC characteristics of autism when compared to those demonstrated by toddlers at an LLA. There were no significant differences between groups on expressive vocabulary, language profiles (i.e., the relationship between receptive and expressive scores), or restrictive and repetitive behaviors. Within the ELA group, the SC characteristics of autism were significantly associated with their global receptive and expressive language skills.

CONCLUSIONS

On the basis of the FYI-Lite screening tool, toddlers at an ELA are demonstrating delays in language and SC skills when compared to toddlers identified with an LLA. For toddlers at an ELA, the SC characteristics of autism are significantly associated with early language skills.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.27969444.

The relationship between autistic traits and problematic smartphone use in adolescents: The serial mediating role of anxiety and executive dysfunction

BACKGROUND

Based on the Interaction of Person-Affect-Cognition-Execution (I-PACE) model, this study aimed to explore the relationship between autistic traits and problematic smartphone use (PSU) among Chinese adolescents and to examine the serial mediation effect of anxiety and executive dysfunction in the association between autistic traits and PSU.

METHODS

The Autism-Spectrum Quotient, Smartphone Addiction Scale, the trait version of the State-Trait Anxiety Inventory, and Dysexecutive Questionnaire were administered to a sample comprising 412 senior high school students (average age = 17.05 years, SD = 0.65). Structural equation models were utilized to explore the simple and serial mediating role of anxiety and executive dysfunction played in the association between autistic traits and PSU.

RESULTS

This study found that social rather than non-social autistic traits were positively associated with anxiety, executive dysfunction, and PSU. Furthermore, after controlling for gender, anxiety and executive dysfunction acted as sequential mediators in the connection between social autistic trait and PSU. However, non-social autistic trait did not predict anxiety, executive dysfunction, or PSU.

CONCLUSION

This study supports the I-PACE model and deepens understanding of PSU formation. Furthermore, the findings underscore the importance of addressing social challenges faced by adolescents with high autistic traits, providing a viable potential intervention pathway to promote healthy smartphone use in this population.

A transdiagnostic approach of negative symptoms in psychiatric disorders: replication of a two-factor structure in major depressive disorder and bipolar disorder

Recent empirical findings suggest that negative symptoms are not limited to schizophrenia (SCZ) but also present in major depressive disorder (MDD) and bipolar disorder (BD) patients. Although SCZ patients generally showed a latent structure comprising the motivation and pleasure (MAP) and expression (EXP) factors, it remains unclear whether the same latent structure exists in MDD and BD patients. We administered the Clinical Assessment Interview for Negative Symptoms (CAINS) and the Brief Negative Symptom Scale (BNSS) to 179 MDD patients and 152 BD patients. Confirmatory Factor Analysis (CFA) was conducted to examine the one-factor model, the two-factor model of the MAP and the EXP domain, the five-factor model of anhedonia, avolition, asociality, alogia, and blunted affect, and the hierarchical model comprising the first-order five-factor, and the second-order two-factor (MAP and EXP factors). We further examined the correlations between demographics and the negative symptom dimensions found in the best factor model. The CFA showed that, when the CAINS and the BNSS were combined together, the two-factor model of MAP and EXP provided the best model fit than other competing models, in the MDD alone sample, BD alone sample, and the combined clinical sample. The two-factor model of the MAP and EXP appears to be a stable, transdiagnostic latent structure of negative symptoms across BD and MDD. Clarifying negative symptoms in MDD and BD can facilitate future research on the underlying neural mechanisms of the MAP and EXP dimensions.

Assessing Restricted and Repetitive Behaviours in Online-Sampled Autistic and Non-autistic Individuals: Factor Structure of the Repetitive Behaviours Questionnaire for Adults (RBQ-2A)

The Repetitive Behaviours Questionnaire for Adults (RBQ-2A) measures two factors of restricted and repetitive behaviours (RRBs) associated with autism. However, the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) provides four criteria for RRBs: repetitive motor behaviours, insistence on sameness, restricted interests, and interest in sensory aspects of the environment (or atypical sensitivity). The current paper aimed to examine whether the RBQ-2A is a psychometrically sound measure of these four factors. Study 1 had university students (N = 368) complete the RBQ-2A and other related measures online and revealed that the RBQ-2A can assess the factors highlighted in the DSM-5 and that these four factors comprise a general RRB construct. Study 2 had individuals disclosing a diagnosis of autism (N = 283) complete the RBQ-2A and other related measures online and supported that this four-factor structure provided good psychometric properties. While the current paper provides findings for an online autistic population, further research is needed to generalize these findings to autistic individuals less likely to partake in online studies (e.g., those with intellectual or language disabilities). Overall, the results suggest that the RBQ-2A reliably and validly assesses RRBs.

Clinical and Family Implications of Cannabidiol (CBD)-Dominant Full-Spectrum Phytocannabinoid Extract in Children and Adolescents with Moderate to Severe Non-Syndromic Autism Spectrum Disorder (ASD): An Observational Study on Neurobehavioral Management

Autism Spectrum Disorder (ASD) encompasses a wide range of neurodevelopmental conditions characterized by deficits in social interaction, communication and behavior. Current pharmacological options are limited and feature significant side effects. In this study, we conducted a retrospective, observational, and cross-sectional cohort study to evaluate the effects of Cannabidiol (CBD)-dominant, full-spectrum cannabis extract, containing Tetrahydrocannabinol (THC) in a ratio of 33:1 (CBD:THC), on non-syndromic children and adolescents (5-18 years old) with moderate to severe ASD. Thirty volunteers were recruited, underwent neuropsychological evaluations and were treated with individualized doses of CBD-dominant extract. Clinical assessments were conducted by the designated clinician. Additionally, parents or caregivers were independently interviewed to assess perceived treatment effects. We found significant improvements in various symptomatic and non-symptomatic aspects of ASD, with minimal untoward effects, as reported by both clinical assessments and parental perceptions. The observed improvements included increased communicative skills, attention, learning, eye contact, diminished aggression and irritability, and an overall increase in both the patient's and family's quality of life. Despite its limitations, our findings suggest that treatment with full-spectrum CBD-dominant extract may be a safe and effective option for core and comorbid symptoms of ASD, and it may also increase overall quality of life for individuals with ASD and their families.

The first six months of life: A systematic review of early markers associated with later autism

There is now good evidence that behavioural signs of autism spectrum conditions (autism) emerge over the first two years of life. Identifying clear developmental differences early in life may facilitate earlier identification and intervention that can promote longer-term quality of life. Here we present a systematic review of studies investigating behavioural markers of later autism diagnosis or symptomology taken at 0-6 months. The following databases were searched for articles published between 01/01/2000 and 15/03/2022: Embase, Medline, Scopus, PubMed, PsycINFO, CINAHL, Web of Science and Proquest. Twenty-five studies met inclusion criteria: assessment of behaviour at 0-6 months and later assessment of autism symptomology or diagnosis. Studies examined behaviours of attention, early social and communication behaviours, and motor behaviours, as well as composite measures. Findings indicated some evidence of measures of general attention, attention to social stimuli, and motor behaviours associated with later autism diagnosis or symptomology. Findings were inconsistent regarding social and communication behaviours, with a lack of repeated or validated measures limiting drawing firm conclusions. We discuss implications of the findings and suggest recommendations for future research.

Early postnatal development of the MDGA2+/- mouse model of synaptic dysfunction

Synaptic dysfunction underlies many neurodevelopmental disorders (NDDs). The membrane-associated mucin domain-containing glycosylphosphatidylinositol anchor proteins (MDGAs) regulate synaptic development by modulating neurexin-neuroligin complex formation. Since understanding the neurodevelopmental profile and the sex-based differences in the manifestation of the symptoms of NDDs is important for their early diagnosis, we tested a mouse model haploinsufficient for MDGA2 (MDGA2+/-) on a neurodevelopmental test battery, containing sensory, motor, and cognitive measures, as well as ultrasonic vocalizations. When male and female MDGA2+/- and wildtype (WT) C57BL/6 J mice were examined from 2 to 23 days of age using this test battery, genotype and sex differences in body weight, sensory-motor processes, and ultrasonic vocalizations were observed. The auditory startle reflex appeared earlier in the MDGA2+/- than in WT mice and the MDGA2+/- mice produced fewer ultrasonic vocalizations. The MDGA2+/- mice showed reduced locomotion and rearing than WT mice in the open field after 17 days of age and spent less time investigating a novel object than WT mice at 21 days of age. Female MDGA2+/- mice weighed less than WT females and showed lower grip strength, indicating a delay in sensory-motor development in MDGA2+/- mice, which appears to be more pronounced in females than males. The behavioural phenotypes resulting from MDGA2 haploinsufficiency suggests that it shows delayed development of motor behaviour, grip strength and exploratory behaviour, non-social phenotypes of NDDs.

Sensory Over-responsivity: A Feature of Childhood Psychiatric Illness Associated With Altered Functional Connectivity of Sensory Networks

BACKGROUND

Sensory over-responsivity (SOR) is recognized as a common feature of autism spectrum disorder. However, SOR is also common among typically developing children, in whom it is associated with elevated levels of psychiatric symptoms. The clinical significance and neurocognitive bases of SOR in these children remain poorly understood and actively debated.

METHODS

This study used linear mixed-effects models to identify psychiatric symptoms and network-level functional connectivity (FC) differences associated with parent-reported SOR in the Adolescent Brain Cognitive Development (ABCD) Study, a large community sample (9 to 12 years of age) (N = 11,210).

RESULTS

Children with SOR constituted 18% of the overall sample but comprised more than half of the children with internalizing or externalizing scores in the clinical range. Controlling for autistic traits, both mild and severe SOR were associated with greater concurrent symptoms of depression, anxiety, obsessive-compulsive disorder, and attention-deficit/hyperactivity disorder. Controlling for psychiatric symptoms and autistic traits, SOR predicted increased anxiety, attention-deficit/hyperactivity disorder, and prodromal psychosis symptoms 1 year later and was associated with FC differences in brain networks supporting sensory and salience processing in datasets collected 2 years apart. Differences included reduced FC within and between sensorimotor networks, enhanced sensorimotor-salience FC, and altered FC between sensory networks and bilateral hippocampi.

CONCLUSIONS

SOR is a common, clinically relevant feature of childhood psychiatric illness that provides unique predictive information about risk. It is associated with differences in brain networks that subserve tactile processing, implicating a neural basis for sensory differences in affected children.

Prenatal exposure to organophosphate pesticides and autism spectrum disorders in 11-year-old children in the French PELAGIE cohort

BACKGROUND

Organophosphate (OP) pesticides act by inhibiting acetylcholinesterase activity at synaptic junctions and have already been linked with deleterious effects on neurodevelopment, including autism spectrum disorders (ASD).

OBJECTIVES

To investigate the association of prenatal exposure to OP pesticides with traits related to ASD in 11-year-old children.

METHODS

The "Childhood Autism Spectrum Test" (CAST) parent questionnaire was used to screen for autistic traits in 792 children from the French PELAGIE cohort. Prenatal maternal urine samples were collected <19 weeks of gestation in which metabolites of organophosphate insecticides were assessed for 185 of them. Negative binomial regression models were performed to explore the association between the CAST score and 8 groups of urine components, adjusted for potential ASD risk factors.

RESULTS

In these urine samples, dialkylphosphates (DAP) were detected most often (>80%), terbufos and its metabolites least often (<10%). No association with ASD was found for DAP, terbufos or its metabolites. Incidence rate ratios (IRRs) increased with maternal urinary diazinon concentrations, from 1.11 (95% CI: 0.87-1.42) to 1.17 (95% CI: 0.94-1.46). Higher CAST scores were statistically significantly associated with the maternal urine samples in which chlorpyrifos or two of its metabolites (chlorpyrifos-oxon and 3,5,6-trichloro-2-pyridinol) were detected. The IRR for exposure to chlorpyrifos or chlorpyrifos-oxon was 1.27 (95%CI: 1.05-1.52) among all children, and 1.39 (95%CI: 1.07-1.82) among boys.

CONCLUSION

These findings suggest an increase in autistic traits among 11-year-old children in association with prenatal maternal exposure to chlorpyrifos and possibly diazinon. These associations were previously suspected in the literature, in particular for chlorpyrifos. Further work establishing the causal mechanisms behind these risk association is needed.

The impact of COVID-19 measures on parent-reported restricted and repetitive behaviours in pre-school children with autism

Background

COVID-19 restrictive measures have had a considerable impact on daily life routines, which may be especially challenging for families of children with autism. In pre-schoolers with autism, it is likely that the disruption of routines mainly impacts the presence of restrictive and repetitive behaviours (RRBs). Furthermore, influence of comorbid conditions, secondary behavioural difficulties and home environment characteristics on RRBs was explored.

Method

A cross-sectional online survey design was used to collect parent-report data on 254 children with autism (2.5–6 years) during lockdown in the early months of the pandemic. RRBs were assessed using the Repetitive Behaviour Scale-Revised (RBS-R).

Results

Parents reported a significant increase in stereotypic, self-injurious, compulsive and ritualistic behaviour, and restricted interests after implementation of COVID-19 restrictions. The presence of a co-occurring condition, such as language impairments or intellectual disability, was associated with more self-injurious and stereotypic behaviour. However, there was no effect of home environment on RRBs. Further, most children showed increases in internalising and/or externalising behaviour. Increased inattentive behaviour was associated with more ritualistic and stereotypic behaviour, and restricted interests. Decreases in hyperactivity were related to more restricted interests. Importantly, in a subset of children, parents reported less behavioural difficulties during the lockdown.

Conclusions

Findings highlight the importance of flexible implementation and continuity of care for pre-schoolers with autism and support for parents. Further follow-up of children with autism and RRBs, and co-occurring behavioural difficulties is needed and could enhance our understanding of the long-term effects associated with sudden restrictive measures to daily routines.

Does the autism phenotype differ when selecting groups by neurodevelopmental versus genetic diagnosis? An observational study comparing autism and sex chromosome trisomy

Background: Autism is diagnosed on the basis of social and non-social behavioural features that are assumed to cluster together, and assumed to be distinct from other aspects of development, such as language ability. It is unclear, however, if these assumptions are valid. This study presents a novel approach to answering this question by investigating whether correlations between autism features are similar for groups selected on behavioural versus genetic diagnosis. Methods: The autism phenotype was assessed by diagnostic interview in young people aged 7 to 14 diagnosed with autism ( N=61) or sex chromosome trisomy (SCT; N=49). Data were analysed by confirmatory factor analysis and MANOVA. Results: Autism features showed a similar factor structure and were distinct from language ability in both groups. However, the SCT group was more likely to show clinically-significant difficulties in just some aspects of autism and a lower level of non-social autism features for their social-communication disabilities. Conclusions: We suggest the group differences emerged because autism diagnostic criteria do not map exactly on the autism phenotype as it manifests "naturally". Conventional diagnostic criteria for autism miss those with uneven profiles of difficulty and those with relatively low levels of restricted and repetitive behaviours and interests.

Targeted Tshz3 deletion in corticostriatal circuit components segregates core autistic behaviors

We previously linked TSHZ3 haploinsufficiency to autism spectrum disorder (ASD) and showed that embryonic or postnatal Tshz3 deletion in mice results in behavioral traits relevant to the two core domains of ASD, namely social interaction deficits and repetitive behaviors. Here, we provide evidence that cortical projection neurons (CPNs) and striatal cholinergic interneurons (SCINs) are two main and complementary players in the TSHZ3-linked ASD syndrome. In the cerebral cortex, TSHZ3 is expressed in CPNs and in a proportion of GABAergic interneurons, but not in cholinergic interneurons or glial cells. In the striatum, TSHZ3 is expressed in all SCINs, while its expression is absent or partial in the other main brain cholinergic systems. We then characterized two new conditional knockout (cKO) models generated by crossing Tshz3^flox/flox with Emx1-Cre (Emx1-cKO) or Chat-Cre (Chat-cKO) mice to decipher the respective role of CPNs and SCINs. Emx1-cKO mice show altered excitatory synaptic transmission onto CPNs and impaired plasticity at corticostriatal synapses, with neither cortical neuron loss nor abnormal layer distribution. These animals present social interaction deficits but no repetitive patterns of behavior. Chat-cKO mice exhibit no loss of SCINs but changes in the electrophysiological properties of these interneurons, associated with repetitive patterns of behavior without social interaction deficits. Therefore, dysfunction in either CPNs or SCINs segregates with a distinct ASD behavioral trait. These findings provide novel insights onto the implication of the corticostriatal circuitry in ASD by revealing an unexpected neuronal dichotomy in the biological background of the two core behavioral domains of this disorder.

Heritability of social behavioral phenotypes and preliminary associations with autism spectrum disorder risk genes in rhesus macaques: A whole exome sequencing study

Nonhuman primates and especially rhesus macaques (Macaca mulatta) have been indispensable animal models for studies of various aspects of neurobiology, developmental psychology, and other aspects of neuroscience. While remarkable progress has been made in our understanding of influences on atypical human social behavior, such as that observed in autism spectrum disorders (ASD), many significant questions remain. Improved understanding of the relationships among variation in specific genes and variation in expressed social behavior in a nonhuman primate would benefit efforts to investigate risk factors, developmental mechanisms, and potential therapies for behavioral disorders including ASD. To study genetic influences on key aspects of social behavior and interactions-individual competence and/or motivation for specific aspects of social behavior-we quantified individual variation in social interactions among juvenile rhesus macaques using both a standard macaque ethogram and a macaque-relevant modification of the human Social Responsiveness Scale. Our analyses demonstrate that various aspects of juvenile social behavior exhibit significant genetic heritability, with estimated quantitative genetic effects similar to that described for ASD in human children. We also performed exome sequencing and analyzed variants in 143 genes previously suggested to influence risk for human ASD. We find preliminary evidence for genetic association between specific variants and both individual behaviors and multi-behavioral factor scores. To our knowledge, this is the first demonstration that spontaneous social behaviors performed by free-ranging juvenile rhesus macaques display significant genetic heritability and then to use exome sequencing data to examine potential macaque genetic associations in genes associated with human ASD.

Social communication in fragile X syndrome: pilot examination of the Brief Observation of Social Communication Change (BOSCC)

Background

Social communication is a key area of difficulty in fragile X syndrome (FXS) and there are not yet adequate outcome measurement tools. Appropriate outcome measures for FXS have been identified as a key area of research interest in order to evaluate future therapeutic trials. The Brief Observation of Social Communication Change-Minimally Verbal (BOSCC-MV), an outcome measure with strong psychometrics developed for autism spectrum disorder, has promise as an outcome measure to assess social communication change with FXS participants.

Methods

We examined the BOSCC-MV via central coders in this multi-site-trial to assess its appropriateness for FXS. Eighteen minimally verbal males ages 3–12 years were enrolled and assessed on two consecutive days and 7 participants completed a third visit 6 months later. We examined test-retest reliability, inter-rater reliability, and both convergent and divergent validity with standard clinical measures including the Autism Diagnostic and Observation Schedule-2, Vineland 3, Social Responsiveness Scale, and the Aberrant Behavior Checklist.

Results

The BOSCC-MV in FXS demonstrated strong inter-rater and test-retest reliability, comparable to previous trials in idiopathic ASD. Strong convergent validity was found with Autism Diagnostic Observation Schedule-2 and Vineland-3. Divergent validity was demonstrated between BOSCC-MV and unrelated measures.

Conclusions

The BOSCC-MV shows promise as a FXS social communication outcome measure, warranting further large-scale evaluation.

Latent Structure of Combined Autistic and ADHD Symptoms in Clinical and General Population Samples: A Scoping Review

Background: Many phenotypic studies have estimated the degree of comorbidity between Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD), but few have examined the latent, or unobserved, structure of combined ASD and ADHD symptoms. This is an important perquisite toward better understanding the overlap between ASD and ADHD. Methods: We conducted a scoping review of studies that examined the factor or latent class structure of ASD and ADHD symptoms within the same clinical or general population sample. Results: Eight studies met final inclusion criteria. Four factor analysis studies found that ASD and ADHD domains loaded separately and one found that some ASD and ADHD domains loaded together. In the three latent class studies, there were evidence of profiles with high levels of co-occurring ASD and ADHD symptoms. Conclusions: Our scoping review provides some evidence of phenotypic overlap between ASD and ADHD at the latent, or unobserved, level, particularly when using a "person-centered" (latent class analysis) vs. a "variable-centered" (factor analysis) approach.

Autistic adults' subjective experiences of hoarding and self-injurious behaviors

LAY ABSTRACT

Hoarding and self-injurious behaviors are relatively common in autism, but knowledge about their expressions in adulthood is scarce. Through interviews collecting subjective experiences of autistic adults, these behaviors were explored, and categorized to their underlying purposes. Findings portray the occurrence of these behaviors in the lives of autistic adults, their self-regulatory purposes, and their relationship to other behaviors in the domain of Restrictive and Repetitive Behaviors and Interests.

Understanding Oneself to Understand Others: The Role of Alexithymia and Anxiety in the Relationships Between Autistic Trait Dimensions and Empathy

People on the autism spectrum may have difficulty inferring others' emotions (cognitive empathy), but may share another's emotions (affective empathy) and exhibit heightened personal distress. The present study examined independent autistic trait dimensions (social difficulties and restricted/repetitive behaviours) and the roles alexithymia and trait anxiety have in explaining this profile of empathy. Results from the general population (n = 301) revealed that pronounced social difficulties and not restricted/repetitive behaviours related to reduced cognitive and affective empathy, and heightened personal distress. However, both dimensions, through alexithymia and anxiety, indirectly influenced empathy. Surprisingly, while the dimensions indirectly improved affective empathy, pronounced social difficulties directly reduced affective empathy. This study motivates a nuanced model of empathy by including autistic trait dimensions, anxiety, and alexithymia.

Genetic architecture of reciprocal social behavior in toddlers: Implications for heterogeneity in the early origins of autism spectrum disorder

Impairment in reciprocal social behavior (RSB), an essential component of early social competence, clinically defines autism spectrum disorder (ASD). However, the behavioral and genetic architecture of RSB in toddlerhood, when ASD first emerges, has not been fully characterized. We analyzed data from a quantitative video-referenced rating of RSB (vrRSB) in two toddler samples: a community-based volunteer research registry (n = 1,563) and an ethnically diverse, longitudinal twin sample ascertained from two state birth registries (n = 714). Variation in RSB was continuously distributed, temporally stable, significantly associated with ASD risk at age 18 months, and only modestly explained by sociodemographic and medical factors (r2 = 9.4%). Five latent RSB factors were identified and corresponded to aspects of social communication or restricted repetitive behaviors, the two core ASD symptom domains. Quantitative genetic analyses indicated substantial heritability for all factors at age 24 months (h2 ≥ .61). Genetic influences strongly overlapped across all factors, with a social motivation factor showing evidence of newly-emerging genetic influences between the ages of 18 and 24 months. RSB constitutes a heritable, trait-like competency whose factorial and genetic structure is generalized across diverse populations, demonstrating its role as an early, enduring dimension of inherited variation in human social behavior. Substantially overlapping RSB domains, measurable when core ASD features arise and consolidate, may serve as markers of specific pathways to autism and anchors to inform determinants of autism's heterogeneity.

Dimensions of Autistic Traits Rated by Parents of Children and Adolescents with Suspected Autism Spectrum Disorders

To examine the factor structure of autism spectrum disorder (ASD) and the psychometric properties of the German Symptom Checklist for Autism Spectrum Disorders (SCL-ASD). Data were collected from 312 clinical referrals with suspected ASD (2–18 years). Confirmatory factor analyses and analyses of reliability, convergent and divergent validity were performed. A bifactor model with one general ASD factor and two specific factors (interaction-communication; restricted, repetitive behaviors) provided an adequate data fit. Internal consistencies of the SCL-ASD subscales and the total scale were > .70. Correlations with measures of ASD traits were higher than correlations with measures of externalizing and internalizing symptoms. The results support a factor structure consistent with DSM-5/ICD-11 criteria. The SCL-ASD has sound psychometric properties.

Repetitive Behavior in Children and Adolescents: Psychometric Properties of the German Version of the Repetitive Behavior Scale-Revised

Restricted repetitive behaviors (RRBs) are a core feature of autism spectrum disorders (ASD) and further occur in intellectual disability (ID), mental disorders (MD), and in typically developed people (TD). There is a need of a valid and reliable measure to record RRBs as transdiagnostic symptom, which captures RRBs heterogeneity and evaluates severity. The Repetitive Behavior Scale-Revised (RBS-R) is an established screening instrument for RRBs, but was predominantly limited to ASD samples. We examined the psychometric properties of the German version of the RBS-R in 948 participants with ASD, ID, MD and TD aged 4 to 17 years. The suitability was proofed delivering a four-factor solution, good internal consistency, external validity as well as group, age, and sex effects.

Quantitative genome-wide association study of six phenotypic subdomains identifies novel genome-wide significant variants in autism spectrum disorder

Autism spectrum disorders (ASD) are highly heritable and are characterized by deficits in social communication and restricted and repetitive behaviors. Twin studies on phenotypic subdomains suggest a differing underlying genetic etiology. Studying genetic variation explaining phenotypic variance will help to identify specific underlying pathomechanisms. We investigated the effect of common variation on ASD subdomains in two cohorts including >2500 individuals. Based on the Autism Diagnostic Interview-Revised (ADI-R), we identified and confirmed six subdomains with a SNP-based genetic heritability h²_SNP = 0.2-0.4. The subdomains nonverbal communication (NVC), social interaction (SI), and peer interaction (PI) shared genetic risk factors, while the subdomains of repetitive sensory-motor behavior (RB) and restricted interests (RI) were genetically independent of each other. The polygenic risk score (PRS) for ASD as categorical diagnosis explained 2.3-3.3% of the variance of SI, joint attention (JA), and PI, 4.5% for RI, 1.2% of RB, but only 0.7% of NVC. We report eight genome-wide significant hits-partially replicating previous findings-and 292 known and novel candidate genes. The underlying biological mechanisms were related to neuronal transmission and development. At the SNP and gene level, all subdomains showed overlap, with the exception of RB. However, no overlap was observed at the functional level. In summary, the ADI-R algorithm-derived subdomains related to social communication show a shared genetic etiology in contrast to restricted and repetitive behaviors. The ASD-specific PRS overlapped only partially, suggesting an additional role of specific common variation in shaping the phenotypic expression of ASD subdomains.

A Conceptual Framework for Understanding the Cultural and Contextual Factors on Autism Across the Globe

Autism research is heavily skewed toward western high-income countries. Culturally appropriate screening and diagnostic instruments for autism are lacking in most low- and middle-income settings where the majority of the global autism population lives. To date, a clear overview of the possible cultural and contextual factors that may affect the process of identifying and diagnosing individuals with autism spectrum disorders (ASD) is missing. This study aims to outline these factors by proposing a conceptual framework. A multidisciplinary review approach was applied to inform the development of the conceptual framework, combining a systematic review of the relevant autism research literature with a wider literature search spanning key texts in global mental health, cultural psychiatry, cross-cultural psychology, and intellectual disability research. The resulting conceptual framework considers the identification, help-seeking, and diagnostic process at four interrelated levels: (a) the expression; (b) recognition; (c) interpretation; and (d) reporting of autism symptoms, and describes the cultural and contextual factors associated with each of these levels, including cultural norms of typical and atypical behavior, culture-specific approaches to parenting, mental health literacy, cultural beliefs, attitudes and stigma, as well as the affordability, availability, accessibility, and acceptability of services. This framework, mapping out the cultural and contextual factors that can affect the identification, help-seeking, and diagnosis of ASD may function as a springboard for the development of culturally appropriate autism screening and diagnostic instruments, and inform future cross-cultural autism research directions. The framework also has relevance for clinicians and policy makers aiming to improve support for underserved autism populations worldwide. Autism Res 2020, 13: 1029-1050. © 2020 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: The vast majority of autism research is conducted in western high-income settings. We therefore know relatively little of how culture and context can affect the identification, help-seeking, and diagnosis of autism across the globe. This study synthesizes what is known from the autism research literature and a broader literature and maps out how culture and context may affect (a) the expression, (b) recognition, (c) interpretation, and (d) reporting of autism symptoms.

Inattention and hyperactive/impulsive component scores do not differentiate between autism spectrum disorder and attention-deficit/hyperactivity disorder in a clinical sample

Background

Although there is high co-occurrence between ASD and ADHD, the nature of this co-occurrence remains unclear. Our study aimed to examine the underlying relationship between ASD and ADHD symptoms in a combined sample of children with a primary clinical diagnosis of ASD or ADHD.

Methods

Participants included children and youth (aged 3-20 years) with a clinical diagnosis of ASD (n = 303) or ADHD (n = 319) for a total of 622 participants. Parents of these children completed the social communication questionnaire (SCQ), a measure of autism symptoms, and the strengths and weaknesses of ADHD and normal behavior (SWAN) questionnaire, a measure of ADHD symptoms. A principal component analysis (PCA) was performed on combined SCQ and SWAN items, followed by a profile analysis comparing normalized component scores between diagnostic groups and gender.

Results

PCA revealed a four-component solution (inattention, hyperactivity/impulsivity, social-communication, and restricted, repetitive, behaviors, and interests (RRBI)), with no overlap between SCQ and SWAN items in the components. Children with ASD had higher component scores in social-communication and RRBI than children with ADHD, while there was no difference in inattentive and hyperactive/impulsive scores between diagnostic groups. Males had higher scores than females in social-communication, RRBI, and hyperactivity/impulsivity components in each diagnostic group.

Limitations

We did not formally assess children with ASD for ADHD using our research-criteria for ADHD, and vice versa. High rates of co-occurring ADHD in ASD, for example, may have inflated component scores in inattention and hyperactivity/impulsivity. A disadvantage with using single informant-based reports (i.e., parent-rated questionnaires) is that ASD and ADHD symptoms may be difficult to distinguish by parents, and may be interpreted differently between parents and clinicians.

Conclusions

ASD and ADHD items loaded on separate components in our sample, suggesting that the measurement structure cannot explain the covariation between the two disorders in clinical samples. High levels of inattention and hyperactivity/impulsivity were seen in both ASD and ADHD in our clinical sample. This supports the need for a dimensional framework that examines neurodevelopmental domains across traditional diagnostic boundaries. Females also had lower component scores across social-communication, RRBI, and hyperactivity/impulsivity than males, suggesting that there may be gender-specific phenotypes related to the two conditions.

Effects of CBD-Enriched Cannabis sativa Extract on Autism Spectrum Disorder Symptoms: An Observational Study of 18 Participants Undergoing Compassionate Use

Autism Spectrum Disorders comprise conditions that may affect cognitive development, motor skills, social interaction, communication, and behavior. This set of functional deficits often results in lack of independence for the diagnosed individuals, and severe distress for patients, families, and caregivers. There is a mounting body of evidence indicating the effectiveness of pure cannabidiol (CBD) and CBD-enriched Cannabis sativa extract (CE) for the treatment of autistic symptoms in refractory epilepsy patients. There is also increasing data support for the hypothesis that non-epileptic autism shares underlying etiological mechanisms with epilepsy. Here we report an observational study with a cohort of 18 autistic patients undergoing treatment with compassionate use of standardized CBD-enriched CE (with a CBD to THC ratio of 75/1). Among the 15 patients who adhered to the treatment (10 non-epileptic and five epileptic) only one patient showed lack of improvement in autistic symptoms. Due to adverse effects, three patients discontinued CE use before 1 month. After 6-9 months of treatment, most patients, including epileptic and non-epileptic, showed some level of improvement in more than one of the eight symptom categories evaluated: Attention Deficit/Hyperactivity Disorder; Behavioral Disorders; Motor Deficits; Autonomy Deficits; Communication and Social Interaction Deficits; Cognitive Deficits; Sleep Disorders and Seizures, with very infrequent and mild adverse effects. The strongest improvements were reported for Seizures, Attention Deficit/Hyperactivity Disorder, Sleep Disorders, and Communication and Social Interaction Deficits. This was especially true for the 10 non-epileptic patients, nine of which presented improvement equal to or above 30% in at least one of the eight categories, six presented improvement of 30% or more in at least two categories and four presented improvement equal to or above 30% in at least four symptom categories. Ten out of the 15 patients were using other medicines, and nine of these were able to keep the improvements even after reducing or withdrawing other medications. The results reported here are very promising and indicate that CBD-enriched CE may ameliorate multiple ASD symptoms even in non-epileptic patients, with substantial increase in life quality for both ASD patients and caretakers.

Construct Validity and Cross Validity of a Test Battery Modeling Autism Spectrum Disorder (ASD) in Mice

Modeling in other organism species is one of the crucial stages in ascertaining the association between gene and psychiatric disorder. Testing Autism Spectrum Disorder (ASD) in mice is very popular but construct validity of the batteries is not available. We presented here the first factor analysis of a behavioral model of ASD-like in mice coupled with empirical validation. We defined fourteen measures aligning mouse-behavior measures with the criteria defined by DSM-5 for the diagnostic of ASD. Sixty-five mice belonging to a heterogeneous pool of genotypes were tested. Reliability coefficients vary from .68 to .81. The factor analysis resulted in a three- factor solution in line with DSM criteria: social behavior, stereotypy and narrowness of the field of interest. The empirical validation with mice sharing a haplo-insufficiency of the zinc-finger transcription factor TSHZ3/Tshz3 associated with ASD shows the discriminant power of the highly loaded items.

Social and non-social autism symptoms and trait domains are genetically dissociable

The core diagnostic criteria for autism comprise two symptom domains - social and communication difficulties, and unusually repetitive and restricted behaviour, interests and activities. There is some evidence to suggest that these two domains are dissociable, though this hypothesis has not yet been tested using molecular genetics. We test this using a genome-wide association study (N = 51,564) of a non-social trait related to autism, systemising, defined as the drive to analyse and build systems. We demonstrate that systemising is heritable and genetically correlated with autism. In contrast, we do not identify significant genetic correlations between social autistic traits and systemising. Supporting this, polygenic scores for systemising are significantly and positively associated with restricted and repetitive behaviour but not with social difficulties in autistic individuals. These findings strongly suggest that the two core domains of autism are genetically dissociable, and point at how to fractionate the genetics of autism.

A comprehensive psychometric analysis of autism-spectrum quotient factor models using two large samples: Model recommendations and the influence of divergent traits on total-scale scores

The Autism-Spectrum Quotient (AQ) is a psychometric scale that is commonly used to assess autistic-like traits and behaviors expressed by neurotypical individuals. A potential strength of the AQ is that it provides subscale scores that are specific to certain dimensions associated with autism such as social difficulty and restricted interests. However, multiple psychometric evaluations of the AQ have led to substantial disagreement as to how many factors exist in the scale, and how these factors are defined. These challenges have been exacerbated by limitations in study designs, such as insufficient sample sizes as well as a reliance on Pearson, rather than polychoric, correlations. In addition, several proposed models of the AQ suggest that some factors are uncorrelated, or negatively correlated, which has ramifications for whether total-scale scores are meaningfully interpretable-an issue not raised by previous work. The aims of the current study were to provide: (a) guidance as to which models of the AQ are viable for research purposes, and (b) evidence as to whether total-scale scores are adequately interpretable for research purposes. We conducted a comprehensive series of confirmatory factor analyses on 11 competing AQ models using two large samples drawn from an undergraduate population (n = 1,702) and the general population (n = 1,280). Psychometric evidence largely supported using the three-factor model described by Russell-Smith et al. [Personality and Individual Differences 51(2), 128-132 (2011)], but did not support the use of total-scale scores. We recommend that researchers consider using AQ subscale scores instead of total-scale scores. Autism Res 2020, 13: 45-60. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: We examined 11 different ways of scoring subscales in the popular Autism-Spectrum Quotient (AQ) questionnaire in two large samples of participants (i.e., general population and undergraduate students). We found that a three-subscale model that used "Social Skill," "Patterns/Details," and "Communication/Mindreading" subscales was the best way to examine specific types of autistic traits in the AQ. We also found some weak associations between the three subscales-for example, being high on the "Patterns/Details" subscale was not predictive of scores on the other subscales. This means that meaningful interpretation of overall scores on the AQ is limited.

Testing the Empathizing-Systemizing theory of sex differences and the Extreme Male Brain theory of autism in half a million people

In the largest study to date of autistic traits, we test 10 predictions from the Empathizing–Systemizing (E-S) theory of sex differences and the Extreme Male Brain (EMB) theory of autism. We confirmed that typical females on average are more empathic, typical males on average are more systems-oriented, and autistic people on average show a “masculinized” profile. The strengths of the study are the inclusion of a replication sample and the use of big data. These two theories can be considered to have strong support. We demonstrate that D-scores (difference between E and S) account for 19 times the variance in autistic traits than do other demographic variables, including sex, underscoring the importance of brain types in autism.

The Empathizing–Systemizing (E-S) theory of typical sex differences suggests that individuals may be classified based on empathy and systemizing. An extension of the E-S theory, the Extreme Male Brain (EMB) theory suggests that autistic people on average have a shift towards a more masculinized brain along the E-S dimensions. Both theories have been investigated in small sample sizes, limiting their generalizability. Here we leverage two large datasets (discovery n = 671,606, including 36,648 autistic individuals primarily; and validation n = 14,354, including 226 autistic individuals) to investigate 10 predictions of the E-S and the EMB theories. In the discovery dataset, typical females on average showed higher scores on short forms of the Empathy Quotient (EQ) and Sensory Perception Quotient (SPQ), and typical males on average showed higher scores on short forms of the Autism Spectrum Quotient (AQ) and Systemizing Quotient (SQ). Typical sex differences in these measures were attenuated in autistic individuals. Analysis of “brain types” revealed that typical females on average were more likely to be Type E (EQ > SQ) or Extreme Type E and that typical males on average were more likely to be Type S (SQ > EQ) or Extreme Type S. In both datasets, autistic individuals, regardless of their reported sex, on average were “masculinized.” Finally, we demonstrate that D-scores (difference between EQ and SQ) account for 19 times more of the variance in autistic traits (43%) than do other demographic variables including sex. Our results provide robust evidence in support of both the E-S and EMB theories.

Functional connectivity in ASD: Atypical pathways in brain networks supporting action observation and joint attention

Autism Spectrum Disorder (ASD) is a developmental disorder characterized by impaired social communication, including attending to and interpreting social cues, initiating and responding to joint attention, and engaging in abstract social cognitive reasoning. Current studies emphasize a underconnectivity in ASD, particularly for brain systems that support abstract social reasoning and introspective thought. Here, we evaluate intrinsic connectivity in children with ASD, targeting brain systems that support the developmental precursors to social reasoning, namely perception of social cues and joint attention. Using resting state fMRI made available through the Autism Brain Imaging Data Exchange (ABIDE), we compute functional connectivity within and between nodes in the action observation, attention and social cognitive networks in children and adolescents with ASD. We also compare connectivity strength to observational assessments that explicitly evaluate severity of ASD on two distinct subdomains using the ADOS-Revised schedule: social affective (SA) and restricted, repetitive behaviors (RRB). Compared to age-matched controls, children with ASD have decreased functional connectivity in a number of connections in the action observation network, particularly in the lateral occipital cortex (LOTC) and fusiform gyrus (FG). Distinct patterns of connections were also correlated with symptom severity on the two subdomains of the ADOS. ADOS-SA severity most strongly correlated with connectivity to the left TPJ, while ADOS-RRB severity correlated with connectivity to the dMPFC. We conclude that atypical connectivity in the action observation system may underlie some of the more complex deficits in social cognitive systems in ASD.

Child, Maternal and Demographic Factors Influencing Caregiver-Reported Autistic Trait Symptomatology in Toddlers

Current research on children's autistic traits in the general population relies predominantly on caregiver-report, yet the extent to which individual, caregiver or demographic characteristics are associated with informants' ratings has not been sufficiently explored. In this study, caregivers of 396 Singaporean two-year-olds from a birth cohort study completed the Quantitative Checklist for Autism in Toddlers. Children's gender, cognitive functioning and birth order, maternal age, and ethnic group membership were not significant predictors of caregiver-reported autistic traits. Poorer child language development and higher maternal depressive symptoms significantly predicted more social-communicative autistic traits, while lower maternal education predicted more behavioural autistic traits. Children's language and informants' educational level and depressive symptomatology may need to be considered in caregiver-reports of autistic traits.

Association of Rigid-Compulsive Behavior with Functional Constipation in Autism Spectrum Disorder

Based upon checklist data from the Autism Speaks Autism Treatment Network, we hypothesized that functional constipation (FC) would be associated with rigid-compulsive behavior in children with autism spectrum disorder (ASD). We used the Questionnaire on Pediatric Gastrointestinal Symptoms-Rome III to assess FC symptoms in 108 children with ASD. As hypothesized, FC was associated with parent ratings on the Repetitive Behavior Scales-Revised (RBS-R) Compulsive, Ritualistic, and Sameness subscales in the overall population. Of note, FC was less common in children who were not taking medications that target behavior or treat FC. In the medication-free children, rigid-compulsive behavior was not significantly associated with FC. More research is needed to understand the mechanisms underlying these associations.

The Survey of Favorite Interests and Activities: Assessing and understanding restricted interests in children with autism spectrum disorder

Restricted interests are an established diagnostic symptom of autism spectrum disorder. While there is considerable evidence that these interests have maladaptive consequences, they also provide a range of benefits. This article introduces a new instrument, the Survey of Favorite Interests and Activities, and uses it to examine the nature of restricted interests in autism spectrum disorder. Respondents report substantial benefits of restricted interests as well as areas of difficulty. The Survey of Favorite Interests and Activities assesses Social Flexibility, Perseveration, Respondent Discomfort, Adaptive Coping, and Atypicality. All scales have Cronbach's α > 0.70. Age and socioeconomic status have little effect on Survey of Favorite Interests and Activities scales; nor does gender with the exception of interest Atypicality. The expected pattern of correlations with existing scales was found. Research and clinical implications are discussed.

Measuring Changes in Social Communication Behaviors: Preliminary Development of the Brief Observation of Social Communication Change (BOSCC)

Psychometric properties and initial validity of the Brief Observation of Social Communication Change (BOSCC), a measure of treatment-response for social-communication behaviors, are described. The BOSCC coding scheme is applied to 177 video observations of 56 young children with ASD and minimal language abilities. The BOSCC has high to excellent inter-rater and test-retest reliability and shows convergent validity with measures of language and communication skills. The BOSCC Core total demonstrates statistically significant amounts of change over time compared to a no change alternative while the ADOS CSS over the same period of time did not. This work is a first step in the development of a novel outcome measure for social-communication behaviors with applications to clinical trials and longitudinal studies.

EDUTEA: A DSM-5 teacher screening questionnaire for autism spectrum disorder and social pragmatic communication disorder

Teacher's reports about child psychopathology are often useful because they make it possible to compare children's development within their normative peer group. The EDUTEA questionnaire aims to provide clinicians and researchers with a brief tool that can be used to screen autism spectrum disorders and social communication disorders in school settings. Method: It was designed according to DSM-5 criteria and validated in a sample of 2,660 Spanish schoolers. Results: The EDUTEA showed a two-factor structure with high internal reliability: Social communication impairments (α=.95) and Restricted behaviour patterns (α=.93). The ROC curve showed that the area under the curve was highly predictive (.90). We propose using a cut-off score of 10, which gives high values of sensitivity (87%), specificity (91.2%) and positive predictive value (.87). Moderate correlations were found with the severity score of the Autism Diagnostic Observation Schedule (ADOS-2) and the child pragmatic competence. Conclusions: The EDUTEA could be useful in ASD screening protocols in schools.

Phenotyping, Etiological Factors, and Biomarkers: Toward Precision Medicine in Autism Spectrum Disorders

Despite the progress made in understanding the biology of autism spectrum disorder (ASD), effective biological interventions for the core symptoms remain elusive. Because of the etiological heterogeneity of ASD, identification of a "one-size-fits-all" treatment approach will likely continue to be challenging. A meeting was convened at the University of Missouri and the Thompson Center to discuss strategies for stratifying patients with ASD for the purpose of moving toward precision medicine. The "white paper" presented here articulates the challenges involved and provides suggestions for future solutions.

ASD Validity

ASD research is at an important crossroads. The ASD diagnosis is important for assigning a child to early behavioral intervention and explaining a child’s condition. But ASD research has not provided a diagnosis-specific medical treatment, or a consistent early predictor, or a unified life course. If the ASD diagnosis also lacks biological and construct validity, a shift away from studying ASD-defined samples would be warranted. Consequently, this paper reviews recent findings for the neurobiological validity of ASD, the construct validity of ASD diagnostic criteria, and the construct validity of ASD spectrum features. The findings reviewed indicate that the ASD diagnosis lacks biological and construct validity. The paper concludes with proposals for research going forward.

Psychometric properties of the Mandarin version of the Childhood Autism Spectrum Test (CAST): an exploratory study

Limited studies have investigated the latent autistic traits in the mainland Chinese population for autism spectrum conditions (ASC). This study explored the psychometric properties of a Mandarin Chinese version of the CAST in a sample consisting of 737 children in mainstream schools and 50 autistic cases. A combination of categorical data factor analysis and item response theory suggested a good-fit model of a two-factor solution for 28 items on the Mandarin CAST including social and communication, and inflexible/stereotyped language and behaviours (Goodness-of-fit indices: RMSEA = 0.029, CFI = 0.957, TLI = 0.950, SRMR = 0.064). The correlation between the two factors was moderate (GFC = 0.425). This study provided evidence for the CAST as a multidimensional measure for ASC screening in a Chinese population and also showed that the symptom manifestation of ASC in Chinese children shares similarity with western populations.

Exploring the proposed DSM-5 criteria in a clinical sample

The proposed DSM-5 criteria for Autism Spectrum Disorder (ASD) depart substantially from the previous DSM-IV criteria. In this file review study of 131 children aged 2-12, previously diagnosed with either Autistic Disorder or Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS), 63 % met the new DSM-5 ASD criteria, including 81 % previously diagnosed with Autistic Disorder and only 17 % of those with PDD-NOS. The proportion of children meeting DSM-5 differed by IQ grouping as well, with higher rates in lower IQ groups. Children who did meet criteria for ASD had significantly lower levels of cognitive and adaptive skills and greater autism severity but were similar in age. These findings raise concerns that the new DSM-5 criteria may miss a number of children who would currently receive a diagnosis.