Deconstructing the repetitive behaviour phenotype in autism spectrum disorder through a large population-based analysis

Characterising Insistence on Sameness and Circumscribed Interests: A Qualitative Study of Parent Perspectives

Manifestations of insistence on sameness (IS) and circumscribed interests (CI) are complex, with individuals varying considerably, not only in the types of behaviours they express, but also in terms of a behaviour's frequency, intensity, trajectory, adaptive benefits, and impacts. However, current quantitative RRB instruments capture only certain aspects of these behaviours (e.g., mostly frequency or general "severity"). Thus, the current study utilised a semi-structured caregiver interview to provide an in-depth, qualitative characterization of different aspects of IS and CI presentation. Caregivers of 27 autistic children and adolescents displaying IS and/or CI behaviours (3-16 years; 18 males; 9 females) participated in a semi-structured interview. Responses were analysed using thematic framework analysis. Framework analysis identified nine different aspects of IS and CI presentation: (1) intensity, (2) frequency, (3) emergence of behaviour, (4) changes over time, (5) day-to-day fluctuations, (6) purpose/adaptive benefit, (7) experiences of distress, (8) challenges for the individual, their family, and their socialisation, and (9) management strategies and their effectiveness. Autistic children and adolescents were reported to vary greatly on each of these dimensions. Findings demonstrate the complexity of IS and CI presentations and highlight the need for more comprehensive quantitative assessments that independently assess the frequency, intensity, and impact of behaviours. Further, findings reported here emphasize the need for ecologically valid measures that assess the contexts in which these behaviours occur and how their presentations can change within and across days.

Characteristics of restricted interests in girls with ASD compared to boys: a systematic review of the literature

The existence of a female phenotype profile in autistic spectrum disorder is one of the current hypotheses to explain the diagnostic discrepancy between men and women. In this context, an international literature review was carried out to evidence and describe the characteristics of restricted interests found in girls with autistic spectrum disorder. A documentary search was conducted on PubMed and a systematic literature review was carried out based on the PRISMA methodology. We selected studies with a population of boys and girls diagnosed as autistic according to the DSM-IV or the DSM-5, in which quantitative and descriptive comparisons of restricted interests, according to gender were carried out. Nineteen studies were found to be relevant. Fifteen enabled a refining of the characteristics of restricted interests among females: fewer restricted interests were identified in comparison with boys, and the autistic girls' interests seem to be closer to those of neurotypical girls than to those of autistic boys, which thus led to more complex screening. Age and Intelligence quotient seem to be two factors that trigger variations in restricted interests differently according to gender. Representations among professionals also have an impact on diagnoses among girls. For future research, one of the perspectives could be a comparison between girls with autism and neurotypical girls to limit gender bias. The present results contribute to potentially extending knowledge of a female phenotypical profile in autism and show the need to improve the general population's awareness, to improve health professionals' training and possibly to revise the diagnostic tools.

The developmental trajectory of diurnal cortisol in autistic and neurotypical youth

Increasing age and puberty affect the hypothalamic pituitary adrenal (HPA) axis maturation, which is likely associated with an increase in environmental demands (e.g., social) and vulnerability for the onset of psychiatric conditions (e.g., depression). There is limited research as to whether such patterns are consonant in youth with autism spectrum disorder (ASD), a condition marked by social challenges, dysregulation of the HPA axis, and higher rates of depression setting the stage for enhanced vulnerability during this developmental period.The current study interrogated diurnal cortisol by examining (1) cortisol expression longitudinally over the pubertal transition between autistic and neurotypical youth, (2) the trajectory of diurnal cortisol and the unique contributions of age vs. puberty, and (3) potential sex differences. As hypothesized, results indicate autistic compared to typically developing youth demonstrate a shallower diurnal slope and elevated evening cortisol. These differences were in the context of higher cortisol and flatter rhythms based on age and pubertal development. Also, sex-based differences emerged such that females in both groups had higher cortisol, flatter slopes, and higher evening cortisol than males. The results show that despite the trait-like stability of diurnal cortisol, HPA maturation is impacted by age, puberty, sex, as well as an ASD diagnosis.

Sex and gender in neurodevelopmental conditions

Health-related conditions often differ qualitatively or quantitatively between individuals of different birth-assigned sexes and gender identities, and/or with different gendered experiences, requiring tailored care. Studying the moderating and mediating effects of sex-related and gender-related factors on impairment, disability, wellbeing and health is of paramount importance especially for neurodivergent individuals, who are diagnosed with neurodevelopmental conditions with uneven sex/gender distributions. Researchers have become aware of the myriad influences that sex-related and gender-related variables have on the manifestations of neurodevelopmental conditions, and contemporary work has begun to investigate the mechanisms through which these effects are mediated. Here we describe topical concepts of sex and gender science, summarize current knowledge, and discuss research and clinical challenges related to autism, attention-deficit/hyperactivity disorder and other neurodevelopmental conditions. We consider sex and gender in the context of epidemiology, behavioural phenotypes, neurobiology, genetics, endocrinology and neighbouring disciplines. The available evidence supports the view that sex and gender are important contributors to the biological and behavioural variability in neurodevelopmental conditions. Methodological caveats such as frequent conflation of sex and gender constructs, inappropriate measurement of these constructs and under-representation of specific demographic groups (for example, female and gender minority individuals and people with intellectual disabilities) limit the translational potential of research so far. Future research and clinical implementation should integrate sex and gender into next-generation diagnostics, mechanistic investigations and support practices.

Examination of pubertal timing and tempo in females and males with autism spectrum disorder compared to typically developing youth

Autism spectrum disorder (ASD) is characterized by impaired social communication and poor adaptation to change; thus, pubertal development may be precarious. Pubertal timing and tempo were measured in 244 youth (7.9% Black, 83.3% White, and 8.7% multiracial) with ASD (N = 140) and typical development (N = 104). Pubertal development was measured using Tanner staging of Genital (G, males), Breast (B, females), and pubic hair (PH) in both sexes at Year 1 (10-13 years), Year 2 (11-14 years), and Year 3 (12-15 years). Nonlinear mixed effects models analyzed interindividual differences in timing and tempo. For both sexes, ASD and higher body mass index were associated with earlier pubertal timing. Males generally exhibited faster tempo than females. Linear regression models did not show associations between pubertal timing and internalizing symptoms at time three. Findings showing advanced pubertal maturation in ASD youth suggest greater risk of psychological, social, and physiological challenges. LAY SUMMARY: Youth with ASD have difficulty in social communication and adaption to change, thus puberty may be a challenging transition. The study examined onset (timing) and progression (tempo) of puberty over three years, using physical exam, in 244 adolescents with and without ASD, enrolled at ages 10-13. ASD youth started puberty earlier, while males generally progressed at a faster pace. Further examination of puberty in ASD should identify impact on social, behavioral, and mental health outcomes.

Big Data Approach to Characterize Restricted and Repetitive Behaviors in Autism

OBJECTIVE

Despite being a core diagnostic feature of autism spectrum disorder (ASD), demographic, developmental and clinical correlates of restricted and repetitive behaviors and interests (RRB) remain poorly characterized. This study aimed to utilize the largest available RRB data set to date to provide a comprehensive characterization of how distinct RRB domains vary according to a range of individual characteristics.

METHOD

Data were obtained from 17,581 children and adolescents with ASD (mean_age= 8.24 years, SD_age= 4.06) from the Simons Foundation Powering Autism Research for Knowledge cohort. Caregivers completed the Repetitive Behavior Scale-Revised questionnaire as a measure of repetitive motor behaviors, self-injurious behaviors, compulsions, insistence on sameness, and circumscribed interests RRB domains. Caregivers also provided information on children's cognitive functioning, language ability, and social and communication impairments.

RESULTS

Male sex was associated with higher severity of repetitive motor behaviors and restricted interests and with lower severity of compulsions and self-injurious behaviors; no sex differences were found for the insistence on sameness domain. Although repetitive motor behaviors showed a mostly linear (negative) association with age, other RRB domains showed more complex and nonlinear pattern of associations. Higher severity of social and communication impairments provided significant independent contribution in predicting higher severity of all RRB domains at the p < .001 level; however, these effects were small (d < 0.25). The strongest of these effects was observed for insistence on sameness (d = 0.24), followed by repetitive motor behaviors (d = 0.21), compulsions (d = 0.17), restricted interests (d = 0.14), and self-injurious behaviors (d = 0.12).

CONCLUSION

Findings reported here provide further evidence that RRB subdomains show a somewhat distinct pattern of associations with demographic, developmental, and clinical variables, with a key implication that separate consideration of these domains can help to facilitate efforts to understand diverse ASD etiology and to inform the design of effective interventions.

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.

Toward better characterization of restricted and unusual interests in youth with autism

LAY ABSTRACT

Despite being highly prevalent among people with autism, restricted and unusual interests remain under-researched and poorly understood. This article confirms that restricted interests are very frequent and varied among children and adolescents with autism. It also further extends current knowledge in this area by characterizing the relationship between the presence, number, and type of restricted interests with chronological age, sex, cognitive functioning, and social and communication symptoms.

Bilingualism effects in pronoun comprehension: Evidence from children with autism

The prevalence of autism worldwide has risen steadily in the last two decades, while bilingualism is also becoming increasingly prevalent in today's rapidly globalizing world. The current study aimed to investigate bilingualism effects in the pronoun resolution skills of children with autism in comparison to age-matched monolingual children with autism, as well as monolingual and bilingual children of typical development (Ν = 20 participants per group). Results showed that autistic children had general difficulty anchoring ambiguous pronouns to entities that were linguistically expressed in discourse, yet, the bilingual children with autism were more sensitive to the topicality of the entities in syntactic subject position and more prone to identify them as suitable referents of ambiguous null pronouns as compared to their monolingual peers. The findings suggest that bilingualism is not detrimental to autistic children's pronoun resolution skills. The current study aimed at determining how bilingualism influences ambiguous pronoun comprehension in children with autism as compared to bilingual and monolingual children of typical development. The findings show that bilingualism was not detrimental to the autistic children's pronoun resolution skills, further suggesting that having acquired more than one language does not exacerbate autistic children's deficits in the comprehension of pronouns.

Toward better characterization of restricted and repetitive behaviors in individuals with germline heterozygous PTEN mutations

This study aimed to further our understanding of restricted and repetitive behaviors (RRB) among individuals with germline pathogenic mutations in PTEN by providing multimethod characterization and comparison of key RRB subdomains across individuals with PTEN mutations with autism spectrum disorder (ASD) (PTEN-ASD), with PTEN mutations without ASD (PTEN-No ASD) and with ASD and macrocephaly but without PTEN mutations (Macro-ASD). Of 86 total research participants, 38 had PTEN-ASD (M_age  = 8.93 years, SD_age  = 4.75), 25 Macro-ASD (M_age  = 11.99 years; SD_age  = 5.15), and 23 PTEN-No ASD (M_age  = 8.94 years; SD_age  = 4.85). The Repetitive Behavior Scale-Revised (RBS-R) and the Autism Diagnostic Interview-Revised (ADI-R) were used as measures of distinct RRB domains. There were significant group differences in the RBS-R repetitive motor behaviors (RMB; F = 4.52, p = 0.014, ω²  = 0.08), insistence on sameness (IS; F = 4.11, p = 0.02, ω²  = 0.05), and circumscribed interests (CI; F = 7.80, p = 0.001, ω²  = 0.14) scales. Post hoc comparisons showed that the PTEN-No ASD group had significantly lower RMB, IS, and CI scores compared to both PTEN-ASD and Macro-ASD groups. Importantly, PTEN-No ASD group still showed elevated RRB levels. Furthermore, there was a portion of individuals in PTEN-No ASD group whose Full-Scale Intelligence Quotient (FSIQ) was >70 that did not show floor level scores in the RMB domain. After adjusting for age and FSIQ scores, group differences were no longer statistically significant. RMB, IS, and CI domains showed distinct association patterns with sex, age, and FSIQ. This investigation provides the largest and most comprehensive characterization of distinct RRB domains in individuals with PTEN mutations to date. Despite the limitations, our findings have important assessment and treatment implications.

Drug development for Autism Spectrum Disorder (ASD): Progress, challenges, and future directions

In 2017, facing lack of progress and failures encountered in targeted drug development for Autism Spectrum Disorder (ASD) and related neurodevelopmental disorders, the ISCTM with the ECNP created the ASD Working Group charged to identify barriers to progress and recommending research strategies for the field to gain traction. Working Group international academic, regulatory and industry representatives held multiple in-person meetings, teleconferences, and subgroup communications to gather a wide range of perspectives on lessons learned from extant studies, current challenges, and paths for fundamental advances in ASD therapeutics. This overview delineates the barriers identified, and outlines major goals for next generation biomedical intervention development in ASD. Current challenges for ASD research are many: heterogeneity, lack of validated biomarkers, need for improved endpoints, prioritizing molecular targets, comorbidities, and more. The Working Group emphasized cautious but unwavering optimism for therapeutic progress for ASD core features given advances in the basic neuroscience of ASD and related disorders. Leveraging genetic data, intermediate phenotypes, digital phenotyping, big database discovery, refined endpoints, and earlier intervention, the prospects for breakthrough treatments are substantial. Recommendations include new priorities for expanded research funding to overcome challenges in translational clinical ASD therapeutic research.

Brief Report: Role of Parent-Reported Executive Functioning and Anxiety in Insistence on Sameness in Individuals with Germline PTEN Mutations

This study aimed to characterize the relationship between insistence on sameness (IS), executive functioning (EF) and anxiety among individuals with PTEN mutations and individuals with macrocephalic ASD. The sample included 38 individuals with PTEN mutation and ASD diagnosis (PTEN-ASD; M_age = 8.93 years, SD_age = 4.75), 23 with PTEN mutation without ASD (PTEN-no ASD; M_age = 8.94 years; SD_age = 4.85) and 25 with ASD and macrocephaly but with no PTEN mutation (Macro-ASD; M_age = 11.99 years; SD_age = 5.15). The final model accounted for 45.7% of variance in IS, with Set-Shifting EF subdomain as a unique independent predictor (t = 4.12, p < 0.001). This investigation provides the first preliminary evidence for the EF-anxiety-IS interrelationship in individuals with PTEN mutations and with macrocephalic ASD.

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

Camouflaging refers to behavioral adaptations that individuals with autism spectrum disorder (ASD), especially females, use to mask symptoms during social situations. Compensation is a component of camouflaging in which an individual's observed behavior is considerably better than actual ability. The study explored diagnostic, sex-based, and compensatory differences using the Contextual Assessment of Social Skills (CASS). The sample included 161 youth 10:0-to-16:11 years (115 males, 46 females). T-tests were performed based on sex (female, male) or High (good ADOS + poor Theory of Mind (TOM)) compared to Low (poor ADOS + poor TOM) Compensation groups. Comparisons were examined for Social Affect (SA), Restricted Repetitive Behavior, (RRB), IQ, social behavior (Positive Affect, Overall Involvement) and communication (Vocal Expression, Gestures). Females exhibited fewer RRB t(158) = 3.05, P = 0.003, d = 0.54. For the CASS, females evidenced more Vocal Expressiveness t(157) = -2.03, P = 0.05, d = 0.35, which corroborates sex-based differences in the literature. Compensation group differences indicated the High compared to Low group showed stronger Social and Communication behaviors on the CASS for Vocal Expression t(72) = 2.56, P = 0.01, d = 0.62, and overall rapport t(72) = 2.36, P = 0.02, d = 0.56. Several differences were observed when the groups were stratified based on level of compensation, with the High compensation participants showing stronger social engagement and communication behaviors. Findings may inform efforts to understand camouflaging, compensation, and clinical practices for male and female adolescents with ASD. A more nuanced consideration of camouflaging alongside compensation models reveals subtle differences in cognition, behavior, and affect that may reflect underlying profiles of challenge and strength in youth with ASD. LAY SUMMARY: Camouflaging refers to ways individuals with autism spectrum disorder (ASD), especially females, mask symptoms. Compensation occurs when a person's observed behavior appears more typical than what would be expected based on underlying ability and symptoms. The study explored camouflaging and compensation differences in 161 youth with ASD. Findings suggest sex-based differences with females showing better vocal expression. However, several compensation differences were observed with the High compensators showing stronger social communication and rapport. A more nuanced consideration of camouflaging using compensation models reveal subtle differences in underlying challenge and strength.