Etiological influences on the stability of autistic traits from childhood to early adulthood: evidence from a twin study

Investigating the neurodevelopmental correlates of early adolescent-onset emotional problems

BACKGROUND

Emotional problems (EPs) increase sharply after mid-adolescence. Earlier EPs are associated with poorer long-term outcomes, and their underlying mechanisms may differ to later-onset EPs. Given an established relationship between ADHD, autism, and later depression, we aimed to examine associations between neurodevelopmental conditions and correlates and early adolescent-onset EPs.

METHODS

Adolescents in two UK population cohorts, Avon Longitudinal Study of Parents and Children (ALSPAC) and Millennium Cohort Study (MCS), were included. Individuals scoring >6 on the Strengths and Difficulties Questionnaire (SDQ) emotional problems subscale between ages 11-14 were defined as having early adolescent-onset EP, whilst those scoring >6 for the first time at 16-25 were defined as having later-onset EP. We tested associations between early adolescent-onset EP (total cases = 887, controls = 19,582) and ICD-10/DSM-5 neurodevelopmental conditions and known correlates, including: sex, birth complications, low cognitive ability, special educational needs (SEND), and epilepsy. Analyses were conducted separately in ALSPAC and MCS then meta-analysed.

RESULTS

In the meta-analysis of both cohorts, early adolescent-onset EPs were associated with female sex and greater likelihood of low cognitive ability, SEND, autism, ADHD, and reading difficulties. Compared to later-onset EP, early adolescent-onset EPs were associated with male sex, low cognitive ability, SEND, epilepsy, ASD, ADHD, and reading difficulties.

LIMITATIONS

A clinical definition of depression/anxiety was available only in ALSPAC, instead we primarily defined EP via questionnaires, which capture a broader phenotype.

CONCLUSIONS

Individuals with early adolescent-onset EP are likely to have a co-occurring neurodevelopmental condition. Clinicians should consider assessing for neurodevelopmental conditions in young adolescents with EPs.

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.

Rumination and altered reactivity to sensory input as vulnerability factors for developing post-traumatic stress symptoms among adults with autistic traits

OBJECTIVE

Recent literature has suggested that individuals with autism spectrum disorder (ASD) or autistic traits (ATs) would be more likely to encounter traumatic events in their lifetime and to develop post-traumatic stress disorder (PTSD). However, the nature of this relationship has not yet been fully elucidated. The aims of this study were to evaluate the relationship between AT and PTSD and to investigate which specific autistic dimension was more associated with trauma and stress-related symptoms.

METHODS

A total of 68 subjects with ASD and 64 healthy controls (HCs) were assessed with the Adult Autism Subthreshold Spectrum (AdAS Spectrum) and the Trauma and Loss Spectrum (TALS) questionnaires. Statistical analyses included Mann-Whitney U test, chi-square test, calculation of Spearman's coefficients, and logistic regression analysis.

RESULTS

Patients with significant AT reported a 30% rate of PTSD and higher TALS total and domain scores than HCs, among whom no PTSD was found instead. Significant positive correlations were reported between AdAS Spectrum and TALS-SR scores in the whole sample. AdAS Spectrum total scores were statistically predictive of the presence of PTSD. High scores at AdAS Spectrum Inflexibility and adherence to routine and Restrictive interest and rumination domains were identified as positive predictors of a probable PTSD.

CONCLUSION

Compared to HCs, subjects with significant AT are more likely to present symptoms of PTSD. In particular, AT related to ruminative thinking, narrow interests, and sensorial reactivity would seem to predict the presence of post-traumatic stress symptomatology.

Maternal Autistic Traits and Adverse Birth Outcomes

Importance

Women with a high level of autistic traits in the general population may experience larger health disparities during pregnancy, particularly women diagnosed with autism spectrum disorder (ASD), which in turn may be associated with increased risk of adverse birth outcomes.

Objective

To investigate the association between maternal autistic traits and the risk of adverse birth outcomes in the general population.

Design, Setting, and Participants

This cohort study included mothers of singletons from a nationwide, multicenter prospective birth cohort, the Japan Environmental Children's Study. Expecting mothers were recruited between January 2011 and March 2014. Data were analyzed between June 2021 and November 2023.

Exposures

Autistic traits were self-reported during the second and third trimesters using the short form of the Autism-Spectrum Quotient Japanese version (AQ-J10) (score range, 0-10; clinical range, ≥7).

Main Outcomes and Measures

Data on preterm birth (<37 weeks' gestation) and neonates born small for gestational age (SGA) were transcribed from medical records. Additional analysis of gestational age groups (very preterm birth, <32 weeks' gestation; moderate-to-late preterm birth, 32-36 weeks' gestation) was also performed.

Results

Among 87 687 women (mean [SD] age, 31.2 [5.0] years) included in the study, 2350 (2.7%) had AQ-J10 scores within the clinical range yet only 18 (0.02%) were diagnosed with ASD. A higher AQ-J10 score was associated with an increased risk of all birth outcomes, including preterm births (relative risk [RR] per 1-SD increase, 1.06; 95% CI, 1.03-1.09), moderate-to-late preterm births (RR per 1-SD increase, 1.05; 95% CI, 1.01-1.08), very preterm births (RR per 1-SD increase, 1.16; 95% CI, 1.06-1.26), and child born SGA (RR per 1-SD increase, 1.04; 95% CI, 1.01-1.06) after adjusting for maternal and pregnancy-related factors. The risks of all outcomes increased with higher AQ-J10 scores; compared with women below the clinical range, women within the clinical range had greater risk of preterm births (RR, 1.16; 95% CI, 1.07-1.26), moderate-to-late preterm births (RR, 1.12; 95% CI, 1.03-1.22), very preterm births (RR, 1.49; 95% CI, 1.18-1.89), and a child born SGA (RR, 1.11; 95% CI, 1.04-1.19).

Conclusions and Relevance

In this cohort study, higher level of maternal autistic traits was associated with increased risk of adverse birth outcomes, particularly very preterm birth. Acknowledging the risks and providing tailored and timely antenatal care support to women with a high level of autistic traits in the general population, particularly women with autistic traits within the clinical range, regardless of formal diagnosis, is warranted.

After one year in university; a robust decrease in autistic traits reporting among autistic students

Background

Previous research on autistic students enrolled in university support programs has reported moderate improvement in anxiety/depression or adaptive behavior. However, alterations in autistic traits have not been examined.

Methods

This longitudinal study evaluated changes in university students' autistic trait and state/trait anxiety levels. Participants were 24 neurotypically developed (ND) students with high levels of social anxiety symptoms (High SA), 30 ND students with low levels of SA symptoms (Low SA), and 41 autistic students (the primary focus of this study) residing with an ND peer student mentor as part of participating in the university's integration support program. Autism spectrum quotient [AQ and State Trait Anxiety Inventory STAI] data were collected during the first semester of two consecutive academic years (T1, T2), as well as baseline (T1) levels of social anxiety, depression, and obsessive-compulsive symptoms.

Results

Significant interaction between group and time was observed, denoting a sharp decrease (2.9 SD) from T1 to T2 in the overall autistic trait level among the autistic group (AQ "attention switching" subscale demonstrating the most robust decrease), and a moderate decrease (0.5 SD) among the high SA group. Only for the autistic students were more compulsive symptoms at T1 associated with a lesser decrease in AQ scores (T1-T2), which in turn was negatively correlated with their T1 year-end grade point average.

Conclusion

The findings suggest that attending post-secondary education (while partaking in a support/transition program) is followed by a profound change of the individual's subjective experience of autism, characterized by a sharp decline in the level of autistic traits, particularly attention switching. This change is independent of alterations in well-being indices, such as anxiety, that are known to characterize students attending university.

Altered intrinsic brain activity and connectivity in unaffected parents of individuals with autism spectrum disorder: a resting-state fMRI study

Objectives: Autism spectrum disorder (ASD) is a juvenile onset neurodevelopmental disorder with social impairment and stereotyped behavior as the main symptoms. Unaffected relatives may also exhibit similar ASD features due to genetic factors. Although previous studies have demonstrated atypical brain morphological features as well as task-state brain function abnormalities in unaffected parents with ASD children, it remains unclear the pattern of brain function in the resting state.

Methods: A total of 42 unaffected parents of ASD children (pASD) and 39 age-, sex-, and handedness-matched controls were enrolled. Multiple resting-state fMRI (rsfMRI) analyzing methods were applied, including amplitude of low-frequency fluctuation (ALFF), regional homogeneity (ReHo), degree centrality (DC), and functional connectivity (FC), to reveal the functional abnormalities of unaffected parents in ASD-related brain regions. Spearman Rho correlation analysis between imaging metric values and the severity of ASD traits were evaluated as well.

Results: ALFF, ReHo, and DC methods all revealed abnormal brain regions in the pASD group, such as the left medial orbitofrontal cortex (mOFC) and rectal gyrus (ROI-1), bilateral supplementary motor area (ROI-2), right caudate nucleus head and right amygdala/para-hippocampal gyrus (ROI-3). FC decreasing was observed between ROI-1 and right anterior cingulate cortex (ACC), ROI-2, and bilateral precuneus. FC enhancing was observed between ROI-3 and right anterior cerebellar lobe, left medial temporal gyrus, left superior temporal gyrus, left medial frontal gyrus, left precentral gyrus, right postcentral gyrus in pASD. In addition, ALFF values in ROI-1, DC values in ROI-3 were positively correlated with AQ scores in pASD (ρ₁ = 0.298, P₁ = 0.007; ρ₂ = 0.220, P₂ = 0.040), while FC values between ROI-1 and right ACC were negatively correlated with AQ scores (ρ₃ = −0.334, P₃ = 0.002).

Conclusion: rsfMRI metrics could be used as biomarkers to reveal the underlying neurobiological feature of ASD for unaffected parents.

Decreased interoceptive accuracy in children with autism spectrum disorder and with comorbid attention deficit/hyperactivity disorder

Interoception refers to the awareness of internal physiological state. Several previous studies reported that people with autism spectrum disorders (ASD) and adults with attention-deficit/hyperactivity disorder (ADHD) have diverse patterns of interoception, but the extent of literature is limited and inconsistent. This study aimed to investigate the interoceptive accuracy (IA) in children with ASD, children with comorbid ASD and ADHD, and typically developing (TD) children with high and low levels of autistic traits. We administered the eye-tracking interoceptive accuracy task (EIAT) to 30 children with ASD, 20 children with comorbid ASD and ADHD, and 63 TD controls with high and low levels of autistic traits. Parent-report scales concerning ASD and ADHD symptoms were collected. ASD children with and without comorbid ADHD both exhibited lower IA than TD children. Reduced IA was also found in TD children with high-autistic traits relative to those with low-autistic traits. IA was negatively correlated with autistic and ADHD symptoms. Atypical cardiac interoception could be found in children with ASD. Difficulties in sensing and comprehending internal bodily signals in childhood may be related to both ASD and ADHD symptoms.

Mapping the genetic and environmental aetiology of autistic traits in Sweden and the United Kingdom

Background

Autistic traits are influenced by both genetic and environmental factors, and are known to vary geographically in prevalence. But to what extent does their aetiology also vary from place to place?

Methods

We applied a novel spatial approach to data on autistic traits from two large twin studies, the Child and Adolescent Twin Study in Sweden (CATSS; N = 16,677, including 8307 twin pairs) and the Twins Early Development Study in the UK (TEDS; N = 11,594, including 5796 twin pairs), to explore how the influence of nature and nurture on autistic traits varies from place to place.

Results

We present maps of gene‐ and environment‐ by geography interactions in Sweden and the United Kingdom (UK), showing geographical variation in both genetic and environmental influences across the two countries. In Sweden genetic influences appear higher in the far south and in a band running across the centre of the country. Environmental influences appear greatest in the south and north, with reduced environmental influence across the central band. In the UK genetic influences appear greater in the south, particularly in more central southern areas and the southeast, the Midlands and the north of England. Environmental influences appear greatest in the south and east of the UK, with less influence in the north and the west.

Conclusions

We hope this systematic approach to identifying aetiological interactions will inspire research to examine a wider range of previously unknown environmental influences on the aetiology of autistic traits. By doing so, we will gain greater understanding of how these environments draw out or mask genetic predisposition and interact with other environmental influences in the development of autistic traits.

Autistic traits are associated with faster pace of aging: Evidence from the Dunedin study at age 45

Growing evidence indicates that the defining characteristics of autism spectrum disorder (ASD) are distributed throughout the general population; hence, understanding the correlates of aging in people with high autistic traits could shed light on ASD and aging. 915 members of the Dunedin longitudinal birth cohort completed a measure of autistic traits at age 45. A composite measure of the "pace of aging" was derived by tracking the decline in 19 biomarkers across ages 26, 32, 38, and 45 years. Facial age was also assessed. Reports of perceived health were collected from participants themselves, informants, and interviewers. Higher self-reported autistic traits significantly correlated with a faster pace of aging, older facial age, and poorer self-, informant-, and interviewer-rated health. After control for sex, SES and IQ, autistic traits were significantly associated with each variable: pace of aging (β = 0.09), facial age (β = 0.08), self- (β = -0.15), informant (β = -0.12), and interviewer-rated (β = -0.17) health. Autistic traits measured at age 45 are associated with faster aging. Participants with high autistic traits appear to be more vulnerable to poor health outcomes, as previously reported for those clinically diagnosed with ASD. Therefore, autistic traits may have important health implications. Replicating these findings in samples of autistic people is needed to identify the mechanism of their effect on aging and physical health to improve outcomes for those with ASD diagnoses or high autistic traits. LAY SUMMARY: The role that autistic traits have in relation to health outcomes has not been investigated. We looked at how physical health and aging (measured with self-reported questions and decline in multiple biological measures) were related to autistic traits (measured with a questionnaire, at age 45). We found that higher autistic traits were associated with poorer reports of physical health, and a faster pace of aging. This suggests that both those with autism and those with higher autistic traits may be more likely to experience poorer health outcomes.

Effectiveness of Equine-Assisted Activities and Therapies for Improving Adaptive Behavior and Motor Function in Autism Spectrum Disorder

Equine-assisted activities and therapies (EAAT) have been suggested to improve adaptive behavior, and possibly motor function, in autism spectrum disorder (ASD). This study investigated the effects of EAAT on adaptive behavior and motor function in 15 children with ASD (13 males) aged 7–15 years as well as the impact of EAAT on the magnitude of stress in the parent–child system and the evolution in the child interaction with both the trained therapist and the therapeutic animal through the 20 weekly sessions of EAAT. EAAT were associated with greater adaptive behavior and coordination (all p ≤ 0.01) as well as a progressive improvement in the child’s abilities to respond to the increasing complexity of such form of positive behavioral support (all p < 0.001). However, EAAT did not prove to be effective in reducing parental distress. Collectively, preliminary evidence presented here may have important public health implications and gives reason to hope that EAAT could possibly be an effective option in ASD, warranting further investigation of its potential benefits in clinical trials among larger samples.

Investigating attention-deficit hyperactivity disorder and autism spectrum disorder traits in the general population: What happens in adult life?

BACKGROUND

Attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are generally considered early-onset disorders so most research has therefore tended to focus on children. Differences between ADHD/ASD in adult life and childhood have been noted, but few population-based studies have examined them in adulthood. Furthermore, the interpretation of findings is hampered by changes in measure and from parent report to self-report.

METHOD

We examined continuous/trait measures of parent- and self-rated ADHD and ASD in adulthood (age 25 years) in a UK prospective longitudinal sample ALPSAC (the Avon Longitudinal Study of Parents and Children), using many of the same measures that parents reported on in childhood (N = 6,064). Our aim was to investigate these traits in this population for mean-level sex differences, overlaps with other cognitive, learning and communication problems and their associations with polygenic risk scores (PRS) for neuropsychiatric disorders (ADHD, ASD, schizophrenia, depression and anxiety).

RESULTS

ADHD and ASD traits in adulthood, as in childhood, showed associations with childhood cognitive, learning and communication problems and adult communication/language measures, although less so for self-ratings than parent-ratings. Males had higher ADHD and ASD trait levels, but this was not as marked as in childhood. In adulthood, ADHD (both parent- and self-rated) and ASD (parent-rated) symptoms showed associations with ADHD PRS; self-reported ADHD also showed association with depression PRS, whereas self-reported ASD did not show strong PRS associations.

CONCLUSIONS

Our findings suggest that in young adults, ADHD and ASD symptoms have similar characteristics as they do in childhood. Associations with other cognitive, learning and communication problems, and ADHD PRS were somewhat less pronounced for self-reported adult ADHD and ASD symptoms, suggesting that even at age 25, parent reports, where available, could be clinically useful.

Higher levels of autistic traits associated with lower levels of self-efficacy and wellbeing for performing arts professionals

This study sought for the first time to identify the extent to which autistic people are pursuing careers in the performing arts, and to determine the nature of the relationship between individuals' autistic traits and their reported wellbeing. To address these aims, we recruited a self-selecting, community-based sample of individuals working in the performing arts and invited them to complete an online survey. A total of 1,427 respondents took part. We collected responses on participants' backgrounds, including diagnostic history as well as measures assessing their level of autistic traits, perceived occupational self-efficacy, quality of life, and mental health. They were also asked open-ended questions about support needed, received, or desired in their workplace. Eleven of the 1,427 professionals (1%) reported a clinical diagnosis of autism. Correlational analyses demonstrated that higher levels of autistic traits were significantly associated with lower levels of quality of life, lower levels of occupational self-efficacy and greater severity of mental health conditions. Almost half the sample of professionals (N = 621; 44%) reported a desire for more employment-based support, and autistic traits were significantly higher in those participants who wanted greater support. Within the community of those working in the performing arts, there are a minority of individuals who are autistic or who have high levels of autistic traits. We have demonstrated for the first time that these individuals may be especially vulnerable to lower wellbeing.

Etiology of Autism Spectrum Disorders and Autistic Traits Over Time

IMPORTANCE

The frequency with which autism spectrum disorders (ASDs) are diagnosed has shown a marked increase in recent years. One suggestion is that this is partly because of secular changes in the environment, yet to our knowledge this hypothesis lacks evidence.

OBJECTIVE

To assess whether the relative importance of genetic and environmental associations with ASD and autistic traits has changed over a 16-year and 26-year period.

DESIGN, SETTING, AND PARTICIPANTS

A twin design was used to assess whether the heritability of ASD and autistic traits has changed over time. Data from 2 nationwide Swedish twin cohorts was used: the Swedish Twin Registry (STR; participants born between January 1982 and December 2008) and the Child and Adolescent Twin Study in Sweden (CATSS; participants born between January 1992 and December 2008). Autism spectrum disorder diagnoses were identified for twins in the STR, with follow-up to 2013. Questionnaires assigned screening diagnoses of ASD to CATSS participants and assessed autistic traits. Analyses were performed from September 1, 2018, to March 31, 2019.

EXPOSURES

Each sample was divided into several birth cohorts covering 1982 to 1991 (for the STR only), 1992-1995, 1996-1999, 2000-2003, and 2004-2008.

OUTCOMES

We assessed whether the genetric and environment variance underlying autistic traits changed across birth cohorts and examined whether the relative contribution of genetics and environment to liability for autism changed across birth cohorts.

RESULTS

Data were available for 22 678 twin pairs (5922 female same-sex pairs [26.1%], 5563 male same-sex pairs [24.5%], and 11193 opposite-sex pairs [49.4%]) in the STR and 15 280 pairs (4880 female same-sex pairs [31.9%], 5092 male same-sex pairs [33.3%], and 5308 opposite-sex pairs [34.7%]) in CATSS. The heritability of ASD diagnoses in the STR ranged from 0.88 (95% CI, 0.74-0.96) to 0.97 (95% CI, 0.89-0.99). The heritability of screening diagnoses in CATSS varied from 0.75 (95% CI, 0.58-0.87) to 0.93 (95% CI, 0.84-0.98). Autistic traits showed a modest variance increase over time that was associated with increases in genetic and environmental variance, with the total variance increasing from 0.95 (95% CI, 0.92-0.98) to 1.17 (95% CI, 1.13-1.21) over time.

CONCLUSIONS AND RELEVANCE

Weak evidence was found for changes in the genetic and environmental factors underlying ASD and autistic traits over time. Genetic factors played a consistently larger role than environmental factors. Environmental factors are thus unlikely to explain the increase in the prevalence of ASD.

Gastrointestinal Symptoms and Feeding Problems and Their Associations with Dietary Interventions, Food Supplement Use, and Behavioral Characteristics in a Sample of Children and Adolescents with Autism Spectrum Disorders

Autism spectrum disorders (ASD) are characterized by impairments in social interaction, communication, and restricted, stereotyped behavior. Gastrointestinal (GI), nutritional, and feeding problems are often reported in ASD. We investigated the prevalence of GI symptoms, food selectivity, and mealtime difficulties, and their associations with dietary interventions, food supplement use, and behavioral characteristics in a sample involving 247 participants with ASD and 267 controls aged 2-18 years. Data were collected by a questionnaire. GI symptoms were observed in 88.9% of children and adolescents with ASD, more often in girls than in boys. High rates of food selectivity (69.1%) and mealtime problems (64.3%) were found. Food supplements were used by 66.7% of individuals, mainly vitamins/minerals, probiotics, and omega-3 fatty acids. In the ASD sample, 21.2% of subjects followed a diet, mostly based on gluten and milk restriction, including individuals exhibiting food selectivity. Frequency of GI symptoms, food selectivity, and mealtime problems correlated weakly, but significantly with behavioral characteristics in the ASD group, but not with food supplement use. The study demonstrated that higher frequency of GI symptoms, food selectivity, and mealtime problems are a common problem in pre-schoolers, schoolchildren, and adolescents with ASD, and together with dietary modification, they are significantly associated with ASD.

Early environmental risk factors for neurodevelopmental disorders - a systematic review of twin and sibling studies

While neurodevelopmental disorders (NDDs) are highly heritable, several environmental risk factors have also been suggested. However, the role of familial confounding is unclear. To shed more light on this, we reviewed the evidence from twin and sibling studies. A systematic review was performed on case control and cohort studies including a twin or sibling within-pair comparison of neurodevelopmental outcomes, with environmental exposures until the sixth birthday. From 7,315 screened abstracts, 140 eligible articles were identified. After adjustment for familial confounding advanced paternal age, low birth weight, birth defects, and perinatal hypoxia and respiratory stress were associated with autism spectrum disorder (ASD), and low birth weight, gestational age and family income were associated with attention-deficit/hyperactivity disorder (ADHD), categorically and dimensionally. Several previously suspected factors, including pregnancy-related factors, were deemed due to familial confounding. Most studies were conducted in North America and Scandinavia, pointing to a global research bias. Moreover, most studies focused on ASD and ADHD. This genetically informed review showed evidence for a range of environmental factors of potential casual significance in NDDs, but also points to a critical need of more genetically informed studies of good quality in the quest of the environmental causes of NDDs.

The stability of autistic traits in transgender adults following cross-sex hormone treatment

Background: Recent research has shown that a high percentage of treatment-seeking transgender adults who were assigned female at birth (AFAB) reported scores above the clinical cutoff for autistic traits. It is unclear whether those scores reflect a stable trait or may be inflated by the high levels of anxiety typically associated with transgender people attending clinical services. Aims: This longitudinal study aims to explore the impact of Cross-sex Hormone Treatment (CHT) on levels autistic traits, independent of changes in anxiety. Method: Transgender adults who were assessed at a national transgender health service in the UK, who had not previously received CHT and who had completed the AQ-Short as a measure of autistic traits pre- and one-year post-CHT were included in the study (n = 118). Anxiety was assessed at the same time points using the Hospital Anxiety and Depression Scale. Results: AQ-Short scores remained very stable over time (ICC = 0.7; CIs 0.591-0.779) but anxiety showed little consistency (ICC = 0.386; CIs 0.219 to 0.531). Repeated measures ANOVA found a main effect of assigned sex with AFAB having higher AQ-Short scores. There was no change in AQ-Short scores and no significant interaction between assigned sex and change in AQ-Short scores. Conclusion: This study confirmed that treatment seeking transgender AFAB people have higher levels of autistic traits at follow-up compared to AMAB transgender people and that these traits are stable following one year of CHT regardless of assigned sex. This may have clinical implications regarding the support that transgender people may require following medical transition.

The mediating effect of trauma and stressor related symptoms and ruminations on the relationship between autistic traits and mood spectrum

An increasing number of studies highlighted significant correlations between autistic traits (AT) and mood spectrum symptoms. Moreover, recent data showed that individuals with high AT are likely to develop trauma and stressor-related disorders. This study aims to investigate the relationship between AT and mood symptoms among university students, focusing in particular on how AT interact with ruminations and trauma-related symptomatology in predicting mood symptoms. 178 students from three Italian Universities of excellence were assessed with The Structured Clinical Interview for DSM-5 (SCID-5), the Adult Autism Subthreshold Spectrum (AdAS Spectrum), the Ruminative Response Scale (RRS), the Trauma and Loss Spectrum (TALS) and the Moods Spectrum (MOODS). Considering the AdAS Spectrum total scores, 133 subjects (74.7%) were categorized as "low scorers" and 45 subjects (25.3%) as "high scorers". Students in the high scorer group showed significantly higher scores on RRS, TALS-SR and MOOD-SR total scores. Total and direct effects of AdAS Spectrum total score on MOODS-SR total score were both statistically significant. AdAS Spectrum total score also showed a significant indirect effect on MOODS-SR total score through TALS and RRS total scores. Results showed a significant relationship between AT and mood spectrum, which is partially mediated by ruminations and trauma/stressor-related symptomatology.

Genetic and environmental contribution to the overlap between ADHD and ASD trait dimensions in young adults: a twin study

BACKGROUND

Traits of attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are strongly associated in children and adolescents, largely due to genetic factors. Less is known about the phenotypic and aetiological overlap between ADHD and ASD traits in adults.

METHODS

We studied 6866 individuals aged 20-28 years from the Swedish Study of Young Adult Twins. Inattention (IA) and hyperactivity/impulsivity (HI) were assessed using the WHO Adult ADHD Self-Report Scale-V1.1. Repetitive and restricted behaviours (RRB) and social interaction and communication (SIC) were assessed using the Autism-Tics, ADHD, and other Comorbidities inventory. We used structural equation modelling to decompose covariance between these ADHD and ASD trait dimensions into genetic and shared/non-shared environmental components.

RESULTS

At the phenotypic level, IA was similarly correlated with RRB (r = 0.33; 95% Confidence Interval (CI) 0.31-0.36) and with SIC (r = 0.32; 95% CI 0.29-0.34), whereas HI was more strongly associated with RRB (r = 0.38; 95% CI 0.35-0.40) than with SIC (r = 0.24; 95% CI 0.21-0.26). Genetic and non-shared environmental effects accounted for similar proportions of the phenotypic correlations, whereas shared environmental effects were of minimal importance. The highest genetic correlation was between HI and RRB (r = 0.56; 95% 0.46-0.65), and the lowest was between HI and SIC (r = 0.33; 95% CI 0.23-0.43).

CONCLUSIONS

We found evidence for dimension-specific phenotypic and aetiological overlap between ADHD and ASD traits in adults. Future studies investigating mechanisms underlying comorbidity between ADHD and ASD may benefit from exploring several symptom-dimensions, rather than considering only broad diagnostic categories.

Differences of Symptom Distribution Across Adult Age in High Functioning Individuals on the Autism Spectrum Using Subscales of the Autism Spectrum Quotient

Little is known about the distribution of symptoms of Autism Spectrum Disorder (ASD) across the lifespan. In this cross-sectional study, we examined differences between subscales of the Autism Spectrum Quotient (AQ) between different age groups. 654 Subjects referred to an outpatient University Clinic with specialized expertise in ASD were included. Data collection, including self-report and report by spouses, was performed from 2008 to 2014. Results show no significant differences between the different age groups. AQ scores based on self-report corresponded remarkably well with those from their spouses. In conclusion, the main traits of an ASD appear stable between the different age groups. Also, the results show that using the AQ, patients have largely the same appreciation of symptoms as their spouses.

Correlates of autistic traits among patients with borderline personality disorder

BACKGROUND

Despite discrete autism-related dimensions, such as deficits in communication, empathy and mentalizing are likely to affect the development of personality and despite they actually frequently occur in borderline patients, no research has so far investigated the relationship between autistic traits and Borderline Personality Disorder (BPD). The objective of this study is to investigate the clinical significance of autistic traits in subjects with BPD.

METHODS

The sample included 50 patients with a clinical diagnosis of BPD and 69 healthy controls. The Structured Clinical Interview for DSM-5 Clinician Version was used to establish the presence of comorbid mental disorders among BPD subjects and to confirm the absence of lifetime mental disorders in the control group. Participants were also asked to fill three self-report instruments: the Adult Autism Subthreshold Spectrum (AdAS Spectrum), the Autism Spectrum Quotient (AQ) and the Mood Spectrum Self-Report (MOODS-SR).

RESULTS

Patients with BPD reported higher autistic traits than healthy individuals. Moreover, autistic traits were shown to exert a significant impact on some clinical features and associated manifestation of BPD, such as suicidality and lifetime exposure to physical and/or sexual abuse.

CONCLUSIONS

Subthreshold autism spectrum may be relevant for subjects suffering from BPD and future research may further address clinical correlates of autistic traits among patients with this disorder.

Developmental Changes Within the Genetic Architecture of Social Communication Behavior: A Multivariate Study of Genetic Variance in Unrelated Individuals

BACKGROUND

Recent analyses of trait-disorder overlap suggest that psychiatric dimensions may relate to distinct sets of genes that exert maximum influence during different periods of development. This includes analyses of social communication difficulties that share, depending on their developmental stage, stronger genetic links with either autism spectrum disorder or schizophrenia. We developed a multivariate analysis framework in unrelated individuals to model directly the developmental profile of genetic influences contributing to complex traits, such as social communication difficulties, during an approximately 10-year period spanning childhood and adolescence.

METHODS

Longitudinally assessed quantitative social communication problems (N ≤ 5551) were studied in participants from a United Kingdom birth cohort (Avon Longitudinal Study of Parents and Children; age range, 8-17 years). Using standardized measures, genetic architectures were investigated with novel multivariate genetic-relationship-matrix structural equation models incorporating whole-genome genotyping information. Analogous to twin research, genetic-relationship-matrix structural equation models included Cholesky decomposition, common pathway, and independent pathway models.

RESULTS

A two-factor Cholesky decomposition model described the data best. One genetic factor was common to Social Communication Disorder Checklist measures across development; the other accounted for independent variation at 11 years and later, consistent with distinct developmental profiles in trait-disorder overlap. Importantly, genetic factors operating at 8 years explained only approximately 50% of genetic variation at 17 years.

CONCLUSIONS

Using latent factor models, we identified developmental changes in the genetic architecture of social communication difficulties that enhance the understanding of autism spectrum disorder- and schizophrenia-related dimensions. More generally, genetic-relationship-matrix structural equation models present a framework for modeling shared genetic etiologies between phenotypes and can provide prior information with respect to patterns and continuity of trait-disorder overlap.

Arid1b Haploinsufficiency Causes Abnormal Brain Gene Expression and Autism-Related Behaviors in Mice

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with core symptoms that include poor social communication, restricted interests, and repetitive behaviors. Several ASD mouse models exhibit impaired social interaction, anxiety-like behavior, and elevated perseveration. Large-scale whole exome sequencing studies identified many genes putatively associated with ASD. Like chromodomain helicase DNA binding protein 8 (CHD8), the most frequently mutated gene in individuals with ASD, the candidate gene AT-rich interaction domain 1B (ARID1B) encodes a chromatin remodeling factor. Arid1b heterozygous knockout (hKO) mice exhibited ASD-like traits related to social behavior, anxiety, and perseveration, in addition to associated features reported in some cases of ASD, such as reduced weight, impaired motor coordination, and hydrocephalus. Hydrocephalus was present in 5 of 91 hKO mice, while it was not observed in wild-type littermates (0 of 188). Genome-wide gene expression patterns in Arid1b hKO mice were similar to those in ASD patients and Chd8-haploinsufficient mice, an ASD model, and to developmental changes in gene expression in fast-spiking cells in the mouse brain. Our results suggest that Arid1b haploinsufficiency causes ASD-like phenotypes in mice.