Developmental trajectories of autistic social traits in the general population

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

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

5-year mental health outcomes for children and adolescents presenting with psychiatric symptoms to general practitioners in England: a retrospective cohort study

BACKGROUND

Little information is available on the clinical trajectories of children and adolescents who attend general practice (GP) with psychiatric symptoms. We aimed to examine 5-year service use in English primary care for children and adolescents with neurodevelopmental or mental health symptoms or diagnoses.

METHODS

In this retrospective cohort study, we used anonymised primary care health records from the Clinical Practice Research Datalink Aurum database (CPRD-Aurum). We identified children and adolescents (aged 3-18 years) presenting to primary care in England between Jan 1, 2000, and May 9, 2016, with a symptom or diagnosis of a mental health, behavioural, or neurodevelopmental condition. Participants were excluded if they had less than 1 year of follow-up. We followed up participants from their index date until either death, transfer out of the practice, or the end of data collection on May 5, 2021, and for trajectory analysis we limited follow-up to 5 years. We used group-based multi-trajectory models to identify clusters with similar trajectories over 5 years of follow-up for three primary outcomes: mental health-related GP contacts, psychotropic medication prescriptions, and specialist mental health-care contact. We did survival analysis to examine the associations between trajectory-group membership and hospital admission for self-harm or death by suicide, as indicators of severe psychiatric distress.

FINDINGS

We included 369 340 children and adolescents, of whom 180 863 (49·0%) were girls, 188 438 (51·0%) were boys, 39 (<0·1%) were of indeterminate gender, 290 125 (78·6%) were White, 9161 (2·5%) were South Asian, 10 418 (2·8%) were Black, 8115 (2·2%) were of mixed ethnicity, and 8587 (2·3%) were other ethnicities, and the median age at index presentation was 13·6 years (IQR 8·4-16·7). In the best-fitting, seven-group, group-based multi-trajectory model, over a 5-year period, the largest group (low contact; 207 985 [51·2%]) had low rates of additional service contact or psychotropic prescriptions. The other trajectory groups were moderate, non-pharmacological contact (43 836 [13·0%]); declining contact (25 469 [8·7%]); year-4 escalating contact (18 277 [6·9%]); year-5 escalating contact (18 139; 5·2%); prolonged GP contact (32 147 [8·6%]); and prolonged specialist contact (23 487 [6·5%]). Non-White ethnicity and presentation in earlier study years (eg, 2000-2004) were associated with low-contact group membership. The prolonged specialist-contact group had the highest risk of hospital admission for self-harm (hazard ratio vs low-contact group 2·19 [95% CI 2·03-2·36]) and suicide (2·67 [1·72-4·14]).

INTERPRETATION

Most children and adolescents presenting to primary care with psychiatric symptoms or diagnoses have low or declining rates of ongoing contact. If these trajectories reflect symptomatic improvement, these findings provide reassurance for children and adolescents and their caregivers. However, these trajectories might reflect an unmet need for some children and adolescents.

FUNDING

National Institute for Health and Care Research and the Wellcome Trust.

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

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

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

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

A longitudinal study of autism spectrum disorder characteristics in adolescents with restrictive type anorexia nervosa during and after underweight

OBJECTIVES

This prospective, longitudinal study aims to compare the prevalence of autism spectrum disorder (ASD) characteristics in adolescents with anorexia nervosa (AN) during and after underweight in order to help unravel the complex link between both conditions.

METHODS

24 adolescents with AN completed the youth self-report, autism spectrum quotient (AQ) or autism spectrum quotient adolescent version (AQ - adolescent) and a questionnaire designed by the researchers during a state of underweight and after weight recovery.

RESULTS

AQ total score and several AQ subscale scores at the time of underweight are significantly higher than after weight recovery with medium to large effect sizes. Linear modelling cannot prove a significant effect of weight gain, internalizing problems or medication use on AQ score, but it does show an association between AQ during underweight and AQ after weight recovery.

CONCLUSIONS

The results highlight the complexity of the link between AN and ASD characteristics. Although a clear change in AQ score is seen in part of the participants, this effect cannot be generalized and a link with weight change cannot be demonstrated. It seems likely that ASD characteristics in AN are a combination of trait and state: underweight and starvation might exacerbate potentially present traits. Part of our results may indicate the existence of subgroups based on AQ score during underweight. Our study supports the theory that more ASD characteristics at T1 may result in a poorer outcome and a higher need for specified and intensive treatment.

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.

Co-development of attention deficit hyperactivity disorder and autistic trait trajectories from childhood to early adulthood

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) and autism, defined as traits or disorders, commonly co-occur. Developmental trajectories of ADHD and autistic traits both show heterogeneity in onset and course, but little is known about how symptom trajectories co-develop into adulthood.

METHODS

Using data from a population cohort, the Avon Longitudinal Study of Parents and Children, we examined correlations between ADHD and autistic traits across development, using the Social Communication Disorders Checklist and ADHD subscale of the Strengths and Difficulties Questionnaire. We modelled joint developmental trajectories of parent-reported ADHD and autistic traits between 4 and 25 years, then characterised trajectory classes based on sociodemographic, perinatal, psychopathology, cognition and social functioning variables and tested for associations with neurodevelopmental/psychiatric polygenic scores (PGS).

RESULTS

Three classes of trajectories were identified; a typically developing majority with low-stable ADHD-autistic traits (87%), a male-predominant subgroup with child/adolescent-declining traits (6%) and a subgroup with late-emerging traits (6%). ADHD-autistic trait correlations were greatest in young adulthood for the two nontypically developing classes. There were higher rates of emotional and conduct problems, low IQ, childhood seizures and poor social functioning in the declining and late-emerging classes compared to the low-stable class. Emotional, conduct and peer problems were more prevalent during childhood in the childhood/adolescent-declining class compared to other classes, but were more prevalent in young adulthood in the late-emerging class. Neurodevelopmental/psychiatric PGS also differed: both nontypically developing classes showed elevated ADHD PGS compared to the low-stable group, and the late-emerging group additionally showed elevated schizophrenia PGS and decreased executive function PGS, whereas the declining group showed elevated broad depression PGS.

CONCLUSIONS

Distinct patterns of ADHD-autism co-development are present across development in the general population, each with different characterising factors and genetic signatures as indexed by PGS.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Childhood diagnoses in individuals identified as autistics in adulthood

Background

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

Methods

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

Results

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

Limitations

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

Conclusion

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

Supplementary Information

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