Developmental functioning and symptom severity influence age of diagnosis in Canadian preschool children with autism

Zwaigenbaum, Lonnie; Duku, Eric; Fombonne, Éric; Szatmári, Péter; Smith, Isabel M.; Bryson, Susan E.; Mirenda, Pat; Vaillancourt, Tracy; Volden, Joanne; Georgiades, Stelios; Roberts, Wendy; Bennett, Teresa; Elsabbagh, Mayada; Waddell, Charlotte; Steiman, Mandy; Simon, Rebecca; Bruno, Ruth

doi:10.1093/pch/pxy076

Cited by 32 publications

(23 citation statements)

References 42 publications

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“…We, like others, found that those without cognitive delay (Mazurek et al, 2014; Shattuck et al, 2009; Zwaigenbaum et al, 2019) and those whose parents did not have concerns over their socio-behavioural difficulties were diagnosed later (Daniels & Mandell, 2014). Several potential explanations might underlie this result.…”

Section: Discussionsupporting

confidence: 67%

“…after they have started school at around age 5), can inform the development of effective strategies to improve earlier identification of ASD. Previous studies have shown that receiving a late ASD diagnosis is associated both with clinical factors such as higher cognitive ability ( Mazurek et al, 2014 ; Shattuck et al, 2009 ; Zwaigenbaum et al, 2019 ), milder autistic symptoms ( Fountain et al, 2011 ; Mandell et al, 2005 ; Mazurek et al, 2014 ; Sheldrick et al, 2017 ; Zwaigenbaum et al, 2019 ), diagnostic overshadowing ( Miodovnik et al, 2015 ) and with socio-demographic factors including sex, socio-economic status and access to healthcare ( Bickel et al, 2015 ; Brett et al, 2016 ; Daniels & Mandell, 2014 ; Fountain et al, 2011 ; Mandell et al, 2005 ; Mazurek et al, 2014 ; Shattuck et al, 2009 ; Sheldrick et al, 2017 ; Williams et al, 2008 ; Zwaigenbaum et al, 2019 ). It should be acknowledged, however, that findings about socio-demographic factors have been inconsistent, likely due to methodological differences and variation between countries in their healthcare systems ( Daniels & Mandell, 2014 ).…”

mentioning

confidence: 99%

“…Nevertheless, there are currently important gaps in our understanding of late ASD diagnosis that constrain efforts to address this problem. First, most studies have focused on those in primary education, meaning that we know little of what factors predict very late diagnoses, that is, those given in adolescence ( Fountain et al, 2011 ; Shattuck et al, 2009 ; Williams et al, 2008 ; Zwaigenbaum et al, 2019 ). Second, much of the evidence in this area is based on data from clinic-referred samples, limiting its generalizability ( Bickel et al, 2015 ; Brett et al, 2016 ; Mandell et al, 2005 ; Mazurek et al, 2014 ).…”

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confidence: 99%

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

Hosozawa

Sacker

Mandy

et al. 2020

Autism

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

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Section: Discussionsupporting

confidence: 67%

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confidence: 99%

mentioning

confidence: 99%

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

Hosozawa

Sacker

Mandy

et al. 2020

Autism

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“…In reality, delays tend to occur between initial concerns, referrals, a confirmed diagnosis, and access to intervention 9899100125. The nature of emerging signs and symptoms reliably accounts for some of the variation in age at diagnosis 126127128. Several social determinants can modify the age of diagnosis by increasing or decreasing the likelihood of identification of signs, help-seeking, and/or access to services.…”

Section: Early Identification and Interventionmentioning

confidence: 99%

Linking risk factors and outcomes in autism spectrum disorder: is there evidence for resilience?

Elsabbagh

2020

BMJ

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Autism spectrum disorder (referred to here as autism) is one of several overlapping neurodevelopmental conditions that have variable impacts on different individuals. This variability results from dynamic interactions between biological and non-biological risk factors, which result in increasing differentiation between individuals over time. Although this differentiation continues well into adulthood, the infancy period is when the brain and behavior develop rapidly, and when the first signs and symptoms of autism emerge. This review discusses advances in our understanding of the causal pathways leading to autism and overlapping neurodevelopmental conditions. Research is also mapping trajectories of brain and behavioral development for some risk groups, namely later born siblings of children with autism and/or infants referred because of developmental concerns. This knowledge has been useful in improving early identification and establishing the feasibility of targeted interventions for infant risk groups before symptoms arise. However, key knowledge gaps remain, such as the discovery of protective factors (biological or environmental) that may mitigate the impact of risk. Also, the dynamic mechanisms that underlie the associations between risk factors and outcomes need further research. These include the processes of resilience, which may explain why some individuals at risk for autism achieve better than expected outcomes. Bridging these knowledge gaps would help to provide tools for early identification and intervention that reflect dynamic developmental pathways from risk to outcomes.

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“…It has been established that individuals with more challenges will likely be given a diagnosis of autism early in life in contrast to those with more subtle clinical/symptomatic differences (Zwaigenbaum et al 2019). Although our knowledge of the prevalence of autism in adulthood is limited, a United Kingdom study by Brugha et al (2009) estimated the prevalence to be ~ 1%.…”

Section: Diagnosis In Mid-to Late-lifementioning

confidence: 99%

Strategies for Research, Practice, and Policy for Autism in Later Life: A Report from a Think Tank on Aging and Autism

Edelson

Nicholas

Stoddart

et al. 2020

J Autism Dev Disord

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Over the past decade, there has been a growing interest in adults on the autistic spectrum, and more recently, the challenges related to aging in this population. A two-day Think Tank meeting, focused on aging in autism, was convened amongst international leaders in the field of autism research and practice. This meeting included a series of presentations addressing the current status of aging research, followed by discussions regarding priorities going forward. Attendees shared their thoughts and concerns regarding community services, government policies, societal perspectives and physical and mental health. The goal of these discussions was to consider systematic approaches aimed at providing meaningful supports that can ensure a quality of life for seniors on the autism spectrum.

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Developmental functioning and symptom severity influence age of diagnosis in Canadian preschool children with autism

Cited by 32 publications

References 42 publications

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

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

Linking risk factors and outcomes in autism spectrum disorder: is there evidence for resilience?

Strategies for Research, Practice, and Policy for Autism in Later Life: A Report from a Think Tank on Aging and Autism

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