Autism phenotype versus registered diagnosis in Swedish children: prevalence trends over 10 years in general population samplesBMJ 2015; 350 doi: https://doi.org/10.1136/bmj.h1961 (Published 28 April 2015) Cite this as: BMJ 2015;350:h1961
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The demonstration by Lundström and colleagues1 that changes in diagnostic practices are driving the rise in prevalence of autism spectrum disorder (ASD) at the population level in Sweden mirrors and validates what clinicians in various jurisdictions are likely experiencing at the “coal face”. In the Canadian province of British Columbia, for example, more and more children are referred to specialized teams for diagnostic assessment of possible ASD. These increased rates of referral reflect greater awareness of a condition in the community2, incentives to diagnose ASD in jurisdictions with diagnosis-specific funding and support programs3, and the complex array of political factors that underlie disease activism.4
A substantial proportion of referred cases now consist of young children two to three years of age among whom ASD-related phenomena of social reciprocity and social communication may be mild, and whose low level restricted and repetitive behaviors may be hard to distinguish from such behaviors that are not uncommon among young who are not on the autism spectrum.5,6. The diagnostic challenge is heightened by the fact that impairment is difficult to operationalize in young children, and for many of these children, it remains a largely subjective judgment whether to attribute the impairment that appears to be present to ASD symptoms or to delays or impairment in language or executive functioning skills which are frequently present. Nevertheless, these children may meet criteria for ASD, and hence contribute to the rising prevalence of ASD in the population. At the other end of the spectrum, children known to have moderate or severe impairment in other neurodevelopmental domains, such as cognitive-adaptive functioning, are also increasingly referred for assessment of possible ASD in order to be diagnostically comprehensive, but also to access diagnosis-specific funding and supports. The inclusion of these children further contributes to the rising prevalence of ASD, even though their main needs may relate to impairments in language and adaptive behaviors.
This situation confronts us with the question: what does it mean to be diagnosed with autism spectrum disorder in 2015? In Rutter’s classic 1985 paper on treatment of autistic children,7 his concern is clearly with children who are very much impaired by autism along with the comorbidities and functional complexities that are so prevalent among children with neurodevelopmental conditions.8,9 Inclusion of an increasing number of children with mild symptoms and mild impairment under the diagnostic category must lead to changes in how clinicians and the public perceive autism and ASD. Though there is no evidence to date of ASD being overdiagnosed when DSM criteria are carefully applied, the inclusion of ever larger segments of the population under mental health diagnosis categories can lead to a trivialization of the significance of mental health conditions broadly, along with misappropriation of funds and resources to where they are not really needed.10 Clinical experience aligns with Lundström’s population-based findings, and collectively support the notion that the characteristics of persons included under the category of ASD must be changing, if the prevalence of diagnosed ASD is increasing while the prevalence of the autism phenotype remains stable. The problem is that policies which tie publically-funded services and supports to a diagnostic category (such as ASD) tend not take changes in the nature of the population into account. A more progressive approach to regulating access to services and supports takes careful account of the child’s unique profile of functional strengths and needs, and is less focused on his or her given diagnosis.11,12
1. Lundström S, Reichenberg A, Anckarsäter H, et al. Autism phenotype versus registered diagnosis in Swedish children: prevalence trends over 10 years in general population samples. BMJ 2015; 350:h1961.
2. Dalembert G, Brosco JP. Do politics affect prevalence? An overview and the
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3. Ministry for Children and Families, British Columbia. Autism Funding Programs http://www.mcf.gov.bc.ca/autism/funding_programs.htm
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8. Gillberg C, Fernell E. Autism plus versus autism pure. J Autism Dev Disord 2014;44:3274-6
9. Miller AR, Mâsse LC, Shen J et al. Diagnostic status, functional status and complexity among Canadian children with neurodevelopmental disorders and disabilities: a population-based study. Disabil Rehabil. 2013; 35(6):468-78.
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conditions among children with special health needs. Pediatrics 2012; 129(3):e714-22.
12. Miller AR, Shen J, Mâsse LC. Child functional characteristics explain child and family outcomes better than diagnosis: population-based study of children with autism or other neurodevelopmental disorder/disabilities. Health Reports, submitted.
Competing interests: No competing interests