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Abstract
Most neurodevelopmental disorders are defined by their clinical symptoms and many disorders share common features. Recently there has been an increase in the number of children diagnosed with autism spectrum disorder, although concerns have been raised about the accuracy of the reported prevalence rates. This article reviews the essential features of autism spectrum disorder and describes other conditions that may include similar symptoms that may be misdiagnosed as autism spectrum disorder (primary communication disorders, anxiety disorders, attachment disorders, intellectual disability, vision and hearing impairment, and normal variations). An approach to differential diagnosis is discussed with particular attention to evaluation of young children.
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Affiliation(s)
- Mark D Simms
- Section of Developmental Pediatrics, Department of Pediatrics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA; Child Development Center, Children's Hospital of Wisconsin, PO Box 1997, Mail Station 744, Milwaukee, WI 53226, USA.
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Schelly D, Jiménez González P, Solís PJ. The diffusion of autism spectrum disorder in Costa Rica: Evidence of information spread or environmental effects? Health Place 2015; 35:119-27. [DOI: 10.1016/j.healthplace.2015.07.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 07/16/2015] [Accepted: 07/31/2015] [Indexed: 12/30/2022]
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3
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Kahana E, Lee JE, Kahana J, Goler T, Kahana B, Shick S, Burk E, Barnes K. Childhood Autism and Proactive Family Coping: Intergenerational Perspectives. Journal of Intergenerational Relationships 2015. [DOI: 10.1080/15350770.2015.1026759] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Kotajima-Murakami H, Sato A, Ikeda K. [Pathology and treatment of autism spectrum disorders]. Nihon Yakurigaku Zasshi 2015; 145:193-200. [PMID: 25864830 DOI: 10.1254/fpj.145.193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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5
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Abstract
BACKGROUND Autism spectrum disorders (ASDs) are persistent disabling neurodevelopmental disorders clinically evident from early childhood. For the first time, the burden of ASDs has been estimated for the Global Burden of Disease Study 2010 (GBD 2010). The aims of this study were to develop global and regional prevalence models and estimate the global burden of disease of ASDs. METHOD A systematic review was conducted for epidemiological data (prevalence, incidence, remission and mortality risk) of autistic disorder and other ASDs. Data were pooled using a Bayesian meta-regression approach while adjusting for between-study variance to derive prevalence models. Burden was calculated in terms of years lived with disability (YLDs) and disability-adjusted life-years (DALYs), which are reported here by world region for 1990 and 2010. RESULTS In 2010 there were an estimated 52 million cases of ASDs, equating to a prevalence of 7.6 per 1000 or one in 132 persons. After accounting for methodological variations, there was no clear evidence of a change in prevalence for autistic disorder or other ASDs between 1990 and 2010. Worldwide, there was little regional variation in the prevalence of ASDs. Globally, autistic disorders accounted for more than 58 DALYs per 100 000 population and other ASDs accounted for 53 DALYs per 100 000. CONCLUSIONS ASDs account for substantial health loss across the lifespan. Understanding the burden of ASDs is essential for effective policy making. An accurate epidemiological description of ASDs is needed to inform public health policy and to plan for education, housing and financial support services.
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Affiliation(s)
- A J Baxter
- School of Population Health,University of Queensland,Herston,Australia
| | - T S Brugha
- Department of Health Sciences,University of Leicester,Leicester General Hospital,UK
| | - H E Erskine
- School of Population Health,University of Queensland,Herston,Australia
| | - R W Scheurer
- Queensland Centre for Mental Health Research,Wacol,Australia
| | - T Vos
- School of Population Health,University of Queensland,Herston,Australia
| | - J G Scott
- Queensland Centre for Mental Health Research,Wacol,Australia
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6
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Abstract
Autism spectrum disorders are an issue of increasing public health significance. The incidence of autism spectrum disorders has been increasing in recent years, and they are associated with significant personal and financial impacts for affected persons and their families. In recent years, a large number of scientific studies have been undertaken, which investigate genetic and environmental risk factors for autism, with more studies underway. At present, much remains unknown regarding autism spectrum disorder risk factors, but the emerging picture of causation is in many cases complex, with multiple genes and gene-environment interactions being at play. The complexity and uncertainty surrounding autism spectrum disorder risk factors raise a number of questions regarding the ethical considerations that should be taken into account when undertaking autism spectrum disorder risk communication. At present, however, little has been written regarding autism spectrum disorder risk communication and ethics. This article summarizes the findings of a recent conference investigating ethical considerations and policy recommendations in autism spectrum disorder risk communication, which to the authors' knowledge is the first of its kind. Here, the authors discuss a number of issues, including uncertainty; comprehension; inadvertent harm; justice; and the appropriate roles of clinicians, scientists, and the media in autism spectrum disorder risk communication.
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7
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Abstract
OBJECTIVES To update UK studies begun in the early 1990s on the annual prevalence and incidence rates of autism in children; undertaken in response to a March 2012 press release, widely covered by the media, from the US Centre for Disease Control (CDC) reporting that the autism prevalence rate in 2008 in 8-year-old US children was 1 in 88, a 78% increase from a CDC estimate in 2004. This finding suggested a continuation of the dramatic increase in children diagnosed as autistic, which occurred in the 1990s. DESIGN Population study using the UK General Practice Research Database (GPRD). METHODS Annual autism prevalence rates were estimated for children aged 8 years in 2004-2010 by dividing the number diagnosed as autistic in each or any previous year by the number of children active in the study population that year. We also calculated annual incidence rates for children aged 2-8 years, by dividing the number newly diagnosed in 2004-2010 by the same denominators. RESULTS Annual prevalence rates for each year were steady at approximately 3.8/1000 boys and 0.8/1000 girls. Annual incidence rates each year were also steady at about 1.2/1000 boys and 0.2/1000 girls. CONCLUSIONS Following a fivefold increase in the annual incidence rates of autism during the 1990s in the UK, the incidence and prevalence rates in 8-year-old children reached a plateau in the early 2000s and remained steady through 2010. Whether prevalence rates have increased from the early 2000s in the USA remains uncertain.
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Affiliation(s)
- Brent Taylor
- General and Adolescent Paediatric Unit, UCL Institute of Child Health, London, UK
| | - Hershel Jick
- Boston Collaborative Drug Surveillance Program, Boston University School of Medicine, Lexington, Massachusetts, USA
| | - Dean MacLaughlin
- Boston Collaborative Drug Surveillance Program, Boston University School of Medicine, Lexington, Massachusetts, USA
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Mazumdar S, Winter A, Liu KY, Bearman P. Spatial clusters of autism births and diagnoses point to contextual drivers of increased prevalence. Soc Sci Med 2013; 95:87-96. [PMID: 23267775 PMCID: PMC3612561 DOI: 10.1016/j.socscimed.2012.11.032] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 08/28/2012] [Accepted: 11/28/2012] [Indexed: 12/16/2022]
Abstract
Autism prevalence has risen dramatically over the past two decades in California. Although often suggested to have been crucial to the rise of autism, environmental and social contextual drivers of diagnosis have not been extensively examined. Identifying the spatial patterning of autism cases at birth and at diagnosis can help clarify which contextual drivers are affecting autism's rising prevalence. Children with autism not co-morbid with mental retardation served by the California Department of Developmental Services during the period 1992-2005 were matched to California's Birth Master Files. We search for spatial clusters of autism at time of birth and at time of diagnosis using a spatial scan approach that controls for key individual-level risk factors. We then test whether indicators of neighborhood-level diagnostic resources are associated with the diagnostic clusters and assess the extent of clustering by autism symptom severity through a multivariate scan. Finally, we test whether children who move into neighborhoods with higher levels of resources are more likely to receive an autism diagnosis relative to those who do not move with regard to resources. Significant birth and diagnostic clusters of autism are observed independent of key individual-level risk factors. While the clusters overlap, there is a strong positive association between the diagnostic clusters and neighborhood-level diagnostic resources. In addition, children with autism who are higher functioning are more likely to be diagnosed within a cluster than children with autism who are lower functioning. Most importantly, children who move into a neighborhood with more diagnostic resources than their previous residence are more likely to subsequently receive an autism diagnosis than children whose neighborhood resources do not change. We identify birth and diagnostic clusters of autism in California that are independent of individual-level autism risk factors. Our findings implicate a causal relationship between neighborhood-level diagnostic resources and spatial patterns of autism incidence but do not rule out the possibility that environmental toxicants have also contributed to autism risk.
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Affiliation(s)
- Soumya Mazumdar
- Australian Primary Health Care Research Institute, Australian National University, Level 1, Ian Potter House, Cnr Marcus Clarke and Gordon Streets, Canberra ACT 0200, Australia.
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9
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Abstract
Autism is a neurodevelopmental disorder whose diagnosis is based on three behavioral criteria: unusual reciprocal social interactions, deficits in communication, and stereotyped repetitive behaviors with restricted interests. A large number of de novo single gene mutations and chromosomal deletions are associated with autism spectrum disorders. Based on the strong genetic evidence, mice with targeted mutations in homologous genes have been generated as translational research tools. Mouse models of autism have revealed behavioral and biological outcomes of mutations in risk genes. The field is now poised to employ the most robust phenotypes in the most replicable mouse models for preclinical screening of novel therapeutics.
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Affiliation(s)
- Jacqueline N Crawley
- Robert Chason Chair in Translational Research, M.I.N.D. Institute Professor of Psychiatry and Behavioral Sciences, School of Medicine, University of California, Davis, Sacramento, CA 95817, USA.
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10
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Abstract
Autism is a heterogeneous neurodevelopmental disorder of unknown aetiology that affects 1 in 100-150 individuals. Diagnosis is based on three categories of behavioural criteria: abnormal social interactions, communication deficits and repetitive behaviours. Strong evidence for a genetic basis has prompted the development of mouse models with targeted mutations in candidate genes for autism. As the diagnostic criteria for autism are behavioural, phenotyping these mouse models requires behavioural assays with high relevance to each category of the diagnostic symptoms. Behavioural neuroscientists are generating a comprehensive set of assays for social interaction, communication and repetitive behaviours to test hypotheses about the causes of autism. Robust phenotypes in mouse models hold great promise as translational tools for discovering effective treatments for components of autism spectrum disorders.
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Affiliation(s)
- Jill L Silverman
- National Institute of Mental Health, Porter Neuroscience Research Center, Bethesda, MD 20892-3730, USA
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11
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Abstract
BACKGROUND Autism spectrum disorder (ASD) was once considered to be highly associated with intellectual disability and to show a characteristic IQ profile, with strengths in performance over verbal abilities and a distinctive pattern of 'peaks' and 'troughs' at the subtest level. However, there are few data from epidemiological studies. METHOD Comprehensive clinical assessments were conducted with 156 children aged 10-14 years [mean (s.d.)=11.7 (0.9)], seen as part of an epidemiological study (81 childhood autism, 75 other ASD). A sample weighting procedure enabled us to estimate characteristics of the total ASD population. RESULTS Of the 75 children with ASD, 55% had an intellectual disability (IQ<70) but only 16% had moderate to severe intellectual disability (IQ<50); 28% had average intelligence (115>IQ>85) but only 3% were of above average intelligence (IQ>115). There was some evidence for a clinically significant Performance/Verbal IQ (PIQ/VIQ) discrepancy but discrepant verbal versus performance skills were not associated with a particular pattern of symptoms, as has been reported previously. There was mixed evidence of a characteristic subtest profile: whereas some previously reported patterns were supported (e.g. poor Comprehension), others were not (e.g. no 'peak' in Block Design). Adaptive skills were significantly lower than IQ and were associated with severity of early social impairment and also IQ. CONCLUSIONS In this epidemiological sample, ASD was less strongly associated with intellectual disability than traditionally held and there was only limited evidence of a distinctive IQ profile. Adaptive outcome was significantly impaired even for those children of average intelligence.
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Affiliation(s)
- T Charman
- Centre for Research in Autism and Education, Department of Psychology and Human Development, Institute of Education, London, UK.
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Kerrie S, Austin DW. Ancestry of pink disease (infantile acrodynia) identified as a risk factor for autism spectrum disorders. J Toxicol Environ Health A 2011; 74:1185-94. [PMID: 21797771 PMCID: PMC3173747 DOI: 10.1080/15287394.2011.590097] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2011] [Accepted: 05/05/2011] [Indexed: 05/22/2023]
Abstract
Pink disease (infantile acrodynia) was especially prevalent in the first half of the 20th century. Primarily attributed to exposure to mercury (Hg) commonly found in teething powders, the condition was developed by approximately 1 in 500 exposed children. The differential risk factor was identified as an idiosyncratic sensitivity to Hg. Autism spectrum disorders (ASD) have also been postulated to be produced by Hg. Analogous to the pink disease experience, Hg exposure is widespread yet only a fraction of exposed children develop an ASD, suggesting sensitivity to Hg may also be present in children with an ASD. The objective of this study was to test the hypothesis that individuals with a known hypersensitivity to Hg (pink disease survivors) may be more likely to have descendants with an ASD. Five hundred and twenty-two participants who had previously been diagnosed with pink disease completed a survey on the health outcomes of their descendants. The prevalence rates of ASD and a variety of other clinical conditions diagnosed in childhood (attention deficit hyperactivity disorder, epilepsy, Fragile X syndrome, and Down syndrome) were compared to well-established general population prevalence rates. The results showed the prevalence rate of ASD among the grandchildren of pink disease survivors (1 in 22) to be significantly higher than the comparable general population prevalence rate (1 in 160). The results support the hypothesis that Hg sensitivity may be a heritable/genetic risk factor for ASD.
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Affiliation(s)
- Shandley Kerrie
- Swinburne Autism Bio-Research Initiative (SABRI), Brain and Psychological Sciences Research Centre, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - David W. Austin
- Swinburne Autism Bio-Research Initiative (SABRI), Brain and Psychological Sciences Research Centre, Swinburne University of Technology, Hawthorn, Victoria, Australia
- Address correspondence to David W. Austin, Swinburne Autism Bio-Research Initiative (SABRI), Brain and Psychological Sciences Research Centre, Swinburne University of Technology, Mail H29, PO Box 218, Hawthorn, Victoria 3122, Australia. E-mail:
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Abstract
OBJECTIVE The goal was to determine whether the increasing prevalence of autism, on the basis of educational data, in Wisconsin between 2002 and 2008 was uniform in all school districts or was greatest in districts with lower baseline (2002) prevalence. METHODS Special education counts were obtained for all Wisconsin elementary school districts from 2002 through 2008. The annual prevalence of children being served under the autism category was calculated for each district, districts were grouped into 8 categories (octiles) according to their baseline prevalence, and prevalence trends were plotted according to octile. RESULTS The overall prevalence of use of the autism category in Wisconsin elementary schools increased from 4.9 to 9.0 cases per 1000 children between 2002 and 2008. The magnitude of this increase was not uniform across districts and was inversely associated with baseline prevalence. Prevalence in the lowest octile increased from 0.5 cases per 1000 students in 2002 to 7.0 cases per 1000 students in 2008 (P < .0001), whereas no significant trend was seen for the octile with the highest baseline prevalence (range: 11.2-12.3 cases per 1000 students; P = .11). The highest-octile/lowest-octile prevalence ratio decreased from 24.6 (95% confidence interval: 16.2-37.3) in 2002 to 1.8 (95% confidence interval: 1.6-2.1) in 2008. CONCLUSIONS The prevalence of use of the autism special education category in Wisconsin seems to be leveling off in the school districts with the highest prevalence rates, at ∼12 cases per 1000 students, whereas the gap in prevalence between districts overall has narrowed.
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Affiliation(s)
- Matthew J Maenner
- Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA.
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Charman T, Jones CRG, Pickles A, Simonoff E, Baird G, Happé F. Defining the cognitive phenotype of autism. Brain Res 2010; 1380:10-21. [PMID: 21029728 DOI: 10.1016/j.brainres.2010.10.075] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 10/18/2010] [Accepted: 10/19/2010] [Indexed: 01/21/2023]
Abstract
Although much progress has been made in determining the cognitive profile of strengths and weaknesses that characterise individuals with autism spectrum disorders (ASDs), there remain a number of outstanding questions. These include how universal strengths and deficits are; whether cognitive subgroups exist; and how cognition is associated with core autistic behaviours, as well as associated psychopathology. Several methodological factors have contributed to these limitations in our knowledge, including: small sample sizes, a focus on single domains of cognition, and an absence of comprehensive behavioural phenotypic information. To attempt to overcome some of these limitations, we assessed a wide range of cognitive domains in a large sample (N=100) of 14- to 16-year-old adolescents with ASDs who had been rigorously behaviourally characterised. In this review, we will use examples of some initial findings in the domains of perceptual processing, emotion processing and memory, both to outline different approaches we have taken to data analysis and to highlight the considerable challenges to better defining the cognitive phenotype(s) of ASDs. Enhanced knowledge of the cognitive phenotype may contribute to our understanding of the complex links between genes, brain and behaviour, as well as inform approaches to remediation.
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Affiliation(s)
- T Charman
- Centre for Research in Autism and Education, Department of Psychology and Human Development, Institute of Education, London, UK.
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16
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Abstract
Despite a plethora of studies, we do not know why autism incidence has increased rapidly over the past two decades. Using California data, this study shows that children living very close to a child previously diagnosed with autism are more likely to be diagnosed with autism. An underlying social influence mechanism involving information diffusion drives this result, contributing to 16% of the increase in prevalence over 2000-2005. We eliminate competing explanations (i.e., residential sorting, environmental toxicants, and viral transmission) through seven tests and show that information diffusion simultaneously contributed to the increased prevalence, spatial clustering, and decreasing age of diagnosis.
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Affiliation(s)
- Ka-Yuet Liu
- Columbia University, New York, New York 10027, USA
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Bearman P, King M. Author's Response Commentaries on diagnostic accretion and the increased prevalence of measured autism. Int J Epidemiol 2009. [DOI: 10.1093/ije/dyp263] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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