We provide a systematic review of epidemiological surveys of autistic disorder and pervasive developmental disorders (PDDs) worldwide. A secondary aim was to consider the possible impact of geographic, cultural/ethnic, and socioeconomic factors on prevalence estimates and on clinical presentation of PDD. Based on the evidence reviewed, the median of prevalence estimates of autism spectrum disorders was 62/10 000. While existing estimates are variable, the evidence reviewed does not support differences in PDD prevalence by geographic region nor of a strong impact of ethnic/cultural or socioeconomic factors. However, power to detect such effects is seriously limited in existing data sets, particularly in low-income countries. While it is clear that prevalence estimates have increased over time and these vary in different neighboring and distant regions, these findings most likely represent broadening of the diagnostic concets, diagnostic switching from other developmental disabilities to PDD, service availability, and awareness of autistic spectrum disorders in both the lay and professional public. The lack of evidence from the majority of the world's population suggests a critical need for further research and capacity building in low-and middle-income countries. Autism Res 2012, ••: ••-••.

AI

Molecular Psychiatry

Autism spectrum disorder (ASD) substantially contributes to the burden of mental disorders. Improved awareness and changes in diagnostic criteria of ASD may have influenced the diagnostic rates of ASD. However, while data on trends in diagnostic rates in some individual countries have been published, updated estimates of diagnostic rate trends and ASD-related disability at the global level are lacking. Here, we used the Global Burden of Diseases, Injuries, and Risk Factors Study data to address this gap, focusing on changes in prevalence, incidence, and disability-adjusted life years (DALYs) of ASD across the world. From 1990 to 2019, overall age-standardized estimates remained stable globally. Both prevalence and DALYs increased in countries with high socio-demographic index (SDI). However, the age-standardized incidence decreased in some low SDI countries, indicating a need to improve awareness. The male/female ratio decreased between 1990 and 2019, possibly accounted for by increasing clinical attention to ASD in females. Our results suggest that ASD detection in low SDI countries is suboptimal, and that ASD prevention/treatment in countries with high SDI should be improved considering the increasing prevalence of the disorder. Additionally, growing attention is being paid to ASD diagnosis in females, who might have been left behind by ASD epidemiologic and clinical research previously. ASD burden estimates are underestimated as GBD does not account for mortality in ASD.

Lancet Psychiatry, 2025

Background High-quality estimates of the epidemiology of the autism spectrum and the health needs of autistic people are necessary for service planners and resource allocators. Here we present the global prevalence and health burden of autism spectrum disorder from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 following improvements to the epidemiological data and burden estimation methods. Methods For GBD 2021, a systematic literature review involving searches in PubMed, Embase, PsycINFO, the Global Health Data Exchange, and consultation with experts identified data on the epidemiology of autism spectrum disorder. Eligible data were used to estimate prevalence via a Bayesian meta-regression tool (DisMod-MR 2.1). Modelled prevalence and disability weights were used to estimate health burden in years lived with disability (YLDs) as the measure of non-fatal health burden and disability-adjusted life-years (DALYs) as the measure of overall health burden. Data by ethnicity were not available. People with lived experience of autism were involved in the design, preparation, interpretation, and writing of this Article. Findings An estimated 61•8 million (95% uncertainty interval 52•1-72•7) individuals (one in every 127 people) were on the autism spectrum globally in 2021. The global age-standardised prevalence was 788•3 (663•8-927•2) per 100 000 people, equivalent to 1064•7 (898•5-1245•7) autistic males per 100 000 males and 508•1 (424•6-604•3) autistic females per 100 000 females. Autism spectrum disorder accounted for 11•5 million (7•8-16•3) DALYs, equivalent to 147•6 (100•2-208•2) DALYs per 100 000 people (age-standardised) globally. At the super-region level, age-standardised DALY rates ranged from 126•5 (86•0-178•0) per 100 000 people in southeast Asia, east Asia, and Oceania to 204•1 (140•7-284•7) per 100 000 people in the high-income super-region. DALYs were evident across the lifespan, emerging for children younger than age 5 years (169•2 [115•0-237•4] DALYs per 100 000 people) and decreasing with age (163•4 [110•6-229•8] DALYs per 100 000 people younger than 20 years and 137•7 [93•9-194•5] DALYs per 100 000 people aged 20 years and older). Autism spectrum disorder was ranked within the top-ten causes of non-fatal health burden for people younger than 20 years. Interpretation The high prevalence and high rank for non-fatal health burden of autism spectrum disorder in people younger than 20 years underscore the importance of early detection and support to autistic young people and their caregivers globally. Work to improve the precision and global representation of our findings is required, starting with better global coverage of epidemiological data so that geographical variations can be better ascertained. The work presented here can guide future research efforts, and importantly, decisions concerning allocation of health services that better address the needs of all autistic individuals.

International Electronic Journal of Elementary Education, 2016

From a purely educationist perspective, gaining a deeper understanding of several aspects related to the prevalence of autism/ASD in a given population is of great value in planning and improving educational and psychological intervention for treatment, training, and teaching of children with this disorder. In this article, I present and discuss numerous facets of prevalence studies, beginning with assessing the changes in diagnostic manuals (DSM and ICD) over time. Based on the existing available research literature and empirical studies published during 2000 to 2016, I address the geographical-dimension and age-dimension of prevalence of autism/ASD. Over 50 studies from 21 countries reveals that prevalence rates of autism/ASD among children are on rise. There are inter-national and intra-national, regional/territorial variations with regard to prevalence rates, and I present and discuss possible factors/factor-groups that can explain these variations. Regardless of their geographi...

Clinical Epidemiology

This study aimed to assess whether high-income countries have a lower mean age at the time of diagnosis of autism spectrum disorder (ASD) than low-and middle-income countries. Method: We reviewed studies related to ASD diagnoses and the time of first concerns in low-, middle-, and high-income countries, published in PubMed, SciELO, Lilacs, and ScienceDirect. Thirty articles were included: 13 from low-and middle-income countries and 17 from high-income countries. Results: The average delay between initial concerns and diagnosis was 32.33 months, with initial concerns averaging 23.64 months and diagnosis at 55.97 months. No statistical differences were found between countries with low-, middle-, and high-income. Conclusions: This review found a considerable delay in ASD diagnosis despite an early presence of recognized signs and symptoms. It highlights the urgent need for standardized tools for early ASD diagnosis.

Glob J Intellect Dev Disabil , 2019

The detection of Autism Spectrum Disorders (ASD) in Mexico has been a challenge. Parents, health and educational professionals lack knowledge of key symptoms causing delay in diagnosis, intervention and early treatment. Almost 76% of parents (N=92) expressed their first concern at 23.8 (SD=13.1) months, with a mean diagnosis delay of 41.8 (SD=35.2) months. The referral for a specialized assessment was suggested by medical doctor (35.8%), followed by teachers (27.4%), and psychologists (17.9%). Three professionals were contacted to obtain a formal diagnosis. Parents lose average 6.3 days of work per month to attend for their children´s treatment appointments. Our findings can help develop better health and educational services to achieve timely diagnosis, and early intervention treatment.

Autism is a Neuro-Developmental Disorder affecting socialization and communication with stereotype behaviors. The research Scientists all over world found that genetic and environmental factors are causes of Autism Spectrum Disorders. Over the past decade, worldwide Autism, advanced rehabilitation services and research estimates of increase between 50% to over 2000% in cases of Autism Spectrum Disorder diagnoses. The rise in diagnoses of Autism Spectrum Disorder impacts us all. The national prevalence of autism spectrum disorders in India is 1 out of 250 children (Posserud et.al (2010), The Autism Society 2010, Autism speaks (2008) and Wong (2007). The world seeks greater awareness and understanding of the complexities of the condition to provide evidence based rehabilitation interventions to Children with Autism Spectrum Disorders. The rehabilitation intervention includes Behavioral Management, Cognitive Training, Cognitive Behavior Therapy, Applied Behavior Analysis, Special Education, Speech & Language Therapy, Occupational Therapy, Physiotherapy, Play Therapy, Music Therapy and Parental Counseling. These rehabilitation interventions are evidence based strategies for the accommodation and support to Children with Autism Spectrum Disorder and their families. These rehabilitation interventions cover the major defected areas of social reciprocity, communication and repetitive behaviors of Children with Autism Spectrum Disorders. There is worldwide concern regarding the inclusiveness of Children with Autism in schools and in class rooms that will comfortably accommodate children with wide-ranging disabilities that include autism. A critical concern of teacher’s responsibility for students learning in the inclusive classroom is their lack of knowledge and understanding of, as well as professional preparation for accommodating the characteristics and needs of students with Autism Spectrum (Bellini et al 2011). Keywords: Autism; Autism Spectrum; Neuro-developmental Disability; Behavior; Perceptions; Epistemology & Prevalence.

2013

Molecular Psychiatry, 2002

Introduction: Autism spectrum disorders are marked by socialising and communication barriers as well as repeatable, restricted, and stigmatised behavioural patterns Objectives: This paper describes a retrospective case series study of developmental disability cases to assess autism in patients of various ages Methods: The patients' age, sex, type, location of residence, severity of condition, and year of birth were recorded. Moreover, the time and mode of onset and clinical feature category were analysed and statistically assessed for several clinical factors. Results: Initial symptoms appeared in 43.7% of the children aged one to five years and 41.6% of the children aged six to ten years. Moreover, the varying autism challenges faced by individuals of various ages were investigated. The youngest patient was a one-year-old toddler, while the oldest was a 20-year-old man. It was found that teenagers and young adults were diagnosed at a considerably earlier age than younger children. The greatest apparent variation in the diagnosis stage by patient age was seen in adolescents with PDD-NOS, followed by those with autism and Asperger's syndrome. Currently, the treatment patterns and interventions for patients with autism are aimed at reducing symptoms that interfere with their daily functioning and quality of life. Consequently, therapeutic approaches invariably encompass several practitioners and are customised to an individual. The patients in the study were administered a variety of rehabilitation therapies based on the degree of their disorder, along with atypical antipsychotics such as Atomoxetine (Strattera), Methylphenidate (Concerta), and Risperidone to manage the severity of the disorders. Conclusions: The above survey results facilitate a slightly earlier diagnosis of this developmental disorder, which will also be valuable to prescribers. The primary limitations of this study are a lack of statistics describing the prevalence of autism spectrum disorders and their therapeutic interventions in Saudi Arabia, as well as a lack of previous research on the research topic in Saudi Arabia.

Autism Research, 2022

Prevalence estimates of autism are essential for informing public policy, raising awareness, and developing research priorities. Using a systematic review, we synthesized estimates of the prevalence of autism worldwide. We examined factors accounting for variability in estimates and critically reviewed evidence relevant for hypotheses about biological or social determinants (viz., biological sex, sociodemographic status, ethnicity/race, and nativity) potentially modifying prevalence estimates of autism. We performed the search in November 2021 within Medline for studies estimating autism prevalence, published since our last systematic review in 2012. Data were extracted by two independent researchers. Since 2012, 99 estimates from 71 studies were published indicating a global autism prevalence that ranges within and across regions, with a median prevalence of 100/10,000 (range: 1.09/10,000 to 436.0/10,000). The median male-to-female ratio was 4.2. The median percentage of autism cases with co-occurring intellectual disability was 33.0%. Estimates varied, likely reflecting complex and dynamic interactions between patterns of community awareness, service capacity, help seeking, and sociodemographic factors. A limitation of this review is that synthesizing methodological features precludes a quality appraisal of studies. Our findings reveal an increase in measured autism prevalence globally, reflecting the combined effects of multiple factors including the increase in community awareness and public health response globally, progress in case identification and definition, and an increase in community capacity. Hypotheses linking factors that increase the likelihood of developing autism with variations in prevalence will require research with large, representative samples and comparable autism diagnostic criteria and case-finding methods in diverse world regions over time. Lay Summary We reviewed studies of the prevalence of autism worldwide, considering the impact of geographic, ethnic, and socioeconomic factors on prevalence estimates. Approximately 1/100 children are diagnosed with autism spectrum disorder around the world. Prevalence estimates increased over time and varied greatly within and across sociodemographic groups. These findings reflect changes in the definition of autism and differences in the methodology and contexts of prevalence studies.

The Lancet Psychiatry, 2024

Summary Background High-quality estimates of the epidemiology of the autism spectrum and the health needs of autistic people are necessary for service planners and resource allocators. Here we present the global prevalence and health burden of autism spectrum disorder from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 following improvements to the epidemiological data and burden estimation methods. Methods For GBD 2021, a systematic literature review involving searches in PubMed, Embase, PsycINFO, the Global Health Data Exchange, and consultation with experts identified data on the epidemiology of autism spectrum disorder. Eligible data were used to estimate prevalence via a Bayesian meta-regression tool (DisMod-MR 2.1). Modelled prevalence and disability weights were used to estimate health burden in years lived with disability (YLDs) as the measure of non-fatal health burden and disability-adjusted life-years (DALYs) as the measure of overall health burden. Data by ethnicity were not available. People with lived experience of autism were involved in the design, preparation, interpretation, and writing of this Article. Findings An estimated 61·8 million (95% uncertainty interval 52·1–72·7) individuals (one in every 127 people) were on the autism spectrum globally in 2021. The global age-standardised prevalence was 788·3 (663·8–927·2) per 100 000 people, equivalent to 1064·7 (898·5–1245·7) autistic males per 100 000 males and 508·1 (424·6–604·3) autistic females per 100 000 females. Autism spectrum disorder accounted for 11·5 million (7·8–16·3) DALYs, equivalent to 147·6 (100·2–208·2) DALYs per 100 000 people (age-standardised) globally. At the super-region level, age-standardised DALY rates ranged from 126·5 (86·0–178·0) per 100 000 people in southeast Asia, east Asia, and Oceania to 204·1 (140·7–284·7) per 100 000 people in the high-income super-region. DALYs were evident across the lifespan, emerging for children younger than age 5 years (169·2 [115·0–237·4] DALYs per 100 000 people) and decreasing with age (163·4 [110·6–229·8] DALYs per 100 000 people younger than 20 years and 137·7 [93·9–194·5] DALYs per 100 000 people aged 20 years and older). Autism spectrum disorder was ranked within the top-ten causes of non-fatal health burden for people younger than 20 years. Interpretation The high prevalence and high rank for non-fatal health burden of autism spectrum disorder in people younger than 20 years underscore the importance of early detection and support to autistic young people and their caregivers globally. Work to improve the precision and global representation of our findings is required, starting with better global coverage of epidemiological data so that geographical variations can be better ascertained. The work presented here can guide future research efforts, and importantly, decisions concerning allocation of health services that better address the needs of all autistic individuals.

Journal of autism and developmental disorders, 2003

This paper was commissioned by the committee on the Effectiveness of Early Education in Autism of the National Research Council (NRC). It provides a review of epidemiological studies of pervasive developmental disorders (PDD) which updates a previously published article (The epidemiology of autism: a review. Psychological Medicine 1999; 29: 769-786). The design, sample characteristics of 32 surveys published between 1966 and 2001 are described. Recent surveys suggest that the rate for all forms of PDDs are around 30/10,000 but more recent surveys suggest that the estimate might be as high as 60/10,000. The rate for Asperger disorder is not well established, and a conservative figure is 2.5/10,000. Childhood disintegrative disorder is extremely rare with a pooled estimate across studies of 0.2/10,000. A detailed discussion of the possible interpretations of trends over time in prevalence rates is provided. There is evidence that changes in case definition and improved awareness expla...

Brain Sciences, 2020

The prevalence of Autism Spectrum Disorder (ASD) has increased dramatically in recent decades, supporting the claim of an autism epidemic. Systematic monitoring of ASD allows estimating prevalence and identifying potential sources of variation over time and geographical areas. At present, ASD prevalence estimates are available worldwide, coming either from surveillance systems using existing health and educational databases or from population studies specifically performed. In the present article, we present a review of the ASD prevalence estimates published since 2014. Data confirm a high variability in prevalence across the world, likely due to methodological differences in case detection, and the consistent increase of prevalence estimates within each geographical area.

The epidemiology of autism spectrum disorder and factors contributing to the increase in its prevalence, 2022

Autism spectrum disorder (ASD) is a multifactorial neurodevelopmental disorder which has attracted the interest of researchers in many scientific fields. The prevalence of a disease or a disorder is important for healthcare and socioeconomic reasons. According to the World Health Organization (WHO), currently, 1 in 160 children is born with ASD (0.63%), possibly a conservative estimate, as many studies have reported a prevalence higher than 1%. Even so, the WHO rate is approximately 14 times higher than that reported in the first epidemiological study on ASD, which was conducted in the UK 50 years ago. It is currently estimated that approximately 60 million people worldwide have ASD. Diagnosis and documentation of these individuals is challenging, due to the nature of the disorder and its broad spectrum. Many countries have no epidemiological data on ASD and several epidemiological studies on ASD record significant methodological limitations, but the currently available data indicate that the prevalence of ASD has risen over the years. The interpretation of this trend remains uncertain, but several factors have been documented that may have contributed to this apparent increase, including revision of the diagnostic criteria, overdiagnosis, scientific advances, accessibility to services, increase in social awareness, and improvement in the methodology applied in the epidemiological studies, in addition to environmental and other factors.

Public health reviews

Autism spectrum disorders (ASDs) are estimated to occur among about one percent of children in the United States. This estimate is in line with estimates from other industrialized countries. However, the identified prevalence of ASDs has increased significantly in a short time period based on data from multiple studies including the U.S. Centers for Disease Control and Prevention's (CDC) Autism and Developmental Disabilities Monitoring (ADDM) Network. Whether increases in ASD prevalence are partly attributable to a true increase in the risk of developing ASD or solely to changes in community awareness and identification patterns is not known. It is clear that more children are identified with an ASD now than in the past and the impact on individuals, families, and communities is significant. However, disentangling the many potential reasons for ASD prevalence increases has been challenging. Understanding the relative contribution of multiple factors such as variation in study me...

Canadian Medical Association Journal, 2014

utism spectrum disorder (ASD) encompasses wide variation in symptom severity and functional impact. The core features of ASD include impairments in social communication, repetitive behaviours and restricted interests. Not all people with ASD identify their challenges as a disorder. Autism spectrum disorder affects more than 1% of the population, 1 and a dramatic increase in its recognition is creating huge demands on health care systems for timely and accurate diagnosis. Health care professionals in many capacities encounter people and their families coping with ASD, and optimal care depends on a large network of providers, given the breadth of the associated medical issues. In this review, we outline the current understanding of ASD and suggest best practices for primary care and specialized clinics based on evidence from randomized controlled trials (RCTs) or systematic reviews, if available (Box 1). Although collaboration with educational and social services is necessary, the focus of our review is on medical concerns. We use a fictional case to illustrate how the process may be applied (Box 2). Additional resources for physicians are presented in Box 3. How common is autism? The Autism and Developmental Disabilities Monitoring Network of the US Centers for Disease Control has surveyed ASD among eightyear-olds from up to 14 US centres every two years since 2000. The most recent analysis, which pertains to the 2008 surveillance year, 1 estimates the overall prevalence to be 1 in 88 children-almost double the prevalence reported in the original cohort. These data cannot distinguish between an increase caused by changes in ascertainment and a true increase in prevalence. Global prevalence, as reported in a comprehensive survey of epidemiological reports from 1966 to 2011, 2 suggests that autism is still under-recognized, particularly in developing countries. In Canada, a population prevalence of 1% implies that about 67 000 children, aged 3-20 years have ASD. Boys with ASD outnumber girls by as much as 4:1, but the underlying reasons for this difference remain elusive. 3

International Journal of Special Education, 2014

The prevalence of autism is increasing globally. While most of the published works are done in the Western and European countries, the trend in autism research is shifting towards the Asian continent recently. In this review, we aimed to highlight the current prevalence, diagnosis, treatment and research on Autism Spectrum Disorders (ASD) in Singapore and Malaysia. Based on database searches, we found that the awareness about autism among lay and professional public is higher in Singapore compared to Malaysia. The special education system and approach towards autism treatment is also different between both societies although the culture is similar and the geographic location is close. Main findings and implications were discussed in this review. The lack of study on autism prevalence in this part of the world commands a critical need for further research. Perhaps more collaborative work between both countries could be done to expand the knowledge in autism. Autistic Spectrum Disorder (ASD) is a type of neurodevelopmental disorder affecting the mental, emotion, learning and memory of a person (McCary et al., 2012). According to the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV) (American Psychiatric Association, 2000), ASD is characterized by three features. Firstly, impairment of social interaction, which includes but not limited to impairment in the use of multiple nonverbal behaviours such as eye-to-eye gaze, facial expression, body postures and gestures to regular social interaction. Secondly, impairment in communication, which includes but not limited to delay in or total lack of the development of spoken language, or impairment in the ability to initiate or sustain a conversation with others. Thirdly, there is restricted, repetitive and stereotyped pattern of behaviour, interests, and activities, which include but not limited to inflexible adherence to specific, nonfunctional routines or rituals (APA, 2000). Many official health reports on ASD have shown that there is an increase in the number of ASD cases over the years. One of the most comprehensive ASD prevalence study done so far is the one done by the US Centers for Disease Control and Prevention (CDC)"s Autism and Developmental Disabilities Monitoring (ADDM) Network (Autism and Developmental Disabilities Monitoring Network, 2012). In its latest study in 2008, the rate of US cases rose from one in 110 in 2006 to about one in 88 children in 2008. In fact, the autism numbers skyrocketed since 2002(Autism Spectrum Disorders-Data & Statistics, 2014). This number has caused a public health concern worldwide. Health officials attribute the increase in autism cases through greater awareness, wider screening and better diagnosis (Weintraub, 2011). But the numbers increase at a rate so fast that researchers start to question if these are the true factors that justify the increase (Weintraub, 2011). Growing evidences have shown that environmental and epigenetic factors could contribute towards autism incidence (Persico & Bourgeron, 2006),which include possible causal factors such as genetic mutations (Freitag, 2007) and various environmental agents that would cause birth defects (Arndt, Stodgell, & Rodier, 2005). Yet in all its efforts to understand the underlying cause of ASD which knows no bounds in affecting children across racial, ethnic and socioeconomic groups,

Journal of Child and Adolescent Mental Health, 2013

MMWR. Surveillance Summaries, 2018

Problem/Condition: Autism spectrum disorder (ASD). Period Covered: 2010. Description of System: The Autism and Developmental Disabilities Monitoring (ADDM) Network is an active surveillance system in the United States that provides estimates of the prevalence of ASD and other characteristics among children aged 8 years whose parents or guardians live in 11 ADDM sites in the United States. ADDM surveillance is conducted in two phases. The first phase consists of screening and abstracting comprehensive evaluations performed by professional providers in the community. Multiple data sources for these evaluations include general pediatric health clinics and specialized programs for children with developmental disabilities. In addition, most ADDM Network sites also review and abstract records of children receiving special education services in public schools. The second phase involves review of all abstracted evaluations by trained clinicians to determine ASD surveillance case status. A child meets the surveillance case definition for ASD if a comprehensive evaluation of that child completed by a qualified professional describes behaviors consistent with the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) diagnostic criteria for any of the following conditions: autistic disorder, pervasive developmental disorder-not otherwise specified (including atypical autism), or Asperger disorder. This report provides updated prevalence estimates for ASD from the 2010 surveillance year. In addition to prevalence estimates, characteristics of the population of children with ASD are described. Results: For 2010, the overall prevalence of ASD among the ADDM sites was 14.7 per 1,000 (one in 68) children aged 8 years. Overall ASD prevalence estimates varied among sites from 5.7 to 21.9 per 1,000 children aged 8 years. ASD prevalence estimates also varied by sex and racial/ethnic group. Approximately one in 42 boys and one in 189 girls living in the ADDM Network communities were identified as having ASD. Non-Hispanic white children were approximately 30% more likely to be identified with ASD than non-Hispanic black children and were almost 50% more likely to be identified with ASD than Hispanic children. Among the seven sites with sufficient data on intellectual ability, 31% of children with ASD were classified as having IQ scores in the range of intellectual disability (IQ ≤70), 23% in the borderline range (IQ = 71-85), and 46% in the average or above average range of intellectual ability (IQ >85). The proportion of children classified in the range of intellectual disability differed by race/ethnicity. Approximately 48% of non-Hispanic black children with ASD were classified in the range of intellectual disability compared with 38% of Hispanic children and 25% of non-Hispanic white children. The median age of earliest known ASD diagnosis was 53 months and did not differ significantly by sex or race/ethnicity. Interpretation: These findings from CDC's ADDM Network, which are based on 2010 data reported from 11 sites, provide updated population-based estimates of the prevalence of ASD in multiple communities in the United States. Because the ADDM Network sites do not provide a representative sample of the entire United States, the combined prevalence estimates presented in this report cannot be generalized to all children aged 8 years in the United States population. Consistent with previous reports from the ADDM Network, findings from the 2010 surveillance year were marked by significant variations in ASD prevalence by geographic area, sex, race/ethnicity, and level of intellectual ability. The extent to which this variation might be attributable to diagnostic practices, underrecognition of ASD symptoms in some racial/ethnic groups, socioeconomic disparities in access to services, and regional differences in clinical or school-based practices that might influence the findings in this report is unclear. Public Health Action: ADDM Network investigators will continue to monitor the prevalence of ASD in select communities, with a focus on exploring changes within these communities that might affect both the observed prevalence of ASD and population-based characteristics of children identified with ASD. Although ASD is sometimes diagnosed by 2 years of age, the median age of the first ASD diagnosis remains older than

Revista Brasileira de Psiquiatria, 2013

Pervasive developmental disorders are now commonly referred to as autism spectrum disorders (ASDs). ASDs present with a range of severity and impairments, and often are a cause of severe disability, representing a major public health concern. The diagnostic criteria require delays or abnormal functioning in social interaction, language, and/or imaginative play within the first 3 years of life, resulting in a deviation from the developmental pattern expected for the age. Because establishing a diagnosis of ASD is possible as early as 18-24 months of age, clinicians should strive to identify and begin intervention in children with ASD as soon as signs are manifest. Increasing efforts are underway to make ASD screening universal in pediatric healthcare. Given the crucial importance of early identification and multiple modalities of treatment for ASD, this review will summarize the diagnostic criteria, key areas for assessment by clinicians, specific scales and instruments for assessment, and discussion of evidence-based treatment programs and the role of specific drug therapies for symptom management.

2012

Gamma aminobutyric acid (GABA)-mediated synapses and the oscillations they orchestrate are altered in autism. GABA-acting benzodiazepines exert in some patients with autism paradoxical effects, raising the possibility that like in epilepsies, GABA excites neurons because of elevated intracellular concentrations of chloride. Following a successful pilot study, 1 we have now performed a double-blind clinical trial using the diuretic, chloride-importer antagonist bumetanide that reduces intracellular chloride reinforcing GABAergic inhibition. Sixty children with autism or Asperger syndrome (3-11 years old) received for 3 months placebo or bumetanide (1 mg daily), followed by 1-month wash out. Determination of the severity of autism was made with video films at day 0 (D0) and D90 by blind, independent evaluators. Bumetanide reduced significantly the Childhood Autism Rating Scale (CARS) (D90 À D0; Po0.004 treated vs placebo), Clinical Global Impressions (Po0.017 treated vs placebo) and Autism Diagnostic Observation Schedule values when the most severe cases (CARS values above the mean ± s.d.; n ¼ 9) were removed (Wilcoxon test: P-value ¼ 0.031; Student's t-test: P-value ¼ 0.017). Side effects were restricted to an occasional mild hypokalaemia (3.0-3.5 mM l À 1 K þ ) that was treated with supplemental potassium. In a companion study, chronic bumetanide treatment significantly improved accuracy in facial emotional labelling, and increased brain activation in areas involved in social and emotional perception (Hadjikhani et al., submitted). Therefore, bumetanide is a promising novel therapeutic agent to treat autism. Larger trials are warranted to better determine the population best suited for this treatment.

Behavioural Neurology, 2014

The objective of this study was to evaluate the relations between Transcranial direct current stimulation (tDCS) by anodal current and the work fatigue in lower limb during isokinetic protocol. In this study was evaluated the knee extensors and flexors resulting torques, from an isokinetic assessment, in concentric / concentric muscular action, after tDCS by anodal and sham current. Results showed significant differences between anodal and sham conditions for average peak torque during knee extension phase and work fatigue during knee flexion phase. Anodal tDCS showed not to be a suitable technique to modulated primary motor cortex activity. The preliminary results indicate a negative effect on work fatigue (knee flexion phase) and average peak torque (knee extension phase).

Molecular Psychiatry, 2013

Autism is a severe neurodevelopmental disorder, the aetiology of which remains mainly unknown. Family and twin studies provide strong evidence that genetic factors have a major role in the aetiology of this disease. Recently, whole exome sequencing (WES) efforts have focused mainly on rare de novo variants in singleton families. Although these studies have provided pioneering insights, de novo variants probably explain only a small proportion of the autism risk variance. In this study, we performed exome sequencing of 10 autism multiplex families with the aim of investigating the role of rare variants that are coinherited in the affected sibs. The pool of variants selected in our study is enriched with genes involved in neuronal functions or previously reported in psychiatric disorders, as shown by Gene Ontology analysis and by browsing the Neurocarta database. Our data suggest that rare truncating heterozygous variants have a predominant role in the aetiology of autism. Using a multiple linear regression model, we found that the burden of truncating mutations correlates with a lower non-verbal intelligence quotient (NVIQ). Also, the number of truncating mutations that were transmitted to the affected sibs was significantly higher (twofold) than those not transmitted. Protein-protein interaction analysis performed with our list of mutated genes revealed that the postsynaptic YWHAZ is the most interconnected node of the network. Among the genes found disrupted in our study, there is evidence suggesting that YWHAZ and also the X-linked DRP2 may be considered as novel autism candidate genes.

European Child & Adolescent Psychiatry, 2014

The objective of this study is to compare the time trend of reported diagnoses of autism spectrum disorder (ASD), hyperkinetic disorder, Tourette's syndrome, and obsessive-compulsive disorder across four countries after standardizing the study period, diagnostic codes used to define the conditions and statistical analyses across countries. We use a population-based cohort, including all live-born children in Denmark, Finland, Sweden and Western Australia, from January 1, 1990, through December 31, 2007 and followed through December 31, 2011. The main outcome measure is age-specific prevalence of diagnoses reported to population-based registry systems in each country. We observe an increase in agespecific prevalence for reported diagnoses of all four disorders across birth-year cohorts in Denmark, Finland, Sweden, and (for ASD) Western Australia. Our results highlight the increase in the last 20 years in the number of children and families in contact with health care systems for diagnosis and services for an array of childhood neuropsychiatric disorders, a phenomenon not limited to ASD. Also, the age of diagnosis of the studied disorders was often much higher than what is known of the typical age of Electronic supplementary material The online version of this article (onset of symptoms, and we observe limited leveling off in the incidence rate with increasing age.

Autism research : official journal of the International Society for Autism Research, 2014

Autism spectrum disorders are a set of neurodevelopmental disorders that are highly hereditable. Increased genomic instability has been observed in other heritable paediatric neurobiological disorders; therefore, the aim of our study was to test the hypothesis that DNA damage is increased in children with autism and that B vitamin status may explain variations in genome integrity between autistic and normal children. We compared 35 children with autism, 27 of their siblings without autism and 25 age- and gender-matched community controls for genomic stability using the cytokinesis-block micronucleus cytome (CBMN-cyt) assay, B vitamins and homocysteine, as well as autism-related behaviours. It was found that there were no differences in CBMN-cyt biomarkers between the three groups. Vitamin B2 was significantly raised in children with autism and their siblings compared with controls (P = 0.027 and P = 0.016 respectively) but there was no difference in other B vitamins or homocysteine....

BMJ Open, 2015

Introduction: Individuals with autism spectrum disorder (ASD) have difficulties in communication and social interaction resulting from atypical perceptual and cognitive information processing, leading to an accumulation of anxiety. Extreme overloading experienced internally may not be externally visible. Identifying stressful situations at an early stage may avoid socially problematic behaviour from occurring, such as self-injurious behaviour. Activation of the autonomous nervous system (ANS) is involved in the response to anxiety, which can be measured through heart rate variability and skin conductance with the use of portable devices, non-intrusively and pain-free. Thus, developing innovative analysis of signal perception and reaction is necessary, mainly for non-communicative individuals with autism.

Psychological Reports, 2014

The increased awareness of Autism Spectrum Disorders (ASD) over the last few decades as well as the potential association between ASD and off ending behaviors has spurred a need for increased research in this area. In order to explore any possible relationship between ASD and violent or sexual crime the present study examines all forensic examination reports over a 10-yr. period in Norway where the charged persons were diagnosed with ASD and charged with either a violent ( N = 21) or a sexual ( N = 12) off ense. Diff erences between these two groups regarding previous contact with child welfare and confessions to the off ense were found. There was also a tendency toward more severe mental health problems and less intellectual problems among the violent off enders than the sexual off enders.

Autism Research, 2012

PLoS ONE, 2014

Autism Spectrum Disorders (ASDs) are childhood neurodevelopmental disorders with complex genetic origins. Previous studies have investigated the role of de novo Copy Number Variants (CNVs) and microRNAs as important but distinct etiological factors in ASD. We developed a novel computational procedure to assess the potential pathogenic role of microRNA genes overlapping de novo CNVs in ASD patients. Here we show that for chromosomes # 1, 2 and 22 the actual number of miRNA loci affected by de novo CNVs in patients was found significantly higher than that estimated by Monte Carlo simulation of random CNV events. Out of 24 miRNA genes over-represented in CNVs from these three chromosomes only hsa-mir-4436b-1 and hsa-mir-4436b-2 have not been detected in CNVs from non-autistic subjects as reported in the Database of Genomic Variants. Altogether the results reported in this study represent a first step towards a full understanding of how a dysregulated expression of the 24 miRNAs genes affect neurodevelopment in autism. We also propose that the procedure used in this study can be effectively applied to CNVs/miRNA genes association data in other genomic disorders beyond autism.

Toxics, 2015

A significant body of evidence supports the multifactorial etiology of neurodevelopmental disorders (NDDs) affecting children. The present review focuses on early exposure to environmental chemicals as a risk factor for neurodevelopment, and presents the major lines of evidence derived from epidemiological studies, underlying key uncertainties and research needs in this field. We introduce the exposome concept that, encompassing the totality of human environmental exposures to multiple risk factors, aims at explaining individual vulnerability and resilience to early chemical exposure. In this framework, we synthetically review the role of variable gene backgrounds, the involvement of epigenetic mechanisms as well as the function played by potential effect modifiers such as socioeconomic status. We describe laboratory rodent studies where the neurodevelopmental effects of environmental chemicals are assessed in the presence of either a "vulnerable" gene background or adverse pregnancy conditions (i.e., maternal stress). Finally, we discuss the need for more descriptive and "lifelike" experimental models of NDDs, to identify candidate biomarkers and pinpoint susceptible groups or life stages to be translated to large prospective studies within the exposome framework. OPEN ACCESS Toxics 2015, 3 90

Nature communications, 2014

Autism spectrum disorders (ASDs) are complex and heterogeneous developmental disabilities affecting an ever-increasing number of children worldwide. The diverse manifestations and complex, largely genetic aetiology of ASDs pose a major challenge to the identification of unifying neuropathological features. Here we describe the neurodevelopmental defects in mice that carry deleterious alleles of the Wdfy3 gene, recently recognized as causative in ASDs. Loss of Wdfy3 leads to a regionally enlarged cerebral cortex resembling early brain overgrowth described in many children on the autism spectrum. In addition, affected mouse mutants display migration defects of cortical projection neurons, a recognized cause of epilepsy, which is significantly comorbid with autism. Our analysis of affected mouse mutants defines an important role for Wdfy3 in regulating neural progenitor divisions and neural migration in the developing brain. Furthermore, Wdfy3 is essential for cerebral expansion and fu...

Autism Research and Treatment, 2015

Autism is a neurodevelopmental disorder with serious implications in childhood. There is a significant gap in the identification and provision of health and social services for autism in Africa. The knowledge of autism among health care providers and identifying challenges associated with its management could facilitate bridging the gap and ensuring better outcomes. A self-administered tool, the Knowledge about Childhood Autism among Health Workers (KCAHW) questionnaire, was used in assessing knowledge of autism among 175 medical doctors (participants) attending an annual scientific meeting in northwest Nigeria. Other parameters assessed were sociodemographic and professional characteristics of the participants and challenges encountered in the management of autism. Out of 175 questionnaires distributed, 167 (95.4%) were returned. Good knowledge (KCAHW score ≥15) was significantly associated with being a paediatrician or psychiatrist and practicing in a tertiary health facility ( < 0.05), while poor knowledge (KCAHW score <15) was significant among general practitioners ( < 0.05). The highest knowledge gap was associated with onset of autism and its comorbidities (KCAHW Domain 4) while the least was concerning communication impairments (KCAHW Domain 2). Major challenges encountered in autism management were dearth of specialist services, cost of evaluation, and poor caregiver perspectives of autism.

Molecular Autism, 2014

Background: Histone H3 methylation at lysine 9 (H3K9) is a conserved epigenetic signal, mediating heterochromatin formation by trimethylation, and transcriptional silencing by dimethylation. Defective GLP (Ehmt1) and G9a (Ehmt2) histone lysine methyltransferases, involved in mono and dimethylation of H3K9, confer autistic phenotypes and behavioral abnormalities in animal models. Moreover, EHMT1 loss of function results in Kleefstra syndrome, characterized by severe intellectual disability, developmental delays and psychiatric disorders. We examined the possible role of histone methyltransferases in the etiology of autism spectrum disorders (ASD) and suggest that rare functional variants in these genes that regulate H3K9 methylation may be associated with ASD.

Developmental Medicine & Child Neurology, 2014

Autism spectrum disorders CGH Comparative genomic hybridization CNV Copy number variants

Journal of autism and developmental disorders, 2015

College students with autism may be negatively impacted by lack of understanding about autism on college campuses. Thus, we developed an online training to improve knowledge and decrease stigma associated with autism among college students. Participants (N = 365) completed a pre-test, online training, and post-test. Women reported lower stigma towards autism than men. Participation in the training was associated with decreased stigma and increased knowledge about autism. Although participants exhibited relatively high baseline knowledge of autism, misconceptions were common, particularly in open-ended responses. Participants commonly confused autism with other disorders, such as learning disabilities. This study suggests that online training may be a cost-effective way to increase college students&#39; understanding and acceptance of their peers with autism.

Journal of Autism and Developmental Disorders, 2015

Although misconceptions associated with ASD are apparent worldwide, they may differ across cultures. This study compares knowledge and stigma associated with ASD in a country with limited autism resources, Lebanon, and a country with substantial autism resources, the United States (US). College students in the US (N = 346) and Lebanon (N = 329) completed assessments of knowledge and stigma associated with ASD before and after an online ASD training. Although students in the US exhibited higher overall knowledge and lower stigma towards ASD, certain misconceptions were more apparent in the US than in Lebanon. Participation in the training was associated with decreased stigma and increased knowledge in both countries. Thus, online training may be useful for increasing understanding about ASD internationally.

Autism, 2013

Biological trace element research, 2013

Toxic levels of heavy metals and low levels of essential minerals have been suggested to play a critical role in the pathogenesis of autism spectrum disorders (ASD). This study documents the levels of heavy metals and essential minerals in hair samples of children with ASD in Muscat, the urbanized capital of Oman, Muscat. The study included 27 children with ASD and 27 matched non-ASD controls. Parental interviews were held and dietary intake questionnaires completed in conjunction with the collection of hair samples. Analysis of heavy metals and essential minerals was carried out by inductively coupled plasma mass spectrometry. Chi-square analysis and non-parametric Fisher&#39;s exact tests were used to assess statistical significance. Children with ASD had significantly higher levels of all 11 analyzed heavy metals in their hair samples (P &lt; 0.05), ranging from 150 to 365 % of control levels. ASD children also had significantly higher levels of essential minerals sulfur, sodium,...

Autism Research, 2015

Previous studies reported that the prevalence of Autism Spectrum Conditions (ASC) in mainland China is much lower than estimates from developed countries (around 1%). The aim of the study is to apply current screening and standardized diagnostic instruments to a Chinese population to establish a prevalence estimate of ASC in an undiagnosed population in mainland China. We followed the design development used previously in the UK published in 2009 by Baron-Cohen and colleagues. The Mandarin Childhood Autism Spectrum Test (CAST) was validated by screening primary school pupils (n = 737 children age 6-10 years old) in Beijing and by conducting diagnostic assessments using the Autism Diagnostic Observation Schedule and the Autism Diagnostic Interview-Revised. The prevalence estimate was generated after adjusting and imputing for missing values using the inverse probability weighting. Response was high (97%). Using the UK cutoff (≥15), CAST performance has 84% sensitivity and 96% specificity (95% confidence interval [CI]: 46, 98, and 96, 97, respectively). Six out of 103 children, not previously diagnosed, were found to the meet diagnostic criteria (8.5 after adjustment, 95% CI: 1.6, 15.4). The preliminary prevalence in an undiagnosed primary school population in mainland China was 119 per 10,000 (95% CI: 53, 265). The utility of CAST is acceptable as a screening instrument for ASC in large epidemiological studies in China. Using a comparable method, the preliminary prevalence estimate of ASC in mainland China is similar to that of those from developed countries. Autism Res 2015, ••: ••-••.

• Explore
• Papers
• Topics

• Features
• Mentions
• Analytics
• PDF Packages
• Advanced Search
• Search Alerts

• Journals
• Academia.edu Journals
• My submissions
• Reviewer Hub
• Why publish with us
• Testimonials

• Company
• About
• Careers
• Press
• Help Center
• Terms
• Privacy
• Copyright
• Content Policy