Trends in autism spectrum disorder diagnoses: 1994-2007. J Autism Dev Disord. 2009;39:1099-1111. [PMID: 19294498 DOI: 10.1007/s10803-009-0723-6]

The ALSPAC fetal and neonatal resource: detailed data abstracted from the clinical records of the new-born

In a previous Data Note, we outlined the data obtained from clinical obstetric records concerning many details of the pregnancies resulting in the births of the children in the Avon Longitudinal Study of Parents and Children (ALSPAC). Here we describe the data that have been abstracted from medical records concerning the fetus and neonate. Full details concerning the selection biases regarding the data abstracted are outlined in the previous Data Note. The records that have been abstracted, and described in this Data Note, concern the health of the fetus (measured in relation to the results of fetal monitoring, presentation at various stages of pregnancy, and the method of delivery) as well as the status of the newborn immediately post-delivery. Details of signs, symptoms and treatments of this population of new-born babies, as recorded in the clinical records, are described for the time during which they were in hospital or under the care of a designated midwife. These data add depth to the information collected from elsewhere concerning this period of the child's life: from the questionnaires completed at the time by the mother; and clinical details from neonatal intensive or special care units which will be detailed in a further Data Note.

National screening for Egyptian children aged 1 year up to 12 years at high risk of Autism and its determinants: a step for determining what ASD surveillance needs

This study aimed to provide a national estimate of the prevalence of the high risk of autism spectrum disorder (ASD) and their determinants. A national screening survey was conducted for 41,640 Egyptian children aged 1 to 12 years in two phases. Tools used were Vineland's Adaptive Behavior Scales, Modified Checklist for Autism in Toddlers, Gilliam Autism Rating scale, and Denver II Developmental screening test. The overall prevalence of children at high risk of ASD was 3.3% (95% CI:3.1%-3.5%). Children living without mothers in homes, suffered from convulsions (AOR = 3.67; 95%CI:2.8-4.8), a history of cyanosis after birth (AOR = 1.87; 95% CI:1.35-2.59) or history of LBW babies (AOR = 1.53; 95% CI:1.23-1.89) carried higher odds of being at high risk of ASD.

National screening for Egyptian children aged 1 year up to 12 years at high risk of Autism and its determinants: a step for determining what ASD surveillance needs

This study aimed to provide a national estimate of the prevalence of the high risk of autism spectrum disorder (ASD) and their determinants. A national screening survey was conducted for 41,640 Egyptian children aged 1 to 12 years in two phases. Tools used were Vineland's Adaptive Behavior Scales, Modified Checklist for Autism in Toddlers, Gilliam Autism Rating scale, and Denver II Developmental screening test. The overall prevalence of children at high risk of ASD was 3.3% (95% CI:3.1%–3.5%). Children living without mothers in homes, suffered from convulsions (AOR = 3.67; 95%CI:2.8–4.8), a history of cyanosis after birth (AOR = 1.87; 95% CI:1.35–2.59) or history of LBW babies (AOR = 1.53; 95% CI:1.23–1.89) carried higher odds of being at high risk of ASD.

Current State of Modeling Human Psychiatric Disorders Using Zebrafish

Psychiatric disorders are highly prevalent brain pathologies that represent an urgent, unmet biomedical problem. Since reliable clinical diagnoses are essential for the treatment of psychiatric disorders, their animal models with robust, relevant behavioral and physiological endpoints become necessary. Zebrafish (Danio rerio) display well-defined, complex behaviors in major neurobehavioral domains which are evolutionarily conserved and strikingly parallel to those seen in rodents and humans. Although zebrafish are increasingly often used to model psychiatric disorders, there are also multiple challenges with such models as well. The field may therefore benefit from a balanced, disease-oriented discussion that considers the clinical prevalence, the pathological complexity, and societal importance of the disorders in question, and the extent of its detalization in zebrafish central nervous system (CNS) studies. Here, we critically discuss the use of zebrafish for modeling human psychiatric disorders in general, and highlight the topics for further in-depth consideration, in order to foster and (re)focus translational biological neuroscience research utilizing zebrafish. Recent developments in molecular biology research utilizing this model species have also been summarized here, collectively calling for a wider use of zebrafish in translational CNS disease modeling.

The synergistic interaction between urbanicity and maternal education affecting childcare pressure related to autism spectrum disorder in two national birth cohort studies

To gain a holistic approach for parental help-seeking behavior and ASD diagnosis, this study aimed to use two national birth cohort study datasets to investigate the pathway relationship between personal and social/environmental factors, including maternal perceived childcare pressure, maternal level of education, urbanization at age 3, and the chance of receiving a autism spectrum disorder (ASD) diagnosis at when children are aged 5.5 years (2.5 years later). The 2003 Taiwan Birth Cohort Pilot Study (TBCS-p; N = 1618) and 2005 Taiwan Birth Cohort Study (TBCS; N = 19,183) datasets were used. The TBCS-p and TBCS both showed similar prevalence of ASD (0.3-0.4%). Children with ASD characteristics, as measured using the Modified Checklist of Autism in Toddlers, had 8.27-18.20 times increased likelihood of receiving ASD diagnosis [TBCS confidence interval (CF) of 5.32-12.86; TBCS-p CF of 2.03-163.46]. Pathway analysis showed that, although having a mother with higher education or who lived in a city decreased the chance for ASD diagnosis, the interactive effect of a maternal higher level of education and living in a city led to an increased likelihood for ASD diagnosis. Additionally, mothers who perceived a higher level of childcare pressure were also more likely to seek medical assistance and diagnosis. Access to healthcare (living in the city), maternal level of awareness (level of education), and perceived childcare pressure are all factors that influence help-seeking behavior and diagnosis. Therefore, medical professionals should pay special attention to the developmental condition of children in underserved backgrounds and rural areas to prevent delayed diagnosis.

The Diagnosis of Autism: From Kanner to DSM-III to DSM-5 and Beyond

In this paper we review the impact of DSM-III and its successors on the field of autism-both in terms of clinical work and research. We summarize the events leading up to the inclusion of autism as a "new" official diagnostic category in DSM-III, the subsequent revisions of the DSM, and the impact of the official recognition of autism on research. We discuss the uses of categorical vs. dimensional approaches and the continuing tensions around broad vs. narrow views of autism. We also note some areas of current controversy and directions for the future.

The ALSPAC fetal and neonatal resource: detailed data abstracted from the clinical records of the new-born

In a previous Data Note, we outlined the data obtained from clinical obstetric records concerning many details of the pregnancies resulting in the births of the children in the Avon Longitudinal Study of Parents and Children (ALSPAC). Here we describe the data that have been abstracted from medical records concerning the fetus and neonate. Full details concerning the selection biases regarding the data abstracted are outlined in the previous Data Note. The records that have been abstracted, and described in this Data Note, concern the health of the fetus (measured in relation to the results of fetal monitoring, presentation at various stages of pregnancy, and the method of delivery) as well as the status of the newborn immediately post-delivery. Details of signs, symptoms and treatments of this population of new-born babies, as recorded in the clinical records, are described for the time during which they were in hospital or under the care of a designated midwife. These data add depth to the information collected from elsewhere concerning this period of the child’s life: from the questionnaires completed at the time by the mother; and clinical details from neonatal intensive or special care units which will be detailed in a further Data Note.

Validation of Autism Diagnosis and Clinical Data in the SPARK Cohort

The SPARK cohort was established to facilitate recruitment in studies of large numbers of participants with autism spectrum disorder (ASD). Online registration requires participants to have received a lifetime professional diagnosis by health or school providers although diagnoses are not independently verified. This study was set to examine the validity of self- and caregiver-reported autism diagnoses. Electronic medical records (EMR) of 254 SPARK participants (77.6% male, age 10.7 years) were abstracted. Using two different methods, confirmation of ASD diagnosis in EMRs was obtained in 98.8% of cases. Core clinical features recorded in EMRs were typical of autism samples and showed very good agreement with SPARK cohort data, providing further evidence of the validity of clinical information in the SPARK database.

Exploratory spatial analysis of autism rates in New York school districts: role of sociodemographic and language differences

Background

Literature on autism spectrum disorder (ASD) suggests lower ASD prevalence and higher age of diagnosis among children of color, from lower socioeconomic backgrounds, and from families with lower educational levels. These disparities have been attributed to factors such as limited access to diagnostic and treatment services, less opportunity for upward mobility to locales with ample resources, and linguistic barriers. However, few studies describe prevalence and geographic differences of ASD diagnoses by English Language Learner (ELL) status.

Objectives

The primary objectives of this study are to (1) spatially explore the prevalence of ASD among New York State school districts and (2) examine differences of ASD prevalence rates between ELLs and native English-speaking peers.

Methods

Using the 2016–2017 district-level data on public and non-public school age students (3–21 years old) receiving special education services in New York, we analyzed sociodemographic trends among school districts with varying percentages (low, medium, and high ranges) of students with ASD and ELLs. To do this, we conducted exploratory spatial analyses using GIS software, analysis of school district level demographic data, and multivariate linear regression.

Results

In contrast to prior research on ASD prevalence among minority groups, we found disproportionately higher rates of ASD among school districts with higher proportions of Black and Hispanic students. Geographic analysis revealed statistically significant clustering of school districts with high ASD rates in New York City and Albany. Higher proportions of ELLs tended to be concentrated in densely populated, urban, and geographically smaller school districts and had higher proportions of Black, Hispanic, and Asian students.

Conclusions

Schools with higher rates of ASD and ELL students tend to be concentrated in urban regions throughout New York and have higher representation of Black and Hispanic/Latino students, as well as higher rates of learning disabilities in general. Further research is warranted to explore possible reasons for this phenomenon.

Are school psychologists' special education eligibility decisions reliable and unbiased?: A multi-study experimental investigation

Nearly 50 years of research show persistent racial disproportionality in the identification of special education disabilities, but the underlying mechanisms for these disparities remain largely unexplored. Because ambiguous regulations defining disabilities may allow subjectivity and unlawful differential treatment (i.e., racial bias or discrimination) in the special education eligibility process, an important target of study is disparate treatment of students by race in evaluations required to determine eligibility. School psychologists have long been recognized as highly influential in this process and in schools' resultant decisions. We used a 3 × 2 mixed factorial experimental design in three studies with simulated case report data to measure the influence of race and assessment data on school psychologists' perceptions of students' eligibility for special education in cases centering on emotional disturbance, intellectual disability, or autism, respectively. Participants included 302 practicing school psychologists in three states across the three experiments. There was little evidence of racial disparity, but participants tended to render decisions unsupported by, and even contrary to, evaluation data. Implications for research, practice, and professional development are discussed.

Perceived need for neuropsychological assessment according to geographic location: A survey of Australian youth mental health clinicians

Recent studies have shown that neuropsychological assessment is a scarce resource in youth mental health settings. The need for neuropsychological assessment might differ in metropolitan and nonmetropolitan areas due to characteristics inherent to these different regions. However, no formal studies have investigated this question. The aim of this research was to investigate whether need for neuropsychological assessment in youth mental health settings varies by geographic location. A cross-sectional online survey was completed by clinicians (N = 532) treating or assessing adolescents and young adults attending Australian primary care mental health (headspace) centers. Results indicated a similar need for neuropsychological assessment across the geographic areas. However, neuropsychological assessment was significantly less available to clients in outer regional, remote and very remote areas compared to major cities. Exploratory analyses further revealed that there were significantly fewer clinicians with a postgraduate degree and more clinicians with a bachelor degree in outer regional, remote and very remote areas than in major cities. Given the negative impact of cognitive impairments in youth with a mental illness, these findings reveal a necessity to enhance the availability and access to neuropsychological assessment in rural settings. Several plausible avenues to achieving increased access include increasing the funding available for this resource; providing nonmetropolitan clinicians with sufficient neuropsychological consultation, including rural training and rotations in neuropsychologists' postgraduate training; and exploring the use of tele-health in the provision of neuropsychological assessments in nonmetropolitan settings.

Structured Variation in Parental Beliefs about Autism

We used data from the 2011 Survey of Pathways to Diagnosis and Services (N = 1,420) to evaluate a conceptual model linking social background (race-ethnicity, socioeconomic status [SES]) to parental distress through children's clinical profiles and parental beliefs about the nature and causes of their child's autism. Children's clinical profiles varied by social background; white children and children of more highly educated and affluent parents were less likely to experience comorbid conditions and were more likely to be diagnosed with Asperger's. Parental beliefs also varied such that parents of racial-ethnic minority children and parents of lower SES perceived their child's condition as more uncertain and were less likely to attribute it to genetic causes. Parents of Hispanic children and with lower incomes were more likely to be upset by the child's condition. Although parental beliefs had independent associations with distress, children's clinical profiles contributed more to explaining variation in distress.

Annual trends in prevalence and incidence of autism spectrum disorders in Manitoba preschoolers and toddlers: 2004-2015

OBJECTIVES

Autism spectrum disorders (ASD) are among the leading causes of disabilities in children. We examined the annual prevalence and incidence rate of ASD between 2004 and 2015 in children aged 1 to 5 years residing in Manitoba.

METHODS

A population-based study was conducted using the Manitoba Population Research Data Repository. The study included children aged 1 to 5 years residing in Manitoba between 2004 and 2015. Standard identification algorithm was used to identify ASD cases from hospital abstracts and medical claims. Annual prevalence and incidence rates were calculated for the overall population and then stratified according to sex, region, and socio-economic status (SES). Multivariable negative binomial regression models, adjusted for sex, region, and SES, were used to examine changes in prevalence and incidence over study years.

RESULTS

Among children aged 1 to 5 years, 1685 ASD cases were diagnosed between 2004 and 2015. The crude ASD prevalence increased from 0.46% in 2004 to 0.97% in 2015 (p = 0.002). The crude incidence rate increased from 0.16% in 2004 to 0.39% in 2015 (p = 0.002). The increase in ASD prevalence and incidence was observed in all subgroups based on sex, region, and SES. The adjusted negative binomial model showed an annual relative risk increase, since 2004, for both prevalence and incidence of 1.69 (95% CI 1.56-1.83) and 1.84 (95% CI 1.62-2.09), respectively.

CONCLUSION

During the period from 2004 to 2015, both prevalence and incidence rates of diagnosed ASD in preschoolers and toddlers residing in Manitoba increased significantly.

Brief Report: Regional Variations in Characteristics of ASD Hospitalizations in the U.S

Regional differences in ASD inpatient care remain understudied. We used the Nationwide Inpatient Sample to examine contributory causes and potential determinants associated with regional variations in ASD hospitalizations. We performed univariate and multivariate analyses to identify differences in ASD hospitalizations across four U.S. Census Bureau-defined regions. Our results revealed considerable variations in ASD hospitalizations across U.S. regions. Compared with patients in the Northeast, those in the Midwest, South, and West were less likely to be hospitalized for ASD. Significant differences were observed among regions with regard to the effect of health insurance type, hospital length of stay, hospital bed size, hospital location and teaching status on ASD hospitalizations. The region-specific analysis provides direction for further investigation.

Psychotropic medication in children and adolescents in the United States in the year 2004 vs 2014

BACKGROUND

There is a global perception that psychotropic utilization in children and adolescents is increasing in the US.

METHODS

We present prevalent estimates for all psychotropics prescribed in the US (using commercial claims from Medicare and Medicaid) to children and adolescents in 2004 (total population N = 6,808,453) and in 2014 (total population N = 11,082.260). Further we evaluated if there has been a statistically significant change in prevalence during this time period. Analyses were stratified for the 6 major drug classes, all individuals' psychotropics (87 drugs), age and sex.

RESULTS

The prevalence of psychotropic drug prescription was 8.55% in 2004 and 9.00% in 2014 (age stratified in 2004 and 2014 toddlers: 3.08 and 2.63%, children: 8.74 and 8.73%, adolescents: 10.89% and 12.11). The prevalence for each drug class in 2004 and 2014 was: stimulants/other ADHD drugs 5.0 and 5.8%; antidepressants 2.8 and 2.7%; anxiolytic-hypnotic-sedative 2.2 and 2.3%; mood stabilizers 0.1 and 0.1%; antipsychotics 1.3 and 1.1%; and for drugs treating drug dependence 0.02 and 0.02%.

CONCLUSIONS

The perception that psychotropic utilization in children and adolescents is increasing in the US, derived from the 2 to 3 fold increase seen from the mid 80's to the mid 90's is not valid anymore. There has been a slowdown in the increase of prescribing psychotropics. In the last 10 years, in toddlers there was a decrease in the prescription; in children there was no change; and in adolescents there was a slight increase. The prescription of antidepressants, antipsychotics and mood stabilizers has decreased overall. Graphical abstract In the last 10 years there has been a slowdown in the increase of prescribing psychotropics. In toddlers there was a decrease in the prescription (3.08 and 2.63%); in children (8.74 and 8.73%) there was no change; and in adolescents there was a slight increase (10.89% and 12.11). The prescription of antidepressants, antipsychotics and mood stabilizers has decreased overall.

Safety and Efficacy of Memantine in Children with Autism: Randomized, Placebo-Controlled Study and Open-Label Extension

OBJECTIVE

Abnormal glutamatergic neurotransmission is implicated in the pathophysiology of autism spectrum disorder (ASD). In this study, the safety, tolerability, and efficacy of the glutamatergic N-methyl-d-aspartate (NMDA) receptor antagonist memantine (once-daily extended-release [ER]) were investigated in children with autism in a randomized, placebo-controlled, 12 week trial and a 48 week open-label extension.

METHODS

A total of 121 children 6-12 years of age with Diagnostic and Statistical Manual of Mental Disorders, 4th ed., Text Revision (DSM-IV-TR)-defined autistic disorder were randomized (1:1) to placebo or memantine ER for 12 weeks; 104 children entered the subsequent extension trial. Maximum memantine doses were determined by body weight and ranged from 3 to 15 mg/day.

RESULTS

There was one serious adverse event (SAE) (affective disorder, with memantine) in the 12 week study and one SAE (lobar pneumonia) in the 48 week extension; both were deemed unrelated to treatment. Other AEs were considered mild or moderate and most were deemed not related to treatment. No clinically significant changes occurred in clinical laboratory values, vital signs, or electrocardiogram (ECG). There was no significant between-group difference on the primary efficacy outcome of caregiver/parent ratings on the Social Responsiveness Scale (SRS), although an improvement over baseline at Week 12 was observed in both groups. A trend for improvement at the end of the 48 week extension was observed. No improvements in the active group were observed on any of the secondary end-points, with one communication measure showing significant worsening with memantine compared with placebo (p = 0.02) after 12 weeks.

CONCLUSIONS

This trial did not demonstrate clinical efficacy of memantine ER in autism; however, the tolerability and safety data were reassuring. Our results could inform future trial design in this population and may facilitate the investigation of memantine ER for other clinical applications.

Poverty and Trends in Three Common Chronic Disorders

OBJECTIVES

For asthma, attention-deficit/hyperactivity disorder (ADHD), and autism spectrum disorder (ASD), the objectives were to (1) describe the percent increases in prevalence and comorbidity and how these vary by poverty status, and (2) examine the extent to which poverty status is a predictor of higher than average comorbid conditions.

METHODS

Secondary analyses of the National Survey of Children's Health for years 2003, 2007, and 2011-2012 were conducted to identify trends in parent reported lifetime prevalence and comorbidity among children with asthma, ADHD, and ASD and examine variation by sociodemographic characteristics, poverty status, and insurance coverage. Using 2011-2012 data, multivariable regression was used to examine whether poverty status predicted higher than average comorbid conditions after adjusting for other sociodemographic characteristics.

RESULTS

Parent-reported lifetime prevalence of asthma and ADHD rose 18% and 44%, respectively, whereas the lifetime prevalence of ASD rose almost 400% (from 0.5% to 2%). For asthma, the rise was most prominent among the poor at 25.8%. For ADHD, the percent change by poverty status was similar (<100% federal poverty level [FPL]: 43.20%, 100% to 199% FPL: 52.38%, 200% to 399% FPL: 43.67%), although rise in ASD was associated with being nonpoor (200% to 399% FPL: 43.6%, ≥400% FPL: 36.0%). Publicly insured children with asthma, ADHD, and ASD also had significantly higher odds (1.9×, 1.6×, 3.0×, respectively) of having higher than average comorbidities.

CONCLUSIONS

Poverty status differentially influenced parent-reported lifetime prevalence and comorbidities of these target disorders. Future research is needed to examine parent and system-level characteristics that may further explain poverty's variable impact.

Autism spectrum disorder reporting in lower socioeconomic neighborhoods

Utilizing surveillance data from five sites participating in the Autism and Developmental Disabilities Monitoring Network, we investigated contributions of surveillance subject and census tract population sociodemographic characteristics on variation in autism spectrum disorder ascertainment and prevalence estimates from 2000 to 2008 using ordinal hierarchical models for 2489 tracts. Multivariable analyses showed a significant increase in ascertainment of autism spectrum disorder cases through both school and health sources, the optimal ascertainment scenario, for cases with college-educated mothers (adjusted odds ratio = 1.06, 95% confidence interval = 1.02–1.09). Results from our examination of sociodemographic factors of tract populations from which cases were drawn also showed that after controlling for other covariates, statistical significance remained for associations between optimal ascertainment and percentage of Hispanic residents (adjusted odds ratio = 0.93, 95% confidence interval = 0.88–0.99) and percentage of residents with at least a bachelor’s degree (adjusted odds ratio = 1.06, 95% confidence interval = 1.01–1.11). We identified sociodemographic factors associated with autism spectrum disorder prevalence estimates including race, ethnicity, education, and income. Determining which specific factors influence disparities is complicated; however, it appears that even in the presence of education, racial and ethnic disparities are still apparent. These results suggest disparities in access to autism spectrum disorder assessments and special education for autism spectrum disorder among ethnic groups may impact subsequent surveillance.

Hypothesis on supine sleep, sudden infant death syndrome reduction and association with increasing autism incidence

AIM: To identify a hypothesis on: Supine sleep, sudden infant death syndrome (SIDS) reduction and association with increasing autism incidence.

METHODS: Literature was searched for autism spectrum disorder incidence time trends, with correlation of change-points matching supine sleep campaigns. A mechanistic model expanding the hypothesis was constructed based on further review of epidemiological and other literature on autism.

RESULTS: In five countries (Denmark, United Kingdom, Australia, Israel, United States) with published time trends of autism, change-points coinciding with supine sleep campaigns were identified. The model proposes that supine sleep does not directly cause autism, but increases the likelihood of expression of a subset of autistic criteria in individuals with genetic susceptibility, thereby specifically increasing the incidence of autism without intellectual disability.

CONCLUSION: Supine sleep is likely a physiological stressor, that does reduce SIDS, but at the cost of impact on emotional and social development in the population, a portion of which will be susceptible to, and consequently express autism. A re-evaluation of all benefits and harms of supine sleep is warranted. If the SIDS mechanism proposed and autism model presented can be verified, the research agenda may be better directed, in order to further decrease SIDS, and reduce autism incidence.

Astrocytes and Microglia and Their Potential Link with Autism Spectrum Disorders

The cellular mechanism(s) underlying autism spectrum disorders (ASDs) are not fully understood although it has been shown that various genetic and environmental factors contribute to their etiology. As increasing evidence indicates that astrocytes and microglial cells play a major role in synapse maturation and function, and there is evidence of deficits in glial cell functions in ASDs, one current hypothesis is that glial dysfunctions directly contribute to their pathophysiology. The aim of this review is to summarize microglia and astrocyte functions in synapse development and their contributions to ASDs.

A Pilot Study Examining the Use of the Autism Diagnostic Observation Schedule in Community-Based Mental Health Clinics

Community-based mental health (CMH) services play an important, but relatively understudied role in the identification and treatment of youth with autism spectrum disorder (ASD) who may be receiving care for other psychiatric conditions. Little is known about the role of standardized ASD assessment measures administered by providers working in generalist community-based mental health (CMH) settings. This pilot study extracted data from three CMH clinics to examine the use of the Autism Diagnostic Observation Schedule (ADOS) by 17 CMH providers who received ASD assessment training with 62 youth (Mean = 10.69 years) referred for an ASD diagnostic evaluation. Results indicated that 57% of youths assessed ultimately received an ASD diagnosis. All cases given a final ASD diagnosis were classified as "Autism" or "ASD" on the ADOS. Seventy percent of youth who did not receive a final ASD diagnosis were classified as "Non-Spectrum" on the ADOS. In these false positive cases, report narratives indicated that social communication difficulties identified on the ADOS were explained by symptoms of other mental health conditions (e.g., ADHD, anxiety). Future research is needed to examine the utility of the ADOS when used by CMH providers to facilitate CMH capacity to identify ASD.

Heritability of Autism Spectrum Disorder in a UK Population-Based Twin Sample

IMPORTANCE

Most evidence to date highlights the importance of genetic influences on the liability to autism and related traits. However, most of these findings are derived from clinically ascertained samples, possibly missing individuals with subtler manifestations, and obtained estimates may not be representative of the population.

OBJECTIVES

To establish the relative contributions of genetic and environmental factors in liability to autism spectrum disorder (ASD) and a broader autism phenotype in a large population-based twin sample and to ascertain the genetic/environmental relationship between dimensional trait measures and categorical diagnostic constructs of ASD.

DESIGN, SETTING, AND PARTICIPANTS

We used data from the population-based cohort Twins Early Development Study, which included all twin pairs born in England and Wales from January 1, 1994, through December 31, 1996. We performed joint continuous-ordinal liability threshold model fitting using the full information maximum likelihood method to estimate genetic and environmental parameters of covariance. Twin pairs underwent the following assessments: the Childhood Autism Spectrum Test (CAST) (6423 pairs; mean age, 7.9 years), the Development and Well-being Assessment (DAWBA) (359 pairs; mean age, 10.3 years), the Autism Diagnostic Observation Schedule (ADOS) (203 pairs; mean age, 13.2 years), the Autism Diagnostic Interview-Revised (ADI-R) (205 pairs; mean age, 13.2 years), and a best-estimate diagnosis (207 pairs).

MAIN OUTCOMES AND MEASURES

Participants underwent screening using a population-based measure of autistic traits (CAST assessment), structured diagnostic assessments (DAWBA, ADI-R, and ADOS), and a best-estimate diagnosis.

RESULTS

On all ASD measures, correlations among monozygotic twins (range, 0.77-0.99) were significantly higher than those for dizygotic twins (range, 0.22-0.65), giving heritability estimates of 56% to 95%. The covariance of CAST and ASD diagnostic status (DAWBA, ADOS and best-estimate diagnosis) was largely explained by additive genetic factors (76%-95%). For the ADI-R only, shared environmental influences were significant (30% [95% CI, 8%-47%]) but smaller than genetic influences (56% [95% CI, 37%-82%]).

CONCLUSIONS AND RELEVANCE

The liability to ASD and a more broadly defined high-level autism trait phenotype in this large population-based twin sample derives primarily from additive genetic and, to a lesser extent, nonshared environmental effects. The largely consistent results across different diagnostic tools suggest that the results are generalizable across multiple measures and assessment methods. Genetic factors underpinning individual differences in autismlike traits show considerable overlap with genetic influences on diagnosed ASD.

Carbon monoxide pollution and neurodevelopment: A public health concern

Although an association between air pollution and adverse systemic health effects has been known for years, the effect of pollutants on neurodevelopment has been underappreciated. Recent evidence suggests a possible link between air pollution and neurocognitive impairment and behavioral disorders in children, however, the exact nature of this relationship remains poorly understood. Infants and children are uniquely vulnerable due to the potential for exposure in both the fetal and postnatal environments during critical periods in development. Carbon monoxide (CO), a common component of indoor and outdoor air pollution, can cross the placenta to gain access to the fetal circulation and the developing brain. Thus, CO is of particular interest as a known neurotoxin and a potential public health threat. Here we review overt CO toxicity and the policies regulating CO exposure, detail the evidence suggesting a potential link between CO-associated ambient air pollution, tobacco smoke, and learning and behavioral abnormalities in children, describe the effects of subclinical CO exposure on the brain during development, and provide mechanistic insight into a potential connection between CO exposure and neurodevelopmental outcome. CO can disrupt a number of critical processes in the developing brain, providing a better understanding of how this specific neurotoxin may impair neurodevelopment. However, further investigation is needed to better define the effects of perinatal CO exposure on the immature brain. Current policies regarding CO standards were established based on evidence of cardiovascular risk in adults with pre-existing comorbidities. Thus, recent and emerging data highlighted in this review regarding CO exposure in the fetus and developing child may be important to consider when the standards and guidelines are evaluated and revised in the future.

Blood lead concentrations in Jamaican children with and without autism spectrum disorder

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder manifesting by early childhood. Lead is a toxic metal shown to cause neurodevelopmental disorders in children. Several studies have investigated the possible association between exposure to lead and ASD, but their findings are conflicting. Using data from 100 ASD cases (2–8 years of age) and their age- and sex-matched typically developing controls, we investigated the association between blood lead concentrations (BLC) and ASD in Jamaican children. We administered a questionnaire to assess demographic and socioeconomic information as well as exposure to potential lead sources. We used General Linear Models (GLM) to assess the association of BLC with ASD status as well as with sources of exposure to lead. In univariable GLM, we found a significant difference between geometric mean blood lead concentrations of ASD cases and controls (2.25 μg/dL cases vs. 2.73 μg/dL controls, p < 0.05). However, after controlling for potential confounders, there were no significant differences between adjusted geometric mean blood lead concentrations of ASD cases and controls (2.55 μg/dL vs. 2.72 μg/dL, p = 0.64). Our results do not support an association between BLC and ASD in Jamaican children. We have identified significant confounders when assessing an association between ASD and BLC.

Urbanicity and autism spectrum disorders

The etiology of autism spectrum disorders (ASD) is for the majority of cases unknown and more studies of risk factors are needed. Geographic variation in ASD occurrence has been observed, and urban residence has been suggested to serve as a proxy for etiologic and identification factors in ASD. We examined the association between urbanicity level and ASD at birth and during childhood. The study used a Danish register-based cohort of more than 800,000 children of which nearly 4,000 children were diagnosed with ASD. We found a dose-response association with greater level of urbanicity and risk of ASD. This association was found for residence at birth as well as residence during childhood. Further, we found an increased risk of ASD in children who moved to a higher level of urbanicity after birth. Also, earlier age of ASD diagnosis in urban areas was observed. While we could not directly examine the specific reasons behind these associations, our results demonstrating particularly strong associations between ASD diagnosis and post-birth migration suggest the influence of identification-related factors such as access to services might have a substantive role on the ASD differentials we observed.

A cross-cultural comparison of autistic traits in the UK, India and Malaysia

The disorder of autism is widely recognised throughout the world. However, the diagnostic criteria and theories of autism are based on research predominantly conducted in Western cultures. Here we compare the expression of autistic traits in a sample of neurotypical individuals from one Western culture (UK) and two Eastern cultures (India and Malaysia), using the Autism-spectrum Quotient (AQ) in order to identify possible cultural differences in the expression of autistic traits. Behaviours associated with autistic traits were reported to a greater extent in the Eastern cultures than the Western culture. Males scored higher than females and science students scored higher than non-science students in each culture. Indian students scored higher than both other groups on the Imagination sub-scale, Malaysian students scored higher than both other groups on the Attention Switching sub-scale. The underlying factor structures of the AQ for each population were derived and discussed.

The incidence of diagnosed autism spectrum disorders in Finland

BACKGROUND

Previous reports indicate an increase in incidence of autism spectrum disorders (ASD).

AIMS

First, to assess the incidence of diagnosed ASD in children born between 1996 and 1998, based on nationwide inpatient and outpatient register information. Second, to investigate the incidence rate over time of diagnosed ASD and specifically childhood autism, Asperger's syndrome and pervasive developmental disorder (PDD-NOS) in children born between 1987 and 1998.

METHODS

This is population-based cohort study with children born in Finland between 1 January 1987 and 31 December 2005; a total of more than 1.2 million children. Children were identified in the Finnish Hospital Discharge Register, and the reported diagnoses were based on the International Statistical Classification of Diseases (ICD-10, ICD-9).

RESULTS

The annual incidence rate of diagnosed ASD based on inpatient and outpatient register data was 53.7 per 10,000 (95% CI 50.4-57.2). Incidence was 82.6 per 10,000 in boys and 23.6 per 10,000 in girls, yielding a sex ratio (boys:girls) of 3.5:1. We report an eightfold increase in the incidence rates in children of diagnosed ASD and specifically in childhood autism, Asperger's syndrome and PDD-NOS and born between 1987 and 1992 based on inpatient register information.

CONCLUSIONS

Increased awareness of ASD, more precise diagnostic criteria and changes in practice for diagnosing autism may have had a substantial effect on the increased incidence of inpatient treated ASD cases from 1987 to 1992. Between 1992 and 1998, the incidence rate based on inpatient and outpatient service use remained rather stable.

Association between Kawasaki disease and autism: a population-based study in Taiwan

Objective: The association between Kawasaki disease and autism has rarely been studied in Asian populations. By using a nationwide Taiwanese population-based claims database, we tested the hypothesis that Kawasaki disease may increase the risk of autism in Taiwan. Materials and Methods: Our study cohort consisted of patients who had received the diagnosis of Kawasaki disease (ICD-9-CM: 446.1) between 1997 and 2005 (N = 563). For a comparison cohort, five age- and gender-matched control patients for every patient in the study cohort were selected using random sampling (N = 2,815). All subjects were tracked for 5 years from the date of cohort entry to identify whether they had developed autism (ICD-9-CM code 299.0) or not. Cox proportional hazard regressions were then performed to evaluate 5-year autism-free survival rates. Results: The main finding of this study was that patients with Kawasaki disease seem to not be at increased risk of developing autism. Of the total patients, four patients developed autism during the 5-year follow-up period, among whom two were Kawasaki disease patients and two were in the comparison cohort. Further, the adjusted hazard ratios (AHR) (AHR: 4.81; 95% confidence interval: 0.68–34.35; P = 0.117) did not show any statistical significance between the Kawasaki disease group and the control group during the 5-year follow-up. Conclusion: Our study indicated that patients with Kawasaki disease are not at increased risk of autism.

Treating the whole person with autism: the proceedings of the Autism Speaks National Autism Conference

The identification of autism spectrum disorders has increased dramatically over the past decade, with the latest estimates indicating prevalence as high as 1 in 54 boys. There is greater awareness of medical conditions that co-occur with autism and expansion of treatment options. Closer scrutiny has led to refinement of the diagnostic criteria, and there have been advances in genetics examining potential causal factors. Transition to adulthood is an area of growing concern, and professionals and families require guidance on this issue. This article summarizes the proceedings of the Autism Speaks conference on Treating the Whole Person with Autism: Care across the Lifespan. The conference was organized with the intent of providing a forum for both families and professionals to learn about the most current research in the field. Dr. Sue Swedo provides important background information regarding the changes in the diagnostic criteria for autism spectrum disorders. She particularly deals with the concerns of individuals and families that their autism diagnosis may change. Recommendations for genetic testing and its interpretation are provided by Dr. David Miller. His discussion helps make sense of the utility of genetic testing for ASD, along with demonstration of the complexity of determining which genetic factors are doing what and through which pathways. Dr. Jeremy Veenstra-VanderWeele provides useful background information on how medicines are initially identified and for what purpose and goes on to describe the present and future treatments in pharmacology. Medical issues are addressed by Dr. Paul Carbone, especially the coordination of comprehensive services through the medical home model of care. Dr. Julie Lounds Taylor concludes with guidance on preparation for adulthood, a topic of great importance to families as their child matures and for the professionals who will help guide this transition.

A novel computational biostatistics approach implies impaired dephosphorylation of growth factor receptors as associated with severity of autism

The prevalence of autism spectrum disorders (ASDs) has increased 20-fold over the past 50 years to >1% of US children. Although twin studies attest to a high degree of heritability, the genetic risk factors are still poorly understood. We analyzed data from two independent populations using u-statistics for genetically structured wide-locus data and added data from unrelated controls to explore epistasis. To account for systematic, but disease-unrelated differences in (non-randomized) genome-wide association studies (GWAS), a correlation between P-values and minor allele frequency with low granularity data and for conducting multiple tests in overlapping genetic regions, we present a novel study-specific criterion for 'genome-wide significance'. From recent results in a comorbid disease, childhood absence epilepsy, we had hypothesized that axonal guidance and calcium signaling are involved in autism as well. Enrichment of the results in both studies with related genes confirms this hypothesis. Additional ASD-specific variations identified in this study suggest protracted growth factor signaling as causing more severe forms of ASD. Another cluster of related genes suggests chloride and potassium ion channels as additional ASD-specific drug targets. The involvement of growth factors suggests the time of accelerated neuronal growth and pruning at 9-24 months of age as the period during which treatment with ion channel modulators would be most effective in preventing progression to more severe forms of autism. By extension, the same computational biostatistics approach could yield profound insights into the etiology of many common diseases from the genetic data collected over the last decade.

Autism assessment: the Melton Health model

AIM

The following paper describes the Autism Spectrum Assessment Clinic which operates at Melton Health, a publically funded health service in Melbourne's west.

METHODS

A retrospective audit of 234 children assessed between 2007 and 2012 in the Autism Spectrum Assessment Clinic was undertaken. Characteristics of the children assessed (age, sex, locality, referral source) were examined along with characteristics of the clinic (clinicians, assessment outcome).

RESULTS

A detailed description of the model is provided, including evident changes since the clinic began. Data were split between the 2007 to 2009 and 2010 to 2012 time periods to reflect changes in the operation of the clinic. Overall, 48 girls and 186 boys were assessed with a mean age of 71 months; the average waiting time between referral and assessment was 136.6 days. Across the two time periods, the proportion of children receiving a diagnosis of autism spectrum disorder increased from 43.1% to 66.3%. Changes are evident in the referral sources between the two time periods, and in the disciplines of clinicians involved in the assessment.

CONCLUSIONS

The research illustrates an assessment model, within the Victorian public health context, which currently operates effectively according to best-practice guidelines. This research begins to fill a gap between localised clinical practice and the dissemination of this information to a wider audience, allowing for comparison for other assessment providers. It is hoped that we can contribute more broadly to future assessment processes becoming more consistent, reproducible and equitable for children suspected of having autism spectrum disorders.

Views on the diagnostic labels of autism and Asperger's disorder and the proposed changes in the DSM

With the approaching release of the DSM V in 2013, there has been much debate about the proposal to remove the diagnostic label of Asperger's disorder from the new DSM. This study explored how health and education professionals perceive the conditions of autism and Asperger's disorder and their views on the proposed diagnostic changes. Analysis of the 547 participant responses confirmed an increase stigma is associated with the label of autism, with autism considered to be a more severe than the condition of Asperger's disorder. Approximately half of the participants reported being opposed to proposed diagnostic changes and of the remaining participants, 22% supported the proposed changes and 28% expressed uncertainty.

Autism spectrum disorders--are they really epidemic?

AIM

The aim of this paper is to report on how different external methodological factors influence estimates of ASD prevalence.

METHODS

PubMed searches was conducted using the search terms, "Autism", "Autistic Disorder", "Autism Spectrum Disorders", "Asperger", "Prevalence" and "epidemiology", in combination. In total 49 studies were included. We also performed a manual search for and reviewed related articles referenced in the original articles.

RESULTS

The reported prevalence rates of ASD vary widely, and so do the methodology used in the studies.

CONCLUSION

There are reasons to argue that the methods used in some studies cause the high prevalence rates reported recently.

Toward developmental models of psychiatric disorders in zebrafish

Psychiatric disorders are a diverse set of diseases that affect all aspects of mental function including social interaction, thinking, feeling, and mood. Although psychiatric disorders place a large economic burden on society, the drugs available to treat them are often palliative with variable efficacy and intolerable side-effects. The development of novel drugs has been hindered by a lack of knowledge about the etiology of these diseases. It is thus necessary to further investigate psychiatric disorders using a combination of human molecular genetics, gene-by-environment studies, in vitro pharmacological and biochemistry experiments, animal models, and investigation of the non-biological basis of these diseases, such as environmental effects. Many psychiatric disorders, including autism spectrum disorder, attention-deficit/hyperactivity disorder, mental retardation, and schizophrenia can be triggered by alterations to neural development. The zebrafish is a popular model for developmental biology that is increasingly used to study human disease. Recent work has extended this approach to examine psychiatric disorders as well. However, since psychiatric disorders affect complex mental functions that might be human specific, it is not possible to fully model them in fish. In this review, I will propose that the suitability of zebrafish for developmental studies, and the genetic tools available to manipulate them, provide a powerful model to study the roles of genes that are linked to psychiatric disorders during neural development. The relative speed and ease of conducting experiments in zebrafish can be used to address two areas of future research: the contribution of environmental factors to disease onset, and screening for novel therapeutic compounds.

Modifiable risk factors for schizophrenia and autism--shared risk factors impacting on brain development

Schizophrenia and autism are two poorly understood clinical syndromes that differ in age of onset and clinical profile. However, recent genetic and epidemiological research suggests that these two neurodevelopmental disorders share certain risk factors. The aims of this review are to describe modifiable risk factors that have been identified in both disorders, and, where available, collate salient systematic reviews and meta-analyses that have examined shared risk factors. Based on searches of Medline, Embase and PsycINFO, inspection of review articles and expert opinion, we first compiled a set of candidate modifiable risk factors associated with autism. Where available, we next collated systematic-reviews (with or without meta-analyses) related to modifiable risk factors associated with both autism and schizophrenia. We identified three modifiable risk factors that have been examined in systematic reviews for both autism and schizophrenia. Advanced paternal age was reported as a risk factor for schizophrenia in a single meta-analysis and as a risk factor in two meta-analyses for autism. With respect to pregnancy and birth complications, for autism one meta-analysis identified maternal diabetes and bleeding during pregnancy as risks factors for autism whilst a meta-analysis of eight studies identified obstetric complications as a risk factor for schizophrenia. Migrant status was identified as a risk factor for both autism and schizophrenia. Two separate meta-analyses were identified for each disorder. Despite distinct clinical phenotypes, the evidence suggests that at least some non-genetic risk factors are shared between these two syndromes. In particular, exposure to drugs, nutritional excesses or deficiencies and infectious agents lend themselves to public health interventions. Studies are now needed to quantify any increase in risk of either autism or schizophrenia that is associated with these modifiable environmental factors.

Gene × gene interaction in shared etiology of autism and specific language impairment

BACKGROUND

To examine the relationship between autism spectrum disorders (ASD) and specific language impairment (SLI), family studies typically take a comparative approach where families with one disease are examined for traits of the other disease. In contrast, the present report is the first study with both disorders required to be present in each family to provide a more direct test of the hypothesis of shared genetic etiology.

METHODS

We behaviorally assessed 51 families including at least one person with ASD and at least one person with SLI (without ASD). Pedigree members were tested with 22 standardized measures of language and intelligence. Because these extended families include a nonshared environmental contrast, we calculated heritability, not just familiality, for each measure twice: 1) baseline heritability analysis, compared with; 2) heritability estimates after statistically removing ASD subjects from pedigrees.

RESULTS

Significant increases in heritability on four supra-linguistic measures (including Pragmatic Judgment) and a composite language score but not on any other measures were observed when removing ASD subjects from the analysis, indicating differential genetic effects that are unique to ASD. Nongenetic explanations such as effects of ASD severity or measurement error or low score variability in ASD subjects were systematically ruled out, leaving the hypothesis of nonadditive genetics effects as the potential source of the heritability change caused by ASD.

CONCLUSIONS

Although the data suggest genetic risk factors common to both SLI and ASD, there are effects that seem unique to ASD, possibly caused by nonadditive gene-gene interactions of shared risk loci.

Mood disorders in mothers of children on the autism spectrum are associated with higher functioning autism

Mood disorders occur more frequently in family members of individuals with autism spectrum disorders (ASD) than in the general population. There may be associations between maternal mood disorder history patterns and specific ASD phenotypes. We therefore examined the relationship between maternal mood disorders and child autism spectrum disorders in 998 mother-child dyads enrolled in a national online autism registry and database. Mothers of children with ASD completed online questionnaires addressing their child's ASD as well as their own mood disorder history. In multivariate logistic regression models of ASD diagnoses, the odds of an Asperger disorder versus autistic disorder diagnosis were higher among those children whose mothers had a lifetime history of bipolar disorder (OR 2.11, CI 1.20, 3.69) or depression (OR 1.62, CI 1.19, 2.19). Further, maternal mood disorder onset before first pregnancy was associated with higher odds (OR 2.35, CI 1.48, 3.73) of an Asperger versus autism diagnosis among this sample of children with ASD. These data suggest that differences in maternal mood disorder history may be associated with ASD phenotype in offspring.

Verification of parent-report of child autism spectrum disorder diagnosis to a web-based autism registry

Growing interest in autism spectrum disorder (ASD) research requires increasingly large samples to uncover epidemiologic trends; such a large dataset is available in a national, web-based autism registry, the Interactive Autism Network (IAN). The objective of this study was to verify parent-report of professional ASD diagnosis to the registry's database via a medical record review on a sample of IAN Research participants. Sixty-one percent of families agreed to participate; 98% (n = 116) of whom provided documentation verifying a professionally diagnosed ASD. Results of this study suggest that information collected from parents participating in IAN Research is valid, participants can be authenticated, and that scientists can both confidently use IAN data and recruit participants for autism research.