Final Recommendation Statement
Autism Spectrum Disorder in Young Children: Screening
February 16, 2016
Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.
|Children aged 18 to 30 months||The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for autism spectrum disorder (ASD) in young children for whom no concerns of ASD have been raised by their parents or a clinician.||I|
Clinician SummaryExpand All
|Population||Children aged 18 to 30 months for whom no concerns of autism spectrum disorder (ASD) have been raised by their parents or a clinician|
Grade: I (insufficient evidence)
|Risk Assessment||Although a number of potential risk factors for ASD have been identified, there is insufficient evidence to determine if certain risk factors modify the performance characteristics of ASD screening tests, such as the age at which screening is performed or other characteristics of the child or family.|
|Screening Tests||The most commonly studied tool is the Modified Checklist for Autism in Toddlers (M-CHAT) and its subsequent revisions. A positive finding should lead to a follow-up interview, which, if positive, should lead to a full diagnostic workup for ASD.|
|Treatment and Interventions||Treatments for ASD include behavioral, medical, educational, speech/language, and occupational therapy and complementary and alternative medicine approaches. Treatments for young children are primarily behavioral interventions, particularly early intensive behavioral and developmental interventions.|
|Balance of Benefits and Harms||The USPSTF concludes that there is insufficient evidence to assess the balance of benefits and harms of screening for ASD in young children for whom no concerns of ASD have been raised.|
|Other Relevant USPSTF Recommendations||The USPSTF has made a recommendation on screening for speech and language delays and disorders among children 5 years or younger. These recommendations are available on the USPSTF Web site (http://www.uspreventiveservicestaskforce.org).|
For a summary of the evidence systematically reviewed in making these recommendations, the full recommendation statement, and supporting documents, please go to http://www.uspreventiveservicestaskforce.org.
- Autism (healthfinder.gov)
- Autism Spectrum Disorder (Centers for Disease Control and Prevention)
- Autism Spectrum Disorder (MedlinePlus)
- JAMA Patient Page: Screening for Autism Spectrum Disorder
- Screening for Autism Spectrum Disorder in Young Children: Consumer Guide | Link to File
Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.
The U.S. Preventive Services Task Force (USPSTF) makes recommendations about the effectiveness of specific preventive care services for patients without obvious related signs or symptoms.
It bases its recommendations on the evidence of both the benefits and harms of the service and an assessment of the balance. The USPSTF does not consider the costs of providing a service in this assessment.
The USPSTF recognizes that clinical decisions involve more considerations than evidence alone. Clinicians should understand the evidence but individualize decision making to the specific patient or situation. Similarly, the USPSTF notes that policy and coverage decisions involve considerations in addition to the evidence of clinical benefits and harms.
Autism spectrum disorder is a developmental disorder characterized by persistent and significant impairments in social interaction and communication and restrictive and repetitive behaviors and activities, when these symptoms cannot be accounted for by another condition. In 2010, the prevalence of ASD in the United States was estimated at 14.7 cases per 1000 children, or 1 in 68 children, with substantial variability in estimates by region, sex, and race/ethnicity.1
The USPSTF found adequate evidence that currently available screening tests can detect ASD among children aged 18 to 30 months.
Benefits of Early Detection and Intervention or Treatment
The USPSTF found inadequate direct evidence on the benefits of screening for ASD in toddlers and preschool-age children for whom no concerns of ASD have been raised by family members, other caregivers, or health care professionals. There are no studies that focus on the clinical outcomes of children identified with ASD through screening. Although there are studies suggesting treatment benefit in older children identified through family, clinician, or teacher concerns, the USPSTF found inadequate evidence on the efficacy of treatment of cases of ASD detected through screening or among very young children. Treatment studies were generally very small, few were randomized trials, most included children who were older than would be identified through screening, and all were in clinically referred rather than screen-detected patients.
Harms of Early Detection and Intervention or Treatment
The USPSTF found that the harms of screening for ASD and subsequent interventions are likely to be small based on evidence about the prevalence, accuracy of screening, and likelihood of minimal harms from behavioral interventions.
The USPSTF concludes that there is insufficient evidence to assess the balance of benefits and harms of screening for ASD in children aged 18 to 30 months for whom no concerns of ASD have been raised. Evidence is lacking, of poor quality, or conflicting, and the balance of benefits and harms cannot be determined.
This recommendation applies to children who have not been diagnosed with ASD or developmental delay and for whom no concerns of ASD have been raised by parents, other caregivers, or health care professionals.
A number of tests are available for screening for ASD in children younger than 30 months. The most commonly studied tool is the Modified Checklist for Autism in Toddlers (M-CHAT) and its subsequent revisions (Modified Checklist for Autism in Toddlers With Follow-Up [M-CHAT-F] and Modified Checklist for Autism in Toddlers–Revised, With Follow-Up [M-CHAT-R/F]). The M-CHAT-R/F is a parent-rated scale, and a positive finding leads to a follow-up interview. If the follow-up interview is positive, a full diagnostic workup for ASD is indicated. The screening process assesses communication skills, joint attention, repetitive movement, and pretend play.
Treatments and Interventions
Treatments for ASD include behavioral, medical, educational, speech/language, and occupational therapy and complementary and alternative medicine approaches. Treatments for young children in the target age group for routine screening for ASD are primarily behavioral interventions, particularly early intensive behavioral and developmental interventions, which may include approaches incorporating applied behavior analysis principles, parent training components, and play- or interaction-based interventions. Among the behavioral interventions, those based on applied behavior analysis have the highest-quality data supporting their effects on cognitive and language outcomes. These interventions can be delivered in a home or school setting and are generally time-intensive, with some programs requiring up to 40 hours a week.2
Suggestions for Practice Regarding the I Statement
Potential Preventable Burden
Autism spectrum disorder can cause significant social, communication, and behavioral challenges for affected children and place substantial strain on family members and other caregivers. Treatment and maturation may reduce the effects of the core symptoms of ASD for some children, but others may experience long-term effects on education, employment, and ability to live independently.2 It is important that clinicians listen carefully to parents when concerns are raised by the parents or during an examination and make prompt use of validated tools to assess the need for further diagnostic testing and services. Disparities have been observed in the frequency and age at which ASD is diagnosed among children by race/ethnicity, socioeconomic status, and language of origin, creating concern that certain groups of children with ASD may be systematically underdiagnosed.3 It is important to note that an "I" statement is not a recommendation for or against screening. In the absence of evidence about the balance of benefits and harms, clinicians should use their clinical judgment to decide if screening in children without overt signs and symptoms is appropriate for the population in their care.
Although there is limited evidence about the harms of screening for ASD in children, reported potential harms include misdiagnosis and the anxiety associated with further testing after a positive screening result, particularly if confirmatory testing is delayed because of resource limitations. Behavioral treatments are not generally thought to be associated with significant harms but can place a large time and financial burden on the family. Other treatments for ASD are less well studied and were not included in this review.
A 2004 survey of pediatricians in Maryland and Delaware found that 8% screened specifically for ASD. Few data are available regarding the current prevalence of screening for ASD by clinicians in the United States.4 More recent surveys have found higher rates, although they remain less than 60%.5-8
The Centers for Disease Control and Prevention provides web-based continuing education for clinicians called Autism Case Training (available at https://www.cdc.gov/ncbddd/actearly/autism/case-modules/index.html), as well as other information about ASD for families (available at https://www.cdc.gov/ncbddd/autism/families.html).
The Health Resources and Services Administration’s web site provides links to training resources for professionals (available at https://mchb.hrsa.gov/maternal-child-health-initiatives/autism).
The M-CHAT screening tool is available online for free at https://m-chat.org. Other professional and advocacy organizations have also developed toolkits and resources.
The USPSTF has made a recommendation on screening for speech and language delays and disorders among children 5 years or younger (available at https://www.uspreventiveservicestaskforce.org).
Research Needs and Gaps
Research has focused on screening and diagnostic tools and treatment for symptomatic children, especially those who are severely affected. Good-quality studies are needed to better understand the intermediate and long-term health outcomes of screening for ASD among children without obvious signs and symptoms and whether earlier identification through universal screening is associated with clinically important improvements in health outcomes. These studies are especially needed in populations with low socioeconomic status and minority populations, where access to care may be more limited. A number of different study designs could greatly improve the understanding of the potential of screening. Large, good-quality, randomized clinical trials (RCTs) of treatment that enroll young children with ASD identified through screening and that report patient-centered outcomes are critical to understanding the effects of screening. Treatment could be compared with a wait-list control, less intense treatment, or an alternative treatment, as in the trials reviewed by the USPSTF. Similar studies in children identified through screening have recently begun to be published, indicating that this is a feasible approach.9, 10 Pragmatic quasi-experimental designs, such as stepped-wedge trials, in regions with low screening rates could compare the effects of screening at 18 and 24 months with later screening or case-finding on educational, behavioral, functional, and IQ measures at 6 years. Randomized clinical trials of screening may be feasible in locations where screening is not standard practice or recommended. Studies following up large samples of screen-negative children, although resource-intensive, would provide valuable information regarding screening specificity.
Burden of Disease
Autism spectrum disorder is a developmental disorder characterized by persistent and significant impairments in social interaction and communication and restrictive and repetitive behaviors and activities, when these symptoms cannot be accounted for by another condition. In 2010, the prevalence of ASD in the United States was estimated at 14.7 cases per 1000 children, or 1 in 68 children, with substantial variability in estimates by region, sex, and race/ethnicity.1 This represents a 23% increase from 2008; the reasons for this increase are not completely understood.1
Scope of Review
The USPSTF commissioned a systematic review2 to evaluate the evidence on the accuracy, benefits, and potential harms of brief, formal screening instruments for ASD administered during routine primary care visits, and the benefits and potential harms of early behavioral treatment for children identified with ASD through screening. The review focused on studies of screening in children younger than 3 years who were unselected (ie, not identified because of risk factors or concerns regarding ASD).
Accuracy of Screening Tests
Several screening tools for ASD are available, but the strongest and most applicable evidence is for the M-CHAT/F and M-CHAT-R/F, 2 versions of the same tool. Both use a parent-rated scale that can lead to a follow-up interview, which, if positive, leads to referral for confirmatory diagnosis by a behavioral or developmental specialist. The initial screening process takes 5 to 10 minutes. Two large, good-quality trials conducted in the United States in children aged 16 to 30 months found similar positive predictive values for these tools (approximately 50%) for the detection of ASD in unselected populations.11, 12 The validity of these studies was weakened somewhat by the high dropout rate between screening steps but is still reasonably high for mass screening. There are no data on the specificity or negative predictive value of these screening tools. One study followed up a sample of children who were referred for diagnostic evaluation as a result of screening but not diagnosed with ASD and reported that almost all of these children had another form of developmental delay.12 It is not known whether early detection of these other problems results in improved health outcomes. Although a number of potential risk factors for ASD have been identified, there is insufficient evidence to determine if certain risk factors modify the performance characteristics of ASD screening tests, such as the age at which screening is performed or other characteristics of the child or family.
Effectiveness of Early Detection and Treatment
The USPSTF found no RCTs that directly addressed the overarching question of whether screening for ASD in children 3 years or younger results in improvements to core ASD symptoms, cognitive and intellectual functioning, language and communication skill development, challenging behavior, adaptive behavior, educational placement or achievement, or quality of life for the child and family.
The USPSTF found 26 RCTs of early intensive behavioral and developmental interventions (the most often studied treatment for this age group) for ASD in young children. However, assessment of treatment evidence was complicated by the variation among studies in intervention design, method of delivery, comparators, and outcomes measured, as well as by the heterogeneity in the age, types of symptoms, and symptom severity of the children enrolled. Four RCTs reported cognitive and language outcomes for early intensive behavioral interventions delivered by trained clinicians. Three of the 4 trials (including the largest trial, with 294 children) reported that these interventions improved cognitive scores by 11 to 16 points (Mullen Scales of Early Learning or IQ) compared with a range of comparators (calculated from published data).13-15 The fourth RCT found no effect, but this trial compared different ways of delivering the same intervention.16 The same set of studies showed a similar pattern for language outcomes. Twelve RCTs of play- or interaction-based interventions reported significant improvements in some measures of interaction but not others. The other RCTs evaluated various interventions delivered by parents and found inconsistent or negative results. Studies were very small (most enrolled 20–40 children), and study quality was generally fair.
In addition to the limitations of the evidence in size, study design, and other sources of heterogeneity, it is not clear whether these studies are applicable to children who would be detected through screening. Autism spectrum disorder is a highly heterogeneous condition in terms of onset and course of core clinical ASD symptoms and cognitive and language development.17 All of the treatment studies were conducted in populations of children with a previous diagnosis of ASD, many of whom were referred from specialized ASD programs. Many of the children enrolled in these studies had significant impairments in cognition, language, and behavior identified through case-finding and were older than the age group for which the screening tools were developed. Children identified through screening rather than through case-finding are likely to be younger and have milder symptoms than those in study populations. It is therefore not clear whether young children with ASD detected by screening and not because of parental or clinician concern will experience similar benefits from earlier intervention.
Potential Harms of Screening and Treatment
The USPSTF found little evidence on the harms of screening and treatment. Potential harms include misdiagnosis and the time, effort, and anxiety associated with further testing after a positive screening result. This is of particular concern when there is a delay in confirmatory testing because of resource limitations, which are common.2 Even good-quality studies of screening had a high dropout rate between screening steps and between screening and diagnosis, suggesting that the process may be difficult for some families. Behavioral treatments are not generally thought to be associated with significant harms but can place a large time and financial burden on the family. Other treatments for ASD are less well studied and were not included in the scope of this review. The USPSTF concludes that the potential harms of screening and behavioral treatment are no greater than small.
Estimate of Magnitude of Net Benefit
Overall, the USPSTF found insufficient evidence on screening for ASD in children aged 18 to 30 months for whom no concerns of ASD have been raised by parents, other caregivers, or health care professionals. The USPSTF identified no studies that directly evaluated the benefits or harms of screening for ASD in this age group. Studies on the benefits and harms of treatment were of small size, few were randomized, and all were conducted in populations that may not represent children who would be detected through screening programs alone. The USPSTF concludes that there is insufficient evidence to assess the balance of benefits and harms of screening for ASD in young children.
Response to Public Comment
A draft version of this recommendation statement was posted for public comment on the USPSTF website from August 4, 2015, to August 31, 2015. Many parents of children with ASD, adults with ASD, and clinicians who care for children with ASD wrote to share their personal experiences and concerns. One major area of concern was a perception that the USPSTF was advocating against screening or against the use of screening tools to follow up on parents’ concerns. This was not the USPSTF’s intention, and the USPSTF will be clear when communicating this recommendation that it is not recommending for or against screening but advocating for more research. In the meantime, clinicians should use their clinical judgment, especially when caring for populations in which case-finding may be difficult because of language, access, or other barriers. Furthermore, clinicians should listen carefully to parents’ concerns and use validated tools to assess whether further diagnosis or services are needed. Standardized tools, such as the M-CHAT, may be used diagnostically to follow up on concerns expressed by parents.
Another area of concern was why studies of test accuracy and the effectiveness of treatment were not sufficient to support screening and what kind of research would be needed to support a positive recommendation. In response, the USPSTF revised the recommendation statement to clarify the lack of treatment studies in the population that would likely be identified through screening and to provide greater detail about the different types of studies that could fill this evidentiary gap. Finally, other comments focused on the low cost and lack of harms associated with screening. The USPSTF revised the recommendation statement to clarify that, while the screening tools are relatively easy to administer and behavioral interventions are generally safe, the potential effects of extended treatment, in the absence of clear benefit, on families in terms of time and resources are not negligible.
The American Academy of Pediatrics’ Bright Futures guidelines recommend universal screening for ASD in all children at ages 18 and 24 months in addition to developmental surveillance and monitoring.17, 18 The American Academy of Family Physicians concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for ASD in children for whom no concerns of ASD have been raised by their parents or clinical provider.19 The American Academy of Neurology and the Child Neurology Society recommend routine developmental surveillance be performed on all children to identify those at risk for any type of atypical development, followed by screening specifically for autism using one of the validated instruments (the M-CHAT or Autism Screening Questionnaire).20 The American Academy of Child and Adolescent Psychiatry recommends that the developmental assessment of young children and the psychiatric assessment of all children should routinely include questions about ASD symptomatology.21 The UK National Screening Committee does not recommend systematic population screening, citing concerns about the stability of ASD diagnosis at a young age, lack of data on positive predictive value, and weakness of the evidence for the efficacy of treatment.22
Members of the USPSTF at the time this recommendation was finalized† are Albert L. Siu, MD, MSPH, Chair (Mount Sinai School of Medicine, New York, and James J. Peters Veterans Affairs Medical Center, Bronx, New York); Kirsten Bibbins-Domingo, PhD, MD, MAS, Co-Vice Chair (University of California, San Francisco, San Francisco, California); David C. Grossman, MD, MPH, Co-Vice Chair (Group Health Research Institute, Seattle, Washington); Linda Ciofu Baumann, PhD, RN, APRN (University of Wisconsin, Madison, Wisconsin); Karina W. Davidson, PhD, MASc (Columbia University, New York, New York); Mark Ebell, MD, MS (University of Georgia, Athens, Georgia); Francisco A.R. García, MD, MPH (Pima County Department of Health, Tucson, Arizona); Matthew Gillman, MD, SM (Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, Massachusetts); Jessica Herzstein, MD, MPH (Independent Consultant, Washington, DC); Alex R. Kemper, MD, MPH, MS (Duke University, Durham, North Carolina); Alex H. Krist, MD, MPH (Fairfax Family Practice, Fairfax, and Virginia Commonwealth University, Richmond, Virginia); Ann E. Kurth, PhD, RN, MSN, MPH (New York University, New York, New York); Douglas K. Owens, MD, MS (Veterans Affairs Palo Alto Health Care System, Palo Alto, and Stanford University, Stanford, California); William R. Phillips, MD, MPH (University of Washington, Seattle, Washington); Maureen G. Phipps, MD, MPH (Brown University, Providence, Rhode Island); and Michael P. Pignone, MD, MPH (University of North Carolina, Chapel Hill, North Carolina).
† For a list of current USPSTF members, go to https://www.uspreventiveservicestaskforce.org/uspstf/about-uspstf/current-members.
Source: This article was first published in JAMA on February 16, 2016.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Bibbins-Domingo reported having received grants from the National Institutes of Health and Centers for Disease Control and Prevention and other support from the Institute for Clinical and Economic Review. No other disclosures were reported. Authors followed the policy regarding conflicts of interest described at https://www.uspreventiveservicestaskforce.org/uspstf/about-uspstf/conflict-interest-disclosures.
Funding/Support: The USPSTF is an independent, voluntary body. The US Congress mandates that the Agency for Healthcare Research and Quality (AHRQ) support the operations of the USPSTF.
Disclaimer: Recommendations made by the USPSTF are independent of the US government. They should not be construed as an official position of AHRQ or the US Department of Health and Human Services.
Copyright Notice: USPSTF recommendations are based on a rigorous review of existing peer-reviewed evidence and are intended to help primary care clinicians and patients decide together whether a preventive service is right for a patient’s needs. To encourage widespread discussion, consideration, adoption, and implementation of USPSTF recommendations, AHRQ permits members of the public to reproduce, redistribute, publicly display, and incorporate USPSTF work into other materials provided that it is reproduced without any changes to the work of portions thereof, except as permitted as fair use under the U.S. Copyright Act.
AHRQ and the U.S. Department of Health and Human Services cannot endorse, or appear to endorse, derivative or excerpted materials, and they cannot be held liable for the content or use of adapted products that are incorporated on other Web sites. Any adaptations of these electronic documents and resources must include a disclaimer to this effect. Advertising or implied endorsement for any commercial products or services is strictly prohibited.
This work may not be reproduced, reprinted, or redistributed for a fee, nor may the work be sold for profit or incorporated into a profit-making venture without the express written permission of AHRQ. This work is subject to the restrictions of Section 1140 of the Social Security Act, 42 U.S.C. § 1320b-10. When parts of a recommendation statement are used or quoted, the USPSTF Web page should be cited as the source.
1. Developmental Disabilities Monitoring Network Surveillance Year 2010 Principal Investigators; Centers for Disease Control and Prevention (CDC). Prevalence of autism spectrum disorder among children aged 8 years: autism and developmental disabilities monitoring network, 11 sites, United States, 2010. MMWR Surveill Summ. 2014;63(2):1-21.
2. McPheeters ML, Weitlauf A, Vehorn A, Taylor C, Sathe NA, Krishnaswami S, et al. Screening for Autism Spectrum Disorder in Young Children: A Systematic Evidence Review for the U.S. Preventive Services Task Force. Evidence Synthesis No. 129. AHRQ Publication No. 13-05185-EF-1. Rockville, MD: Agency for Healthcare Research and Quality; 2015.
3. Mandell DS, Wiggins LD, Carpenter LA, et al. Racial/ethnic disparities in the identification of children with autism spectrum disorders. Am J Public Health. 2009;99(3):493-8.
4. Dosreis S, Weiner CL, Johnson L, Newschaffer CJ. Autism spectrum disorder screening and management practices among general pediatric providers. J Dev Behav Pediatr. 2006;27(Suppl 2):S88-94.
5. Gillis JM. Screening practices of family physicians and pediatricians in 2 southern states. Infants Young Child. 2009;22(4):321-31.
6. Radecki L, Sand-Loud N, O'Connor KG, et al. Trends in the use of standardized tools for developmental screening in early childhood: 2002-2009. Pediatrics. 2011;128(1):14-9.
7. Arunyanart W, Fenick A, Ukritchon S, et al. Developmental and autism screening: a survey across six states. Infants Young Child. 2012;25(3):175-87.
8. Zuckerman KE, Mattox K, Donelan K, et al. Pediatrician identification of Latino children at risk for autism spectrum disorder. Pediatrics. 2013;132(3):445-53.
9. Baranek GT, Watson LR, Turner-Brown L, et al. Preliminary efficacy of adapted responsive teaching for infants at risk of autism spectrum disorder in a community sample. Autism Res Treat. 2015;2015:386951.
10. Wetherby AM, Guthrie W, Woods J, et al. Parent-implemented social intervention for toddlers with autism: an RCT. Pediatrics. 2014;134(6):1084-93.
11. Robins DL, Casagrande K, Barton M, Chen CM, Dumont-Mathieu T, Fein D. Validation of the Modified Checklist for Autism in Toddlers, Revised with Follow-Up (M-CHAT-R/F). Pediatrics. 2014;133(1):37-45.
12. Chlebowski C, Robins DL, Barton ML, Fein D. Large-scale use of the Modified Checklist for Autism in low-risk Toddlers. Pediatrics. 2013;131(4):e1121-7.
13. Strain PS, Bovey EH. Randomized, controlled trial of the Leap model of early intervention for young children with autism spectrum disorders. Topics Early Child Spec Educ. 2011;31(3):133-54.
14. Dawson G, Rogers S, Munson J, Smith M, Winter J, Greenson J, et al. Randomized, controlled trial of an intervention for toddlers with autism: the Early Start Denver Model. Pediatrics. 2010;125(1):e17-23.
15. Smith T, Groen AD, Wynn JW. Randomized trial of intensive early intervention for children with pervasive developmental disorder. Am J Ment Retard. 2000;105(4):269-85.
16. Sallows GO, Graupner TD. Intensive behavioral treatment for children with autism: four-year outcome and predictors. Am J Ment Retard. 2005;110(6):417-38.
17. Zwaigenbaum L, Bauman ML, Stone WL, et al. Early identification of autism spectrum disorder: recommendations for practice and research. Pediatrics. 2015;136(Suppl 1):S10-40.
18. Committee on Practice and Ambulatory Medicine; Bright Futures Periodicity Schedule Workgroup. 2016 recommendations for preventive pediatric health care. Pediatrics. 2015 Dec 7. pii: peds.2015-3908. [Epub ahead of print]
19. Recommendations by type: clinical preventive services. American Academy of Family Physicians. https://www.aafp.org/patient-care/clinical-recommendations/cps.html. Accessed December 29, 2015.
20. Filipek PA, Accardo PJ, Ashwal S, Baranek GT, Cook EH Jr, Dawson G, et al. Practice parameter: screening and diagnosis of autism. Report of the Quality Standards Subcommittee of the American Academy of Neurology and the Child Neurology Society. Neurology. 2000;55(4):468-79.
21. Volkmar F, Siegel M, Woodbury-Smith M, King B, McCracken J, State M; American Academy of Child and Adolescent Psychiatry (AACAP) Committee on Quality Issues (CQI). Practice parameter for the assessment and treatment of children and adolescents with autism spectrum disorder. J Am Acad Child Adolesc Psychiatry. 2014;53(2):237-57.
22. The UK NSC recommendation on autism screening in children. UK National Screening Committee. https://legacy.screening.nhs.uk/autism. Accessed July 8, 2015.