Intended for healthcare professionals

Clinical Review State of the Art Review

Autism spectrum disorder: advances in diagnosis and evaluation

BMJ 2018; 361 doi: (Published 21 May 2018) Cite this as: BMJ 2018;361:k1674
  1. Lonnie Zwaigenbaum, professor and developmental pediatrician1 2,
  2. Melanie Penner, assistant professor and developmental pediatrician3
  1. 1Department of Pediatrics, University of Alberta, Edmonton Clinic Health Academy, 11405-87 Avenue, Edmonton, AB, Canada, T6G 1C9
  2. 2Child Health, Glenrose Rehabilitation Hospital, 10230 111th Avenue, Edmonton, AB, Canada, T5G 0B7
  3. 3Holland Bloorview Kids Rehabilitation Hospital, 150 Kilgour Road, Toronto, ON, Canada, M4G 1R8
  1. Correspondence to: L Zwaigenbaum Lonnie.Zwaigenbaum{at}


Autism spectrum disorder (ASD) has a variety of causes, and its clinical expression is generally associated with substantial disability throughout the lifespan. Recent advances have led to earlier diagnosis, and deep phenotyping efforts focused on high risk infants have helped advance the characterization of early behavioral trajectories. Moreover, biomarkers that measure early structural and functional connectivity, visual orienting, and other biological processes have shown promise in detecting the risk of autism spectrum disorder even before the emergence of overt behavioral symptoms. Despite these advances, the mean age of diagnosis is still 4-5 years. Because of the broad consistency in published guidelines, parameters for high quality comprehensive assessments are available; however, such models are resource intensive and high demand can result in greatly increased waiting times. This review describes advances in detecting early behavioral and biological markers, current options and controversies in screening for the disorder, and best practice in its diagnostic evaluation including emerging data on innovative service models.


  • Series explanation: State of the Art Reviews are commissioned on the basis of their relevance to academics and specialists in the US and internationally. For this reason they are written predominantly by US authors

  • Contributors: Both authors helped plan, conduct, and report the work described in the article. Both made substantial contributions to the conception and design of the article, as well as the critical review and synthesis of publications that contributed to the review. Both helped draft and revise the article critically for important intellectual content, approved the final version submitted for publication, and agree to be accountable for all aspects of the work. LZ was responsible for the overall development of the review as guarantor, thus accepts full and ultimate responsibility for the work and the conduct of the study.

  • Competing interests: We have read and understood BMJ policy on declaration of interests and declare the following interests: none.

  • Provenance and peer review: Commissioned; externally peer reviewed.

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