Executive summary

Autism affects the way a person understands and interacts with other people and the world around them. From a diagnostic perspective, the term Autism Spectrum Disorder (herein referred to as autism) is the collective diagnostic term for a group of neurodevelopmental conditions characterised primarily by differences in social-communication skills, and the presence of repetitive behaviours, intense or focussed interests and/or sensory differences (American Psychiatric Association, 2013). The behavioural features of autism are often present before 3 years of age but may not become apparent until the school years or later in life, as social and cognitive demands increase. Many autistic people experience co-occurring conditions such as language and learning difficulties, and a range of medical conditions. For many people, autism is more than a diagnosis – it is central to their identity and sense of self.

This Guideline has been developed to support evidence-based, accurate, timely, and appropriate assessment and clinical diagnosis of autism in Australia. The Guideline focuses on practitioners who are involved in clinical assessment and diagnosis. It was first developed in 2018 by a Guideline Development Group and the Recommendations approved by the National Health and Medical Research Council. The current version is an update of the original Guideline and was conducted by a Guideline Development Group comprising 17 members including autistic people, family members, practitioners, researchers, and community members.

The Guideline presents 66 Consensus-Based Recommendations that span the assessment and diagnostic process that includes making a referral, a Comprehensive Needs Assessment, a Diagnostic Evaluation when indicated, and referral for supports if a need is identified. Recommendations are key elements of practice that must be followed. They are accompanied by Good Practice Points that provide critical context for how each Recommendation should be implemented in clinical practice and applied with a specific population or in specific circumstances. A summary of evidence for each Recommendation is provided in the Supporting Evidence document. The methodology used to update the Guideline is presented in an Administration and Technical Report that accompanies the Guideline.

This updated Guideline continues to provide an evidence-based framework through which practitioners can work effectively, safely and appropriately in conducting assessments for autism in Australia. Professional associations and individual practitioners will benefit from, and are encouraged to endorse, the Recommendations that reflect the best available evidence, modern ways of thinking and talking about evidence, and up-to-date views and perspectives from across the autistic and autism communities. It is recommended that the Guideline be further updated within 5 years.

Plain language summary

This Guideline explains to practitioners involved in assessment and diagnosis of autism how to work in ways that are safe, timely, accurate, and helpful to individuals and their families.

This is a summary of the key messages.

Section 1: Guiding principles

Practitioners should work in partnership with the client to provide timely, accurate, and appropriate assessment, and where relevant, diagnosis. Practitioners should take a principled approach to providing services, including ensuring assessment is individualised, evidence-based, strengths-focused, culturally-affirming, and neurodiversity-affirming.

Section 2: Foundations of Assessment

Practitioners should be competent and provide high quality services that are safe and supportive. They should collect, use, and share information in ways that are helpful, respectful, and accessible. The client should be referred to supports when needed and desired at any point of the assessment and diagnostic process.

Section 3: Making a referral for assessment

Practitioners should discuss the possibility of referring a client for assessment and/or diagnosis of autism as soon as a need is identified. Practitioners should collect information that helps them to understand the client and their context, and whether a referral for assessment may be appropriate and desirable to them.

Section 4: Comprehensive Needs Assessment

Practitioners with specified qualifications and expertise should conduct an Assessment of Functioning and a Medical Evaluation when a diagnosis of autism is being considered. The Assessment of Functioning gives an understanding of the client’s strengths and support needs in everyday activities. The Medical Evaluation gives an understanding of the individual’s health and wellbeing. If the findings of the Comprehensive Needs Assessment suggest a possible diagnosis of autism, the Diagnostic Evaluation should be started.

Section 5: Diagnostic Evaluation

Practitioners with specified qualifications and expertise should conduct a Diagnostic Evaluation to determine whether a client meets criteria for a diagnosis of autism and/or other conditions. They should commence with a Lead Practitioner Diagnostic Evaluation or a Consensus Team Diagnostic Evaluation, depending on which is likely result in a more timely and accurate evaluation. Practitioners should consider a range of information and use their clinical judgement to reach a diagnostic decision. They should discuss the findings with the client and refer for further assessment and support if needed and desired.