ADI-R: Autism Diagnostic Interview–Revised

The Autism Diagnostic Interview–Revised (ADI-R) is a detailed, structured clinical interview used as part of autism diagnostic assessments for both children and adults. It is often used alongside the ADOS-2 (Autism Diagnostic Observation Schedule–Second Edition), questionnaires and information from other relevant settings to provide a comprehensive understanding of an individual’s development, communication, social experiences and patterns of behaviour.

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As autism is a lifelong neurodevelopmental condition, gathering information about early childhood is an important part of the diagnostic process. The ADI-R helps clinicians explore whether relevant characteristics were present during early development and how these may have continued, changed or become less apparent over time. This can be particularly valuable for adults and older children who may have developed strategies to manage or mask their differences.

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What does the ADI-R involve?

Unlike the ADOS-2, which involves direct interaction and observation, the ADI-R is completed through an in-depth interview with someone who knows the individual’s developmental history.

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For a child’s assessment, the interview is usually completed with one or both parents or another primary caregiver. The child does not usually need to attend this part of the assessment.

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For an adult’s assessment, the ADI-R is ideally completed with a parent, caregiver, older sibling or another person who knew the adult well during childhood. The adult may also contribute their own recollections and perspective. A partner or other person who knows them well may provide useful information about their current experiences, although they may not be able to provide the early developmental history required for all parts of the ADI-R.

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We recognise that a suitable childhood informant may not always be available, particularly during an adult assessment. This does not necessarily prevent an assessment from proceeding. Clinicians may consider the adult’s own developmental account alongside available evidence such as school reports, medical records and information from siblings, relatives or other people who have known them for a long time.

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The interview is undertaken by a professional who has received appropriate training in administering and coding the ADI-R. This may include a clinical psychologist, psychiatrist, paediatrician, speech and language therapist or another suitably qualified clinician.

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What areas does the ADI-R explore?

The ADI-R contains 93 items and focuses on three principal areas:

• Language and communication

• Reciprocal social interaction

• Restricted, repetitive or stereotyped behaviours and interests

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Questions explore the individual’s development and experiences across a range of areas, including:

• Early development and developmental milestones

• Language development and any loss of previously acquired skills

• Spoken and non-verbal communication

• Social engagement, relationships and emotional reciprocity

• Childhood play and imagination

• Routines, focused interests and repetitive behaviours

• Sensory responses

• Educational, medical and diagnostic history

• Current presentation and everyday functioning

• Other clinically relevant behaviours or experiences

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The clinician asks follow-up questions and requests specific examples to understand not only whether a characteristic has occurred, but also when it began, how frequently it has been observed and the effect it has had on everyday life.

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Is an ADI-R essential for an adult autism assessment?

No. Although developmental history is an important consideration, completing an ADI-R is not essential for an adult autism diagnosis. It is common for adults to be unable to involve someone who knew them well during early childhood. Parents may have died, become unwell or be unavailable; family relationships may be difficult or estranged; or relatives may have limited or unreliable memories of the person’s early development. Some adults may also prefer not to involve family members.

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A lack of parental or caregiver information should not automatically prevent an adult from accessing an autism assessment. Instead, clinicians consider the best available evidence and acknowledge any limitations within the diagnostic report.

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Where a suitable ADI-R informant is unavailable, developmental information may be gathered from:

• The adult’s own recollections and understanding of their development

• School reports or other educational records

• Medical and previous assessment records

• Photographs, home videos or childhood documents, where relevant

• Siblings, extended family members or family friends

• A partner or another person who can describe the adult’s current presentation

• Information about longstanding patterns across education, employment, relationships and everyday life

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It may not always be possible to obtain detailed or independent evidence from early childhood. In these circumstances, clinicians consider whether the available information is sufficiently consistent, detailed and clinically persuasive to determine whether autistic characteristics are likely to have been present during the developmental period.

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When might the ACIA be used?

The Autism Clinical Interview for Adults (ACIA) may be used as an alternative or complementary clinical interview during an adult autism assessment. It is completed directly with the adult and allows the clinician to explore their developmental history, current experiences and lifelong patterns in depth.

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The ACIA may be particularly helpful when a parent or childhood caregiver is unavailable, when the adult is the main source of their developmental history, or when clinicians need to explore experiences such as masking and the internal impact of social, communication, sensory or behavioural differences.

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Where appropriate, information from a parent, partner, sibling or another informant can still be considered alongside the ACIA. The choice between the ADI-R, ACIA or another developmental interview depends on the individual’s circumstances and the clinical judgement of the assessment team.

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How is the information used?

The ADI-R commonly takes approximately two to three hours to complete, although this varies according to the person’s history and circumstances. Information is recorded and coded using a standardised procedure, and relevant algorithms may be applied. Scores are interpreted within the context of the person’s wider presentation and should not be viewed as a pass-or-fail result.

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Neither the ADI-R nor the ACIA provides a diagnosis when used alone. The findings may be considered alongside:

• Direct clinical observation, such as the ADOS-2

• The child’s, young person’s or adult’s own account

• Information from parents, caregivers or other informants

• School, college, university or workplace information

• Relevant questionnaires and screening measures

• Previous medical, psychological or educational reports

• Consideration of alternative or co-occurring explanations

• Multidisciplinary clinical discussion and judgement

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Bringing these sources together allows the assessment team to determine whether the diagnostic criteria for autism are met and to develop an individualised understanding of the person’s strengths, differences and support needs.