There are a number of tools which are used to diagnose individuals who might be autistic. They usually rely on two main sources of information: descriptions of the person’s development and behaviour collected via an interview and direct observation of that behaviour. 

This section explains the diagnostic tools that might be used for an autism assessment. 

DISCO (Diagnostic Interview for Social and Communication Disorders) 

This is a detailed, semi-structured interview designed to find out about the person's development, behaviour and skills since birth through to their current day-to-day functioning.  

DISCO was developed for use at The Centre for Social and Communication Disorders /now renamed as the Lorna Wing Centres, by Dr Lorna Wing and Dr Judith Gould, as both a clinical and a research instrument for use with children, young people and adults of any age. 

Its special value is that it collects information using a dimensional approach and concerning all aspects of each individual’s skills, challenges and untypical behaviours, not just the features of autism spectrum disorder. Where possible, information concerning the person's history in infancy and childhood is collected from an informant who has known the person from birth. However, when for an adult, there is no informant available to give an early history, the items of the schedule can be completed for current skills, challenges and untypical behaviour. When adults have very good recall of their own lived experience as a child or young person, this can provide useful insights into their earlier development and helps inform the interviewer. 

If no developmental history is available, this does not allow for a formal diagnosis using the ICD or DSM classification systems, but the information gathered from the DISCO does allow the experienced clinician to use their clinical judgement to advise of a working diagnosis in order to help develop a care plan or management programme. 

The DISCO can be used with children, young people and adults of any age; for any level of ability, for any manifestation of an autism spectrum profile from the most obvious to the most subtle. It can also assist in identifying co-existing conditions often associated with the autism spectrum, such as ADHD, tics, dyspraxia and catatonia-like disorders. 

Information gathered from the DISCO can be used to compute diagnostic algorithms based on DSM5, ICD10 and other systems such as the Wing and Gould triad. 

As emphasised in the section on its history, the DISCO should be used in conjunction with psychological assessments, observation and any other sources of reliable information. 

The ADOS (Autism Diagnostic Observation Schedule)  

The ADOS is a semi-structured, standardised assessment of communication, social interaction, and play or imaginative use of materials for individuals who have been referred because of possible autism. 

The ADOS tool differs from the other tools described here as it is not based on developmental data and therefore only looks at current behaviour and skills. 

The ADOS can be used to evaluate individuals at different developmental levels and chronological ages, from toddlers to adults, from individuals with no speech to those who are verbally fluent. 

The ADI-R (Autism Diagnostic Interview - Revised) 

The ADI-R is a clinical diagnostic instrument for assessing autism in children and adults. 

The ADI-R is a revised version of the original ADI and the information obtained can be used in a diagnostic algorithm for autism as described in both the ICD-10 and DSM-IV manuals. 

This tool focuses on behaviour in three main areas: qualities of reciprocal social interaction; communication and language; and restricted and repetitive, stereotyped interests and behaviours. 

The ADI-R is appropriate for children and adults with mental ages from about 18 months and above. 

Next steps

• Read about the diagnostic assessment
• Find out about post-diagnostic support
• Professionals - Find out more about our specialist training in the diagnosis and assessment of autism.