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Comprehensive Guide to the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2)
Key Takeaways
- The Autism Diagnostic Observation Schedule-Second Edition (ADOS-2) is a widely used standardized assessment tool for diagnosing autism based on social communication and repetitive behaviors.
- A clinical autism assessment typically includes a developmental history, behavioral observations, interviews, and standardized assessments like the ADOS-2.
- Autism assessment results can help individuals understand their neurodivergent traits, validate lifelong experiences and guide self-advocacy. Many late-diagnosed adults find relief and empowerment through the diagnostic process.
A note on language in this article
While Prosper Health is a neurodiversity-affirming practice, diagnostic criteria and assessments often use deficit-focused language that isn’t neurodiversity-affirming. We chose to include some of this deficit-based language—which does not reflect how we would usually write about autism—in this article for the sake of accurately portraying diagnostic materials.
Intro to the ADOS-2
A thorough and accurate autism evaluation is essential for identifying the right support strategies to enhance an autistic individual’s communication, education and daily functioning. An autism diagnosis helps people access essential resources, such as social services and specialized education programs, and empowers them to better understand and advocate for their needs.
A clinical autism assessment typically involves a comprehensive developmental history, behavioral observations and standardized tools like the Autism Diagnostic Observation Schedule (ADOS). The ADOS plays a critical role in diagnosing autism by providing a standardized approach. While it is not the sole determinant of an autism diagnosis, the Autism Diagnostic Observation Schedule is considered a useful diagnostic tool that helps clinicians make informed decisions alongside a person’s developmental history and other diagnostic tools. Additionally, the ADOS is not required for an autism diagnosis, since there are other ways to collect data in an assessment.
Understanding the Autism Diagnostic Observation Schedule
The Autism Diagnostic Observation Schedule, now in its Second Edition (ADOS-2), is a semi-structured standardized assessment, which means it combines natural observation with a set of planned activities and questions designed to be given in the same way every time. The duration of the assessment is generally between 40 and 60 minutes.
The provider must follow a specific set of activities, but they can adjust their approach slightly to match the individual’s communication style. They need to follow certain scoring rules to stay consistent and reliable. The Autism Diagnostic Observation Schedule evaluates:
- Communication
- Social interaction
- Play
- Restrictive and repetitive behaviors.
The Autism Diagnostic Observation Schedule is administered by trained professionals experienced in assessments to ensure accurate evaluation and interpretation of results. The professional who uses the ADOS may vary by state but may include:
- Neuropsychologists
- Clinical psychologists
- Psychiatrists
- Developmental pediatricians
- Other healthcare professionals with specialized training in autism assessments
There are different modules based on age and levels of verbal communication. Each module is designed to engage the individual directly and elicit behaviors relevant to autism. For instance, Module 1 is for toddlers, and Module 4 is for adults who fluently communicate verbally.
The examiner observes behaviors during the activities of the Autism Diagnostic Observation Schedule and assigns each behavior a score according to the assessment rules. Whether or not the examiner observes individual behaviors associated with autism does not automatically result in an autism diagnosis. However, the scores contribute to the examiner’s comprehensive evaluation and interpretation of the results.
Interpreting ADOS-2 assessment scores
The Autism Diagnostic Observation Schedule assessment provides scores based on observed behaviors, and these scores help clinicians determine if an individual meets the criteria for autism spectrum disorder according to the DSM-5-TR.
Each behavior associated with autism observed during the Autism Diagnostic Observation Schedule assessment is assigned a score based on standardized guidelines. Higher scores indicate that the examiner observed the person exhibiting more autism-related behaviors. Then, the scores are totaled and compared to cutoff points that indicate different levels of evidence of autism. The examiner then considers these scores along with other information from the evaluation.
The scores alone do not diagnose autism, but they offer important information to be considered along with the individual’s developmental history (which may be provided from caregiver interviews) and other assessments such as cognitive tests. All of this is considered alongside the DSM-5 criteria, which provide the official diagnostic guidelines for autism.
DSM-5 criteria for autism spectrum disorder
On top of using the ADOS-2 for evaluations, the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition Text Revision (DSM-5-TR) is also a key diagnostic tool. The DSM-5-TR contains criteria for diagnoses related to the brain. The criteria for autism spectrum disorder in the DSM-5-TR are listed in two main domains:
- Social communication deficits
- Restrictive repetitive behaviors
It further states that these criteria:
- Must have been present early in development
- Cause significant impairment in important areas of functioning
Aren’t better explained by a different diagnosis
Comparing the Autism Diagnostic Observation Schedule (ADOS-2) with other autism assessment tools
Clinicians use diagnostic tools as part of a comprehensive assessment. The entire diagnostic process also includes a clinical interview, behavioral observations and self-report measures. Other diagnostic tools for diagnosing autism in adults include:
- The Diagnostic Observation Schedule: This is a standardized assessment of social communication and interaction. It has different modules that are tailored to age and verbal communication.
- The Autism Diagnostic Interview-Revised (ADI-R): The ADI-R is a structured interview conducted with someone close to the autistic person, like a family member. It focuses on developmental history and current behaviors.
- The Diagnostic Interview for Social and Communication Disorders (DISCO): This is a structured interview used primarily in the U.K. that helps assess a broad range of autism traits.
- The Developmental, Dimensional, and Diagnostic Interview – Adult Version: The 3Di-Adult is a structured clinical interview with two subscales that map directly onto the DSM criteria of social communication and restrictive and repetitive behaviors.
Supporting tools
Along with the tools used for comprehensive assessment, a clinician may screen for autism or support an accurate diagnosis with supporting tools, but they cannot be used alone to make a formal diagnosis. These may include:
- The Ritvo Autism Asperger Scale-Revised (RAADS-R): A self-report measure of autistic traits
- The Autism Spectrum Quotient (AQ): A screening tool for autism
- The Social Responsiveness Scale, Second Edition (SRS-2): A scale that measures social differences
- The Gilliam Autism Rating Scale, Third Edition (GARS-3): A scale that assists in identifying autistic traits
- The Camouflaging Autistic Traits Questionnaire (CAT-Q): A questionnaire that assesses masking behaviors
- Social Communication Questionnaire (SCQ): A questionnaire that assesses childhood behaviors and traits associated with autism
Recent updates and research on Autism Diagnostic Observation Schedule, the Second Edition (ADOS-2)
The ADOS-2 introduced updates to the ADOS, including the following improvements:
- Administration guidelines
- Scoring algorithms
- Clarified instructions
- Updated classifications
Notably, the ADOS-2 introduced the Toddler Module, which was specifically designed for children aged 12 months to 30 months, whereas the original ADOS assessment didn’t have a toddler module. It was also updated to reflect the DSM-5’s main domains of symptom classification (social affect and restricted and repetitive behaviors) to improve accuracy. Research continues to further refine the ability of the Autism Diagnostic Observation Schedule to accurately diagnose autism.
Research into adult autism diagnoses has also assessed the ADOS-2’s applicability to late-diagnosed individuals because many adults (especially those assigned female at birth) may not receive an autism diagnosis until later in life. The ADOS-2 is highly accurate in identifying autistic adults but can make false positives in adults experiencing psychosis due to an overlap in social communication difficulties. Future research is expected to focus on:
- Early diagnosis, possibly as young as 6 to 12 months
- Integration with technology and other methods for more precise diagnosis
- Cross-cultural applicability
- Identification of autism in adults who weren’t diagnosed in childhood
What ADOS-2 results can tell you
The diagnosing clinician will provide a written report of the Autism Diagnostic Observation Schedule results as well as their clinical recommendations. This report can provide insight into an individual’s social communication patterns as well as behavior and sensory experiences, helping them better understand their neurodivergent traits and how they influence their life. Rather than viewing these results as something to “fix,” they can use this as a tool for self-awareness and empowerment.
For many late-diagnosed adults, ADOS results can provide a sense of relief and validation, helping them understand experiences they’ve had but couldn’t explain. It may help them understand why they have struggled in environments that were not designed with neurodivergence in mind.
The ADOS uses a score to provide a “level” of traits in children: minimal, low, moderate and high––but these levels aren’t provided to adults. However, based on diagnostic criteria from the DSM-5-TR for ASD, individuals are assigned a degree of autism-related challenges called a level of support, which are:
- Level 1: Requiring support
- Level 2: Requiring substantial support
- Level 3: Requiring very substantial support
Support services and networks for autism
An autism diagnosis through the ADOS-2 can open doors to essential support services that help autistic individuals navigate daily life, build meaningful connections and advocate for their needs. These services may include:
- Vocational training
- Supported employment
- Individualized coaching
- Mental health support
- Peer-led groups
- Advocacy organizations
These resources can help provide accommodations that align with an individual’s strengths and challenges.
How Prosper Health can help
At Prosper Health, we are committed to providing neurodiversity-affirming autism assessments and therapy that respect and empower autistic individuals. Our comprehensive evidence-based evaluations are designed to help you understand your neurodivergent traits in a supportive, affirming environment.
We work with most major insurance plans. We recommend neurodiversity-affirming therapy as your next step after an autism assessment to continue to support your journey and help you thrive.
Schedule your intake now to get started on a path that puts you in control of your neurodivergent identity and empowers you to live your best life.
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