Combined ADHD and Autism Assessment in Australia (2026)

If you suspect you might have both ADHD and autism — or if you've been diagnosed with one and wonder about the other — a combined assessment can save you significant time, money, and emotional energy. The overlap between these conditions is far more common than most people realise: approximately 40% of autistic people also meet criteria for ADHD, and an estimated 20-50% of people with ADHD have co-occurring autistic traits or meet full diagnostic criteria for autism. Until 2013, the DSM didn't allow a dual diagnosis, meaning many adults received only one diagnosis when they should have received both.

• Why it matters to assess for both:**
• Symptom overlap can mask one condition: Executive function difficulties, social challenges, sensory sensitivities, and emotional dysregulation occur in both conditions. If only one is identified, the other may be attributed to the diagnosed condition and left untreated.
• Treatment differs: ADHD responds well to stimulant medication; autism does not. Behavioural strategies differ — what works for ADHD (novelty, stimulation) may be distressing for someone who is also autistic (preferring routine and predictability).
• Accurate self-understanding: Many people describe their combined assessment as the moment "everything finally made sense." Understanding which difficulties stem from ADHD, which from autism, and which from the interaction between the two allows for targeted support.
• Practical access to support: An autism diagnosis may open access to NDIS funding, workplace accommodations, and specialist services that are not available with an ADHD diagnosis alone.

• Who should consider a combined assessment?**
• Adults diagnosed with ADHD who also experience sensory sensitivities, difficulty with social communication, rigid routines, or intense focused interests
• Adults diagnosed with autism who also experience chronic disorganisation, impulsivity, difficulty sustaining attention (beyond their areas of interest), and restlessness
• Anyone seeking their first assessment who identifies with features of both conditions
• Children where teachers or clinicians have noted features of both conditions

If you suspect both conditions, it is significantly more efficient and cost-effective to pursue a combined assessment rather than assessing for each condition separately. For more on how the two conditions present together, see our guide on AuDHD and ADHD vs autism.

Not all clinicians who assess ADHD also assess autism, and vice versa. The assessment tools, training, and clinical experience required are different, and many providers specialise in only one condition.

• Psychiatrists:**
• Can diagnose both ADHD and autism in a single assessment process
• Can prescribe medication for ADHD immediately following diagnosis
• Best for adults seeking both diagnoses plus medication management
• Not all psychiatrists are experienced with autism assessment — confirm before booking

• Clinical psychologists:**
• Can diagnose both ADHD and autism
• Often have the most extensive training in the psychometric tools used for autism assessment (ADOS-2, ADI-R)
• Cannot prescribe medication — you will need a separate referral for ADHD medication
• Psychology assessments tend to be more comprehensive (and more expensive) than psychiatrist assessments

• Multidisciplinary teams (gold standard for autism):**
• The gold standard for autism assessment involves a team: typically a psychologist, speech pathologist, and sometimes an occupational therapist
• Multidisciplinary assessment is particularly recommended for children and for complex adult presentations
• Some clinics offer integrated ADHD+autism packages where the ADHD assessment is incorporated into the multidisciplinary process
• More expensive but provides the most thorough evaluation

• Who cannot assess for both:**
• GPs cannot diagnose autism in any state (even in QLD/SA where they can diagnose ADHD)
• Registered psychologists (as distinct from clinical psychologists) may have limited training in autism diagnostic tools
• Occupational therapists and speech pathologists contribute to autism assessments but cannot make the diagnosis independently

Key question to ask providers: Before booking, ask: "Do you assess for both ADHD and autism, and do you use validated diagnostic tools for both conditions?" Some providers will screen for one but formally assess only the other.

A combined assessment is more extensive than assessing for either condition alone. The two conditions require different assessment tools and clinical observations, though there is some overlap in the developmental history and clinical interview components.

• ADHD assessment components:**
• Clinical interview covering attention, impulsivity, hyperactivity, and executive function
• Standardised rating scales (DIVA-5 for adults, Conners/Vanderbilt for children, CAARS for adults)
• Developmental history confirming childhood onset of ADHD symptoms
• Functional impairment assessment across work/school, relationships, and daily life

• Autism assessment components:**
• ADOS-2 (Autism Diagnostic Observation Schedule) — a structured, semi-structured interaction and observation tool administered by a trained clinician. This is considered the gold standard observational assessment.
• ADI-R (Autism Diagnostic Interview-Revised) — a detailed developmental interview, ideally with a parent or someone who knew you as a child
• Self-report questionnaires (AQ-10, RAADS-R, CAT-Q for camouflaging)
• Assessment of social communication, restricted/repetitive behaviours, and sensory processing
• For adults: detailed history of social difficulties, sensory sensitivities, and coping strategies (masking/camouflaging)

• Shared components (assessed once, relevant to both):**
• Comprehensive developmental history
• Mental health history and screening for comorbidities (anxiety, depression, trauma)
• Cognitive testing if learning difficulties are suspected
• Adaptive functioning assessment

• Typical timeline:**
• Adults: 3-5 sessions over 4-8 weeks, plus a feedback session
• Children: 3-6 sessions (including parent interviews, teacher input, and direct assessment), plus a feedback session and written report
• Total assessment time: 8-15 hours of clinical contact

Important note for adults: The ADOS-2 and ADI-R were originally developed for children. While adult modules exist, some adults — particularly women and those who have developed extensive masking strategies — may not present as overtly autistic during a structured clinical observation. Experienced clinicians account for this by weighting developmental history and self-report alongside observational data.

Combined assessments are more expensive than single-condition assessments, but significantly cheaper than doing two separate assessments.

Private combined assessment costs:

Comparison with separate assessments:

Doing both together typically saves $500-$1,500 because the developmental history, clinical interview, and background questionnaires overlap significantly.

• Wait times for combined assessment:**
• Combined assessments have longer wait times than ADHD-only assessments because fewer providers offer both. Expect:
• Private psychiatrist (combined): 3-12 months
• Private psychologist (combined): 2-8 months
• Multidisciplinary clinic: 6-18 months
• Public system: 12-24+ months

Some providers offer shorter waits for telehealth components of the assessment, though the ADOS-2 (autism observation) generally requires an in-person session. For more on ADHD assessment costs specifically, see our assessment cost guide.

Medicare can offset a significant portion of the cost, though the rebate structure requires some navigation.

• Medicare rebates (via Better Access):**
• Your GP provides a Mental Health Treatment Plan (MHTP), which gives access to 10 Medicare-rebated psychology sessions per calendar year
• Clinical psychologist rebate: $145.25 per session (Item 80010)
• Registered psychologist rebate: $101.55 per session (Item 80110)
• Psychiatrist rebate (with GP referral): $455.60 for initial consultation of 45+ minutes (Item 291)
• You can use Better Access sessions for the psychology component of a combined assessment

• Maximising rebates:**
• If the combined assessment spans 4-5 psychology sessions, Medicare rebates could total $580-$726 (clinical psychologist) or $406-$508 (registered psychologist)
• Psychiatrist sessions attract separate rebates on top of psychology rebates
• Some clinics structure their combined assessment to maximise the number of rebatable sessions

• NDIS funding:**
• An autism diagnosis (not ADHD alone) may meet NDIS eligibility criteria as a permanent and significant disability
• NDIS can fund ongoing supports including therapy, occupational therapy, and life skills coaching
• The cost of the diagnostic assessment itself is generally not covered by NDIS — NDIS funds supports for an existing diagnosis, not the assessment process
• However, some participants with existing NDIS plans can have further assessments funded under Capacity Building
• A combined assessment provides the diagnostic evidence needed for an NDIS access request

• Private health insurance:**
• Some policies cover a portion of psychology or psychiatry fees under extras/ancillary cover
• Coverage varies widely — check your specific policy
• Hospital cover may apply if assessment occurs within a hospital-based clinic

• State-based funding:**
• Some state health departments fund diagnostic assessments for children through public developmental services (free but long waits)
• Medicare Urgent Care Clinics do not cover ADHD or autism assessments

For detailed information on Medicare rebates for ADHD services, see our Medicare rebates guide. For information on ADHD and the NDIS, see our ADHD disability guide.

Finding a clinician who is experienced in assessing both ADHD and autism can be challenging. Here are practical strategies.

• What to look for:**
• Providers who explicitly list both ADHD and autism/ASD as areas of assessment (not just treatment)
• Clinical psychologists with training in ADOS-2 administration (this is a specialised skill)
• Multidisciplinary clinics that have both ADHD and autism assessment pathways
• Providers who mention combined or dual neurodevelopmental assessment on their website or profile

• Questions to ask before booking:**
• "Do you assess for both ADHD and autism in the same assessment process?"
• "What diagnostic tools do you use for each condition?" (Look for DIVA-5 or CAARS for ADHD; ADOS-2 and/or ADI-R for autism)
• "Is the assessment conducted by a single clinician or a multidisciplinary team?"
• "What is included in the written report?" (Ensure it covers both conditions with enough detail for NDIS applications if relevant)
• "What is the total cost and how many sessions are involved?"

• Where to search:**
• Our directory allows you to filter providers by condition — look for providers listed under both ADHD and autism
• The Autism Cooperative Research Centre (Autism CRC) maintains resources on diagnostic services
• Your GP may know local providers who assess for both conditions
• State autism associations (e.g., Autism Queensland, Amaze in Victoria) maintain provider lists

• Telehealth considerations:**
• Some components of a combined assessment can be conducted via telehealth (clinical interview, rating scales, developmental history)
• The ADOS-2 typically requires an in-person session, though some clinicians have adapted observational assessment for telehealth during and after COVID-19
• A hybrid model (telehealth for ADHD components, in-person for autism observation) can expand your provider options geographically

If you already have one diagnosis: If you have an existing ADHD diagnosis and are now seeking autism assessment (or vice versa), you do not need to repeat the full assessment for the already-diagnosed condition. Provide your existing diagnostic report to the new assessor — this saves time and money and provides valuable clinical context.

For general information on what to expect during an ADHD assessment, see our guide on what to expect from an ADHD assessment.