Autism Spectrum Disorder (ASD)

Adult Autism Diagnostic Assessments 

Prometheus offers diagnostic assessments for adults with probable Autism Spectrum Disorder. The assessment utilises NICE approved diagnostic assessment tools and processes and is facilitated by experienced clinicians so that you can be confident in the outcome.

About Autism

Autism is a way of being, it is about being different not less, a variation of the ‘norm’. People with autism experience a range of strengths and challenges in daily life. Autism is a neurodevelopmental condition, the core challenges of which are persistent difficulties in social interaction and communication and the presence of restricted and repetitive behaviours and cognitions, resistance to change or restricted interests and sensory differences. The way that autism is expressed in individual people differs at different stages of life, in response to life situation or stressors, and with the presence of coexisting conditions.

Our Diagnostic Assessments

Dr Max Buchanan is a registered clinical psychologist who specialises in adult autism assessments. He has extensive experience of completing diagnostic assessments both in the UK and Canada (NHS and Canadian Provincial equivalent). Max has experience in recognising the female presentation of autism which is slowly becoming better understood. He continues to work in the NHS whilst also offering this service privately to address local need in a timely manner. Please see Max’s page in Meet the Team section.

Referrals can be made via the contacts page, by phone or email. If you have any questions prior to assessment, our team would be happy to answer these.

The ASD Diagnostic Assessment typically comprises of: 

  • Clinical interview with referred person (approx. 2 hours face-to-face whenever possible). Covering topics relating to your background history and development and then becoming ASD specific relating to the quality of your social functioning, social communication, interests, routines, repetitive behaviour, and sensory differences across the course of your life.
  • Developmental History Interview (approx.1.5 – 3 hours typically via video call or telephone). This is with someone who knows you. An extensive interview covering your early development, play and schooling, as well as differences in social interaction and communication, and restricted and repetitive patterns of behaviour and interests associated with the autism spectrum. Ideally this is completed with someone who knew you well when you were a child because signs of autism should be observable in early development. We recognise that not all adults have someone they can contact from their early years so in these situations we would instead hope to speak to someone who knows you well more recently and would also ensure you are asked detailed questions about your own development.
  • Clinical Observation (approx. 2 hours face-to-face). A semi-structured, standardised assessment of communication, social interaction, imaginative use of materials, and restricted and repetitive behaviours for individuals referred because of possible Autism Spectrum Disorder (ASD). This includes some gentle tabletop activities and conversations and will typically be observed by an additional trained clinician, either in person, by video link or recording.
  • Supplementary assessment and materials as necessary or beneficial to the completion of assessment. Sometimes further screening or assessment tools are indicated as part of the overall assessment. We understand that ASD and ADHD can go hand in hand so we can screen or assess for ADHD concurrently if indicated and requested. This would only be completed with your permission. Written reports such as school reports or other assessment reports can also be helpful to the process.
  • Feedback & written report explaining the outcome and reasons for meeting or not meeting ASD diagnostic criteria.

The Autistic Advantage? 

The diagnostic criteria for ASD (DSM-5) are focused on challenges and deficits.  It is an Autism Spectrum Disorderafter all so would have a significant impact on daily life for the diagnosis to be agreed. However, it is very important to recognise that traits associated with autism may be strengths in particular contexts and settings, indeed, each of the diagnostic criteria can be positively reframed. The assessment process will therefore be balanced and include a focus on your own strengths and abilities.  Autism traits can be experienced as either advantageous or disadvantageous dependent upon context. It may not be helpful to try to separate autism strengths from autism weaknesses as there is no boundary between them i.e. hypersensitivity can be an advantage in experiencing art or nature but problematic in some social contexts.

Below are a sample of just a few possible strengths and positive characteristics taken from lived experience examples that you may recognise in yourself.


Word tree from Russell et al, 2019. The larger the word the more people with autism reported this strength in this small study (n=24)

Reference: Russell, G., Kapp, S. K., Elliott, D., Elphick, C., Gwernan-Jones, R., & Owens, C. (2019). Mapping the Autistic Advantage from the Accounts of Adults Diagnosed with Autism: A Qualitative Study. Autism in Adulthood, 1(2), 124-133.

 Other characteristics from clinical conversations include

  • Ability to hyperfocus (“zooming in”, “unwavering focus”, “tenacious”)
  • Attention to Detail (“spotting things others miss”)
  • Good or exceptional memory (particularly related to areas of special interest)
  • Creativity
  • More accepting of difference in others than “neurotypical” people
  • Conversation flowing when discussing topic of interest
  • Ability to quickly ‘read’ the atmosphere in a room
  • Non-conformist, thinking beyond limits – not restricted to socially constructed ideas as to what is possible
  • Compassionate
  • Empathetic
  • Strong sense of justice
  • Perseverant
  • Open, fair, loyal
  • Dedication to a particular area of interest – deep study – above and beyond
  • Sensory engagement and interaction with the world
  • Logical decision making where emotions may interferef
  • Feeling connected and safe when social engagement comes without threat
  • Willingness to practice and perfect
  • Interested primarily in significant contributions to conversation
  • Seeking sincere, positive, genuine friends
  • Fascination with word-based humour, such as puns
  • Conversation free of hidden meaning or agenda


How will I know if an autism diagnostic assessment is indicated for me?

There are a number of ways that can happen. You may have recognised possible autism yourself from discussions with important others or may have come across examples of lived experience of autism via cultural means such as film, books, TV, radio or social media and wondered about your own traits. You may notice traits from the information you have read on this page. You will have opportunity to talk to a Prometheus clinician during the pre-assessment consultation who can ask you relevant questions that might suggest that an assessment is indicated or not. In addition there are screening tools that might help with your understanding. Though simplistic, and not a substitute for full assessment, they can be helpful as one aspect of fact finding. One example is given below.

Adult Autism Screening Questions (AQ-10)

If you are thinking about taking part in a ASD diagnostic assessment, it can be helpful to consider the extent to which you agree with the following 10 statements below.

1) I notice small sounds when others do not

2) I concentrate more on the small details, rather than the whole picture

3) I find it difficult to do more than one thing at once

4) If there is an interruption, I can’t switch back to what I was doing very quickly

5) I find it difficult to ‘read between the lines’ when someone is talking to me

6) I don’t know how to tell if someone listening to me is getting bored

7) When I’m reading a story I find it difficult to work out the characters’ intentions

8) I like to collect information about categories of things (e.g. types of car, types of bird, types of train, types of plant, etc.)

9) I find it difficult to work out what someone is thinking or feeling just by looking at their face

10) I find it difficult to work out people’s intentions

Scoring: Score 1 point for each item you agreed with. If you agreed with 6 or more of the above statements, research suggests that you might consider being referred for a diagnostic assessment, particularly if you have had these experiences since childhood. This test is recommended in ‘Autism: recognition, referral, diagnosis and management of adults on the autism spectrum’ (NICE clinical guideline CG142). www.nice.org.uk/CG142.

Key reference: Allison C, Auyeung B, and Baron-Cohen S, (2012) Journal of the American Academy of Child and Adolescent Psychiatry 51(2):202-12.

Of course, this screen is limited 10 questions and is indicative only.

Prometheus uses DSM-5 (diagnostic and Statistical manual – 5th Edition) criteria when assessing for ASD. It can also be helpful to look at these criteria to see if you recognise traits

 DSM-5 DIAGNOSTIC CRITERIAAutism Spectrum Disorder  299.00 (F84.0)
A.    Persistent deficits in social communication and social interaction across multiple contexts, as manifested by the following, currently or by history (examples are illustrative, not exhaustive, see text):
1. Deficits in social-emotional reciprocity, ranging, for example, from abnormal social approach and failure of normal back-and-forth conversation; to reduced sharing of interests, emotions, or affect; to failure to initiate or respond to social interactions.
2. Deficits in nonverbal communicative behaviors used for social interaction, ranging, for example, from poorly integrated verbal and nonverbal communication; to abnormalities in eye contact and body language or deficits in understanding and use of gestures; to a total lack of facial expressions and nonverbal communication.
3. Deficits in developing, maintaining, and understanding relationships, ranging, for example, from difficulties adjusting behavior to suit various social contexts; to difficulties in sharing imaginative play or in making friends; to absence of interest in peers.
B.    Restricted, repetitive patterns of behavior, interests, or activities, as manifested by at least two of the following, currently or by history (examples are illustrative, not exhaustive; see text):
1. Stereotyped or repetitive motor movements, use of objects, or speech (e.g., simple motor stereotypies, lining up toys or flipping objects, echolalia, idiosyncratic phrases).
2. Insistence on sameness, inflexible adherence to routines, or ritualized patterns or verbal nonverbal behavior (e.g., extreme distress at small changes, difficulties with transitions, rigid thinking patterns, greeting rituals, need to take same route or eat food every day).
3. Highly restricted, fixated interests that are abnormal in intensity or focus (e.g., strong attachment to or preoccupation with unusual objects, excessively circumscribed or perseverative interest).
4. Hyper or hypo reactivity to sensory input or unusual interests in sensory aspects of the environment (e.g. apparent indifference to pain/temperature, adverse response to specific sounds or textures, excessive smelling or touching of objects, visual fascination with lights or movement).
C.    Symptoms must be present in the early developmental period (but may not become fully manifest until social demands exceed limited capacities, or may be masked by learned strategies in later life).
D.    Symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning.  (Note: Although there is no common measure for ‘clinically significant functional impairment’, it typically applies to pervasive/disabling difficulties within areas such as work, housing/home management, relationships, education, self-care, and employment).
E.    These disturbances are not better explained by intellectual disability (intellectual developmental disorder) or global developmental delay. Intellectual disability and autism spectrum disorder frequently co-occur; to make comorbid diagnoses of autism spectrum disorder and intellectual disability, social communication should be below that expected for general developmental level.

Contact us

If you have a general enquiry please email: admin@prometheus-therapy.co.uk or if you wish to arrange an appointment, please complete the online form »