Diagnostic Pathway for Adults



Pathological Demand Avoidance (PDA) is part of the autism spectrum and as such is usually identified during or following an assessment for an Autism Spectrum Disorder (ASD).

Recognition of PDA as part of the Autism Spectrum is fairly recent and remains contentious among professionals, but this is improving all the time due to the increasing bank of peer reviewed research and the National Autistic Society's acceptance of the PDA profile being part of the autism spectrum.

During the process of considering an assessment or diagnosing ASD, clinicians will often refer to one of the diagnostic manuals: ICD-10 (published by the World Health Organisation) or DSM5 (produced by the American Psychiatric Society). Different clinicians and local authorities may have guidelines about working within one of these manuals to provide consistency at a local level, but this is not always the case.

Because PDA is not currently included in either of these diagnostic manuals, and due to varying policies across local authorities and different individual clinicians' opinions, there is an inconsistent approach to the PDA profile of ASD in the UK. 

However, both recent and forthcoming changes to these diagnostic manuals mean that autism spectrum disorder (ASD) is likely to become the most widely-used term, and additional terms will often be used to describe particular profiles presented by individuals, such as 'ASD with a profile of Asperger’s' or 'ASD with a profile of PDA'. 

As a result, clinicians can use their own clinical experience and judgement to describe an individual’s presentation of ASD and remain within the guidelines of the diagnostic manuals. But, some clinicians may continue to be restricted by the policies of their local authority. The National Autistic Society has produced useful information that describes autism profiles and diagnostic criteria in more detail.

Beginning the Diagnostic Pathway – Collating Your Evidence

Securing an assessment for ASD can be a daunting and difficult process, so it may be a good idea to ask a friend or family member to help you. The first step is to collate your 'evidence' and present it in an easy to read way. This can help you to feel more confident when you request a referral for an assessment and provides medical professionals with clear reasons and explanations for your concerns and why an ASD assessment would be beneficial for you.

​​Evidence to support your concerns that you may be on the autism spectrum 

  1. First and foremost it is helpful to list the reasons why you think you may be on the autism spectrum. Some examples could be: difficulties you've had in adulthood and childhood with social communication and social interaction, sensory difficulties, friendships or employment and your need for routine, plus the degree to which you feel these affect different areas of your life.
  2. Print off some information on PDA and provide a brief example of how you identify with the key features of the PDA profile of ASD. The PDA Society’s Professionals Booklet, The PDA Society – About PDA and The National Autistic Society – What is PDA? would all be ideal for this purpose, but just select one to share.
  3. Highlight the relevant sections within these articles to illustrate the atypical features of ASD that individuals with the PDA profile can present with, which may make your difficulties less obvious at first.
  4. Provide evidence from someone else who can support your descriptions, concerns and the current difficulties that you experience in your day to day living. This person could be an extended family member, friend or a professional that has been supporting you, either past or present.
  5. Print off and complete the Extreme Demand Avoidance Questionnaire (EDA-Q), if you have a family member who could provide details of the difficulties that you experienced as a child and complete the EDAQ relating to their observations and experiences of you as a child this can be helpful too.
  6. Provide any information or reports from previous assessments or mental health conditions that you have either been diagnosed with or treated for.
  7. Make duplicates of your information so that you have a file to keep for your own records and one that you can share with professionals.

Why would an assessment and diagnosis be beneficial for you?

​The National Autistic Society provides some helpful pointers that could help you to convey this information.
  • It may help you (and your family, partner, employer, colleagues and friends) to understand why you may experience certain difficulties and what you can do about them
  • It may correct a previous misdiagnosis and mean that any mental health problems can be better addressed (however, it can be difficult to make a diagnosis of autism where there are severe mental health issues, or where someone is receiving treatment)
  • It may help you to get access to appropriate services and benefits
  • Your employer will be required to make any necessary reasonable adjustments
  • It may help women, and those with a demand avoidant profile, who may not before have been recognised as autistic by others

Requesting an Assessment

​Now that you have gathered all your supporting information, make an appointment to see your GP. You may find it helpful to take a friend or family member with you.

  • ​Share your concerns with your GP and provide him/her with your supporting evidence.
  • Be prepared to leave your supporting evidence with your GP for him/her to read through, also your GP may need to forward this information on if a referral for an assessment is agreed.
  • Many GPs may not have an in-depth understanding of Autism. You could take along a copy of the National Autistic Society's guidance for GPs, and tell your GP about the relevant guidelines on autism recognition and referral that should guide their decision to make a referral.
  • If your GP refuses to refer you for a full assessment, ask for the reason why. If you don't feel comfortable discussing their decision then and there, you can ask for a second appointment to talk it through. You could ask to see another GP at the surgery. If you are unable to resolve this decision with your GP, you can make a complaint.

Referral for a Full Assessment for ASD - What Are the Options?

​Your GP should refer you to:

  • Your local NHS commissioned multidisciplinary Adult ASD Diagnostic team.
  • If it isn't possible to refer you to a multidisciplinary team, you could be referred to an individual professional, such as a psychiatrist or clinical psychologist. This professional should be experienced in diagnosing autism, as this will mean you are more likely to be accurately assessed, and will avoid having to go back to your GP to ask for a second referral.
  • You can request that your GP refers you to an alternative NHS specialist within this field. Access to NHS specialist treatment is via your GP and is based on need​.
  • You can request a referal to an independent diagnostic centre service. Your GP would usually need to make an individual funding request  to your Clinical Commissioning Group (CCG).  These requests can sometimes be successful but they can also be refused. You would need to discuss this option with your GP to ensure that the correct process and pathway for any funding required is in accordance with local policies.
  • Private diagnosis (finances depending) is another option. If you wish to see a private specialist, you are still advised to get a referral letter from your GP. However, if you see a private specialist without a GP referral, your GP is not obliged to accept the specialist's recommendations. 
Please be aware that local services are not obliged to accept a private diagnosis and may insist upon you having an NHS diagnosis. But, providing the assessment has been conducted in accordance with NICE pathways there should be very few grounds for not accepting the outcomes of a private assessment. If your private assessment is not accepted by your local services it can be helpful to ask the clinician who conducted the assessment to contact the services involved on your behalf. If this doesn't resolve the issue you could make a complaint to the service concerned, request that your local MP supports you with this matter.

Please note that it can sometimes be hard to find a service or professional with experience of diagnosing autism in adults. Also, the recognition of PDA and the skills in local teams to make an assessment may vary regionally. However, it should still be possible for whoever you see to give you a detailed profile of your strengths and needs.

The following multi-disciplinary services do have the skills and expertise to assess and identify the PDA profile of autism in adults. Costs can vary from approximately £1000 to £3500, but you would need to contact the services directly for further information about waiting times, costs and their referral process. These services may be commissioned by your local CCG or privately by you.

Elizabeth Newson Centre - Nottingham (assessment for adults is a fairly recent service that the ENC offer and so may not be reflected on their website)
Help4Psychology - Norwich
The Lorna Wing Centre - Kent
Axia ASD - Chester
Spectrum North West - Warrington
The Spectrum Diagnostic, Assessment and Therapy Centre - Northern Ireland
The Spectrum Center PDA Outreach Clinic, Dublin - Contact 02887729810 for further information and appointments
Grow Communication - Scotland
Purple House Clinic - Glasgow
Dr Gloria Dura-Vila - London or Psychiatry in London (up to age 21)
Dr Julia Woollatt - Surrey

Please note The PDA Society takes considerable care to ensure the quality and experience of the services that we signpost to parents and professionals. However, the PDA Society is not making any recommendations nor is responsible for the quality, experience or the outcomes of assessments performed by independent services.

The Diagnostic Assessment

​The National Autistic Society provides a clear and concise description of what the diagnostic assessment is likely to involve in step 4 of their information about the assessment and diagnosis process for adults.

Dr Judy Eaton, Consultant Clinical Psychologist has provided the PDA Society with a brief description of what an adult assessment would involve at her independent, specialist assessment and diagnostic centre - Help for Psychology.

​With an adult assessment I talk to either the individual or the individual plus the parent, carer or partner and we go through the person's developmental history. During this I would ask about the types of difficulty that are seen in children with PDA. In addition I would also carry out a cognitive and sensory assessment, a communication screen and I would look at current functioning e.g. employment, mental health etc. Dr Judy Eaton 2017

Assessment Outcomes

The diagnostician will tell you whether or not they think you are autistic. They might do this on the day of the assessment, by phone on a later date or in a written report that they send to you in the post/via email. The report may say that you present a particular autism profile, such as Asperger syndrome or a demand avoidant profile.

Sometimes people are told they aren't autistic and sometimes they may be given a diagnosis they don't agree with. You can seek a second opinion, which either means going back to your GP to explain that you aren't happy with your diagnosis and ask them to refer you elsewhere, or paying for a private assessment.

Please Note: Funding issues can often delay the process of getting a second opinion. There may be no tertiary service in your local area. In some cases, funding for out-of-area referrals and individual funding requests are refused.

Uncertainty or disagreement about the diagnosis

Consider obtaining a second opinion (including referral to a specialised autism team if necessary), if there is uncertainty about the diagnosis or if any of the following apply after diagnostic assessment:

  • Disagreement about the diagnosis within the autism team.
  • Disagreement with the person, their family, partner, carer(s) or advocate about the diagnosis.
  • A lack of local expertise in the skills and competencies needed to reach diagnosis in adults with autism
  • The person has a complex coexisting condition, such as a severe learning disability, a severe behavioural, visual, hearing or motor problem, or a severe mental disorder.

NICE Pathways, Identifying, assessing and diagnosing autism spectrum disorder in adults, Pg. 9, point (6)

What you can do if you are not satisfied at any stage of the process

  • If you are unhappy with any stage of the diagnostic pathway you can try to resolve any issues, in the first instance, by directly giving your feedback to the service involved.
  • If this option does not resolve the issue you can make a complaint about the service involved to your local NHS service.
  • It can be helpful to explain the difficulties that you are experiencing with your local MP to see if he or she is able to support your complaint.
  • Our Free Support Resource can signpost you to services that may be able to help you with this process.
  • If you have a complaint about a private diagnostician they should have their own complaints procedure, as required by the Care Standards Act 2000.

Further Information

​The National Autistic Society provides an in-depth but concise article on Autism - Diagnosis for Adults 

The PDA Development Group has provided a useful factsheet on 'What Makes a Good Diagnostic Assessment For an Individuals with a PDA Profile' which you can download from our website.

​Nice Pathways provides guidance and recommendations to professionals and individuals regarding Identifying, assessing and diagnosing autism spectrum disorder in adults, which you can download from their website.

Further information about PDA can be found in our extensive list of resources.

Please note that the PDA Society are not making any recommendations nor is responsible for the content of sites and links that are external to the PDA Society.

Please contact us if you discover any broken links.