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Diagnosis page

Trigger warning: This section discusses topics which could be triggering. Please only read if you feel safe to do so.



This page talks about all aspects of autism diagnosis:

What should I look for in a diagnostician? Should I seek a diagnosis for myself or my child? What are the advantages and disadvantages? Diagnosis or self-diagnosis? What are the clinical criteria for a diagnosis? And much more.

Diagnose menu
To diagose or not to diagose?

To diagnose, or not to diagnose?

What are the advantages (or disadvantages) of getting an official diagnosis? What needs to be considered before going down that path? Why do some people choose to self-identify as autistic?


Do I really need to know if I am autistic or not?


The vast majority of autistic adults and knowledgeable professionals in the field of autism research would shout a resounding, YES! We also know that, for many parents and adults, it is far from being that simple and clear-cut. 


Some of us identify as autistic or neurodivergent in some way, but aren't fussed about an official diagnosis, while others would like an official confirmation, even if they already know it. But a very important factor to consider is that a diagnosis is (unfortunately) often the only way to receive specific help or adjustments at school, work or in everyday life.

But what if you don't want or need any help? Well, surely every human has the right to live as their true selves, and how can we do that if we are constantly trying to be something we are not? In order to lead a fulfilling life and be true to ourselves, we must know our true selves. We cannot, and should not pretend we aren't straight, gay, bi, trans, asexual, sexual, fluid, tall, short, shy, outgoing, black, white, physically disabled, mentally unwell and so on. And we cannot pretend that we aren't autistic. It is part of our whole identity.

What we choose to do with that knowledge is entirely up to us. That's another very personal decision, but one that can only be made with knowledge and awareness.

Many autistic adults instinctively know that our brains work differently from other people. Most of us were acutely aware of 'something' being different to our peers when we were growing up. But society is cruel and rarely tolerates difference, in whatever form it takes. Instead, we were likely to have been teased, bullied and admonished for acting in any way atypical. We would have been singled out because of stimming, or having intense interests.


Generally speaking, we will have always felt alienated, and prior to diagnosis, we were not able to understand why. 

Why do some people fear an autism diagnosis?


Parents and adults may fear the stigma that still sticks to autism like superglue.


Endless myths and untruths have pervaded throughout recent decades and the only reference to autism that many of us have been exposed to are films such as Rain Man, or to the character, Sheldon in the TV series, The Big Bang Theory. Sometimes it feels to us as though the media is doomed to forever portray autism as a defect or weakness - as something that needs to be treated, cured and prevented. 


Historically, autism has been grossly misunderstood; both by society in general and by those in the medical world. In many countries, autistic children have been hidden away in institutions, forcibly ‘treated’ and abused, and their rights as humans forcibly removed. All of this contributes to autism’s bad reputation and so it’s not surprising that people are still wary of the words, autism and autistic.

What if I know I'm autistic, but I don't want / can't get an official diagnosis?

For a variety of reasons, some adults prefer not to seek an official diagnosis. Such reasons include long waiting times, prohibitively expensive costs, fear of stigma and repercussions from family or work colleagues should they find out, or simply not feeling the need to be diagnosed officially.


As adults, many of us just know deep inside ourselves, that we are autistic. Instinctively, we are already aware of our difference -our different neurotype; our different way of thinking. And so, it will already be an identity with which we either strongly identify or not. For all these reasons, self-identification is considered equally valid.

Self-identifying as autistic
Advantages diagnosis

What are the advantages and disadvantages to seeking an assessment or confirming a diagnosis?

Receive specific adjustments and support at school, home or work.

Confirmation of what we already suspect - validation.

Explanation of our differences, quirks, weirdness, ways of processing information, sensory differences, communication challenges and why we have always felt different.

Confirmation that we are perfectly normal and part of humanity's normal diversity.

A chance to reframe our lives and heal from the trauma caused by not knowing why we always felt a certain way.

The chance to find our 'tribe' or our community, and make meaningful connections that genuinely work for us. To meet others with similar interests.

The option to seek appropriate, and where necessary, adjusted support for our  mental health or any other needs.

Finding out we are autistic means we may be able to identify other family  members who may also be autistic, who need particular understanding or are struggling in a way that we can now better understand.


Knowing our neurotype means knowing what does, and doesn't work for us in terms of employment, relationships and everyday life and giving us the power to adjust our environment accordingly.

Permission to stop trying to 'fit in' or be something we are not.

The opportunity to finally be at peace with ourselves. Understand ourselves. Forgive ourselves. Accept ourselves. Love ourselves. 

Disadvantages diagnosis

The following disadvantages are all possible, although very individual. Some people find out they are autistic and nothing changes. But for some adults, much psychological damage has already been done, as a result of trying to thrive as an autistic person in a non-autistic world. For others, they may have other additional difficulties that make life difficult. Here are some possible disadvantages do receiving an autism diagnosis:

There is still much stigma associated to being autistic. We may face this stigma at home, at school, at work and more importantly in our own minds. We may (wrongly) feel that we are somehow broken or less-than. 

We might discover that those around us do not understand what autism is, and therefore find ourselves even more alienated.

We may have worn our neurotypical mask for so long that it feels almost impossible to remove.


We may face a roller coaster of emotions and a process of grieving, as we work through and unpack the various elements of our diagnosis. We will need time and patience as we reframe various aspects of our lives up to this point.

As we accept our autistic brains, we may feel invalidated by those around us, who do not yet have the understanding or knowledge necessary, in order to do so.

Our autistic 'behaviour' may begin to become more obvious to others as we begin to be our true selves. This may be challenging for us or for our loved ones and may require some professional help to navigate.

It can take time to find our 'tribe' and community. It can also mean that certain people in your life naturally drift away as you begin to be at one with your true self.


Should I seek an assessment for my child?

Some parents wonder if seeking a diagnosis for their child is a good thing or a bad thing, perhaps fearing the repercussions of doing so. This is totally understandable. Other parents may refuse to accept or believe that their child could be autistic due to a misguided sense or fear or shame. And some argue, that it is just an unnecessary, or even harmful label, not wanting their children to be seen as different.


However, the fact remains that autistic children are different. They do have a different processing system and their brains do work differently in some fundamental ways. This is neither wrong nor defective.


We wouldn’t try to run a Mac computer on a Linux operating system; or an Android phone with Apple software. Neither are defective but we still need to know if it’s an Android phone or an iPhone in order for it to function at its best.

Autism runs a different operating system to neurotypical brains. When our autistic children are raised in a purely neurotypical way, this is extremely harmful to them and will stunt their unique talents and gifts. It will damage them physically and psychologically.


They will know that they are somehow different, yet not be able to understand that difference, or why it is unacceptable to their peers and family. They will not have the tools to grow and develop with good self-image and self-esteem, knowing their unique value in society. They will be deprived of experiencing the world in their own unique way.

If you are still unsure about seeking an assessment for your child after reading the section above, listen as much as possible to what autistic adults have to say - especially those of us who weren't diagnosed until later in life. The vast majority of us wish we had known much sooner, and as a parent you must delve deep into your own personal reasons and beliefs and ask, what is truly best for my child, for their future and for their mental health?


Not diagnosing a child doesn’t make them not autistic.  

“As soon as a child is capable of understanding, they will know they are different. Just as a diabetic needs insulin, an autistic child needs accommodations . . . The label gave me knowledge and self-awareness.”


 – Steve Andrews 

“Within every living child exists the most precious bud of self-identity. To search this out and foster it with loving care; that is the essence of educating an autistic child.”


– Dr. Kiyo Kitahara 


Throughout our childhoods we will almost certainly have been labelled as weird, stupid, odd, crazy, disruptive, naughty or lazy. We would have felt our differences exquisitely, but not been able to make sense of, or understand them. Our school reports would have always emphasised our ‘failures’ as not trying hard enough, not listening, talking too much, daydreaming and not reaching our potential. Many of us were mislabelled as slow learners.


As undiagnosed adults, we will have spent a lifetime battling to try to fit get our square-peg-selves into society’s neatly rounded holes - and it has rarely ended well. As adults, we do at least have a choice, and it is never too late to seek a diagnosis.  

Should I seek an assessment as an adult?


“Autists are the ultimate square pegs, and the problem with pounding a square peg into a round hole is not that the hammering is hard work. It’s that you’re destroying the peg.”


 – Paul Collins 

We may have got along OK in primary school, only to have everything fall apart at secondary school. And this is particularly true for girls. The social laws and challenges of school in teenage-hood are some of the hardest we will face in our lifetimes, and they will not stop being difficult as we continue through life as adults, trying to navigate work, home and relationships.  


The mental toll of a lifetime trying to be something we are not, should not be underestimated. By the time we reach adulthood, the constant stream of negativity we have experienced from our families, schools, after school clubs and society in general, will have already been set in stone. As a result, we will suffer distress and loathing for our ‘broken’ selves, causing deep, and often irreversible trauma.


We struggle with our friendships, relationships and jobs, and we are utterly, emotionally exhausted and burnt out. And tragically, for some, the worst outcome of all - suicide - is the result of all that pain and trauma.

This has been the experience of many undiagnosed autistic adults and young people. But it is not because of their autism – it is because the world has not given them permission be themselves, and has not supported them where and when they needed it. Most of us deeply regret not having been diagnosed and supported as children.

So if you are a questioning adult, remember that it is never too late to get the confirmation you need and deserve, or to find and accept your authentic self. 


We will have blamed our ‘wrong’ selves and committed again and again to ‘try harder’.

Or perhaps we just stopped trying and gave up.

Clinical diagnosis

How is autism diagnosed?

For a more human explanation of autistic traits and how they might look, please go back to this page: 



Autism is medically diagnosed using something known as clinical diagnostic guidelines.The traits of autism fit into specific areas of these guidelines. This is a ‘basic’ guide but if you would like more in-depth information, links are also provided.


A clinical diagnosis of autism is based on the guidelines from the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and / or the International Classification of Diseases, eleventh edition (ICD-11).  

What is involved in the clinical diagnostic procedure?  


Although brain medical imaging shows definite differences between autistic and non-autistic brains, there are no blood tests or other simple diagnostic tests for autism. Instead, the clinical diagnosis is made after an in-depth assessment by a knowledgeable clinician, or team of clinicians. This may be a clinical psychologist, specialist speech and language therapist, psychiatrist or another qualified professional.


The typical journey to diagnosis will vary from country to country and between regions. Depending on the available services or health care providers, the process can last between a few months to two years and will roughly follow a similar course: 


1. The adult or parent will approach their family doctor or specialist service to enquire about assessment for autism.

2. Information gathering. For example, childhood milestones, behaviours noticed, school reports and other useful information from family members; tools such as online questionnaires; accounts of how daily life is affected; medical history; reports from other health professionals.  

3. Face to face interviews or observation (children) and the use of various diagnostic tools (described  below).  

4. Diagnosis and full report.  

What is important?

What's important when seeking a diagnosis?

It is vital that whoever does the assessment is up to date with the fast-moving research and most recent diagnostic criteria. In addition, they need to be aware that for women and girls, including those assigned female at birth, there are often differences in the way our autism presents. And that adults may have experienced a lifetime of masking, adaptive behaviour and trauma which can mask their autistic traits. Further, there are cultural differences which need to be taken into account.


In adults, it takes an experienced practitioner to tease apart the subtle differences between autism and mental health disorders, which may well exist alongside autism, but could also have been misdiagnosed instead of autism, at some point in the past.


The clinician should use a variety of different assessment tools, interviews, history taking and observation, as well as input from the autistic adult or young person, parents, family, school teachers and other professionals where appropriate. It is helpful for teenagers and adults to look back at early developmental signs and old school reports, and to have input from people who know you well, or who have known you since childhood.  

Your clinician must be able to take the time necessary, to listen carefully to what you have to say and be able to pick out the important details for a clinical diagnosis. You should feel listened-to, understood and validated.  


As you read the following medical diagnostic criteria, you may notice that the wording used is very negative. The words disorder and deficit are used throughout. Unfortunately, this is exactly as they are currently written in the diagnostic manuals. Many in the autism community are extremely uncomfortable with this heavy emphasis on abnormality and disorder, but it is slowly changing and hopefully will continue to evolve in time.


The DSM-5


For a laymen’s explanation of autistic traits and how they might look, please refer back to this page:

The Diagnostic and Statistical Manual of Mental Disorders (DSM) is released by the American Psychiatric Association and is widely used by many organisations, individuals and governments to diagnosis psychiatric disorders. The most recent, fifth update, was in 2013 – this is known as the DSM-5.


The previous edition (DSM-IV-TR) defined autism under five pervasive developmental disorders (PDDs) which were: autistic disorder, Asperger’s disorder, Rett’s disorder, childhood disintegrative disorder and pervasive developmental disorder not otherwise specified (PDD-NOS). In the DSM-5, these have all been replaced by the single diagnosis of autism spectrum disorder (ASD).


A condensed version of this is shown below, and you can find the full DSM-5 on the CDC website here:   

To meet the diagnostic criteria for ASD a person must: 


‘have persistent deficits in each of three areas of social communication and interaction plus at least two of four types of restricted, repetitive behaviours’.   

The three areas of social communication deficit are: (All three must be present


1. Deficits in social-emotional reciprocity such as abnormal social approach and failure of normal back-and-forth conversation, reduced sharing of interests, emotions or affect or failure to initiate or respond to social interactions.  


2. Deficits in nonverbal communicative behaviour used for social interaction. For example, poorly integrated verbal and nonverbal communication, abnormalities in eye contact and body language, deficits in understanding gestures or a lack of facial expressions and nonverbal communication.  


3. Deficits in developing, maintaining and understanding relationships. For example, difficulties adjusting behaviour to suit various social contexts, difficulties in sharing imaginative play or in making friends or absence of interest in peers.  


The four types of restrictive behaviours are: (At least two are needed)  


1. Stereotyped or repetitive motor movements, use of objects, or speech. Insistence on  sameness, inflexible adherence to routines, or ritualised patterns of verbal or nonverbal  behaviour. For example, extreme distress at small changes, difficulties with transitions, rigid thinking patterns, greeting rituals, a need to take same route or eat same food every day.  


2. Insistence on sameness, inflexible adherence to routines, or ritualised patterns of verbal or nonverbal behaviour. For example, extreme distress at small changes, difficulties with transitions, rigid thinking patters, greeting rituals or the need to take the same route or eat the same food every day.  


3. Highly restricted, fixated interests that are abnormal in intensity or focus. For example, strong attachment to, or preoccupation with unusual objects or excessively circumscribed or perseverative interests.  


4. Hyper- or hypo-reactivity to sensory input or unusual interest in sensory aspects of the  environment. For example, apparent indifference to pain or temperature, adverse response to specific sounds or textures, excessive smelling or touching of objects, visual fascination with lights or movement.  

DSM-5 has also introduced specifiers to help the clinician to describe associated or additional conditions. For example, intellectual impairment, language impairment, genetic conditions, behavioural disorders and catatonia. These specifiers were introduced to assist clinicians to further divide the diagnosis into three levels of support, or ‘severity of the impairments’:   


Level 1 - Requiring support  

Level 2 - Requiring substantial support  

Level 3 - Requiring very substantial support  


These are, however, controversial as they can be difficult to measure, and their use varies from country to country, as well as between clinicians. It is difficult to categorise an autistic person’s support needs as they can vary widely from week to week, day to day, or even hour to hour and depend on so many other factors. Also, the specifiers do not make someone automatically eligible for support.   


The DSM-5 also includes a condition called social (pragmatic) communication disorder, which is separate to autism spectrum disorder. This diagnosis would be given to someone who meets the diagnostic criteria for social and communication difficulties, but not for restrictive and repetitive patterns of behaviours, activities or interests.   




For a laymen’s explanation of autistic traits and how they might look, please check out this page: 

The International Classification of Diseases (ICD) is released by The World Health Organisation (WHO).  The latest manual has been in effect since January 2022 and is the Eleventh Edition (ICD-11).


These guidelines allow for ‘several distinct autism profiles’ and include childhood autism, atypical autism and Asperger syndrome. All are included under the heading of pervasive developmental disorders.  

The ICD-11  is more in line with the DSM-5. Autism is now listed under neurodevelopmental disorders and the term autistic spectrum disorders is used (ASD)


ASD is described as being 


characterised by persistent deficits in the ability to initiate and to sustain reciprocal social interaction and social communication, and by a range of restricted, repetitive, and inflexible patterns of behaviour, interests or activities that are clearly atypical or excessive for the individual’s age and sociocultural context. The onset of the disorder occurs during the developmental period, typically in early childhood, but symptoms may not become fully manifest until later, when social demands exceed limited capacities. Deficits are sufficiently severe to cause impairment in personal, family, social, educational, occupational or other important areas of functioning and are usually a pervasive feature of the individual’s functioning observable in all settings, although they may vary according to social, educational, or other context. Individuals along the spectrum exhibit a full range of intellectual functioning and language abilities.’  


The ICD-11 includes Asperger’s syndrome, childhood disintegrative disorder and certain other generalised developmental disorders under the category of autism. It now includes the same two categories as the DSM-5 (difficulties in interaction and social communication and restricted interests, and repetitive behaviours). However, it has removed language problems, which was included in the ICD-10.   


Also added are detailed guidelines for distinguishing between autism with and without an intellectual disability. There is now less emphasis on childhood play, which reduces cultural and international biases. Instead, there is more interest in the strict rules that children may impose or follow when they play.


More information about the ICD-11 can be found here:



Additional diagnostic tools used as part of the assessment  


In order to collect appropriate information to assist in the diagnostic process, the clinician will use some tools. Different clinicians may have a preference for one or more of these tools and may use a combination of them. They are:  


  • DISCO (Diagnostic Interview for Social and Communication Disorders) 


  • ADI-R (Autism Diagnostic Interview – Revised) 


  • ADOS (Autism Diagnostic Observation Schedule)  


  • 3Di (Developmental, Dimensional and Diagnostic Interview)  


All except the ADOS tool are based on developmental data. ADOS only looks at current behaviour and skills.


More detailed information about these tools can be found here:

Using the term “high-functioning” discounts or dismisses the person’s needs or struggles . . . Using the term “low-functioning” discounts or dismisses a person’s strengths and capabilities.


 – Tom Iland, The Fallacy of High and Low Functioning Autism

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