Getting a diagnosis of autism can be a really positive thing. However, the process can be difficult for adults. This is a step-by-step guide for how to seek a diagnosis.

Step 1: speak to your GP

In most areas, you should book an appointment with your GP and ask them for a referral to a psychiatrist or clinical psychologist, preferably one with experience of diagnosing autism.

Some diagnostic teams accept self-referrals. You can check the Autism Services Directory to find out if you can refer yourself to your local team. However in most areas, you will need a referral from your GP.

Make sure your diagnosis is the only thing you are seeing your GP about. If you try to mention it during a consultation about another subject, your GP may not address it fully.

If you are seeing a different health professional for other reasons (for example, a psychologist if you have depression) you might prefer to ask them for a referral instead.

Step 2: present your case

Your GP needs a reason to refer you for diagnosis, so you will have to explain why you think you could be autistic, and how a diagnosis would benefit you. If you think you might want help with this, ask someone you know to come with you.

You might say that you have been reading about autism, or that you've been in touch with The National Autistic Society. You think that you experience some of the difficulties that people with autism can face, and you would like to seek a formal diagnosis to be sure. Try to give your GP one good example of from each of the areas of difficulty outlined in our explanation of what autism is.

Not all GPs will have an in-depth knowledge of autism, so it's important to explain things as clearly as you can. We have helpful guidance for GPs which may be useful.

A middle-aged autistic man chats to another adult

Know the law and guidelines

It may be worth letting your GP know that you are aware of the strategies, laws and guidelines that professionals should be following, relevant to the country you live in. If your GP does not want to refer you for an assessment, you could show them the information about these to challenge their decision.

There are guidelines that professionals should be following such as those issued by the National Institute for Health and Clinical Excellence (NICE). NICE Clinical Guidelines apply in England and Wales but may also be taken up in Northern Ireland after being reviewed. NICE Clinical guidelines have no formal status in Scotland.

The law in England

The Autism Act (2009) led to the government producing statutory guidance for autistic adults, which is called the autism strategy (England only), published in December 2010 and updated in 2014.

The autism strategy says that local authorities in England must have a clear pathway of diagnosis for adults, meaning that you should be able to have a diagnostic assessment and your GP or local authority should be able to tell you how you can get this assessment.

The law in Northern Ireland

The Northern Ireland Autism Act (2011) says that a strategy should be published to ensure that the needs of people with autism and their families are met throughout their whole lives.

The Health and Social Care Boards Regional Autism Spectrum Disorder Network's Adult Care Pathway (2013) provides guidance on autism assessment, diagnosis, and intervention and says that after screening, adults should be referred to a specialist autism multi-disciplinary team.

The law in Scotland

The Scottish Strategy for Autism (2011) includes goals for improving diagnosis and states that for adults, getting a good quality diagnosis is the key foundation that will lead them to understanding their condition and for the best support to be made available to them.

The law in Wales

Autistic Spectrum Disorder (ASD) Action Plan for Wales (2008) specified a care pathway for adults. This says that your GP should refer you for a local multi-disciplinary assessment by a team with knowledge and expertise in the assessment of adults and Asperger syndrome.

Step 3: getting a referral

If your GP agrees to refer you, we recommend that you tell them about local services which have experience of diagnosing autism. Doing 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.

Be aware, though, that it can sometimes be hard to find a service or professional with experience of diagnosing autism in adults.

You can find diagnostic services in your area by searching the Autism Services Directory (print details out and take them with you), or by contacting our Autism Helpline on 0808 800 4104.

You are most likely to be referred to a diagnostic service (such as a clinic of assessment centre) within your local Clinical Commissioning Group area (in England), your Health Board area (in Scotland), your Local Health Board area (in Wales), or your Health and Social Care Trust area (in Northern Ireland).

You can be referred to a service outside your area, but as this costs more, your local NHS commissioning body might question why you need to go there, or whether you really need a diagnosis.

Private diagnosis is always an option, if you can pay for one, but you may occasionally find that local service providers (for example, social services) will not accept private diagnoses and will insist upon you having an NHS diagnosis, too.

Once you have been referred, there is no more involvement from your GP.

An autistic adult chats to a professional

What if my GP does not refer me?

If your GP decides not to refer you for a diagnosis, 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.

If you want to complain about the referral or diagnostic service you received, there is a complaints procedure that you can follow. The procedure is different in each UK nation. Find out more about the complaints procedure in EnglandScotlandNorthern Ireland or Wales.

The procedures apply to all complaints made about local authorities, GPs and the NHS, including those related to diagnosis. For more information, contact our Autism Helpline or look for local advocacy services in the Autism Services Directory.

Step 4: getting diagnosed

Most adults see a psychiatrist or a clinical psychologist for their diagnosis, although this does vary. Waiting times also vary. You can take someone with you when you go for a diagnosis if you like but they will not play an active part in proceedings (unless the tool being used requires input from family members).

A diagnosis is not a medical examination: you don't need to be examined physically and shouldn't be asked for any samples, such as blood.

There are several 'diagnostic tools' available, and diagnosticians aren't obliged to use a specific tool. You can read about diagnostic tools on the Research Autism website

One example of a diagnostic tool is the DISCO framework. This is a series of questions about your developmental history from when you were a young child (for example, about language, play and cognition). Because it concerns your childhood, parents need to be involved to answer some of the questions. If parents can't be involved, then siblings may be able to take part instead.

Generally, you will not be given a diagnosis on the day. Instead, the diagnostician will write up a report that they send to you in the post. You might have to wait a while before the report arrives. Sometimes, the diagnostician will call you and tell whether or not you are autistic. Then they will send you the report later.

Diagnostic reports can be difficult to read and understand in places. You can call the diagnostician to talk through any parts of the report that you aren't clear about.

A middle-aged autistic woman in conversation with a professional

Step 5: coming to terms with the results

Sometimes people are told they aren't autistic, and sometimes they may be given a diagnosis that 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 diagnosis.

If you go for a second diagnosis, remember that it may reach the same conclusion as your first diagnosis.

If you are diagnosed as autistic, you may have a lot of questions. You might be wondering how you can find out more about your condition, meet other autistic people or access services and support. To find out more about what to do next, download our What next? guide.

Some diagnosticians offer follow-up services after diagnosis and might be able to answer your questions and point you towards support services. However, not all diagnosticians do this.

Support does not automatically follow diagnosis, but having a formal diagnosis does mean that you are more likely to be able to access services and claim any benefits you are entitled to. Not everyone feels they need further support – for some people, simply getting a diagnosis seems to be enough.