Adult Autism Diagnosis


The process of diagnosing Autism in a person over the age of 18 is different from diagnosing a child. Where children are usually referred to a psychologist by a GP, adults currently must go through the Mental Health Service. This can be problematic as, although a lot of adults with Autism do also have mental health issues, Autism itself is not a mental disorder and should not be treated as such. It can also be difficult when a psychologist assessing an adult does not have relevant training in understanding how Autism effects adults or how best to communicate with Autistic adults.


You usually start the diagnostic process by referral from a GP to a psychiatrist who specialises in ASD assessment. It can be a long-winded and daunting process, especially if your GP does not have much experience or knowledge of Autism in adults.

For people with Autism, diagnosis requires a process of observation and clinical examination that can take some time. Part of making a diagnosis is called differential diagnosis. This is the medical term for the process of excluding all the other possible conditions that could cause the same symptoms. There are often other conditions that occur as well as Autism. This can make diagnosis a complex process.

Some private clinicians will accept self-referral so if you are thinking of going private it is worth asking if you need a GP referral or not.


While it is different for everyone, Autistic traits can often make people feel like there is something wrong with them. Knowing that there is a reason why you are different from people around you can be of great comfort and enable you to better use your skills, make accommodations for your difficulties, learn what triggers emotional responses (such as sensory overload) and generally make life a little easier for yourself.

However, there is still some stigma attached to being Autistic, so adults may feel that going through the process of diagnosis is not worth the hassle, especially if they have already developed coping skills or have a supportive network of friends and family.

If your differences are having a negative impact on your life, it is worth investigating a diagnosis with a view to learning coping strategies and potentially accessing support.


Currently, publicly funded diagnostic services exist only for children and adolescents, and for adults who have an intellectual disability. While the New Zealand Autism Spectrum Disorder Guideline (NZ ASD Guideline) recommends that specialist diagnostic assessment should be publicly available for all people who may have ASD, this is not currently the case. Most private diagnostic services accept self-referrals and referrals from agencies, including referrals of adults.

Autism NZ has a process on their website of going from self-assessment online through to clinical assessment. You can access it here.

You can also read the Ministry of Health booklet “How is ASD diagnosed?

If you decide to get assessed for Autism, you can find out more about what is available in your region by contacting your local Parent to Parent Regional Coordinator (RC). You can find out who your RC is on the Parent to Parent website here.


It is up to an individual whether they seek a diagnosis, but if someone believes they are on the Autistic Spectrum and that they want to find out either way, then it is best to get the ball rolling on diagnosis as soon as possible. Current systems are underfunded and over-stretched so you may be waiting a while for a referral appointment. You can go through the private sector, but this can be expensive and again waiting lists are not short.

In short, it is never too early or too late to get an assessment for Autism if that is what you want.

Ministry of Health
Autism NZ
Parent to Parent Inc

louise ratcliffe
Louise Ratcliffe
Information Officer
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