How Many Adults Think They Have Undiagnosed Autism?

More and more adults these days believe they might have undiagnosed Autism Spectrum Disorder.

Has autism become more prevalent in the gene pool, or are more people falsely believing they may be autistic? Or is there another reason for the rise in diagnoses?

The rise in ASD diagnoses certainly helps fuel the increasing number of women and men who believe they may have autism despite never having been clinically assessed for it.

A study in JAMA Network Open found that ASD diagnoses among all age groups spiked 175% between 2011 and 2022, from a rate of just 2.3 to 6.3 per 1,000 people (0.23 to 0.63%).

However, estimating how many women and men think they could have undiagnosed autism is tricky due to the following:

Variability in self-diagnosis
Limited access to formal evaluations
Growing awareness of autism that went below the radar in childhood.

Now, just because a particular condition is usually diagnosed in childhood doesn’t mean that it can’t fly beneath the radar in other kids and teens and not be recognized until adulthood, even middle age.

It may not be until middle age and even older that some individuals could begin suspecting that they are autistic.

This doesn’t mean most aren’t.
This doesn’t mean that the only traits that they have, leading to their suspicion, are quirkiness and deep interests in their hobbies.
Typically, when an adult starts wondering if they could be autistic, they have already identified numerous traits about themselves, not just two or three, that could only be explained by autism.

A person who begins suspecting autism in themselves only in adulthood had traits growing up that had been attributed – or rather, mis-attributed – to other conditions.

So for instance, in my case, any “differentness” or social struggles on my part were attributed to any of the following: musical and artistic talent, hypersensitivity, dwelling too much on a topic or being infatuated or “obsessed” with a new interest, lack of social graces, being too analytical, being disrespectful, being aloof, and just plain being an oddball.

Decades ago, who’d ever think I was actually autistic?

None of the above traits prevented me from correctly answering questions in class, turning in my homework on time, getting good grades, being very verbal, doing household chores and behaving in public.

All of this narrative certainly describes many other late-diagnosed adults (such as myself) or adults who suspect they’re autistic.

Any meltdowns they had in childhood or during their teen years could’ve likely been misdiagnosed as brattyness, oversensitivity or panic attacks.

Not all Autistics have meltdowns (which usually arise from sensory overload), though a large number of them do.

But again, these could be mis-attributed.

Not all autistic people avoid eye contact. Not all Autistics are late talkers, either.

These are all reasons why an adult’s undiagnosed autism could cruise well under the radar during childhood or teen-hood.

But eventually, as social demands and expectations increase as one goes through adulthood, which also involves having to maintain employment, such an individual will start wondering what they “could have” that has caused them so many issues all throughout their life, such as:

• Difficulty making friends or keeping friendships.

• Being accused of being rude when such intentions never existed.

• Sensory sensitivities (which the person may not even label as such).

• Eventually being known as weird or strange no matter what group they’re in.

• Overthinking and over-analyzing so much that it impairs quality of life.

• Having to rehearse anticipated conversations; relying on practiced scripts to interact with people.

• Feeling taxed or drained after social events.

• Lifelong feeling of being alien from other people.

Can we quantitate how many adults suspect they’re autistic?

A 2021 study published in The Lancet Psychiatry highlights that adults, particularly those in their late 20s and 30s, increasingly self-identify with autism.

In this study, researchers found that approximately one in 50 adults reported that they suspected they had autism but had never received a formal diagnosis.

The study suggests that many of these individuals may have gone undiagnosed because autism was historically underdiagnosed in adults, particularly among women and those without intellectual disabilities.

The criteria for an autism diagnosis also changed over time, contributing to differences in how people perceive their symptoms.

An autistic child or adult can also receive a wrong diagnosis or an incomplete one.

For example, being diagnosed with only ADHD when they also have ASD.

As they grow older and learn more about autism, and then take online autism tests (which are guidelines only; not diagnostic), they become convinced that they’re on the Spectrum.

Further studies support the idea that autism may be underdiagnosed in adults.

Research from the National Autistic Society (NAS) in the UK suggests that many adults remain undiagnosed and self-identify later in life.

According to a 2020 NAS report, up to 700,000 adults in the UK may have undiagnosed autism.

How many out of this huge number who actually suspect it is not known.

Undiagnosed ASD is partly due to a lack of awareness and the fact that autism was once primarily associated with childhood diagnoses and severe limitations in the ability to communicate and connect with others.

Many adults report experiencing significant challenges in social interactions, sensory sensitivities and other autism-related traits but have not sought a formal diagnosis — often due to not having the money for an assessment.

Some, especially older, figure why bother? “I’ve gotten this far without the diagnosis; I don’t need to be told what I already know.”

A 2020 survey that was published in Autism Research also found that more than 2,000 adults who were not diagnosed as children reported that they had self-diagnosed autism.

Of those, around 60% had done so after learning about autism through online communities, books or media.

This suggests that growing awareness, especially in the age of the internet and social media, is increasing the number of adults who consider the possibility that they might be autistic.

Furthermore, a 2022 study in The Journal of Autism and Developmental Disorders indicates that more women and individuals with less obvious or more subtle autism traits are now self-identifying.

The study noted that women, in particular, are more likely to go undiagnosed because their symptoms often present differently than those of men, who are more likely to show the stereotypical signs of autism such as odd mannerisms and social ineptness.

As a result, many women may go through life without understanding why they experience social difficulties, sensory overload or intense interests in specific or highly circumscribed subjects.

These so-called narrowed interests are often eccentric.

I know an autistic woman who really gets off on the fact that different colors distinguish renewal years for license plate stickers.

I was once so hyperfixated on wood chippers that when I heard one in the neighborhood while at home, I’d drop what I was doing, jump into my car and try to locate the chipping operation to observe.

All the Adults Out There Who Think They’re Probably Autistic

©Lorra Garrick

While it’s difficult to pinpoint an exact number, research suggests that a significant number of adults, possibly up to one in 50 or more, believe they have undiagnosed autism.

Now, here’s something to ponder: Are people who think they’re autistic usually right, once they get the assessment?

I covered this topic, interviewing a psychologist who specializes in ASD assessments. Read it here.