Why More Adults Are Being Diagnosed with Autism

More and more adults are being diagnosed with autism—and for many, it’s helping make sense of things they’ve wondered about for years. In fact, one study published in the Journal of the American Medical Association Psychiatry found that between 2011 and 2019, the overall rate more than doubled in people 18 and older.

James McPartland, PhD, director of Yale Child Study Center’s Developmental Disabilities Clinic, says he’s seeing more adults than ever seeking evaluations—and there are several reasons behind the trend.

“Awareness of autism is so high, stigmatization is so low, and social media is filled with personal stories about autism,” McPartland says. “You can flick through Instagram or TikTok and think, ‘I’m a person with autism and I know this because I relate to this video.’”

But you can’t diagnose autism with an online quiz or hearing about someone else’s experience, McPartland cautions. Rather, it requires a thorough assessment by qualified clinicians. This is important, he says, because autism can also be misdiagnosed.

Adults may pursue a diagnosis for a variety of reasons, including curiosity, self-understanding, or long-standing questions about how they relate to the world. And unlike in the past, he says, the idea of an autism diagnosis no longer feels as isolating.

“Ten years ago, people were hesitant to seek a diagnosis. Now, some people feel empowered by it,” McPartland says. “Instead of it being viewed as a disability, autism is sometimes viewed as a strength—or even a superpower because of autistic features that can include excellent attention to detail or passion and dedication for certain subjects as well as the ability to focus intensely or for a long time on these topics.”

In some cases, adults feel frustrated or disappointed if they are not diagnosed with autism, McPartland says, especially if they were hoping it would help explain certain life challenges.

“Today, people are more likely to be upset if they don’t receive a diagnosis, whereas before, they might have felt relief,” he says. One reason for that is that having a diagnosis may open people up to a community of support and services, he adds.

According to a study in JAMA Network Open, adults ages 26 to 34 saw the largest jump in diagnosis—a 450% increase—between 2011 and 2022.

This fact doesn’t surprise McPartland. “That age range tends to be a time of self-exploration,” he says. “People may not yet have a partner or kids, and they are interested in and have the resources to pursue a diagnosis.”

To put this in context, McPartland notes that the prevalence of autism in children has also gone up.

“Right now, about 1 in 31 children are diagnosed with autism. A couple of years ago, it was 1 in 36. And if you go back 20 years ago, it was 1 in 1,000,” he says. “Rather than this indicating an ‘epidemic’ of autism, diagnostic criteria have broadened and there is much greater awareness so more people seek and receive diagnoses.”

A diagnosis of autism spectrum disorder is based on symptoms such as persistent challenges in social communication and interaction, along with focused patterns of behaviors, interests, and activities or differences in response to sensory information. These symptoms must be present from early childhood and impact functioning in social, occupational, or other areas of life.

At the Developmental Disabilities Clinic, where children and adults can be evaluated, clinicians use tools such as the Autism Diagnostic Observation Schedule, which includes activities and structured conversations designed to observe behaviors, emotional responses, and interpersonal awareness.

“We have different modules that we use for toddlers up to adults. The criteria are the same across ages, but how we assess it differs,” McPartland says. “You wouldn’t ask a toddler about insight into friendships, for example.”

Diagnosing autism in adults can be especially tricky because it relies heavily on interpreting behaviors and gathering developmental history—which may not always be available.

“Unlike some conditions, there isn’t an IQ score that confirms autism. It’s more subjective,” he notes. “For example, what exactly counts as a sensory issue? Most people don’t like the sound of nails on the chalkboard—does that count as a symptom of autism?”

A critical distinction of an autism diagnosis is its developmental origin, which means onset is in early childhood. “If someone starts noting changes in behavior when they are 18 that just cropped up, that’s not autism. It has to have started in early childhood—even if it wasn’t recognized back then,” he says.

Another challenge can be obtaining someone’s childhood history of symptoms. “In adults, we don’t always have access to what someone was like in early development. If possible, we can talk to a parent, caregiver or someone who knew them back then, or consult records or evaluations, but it’s still complex to do this for someone who is 20 or 30 and coming to our clinic for the first time,” he says.

It's easy to find places that offer autism evaluations, but not all programs offer the same level of expertise. Dr. McPartland advises seeking an evaluation from a center that specializes in autism, such as an academic medical center or programs that specialize in autism and are affiliated with research programs.

“Academic medical centers are a safe bet as a rule, especially if it’s associated with an autism research program because they will have people who take this very seriously and you will get a reliable diagnosis,” he says. “And if you’re not near such a center, call and ask for guidance. They can often point you to a trusted resource.”

Many autism research centers, such as Yale’s, also offer evaluations as part of their research studies. The main difference between an evaluation in the clinic and the research program is that in the clinic, the individual meets with a team that includes a psychologist, a speech–language pathologist, and a psychiatrist. In a research study, the evaluation is conducted by a psychologist.

“Either way, we see an individual over the course of two days, and the second day we have a conversation with them to give our preliminary impressions, and then a report follows that includes recommendations to address the problems for which they sought the evaluation,” he says. “The other main difference is there usually isn’t a waiting list for research and you don’t have to pay for the evaluation or have your insurance cover it.”

Research is an important part of Yale’s Developmental Disabilities Clinic. In fact, Yale School of Medicine was recently awarded a $27.7 million grant from Aligning Research to Impact Autism (ARIA) to develop detailed computer models of the brain to help pinpoint the specific brain circuits involved in communication problems.

“The grant is more focused on pediatrics than adults but it’s an exciting idea. We have been doing autism research at Yale for more than 20 years and we’ve reached a level where we’re collaborating with neurosurgeons and computer scientists, and it’s an awesome manifestation of team science,” McPartland says.

Receiving an autism diagnosis as an adult can be validating to some people.

“You may be getting by in life, but you’re not functioning great or feeling great. This can provide a sense of identity for someone who is experiencing a mismatch between what their life should be like and what it is,” McPartland says. “A diagnosis can provide clarity, and in many cases, access to support and services that can really help.”

Even for those who don’t need services, a diagnosis may offer something just as valuable— understanding. “It can explain why someone sees the world a little differently,” he says. “And that insight can be a real relief.”