Study: Autism Diagnosis Later in Life Linked to Worse Mental Health

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Key Takeaways

  • A new study shows that receiving an autism diagnosis in adulthood rather than childhood can lead to lower quality of life, more severe mental health symptoms, and higher autistic trait levels.
  • Research has also shown that men receive a diagnosis of autism several years sooner than women.
  • Better diagnostic measures and support are needed for all autistic people, but especially autistic adults.

Sam Fleming has had anxiety and depression for as long as he can remember. The 33-year-old has also been coping with social difficulties, sensory challenges, and shutdowns throughout his life. 

Despite his best efforts, no amount of therapy or medication has ever seemed to help, leading Fleming to believe that his own character was to blame for his struggles. That changed when he was diagnosed with autism spectrum disorder (ASD) this summer.

“I recall shaking as the therapist delivered the team's verdict. It was incredibly validating,” Fleming tells Verywell. “I felt like I could finally let out a big breath after holding it for so long. My life has been on hold for 13 years, waiting to hear those words that could finally help me understand myself and start living.”

Fleming's fight to get a referral for a diagnostic assessment started in 2008 when he was 20 years old at the time. An acquaintance pointed out that Fleming had certain traits consistent with Asperger's Syndrome, a term that is no longer an official diagnosis and now falls under the broader category of autism spectrum disorder.

After 10 years of persistent effort, Fleming was referred for the diagnostic assessment by a general practitioner. But he waited another 3.5 years on a waitlist for the assessment.

Autism Diagnosis and Mental Health

Fleming is not alone in his experience. Recently, researchers at Edge Hill University in the United Kingdom found that a significant proportion of autistic adults were not diagnosed until later in life—a group referred to as the "lost generation." For many, the later diagnosis has led to worse quality of life and poor mental health outcomes.

The mixed-method study, which was published in the Journal of Autism and Developmental Disorders, surveyed 420 autistic and typically developing (TD) adults about their quality of life and autistic trait levels. The researchers also conducted interviews with eight autistic people who were diagnosed in adulthood.

Liam Cross, PhD, a co-author of the study, says that the research showed that neurotypical people tend to have a higher quality of life outcomes as they age, which is largely attributable to reduced anxiety and more social support. But that's not the case for autistic adults.

The study interviews revealed that autistic adults did not receive a diagnosis in their childhood for a myriad of reasons. In some cases, their parents were hesitant to pursue a diagnosis because they held negative perceptions of autism.

Jennifer Carty

I felt every different emotion when I got diagnosed. I felt relieved that I finally had a reason as to why my brain worked differently from those around me. I could finally rationalize all of the quirks that I had.

— Jennifer Carty

Some autistic people had lower support needs and were considered "high-functioning," allowing them to slip through the cracks. Others simply did not have access to a formal assessment process.

"It also probably speaks to the culture of the time of the ‘70s, ‘80s, and ‘90s when a lot of these people were growing up and there wasn’t so much awareness of the whole spectrum,” Cross tells Verywell. “It came out just how difficult it is to get a diagnosis—especially for adults—how long it takes, how little funding there is out there for it, how many holes people have to jump through.”

Receiving a diagnosis is critical to improving the lives of autistic people of any age, but especially for adults, Gray Atherton, EdM, PhD, a co-author of the study, tells Verywell.

Atherton says that getting diagnosed with autism provides people an identity and supplies a scientific explanation for their differences, which can prevent them from wrongly attributing the traits to a personal failing.

“I think that the sooner you are able to do that, the better,” says Atherton.

Gender and Autism

The researchers also found that gender plays a significant role in the age of diagnosis and quality of life outcomes for autistic adults. According to the study, men generally received a diagnosis of autism several years earlier than women, putting them at a greater risk of remaining undiagnosed and therefore ineligible for clinical support. 

Women tend to "camouflage" their autistic traits to fit into social situations, even if they do not have a formal diagnosis of autism, according to a small study.

Atherton adds that there’s also a misunderstanding about what autism looks like in females—called a "phenotype." The lack of or conflicting information has probably confused a lot of women who might be wondering if they have ASD.

“The autistic women in our sample were diagnosed predominantly in adulthood whereas males were diagnosed earlier," says Atherton. "So we’re missing that female autistic phenotype in a sense, and we need to figure out how we can clue in parents, educators, diagnosticians, clinicians about how autistic females may present differently, but how they’re still absolutely in need of a diagnosis."

Like so many autistic women, Jennifer Carty was diagnosed post-childhood. The 27-year-old got her official diagnosis just one year ago. But she had not even considered that she might be autistic until she was 25 because she had never fit into the stereotype of an “autistic young boy.” 

Instead, Carty though her sensitivities and struggles were character flaws—a belief that took a serious toll on her mental health.

“I felt every different emotion when I got diagnosed,” Carty tells Verywell. “I felt relieved that I finally had a reason as to why my brain worked differently from those around me. I could finally rationalize all of the quirks that I had."

Carty says that learning that she had ASD also gave her the peace of mind to tell other people about her diagnosis.

"I was also quite resentful towards my schools," she adds. "For example, for not noticing when I was a child—for the fact I slipped through the cracks.”

More Support Needed

Sopagna Braje, PhD, a clinical psychologist specialized in ASD, says the new study demonstrates why age at diagnosis is an important predictor of ASD development. By identifying how variables like age and gender affect mental health outcomes for autistic adults, professionals can target specific groups for early identification and intervention services, she adds.

“As we think about how to improve quality of life for people who may have ASD, it seems like early identification is critical,” says Braje. “This study shows us how important it is to increase public understanding of ASD as well as increasing access to assessment.”

For adults with ASD, Atherton adds that receiving a diagnosis is only half the battle. The subjects of the study, who came from both European and North American countries, spoke of arduous waiting times and stretched services when trying to access clinical support post-diagnosis.

Atherton says that this is why early diagnosis is critical. When kids are diagnosed with ASD, there are built-in systems in place, such as educational support. They also typically have caregivers who can advocate on their behalf. 

When autistic children become adults and leave that formal system, they lose their safety net; an outcome that underscores the need for better systems of care for autistic adults—both in terms of healthcare supports and autistic-led, grassroots movements. 

Even though Fleming is now armed with a diagnosis, he's still waiting for the help it was meant to bring.

“At the end of my 20-page assessment report, I was signposted to a virtual workshop and some online support resources along with a selection of relevant books,” says Fleming. “I haven't been appointed a single point of contact for ongoing autism support. I'm very much on my own."

What This Means For You

It's hard to get an autism diagnosis in adulthood because of the long wait times. There's also a lack of proper healthcare support for autistic adults. But more people are forming communities online to talk about their experiences and challenges.

2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Atherton G, Edisbury E, Piovesan A, Cross L. Autism through the ages: a mixed methods approach to understanding how age and age of diagnosis affect quality of lifeJ Autism Dev Disord. doi:10.1007/s10803-021-05235-x

  2. Beck JS, Lundwall RA, Gabrielsen T, Cox JC, South M. Looking good but feeling bad: “Camouflaging” behaviors and mental health in women with autistic traitsAutism. 2020;24(4):809-821. doi:10.1177/1362361320912147

By Mira Miller
Mira Miller is a freelance writer specializing in mental health, women's health, and culture.