A diagnosis of autism can be a pivotal moment for both a child and their parents. One common question that arises is – how late can autism develop? Parents and caregivers usually seek a diagnosis once certain signs and symptoms appear. However, many questions remain about the development of autism.
A diagnosis can come at any time in a person’s life. However, is autism something that always presents itself in childhood, or can it develop in adulthood? Let’s look at when autism can develop and clear up some misconceptions.
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Understanding autism diagnosis
A diagnosis can be issued when behavioral tests are conducted for the core features of autism spectrum disorder. It can be tricky getting an autism diagnosis due to the fact it can’t be determined by a blood test or brain scan.
Every person on the spectrum has a different pattern of autism symptoms, making it harder to pinpoint the disorder or its severity. My family has gone through this twice, and each time was a different experience.
My younger son, Joey, was missing almost all his major milestones. He wasn’t speaking and struggled with potty training and aggression. He also avoided playing with others and would line up his toys in patterns.
The early intervention service we were using sent a person to our home to evaluate Joey for his diagnosis. The early signs of autism were present, and we were fully expecting a diagnosis for him.
In contrast, his brother was a little older when he was diagnosed. Jeremy hit most of his milestones early. He managed to hit the ones he was a little late on in a reasonable time.Â
However, after learning more about autism spectrum disorder through Joey’s diagnosis process, we began looking at some of Jeremy’s behaviors. We went to a clinic in our home state of Connecticut, where testing was done, and he was also diagnosed on the spectrum.Â
However, Jeremy was also shown to be at a different point on the spectrum. It was an eye-opener for us about how different two people with autism could truly be.
Typical age for autism diagnosis
An autism spectrum disorder diagnosis can come at any time. However, the average age for children to be diagnosed falls between the ages of three and ten years old, depending on where the child falls on the spectrum and when signs of autism develop.
In the US, the average age is around five years old. However, location, poverty, and other diagnoses play a factor in when a child receives a diagnosis.
Despite these ages being average, children can be diagnosed earlier or later depending on when a parent, caregiver, or doctor notices autism-like symptoms. My younger son was diagnosed just before turning two years old.
His autism symptoms were unmistakable. In contrast, his older brother was diagnosed at seven. My older son requires less support, so it was easy to mistake some of his autism symptoms.
Still, many people on the autism spectrum may be diagnosed later in life. Many adults who went undiagnosed as children are seeking out an autism diagnosis in early adulthood as they have learned more about it.
These later diagnoses lead to questions about when the symptoms of autism first developed and if they were missed as children.
How late can autism develop?
Autism is generally recognized in early childhood, often between the ages of two and four, when developmental milestones related to communication, social interaction, and behavior are more apparent.
In some cases, autism can be identified much later, even in adolescence or adulthood. This is often due to the subtler presentation of symptoms, which may not be as evident during early childhood.
In these situations, individuals may have been able to mask their differences, or their symptoms might have been mistaken for other conditions.
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It’s important to note that while autism can be diagnosed later in life, the underlying neurodevelopmental traits are present since early development.
Early signs of autism
If you are wondering if your child is exhibiting signs of autism, there are symptoms to look out for in early childhood. These include:
- not responding to their name
- lack of eye contact
- not smiling
- sensory sensitivities (taste, smell, sounds)
- repetition (both movements and speech)
- lack of pretend play
My younger son demonstrated many of these common signs in early childhood. He didn’t make eye contact, repeated many movements, and demonstrated sensitivity to sound.Â
Instead of engaging in pretend play, he chose to line up his toys in patterns and didn’t interact with others trying to play with him.
Signs of autism in older children and adults
As children get older, other signs of autism may present themselves. Some of these symptoms include:
- not understanding how others feel
- speaking at people instead of to them
- strict adherence to routine
- hyperfixation on certain activities
- getting upset when asked to do something
- taking things too literally
Many of these autism symptoms presented themselves in my older son. He likes to talk to people while constantly pacing rather than having a direct conversation.
My son also hyperfixates on activities like music, sports, and chess and gets upset when asked to do his chores while in the middle of another activity.
Can you develop autism as an adult?
Research suggests that autism develops in early childhood, finding autism spectrum disorders are linked to atypical brain development. Basic neurodevelopment takes place in early childhood, meaning autism won’t develop in later life.
While autism spectrum disorder may not develop in adulthood, some symptoms of autism may begin presenting themselves during that time. This is especially true for people who require less support.
They may start noticing symptoms of autism once they are under greater demand in their adult lives. Often, this contributes to diagnosis as an adult.
Effects of a late autism spectrum disorder diagnosis
While early diagnosis of autism spectrum disorder has been linked to improved response to treatments, a late diagnosis can be linked to other problems.
People diagnosed with autism later in life may experience mental health issues as well as self-doubt. These people may also struggle with social skills and have strained relationships.
Adults diagnosed with autism spectrum disorder may also face challenges that don’t come with early detection. These can include barriers to much-needed healthcare and support systems available to children.
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They also miss out on opportunities for early intervention services and are more likely to have co-occurring conditions with autism.
Understanding the diagnosis of autism
As we learn more about autism spectrum disorder, many people are questioning if they may be on the spectrum. This is leading to questions about how late autism can develop and if they missed potential symptoms and signs when they were children.
While symptoms of autism spectrum disorder can develop in later life for those who require less support, the disorder itself only develops during childhood. Many people who weren’t diagnosed as children receive a diagnosis during adulthood.
Anyone who thinks they may have autism spectrum disorder should seek professional help to possibly get a diagnosis. While they may have missed the window for early intervention, they can still get the support they may need.
FAQs
Q: Can a 20-year-old have autism spectrum disorder?
A: Autism spectrum disorder can affect anyone at any age. However, it can not develop when a person is 20 years old as it occurs during brain development.
Q: Can you develop autism?
A: Autism spectrum disorder (ASD) is a neurodevelopmental disorder that occurs during the child’s development. It’s not possible to develop autism in adulthood.
Q: How do I know if I’m autistic?
A: Several potential early signs of autism spectrum disorders present themselves in early childhood. These include social communication challenges, repetitive behaviors, avoiding eye contact, and sensory reactions.
Q: What causes late-onset autism diagnosis?
A: Many factors can lead to a late-onset autism diagnosis. These factors include the child’s age, developmental milestones, gender if they have high-functioning autism, and socioeconomic status.
Q: At what age does autism show?
A: Early childhood autism can present itself as young as 12 months old. However, most children begin showing signs between three and ten years old. Late-onset autism symptoms can result in a delayed diagnosis.
Resources
Huang, Y., Arnold, S. R., Foley, K.-R., & Trollor, J. N. (2020). Diagnosis of autism in adulthood: A scoping review. Autism, 24(6), 1311-1327 https://doi.org/10.1177/1362361320903128
Mandy, W., Midouhas, E., Hosozawa, M., Cable, N., Sacker, A. and Flouri, E. (2022), Mental health and social difficulties of late-diagnosed autistic children, across childhood and adolescence. J Child Psychol Psychiatr, 63: 1405-1414 https://doi.org/10.1111/jcpp.13587
Paul S. Carbone, Kathleen Campbell, Jacob Wilkes, Gregory J. Stoddard, Kelly Huynh, Paul C. Young, Terisa P. Gabrielsen; Primary Care Autism Screening and Later Autism Diagnosis. Pediatrics August 2020; 146 (2): e20192314. 10.1542/peds.2019-2314 https://publications.aap.org/pediatrics/article/146/2/e20192314/77011?utm_source=TrendMD&utm_medium=TrendMD&utm_campaign=Pediatrics_TrendMD_0?autologincheck=redirected
Stagg, S. D., & Belcher, H. (2019). Living with autism without knowing: receiving a diagnosis in later life. Health Psychology and Behavioral Medicine, 7(1), 348–361 https://doi.org/10.1080/21642850.2019.1684920
https://www.drakeinstitute.com/can-you-develop-autism-later-in-life
