News The latest developments in autism research.

Long-term studies track how autism changes with age

by  /  13 May 2013
Growth chart: Long-term studies suggest that about ten percent of children with autism show dramatic improvement in their symptoms during their teens.

Autism is a lifelong developmental disorder, but paradoxically most studies of the disorder are cross-sectional: They provide only a snapshot of what it looks like at a single point in time.

There are good reasons for this. Following individuals with autism over long periods of time can be expensive and require enormous effort on the part of both the families and the researchers.

Still, it’s the only way to understand what early-life factors help some children with autism do better than others over the long term, something that cannot be assessed in cross-sectional studies.

A handful of long-term studies, each including up to several hundred participants, have now followed people with autism for close to two decades. As the children in some of these studies come of age, researchers are piecing together the disorder’s trajectories.

For instance, one of the largest studies has followed about 300 children from age 2 to 21, and has found that about ten percent of children improve dramatically by their mid-teens. Another 80 percent of the children have symptoms that are remarkably consistent over time.

“We were surprised that such a high proportion of the kids’ trajectories were stable,” says lead investigator Catherine Lord, director of the Institute for Brain Development at New York-Presbyterian Hospital in New York City. “I would have expected more of them to improve, and I would have expected more variability from year to year.”

Meanwhile, a crop of smaller, more targeted longitudinal studies of autism, the result of a surge of interest in this type of study design about a decade ago, is also beginning to bear fruit.

“It’s taken the field really until the last ten years to invest the time and effort into conducting longitudinal studies,” says Tony Charman, chair of clinical child psychology at King’s College London in the U.K. Charman is part of a research team that has followed a group of about 170 people with autism from age 12 to 23, and some of them beginning at age 2.

Varied vectors:

Thanks to new statistical techniques, scientists can now group their study participants based on shared characteristics that unfold over time1. Lord’s team used this approach to divide the children in her study into four groups, based on the trajectory of their symptoms from age 2 to 15 years2.

The small proportion of children who improve tend to both start out with a high verbal intelligence quotient (IQ) and improve their verbal skills early on. This is in line with other studies suggesting that language skills and IQ are the strongest predictors of a child’s outcome.

Studies that focus on more cognitively able children may help researchers to home in on more specific predictors of outcome, says Elizabeth Pellicano, professor of psychology and human development at the University of London.

For example, Pellicano assessed cognitive skills in 37 children with autism and average IQ. She found that children between 4 and 7 years of age who have the strongest executive function skills — required for planning and carrying out complex tasks — also have the strongest theory of mind, or ability to understand others’ thoughts and beliefs, three years later3.

The study suggests that improving executive function skills in children with autism may also yield benefits for theory of mind, Pellicano says.

Another longitudinal study, conducted by researchers in Canada, tracked 39 children with high-functioning autism or Asperger syndrome from about age 4 to age 19. Analysis of some of the data suggests that building theory of mind skills may help children who start out with poor language skills overcome their deficits4.

These findings are typical of the way researchers are using longitudinal studies to parse how changes in one area of development influence another. “That gives us clues with respect to leverage points for intervention,” says Alice Carter, professor of psychology at the University of Massachusetts in Boston, who was not involved in the studies.

Carter’s own work tracked 170 toddlers with autism, assessed at three annual visits starting between 18 and 33 months old. Her team found that children who show more sensory sensitivity as toddlers are more likely to have anxiety as preschoolers5.

Data from longitudinal studies also reveal how the interplay between children with autism and their families or their environment can influence how they fare.

For example, an unpublished analysis of Carter’s data shows that a ‘responsive’ parenting style — meaning that parents are attuned to what a child is paying attention to and often join in — has benefits for children with autism.  The childrenof these parents show greater gains in language skills, Carter’s team found.

Parental engagement:

Lord’s study has yielded similar data: One analysis showed that children whose parents are more engaged in their treatment early on have better verbal and daily living skills as teenagers6. Lord also has unpublished data showing that the children with the best outcomes — who were able to attend college with no extra support — all had parents who had been involved in their treatment beginning at age 2, Lord says.

Because of the small size of most longitudinal studies, it’s especially important for this sort of validation from multiple studies, Lord notes.

Both researchers caution that this should not be interpreted as assigning blame to parents if their children do poorly. But the results do suggest that it’s important to involve parents in interventions for autism. Also, Carter adds, “Longitudinal studies are critical for trying to learn more about the kinds of supports parents really need over time.”

One of the other surprises to have emerged from longitudinal studies is the relative ease of the teen years.

“We anticipated that adolescence would be a time of great difficulty, but in fact it’s a time of behavioral and symptomatic improvement,” says Marsha Mailick, director of the Waisman Center on Mental Retardation and Human Development at the University of Wisconsin, Madison. Mailick leads a longitudinal study of autism in adolescence and adulthood that includes more than 400 families of people with autism, who were age 10 or older when the study began in 1998.

However, this improvement slows down around the time that the teens leave high school7. That may be in part because the structure and routine of school is beneficial for people with autism, she says. Teens with autism also frequently lose access to services around the time they finish school.

As adults, Mailick has found, many people with autism are able to hold down jobs, but few have opportunities for career advancement. Although many adults with the disorder have a stable place to live, only about five percent live completely independently.

On the other hand, Mailick says, “Having a full-time independent job and living in one’s own place is not necessarily the only metric or the only way to think about quality of life.” Mailick says she hopes to continue the study for as long as possible, to find out how people with autism fare as they age.

Lord echoes those ideas. “We just haven’t figured out,” she says, “how to represent in the scientific literature [that] there are young people who have minimal verbal skills who do lead, at age 19 or 21, quite happy lives.”


1: Georgiades S. et al. J. Child Psychol. Psychiatry 54, 206-215 (2013) PubMed

2: Gotham K. et al. Pediatrics 130, e1278-e1284 (2012) PubMed

3: Pellicano E. Autism Res. Epub ahead of print (2013) PubMed

4: Bennett T.A. et al. J. Can. Acad. Child Adolesc. Psychiatry 22, 13-19 (2013) PubMed

5: Green S.A. et al. J. Autism Dev. Disord. 42, 1112-1119 (2012) PubMed

6: Anderson D.K. et al. Am. J. Intellect. Dev. Disabil. 116, 381-397 (2011) PubMed

7: Smith L.E. et al. J. Amer. Acad. Child Adolesc. Psychiatry 51, 622-631 (2012) PubMed

15 responses to “Long-term studies track how autism changes with age”

  1. usethebrainsgodgiveyou says:


    These results challenge the usefulness of ToM as a unifying theory for ASD deficits

    Taken directly from reference #4.


  2. Carrie says:

    As a mother who was and is very involved with my 20 year old son with severe autism. i do NOT fit into the category of a child doing better because of parental involvement. Neither do many of my autism mom friends. If ONLY it were that easy.

    • Jacqueline says:

      Carrie so sorry to hear of your woes, and your friends as well…I have 3 friends whose children are afflicted with autism, we are wondering what the future will bring…I find that in Canada once the child enters school, all the at home help, etc ends…there is no handbook, can’t we at least get some help for these parents?

  3. Niki says:

    If there was a treatment that can cure this disease at the cellular level, would you do it?

  4. Willard says:

    You’d think if they really wanted to see how it played out over time, they’d talk to those of us middle aged adults who’ve lived with the condition for decades. There are support group websites where you can find plenty of adults who weren’t even diagnosed until their 30 or 40s. I understand why the ignorant public thinks Autism is a new phenomenon, but educated researchers should understand that it didn’t just pop into existence out of nowhere.

  5. Anonymous says:

    Recently have a child undergoing assesement for autism, scared, confused .

  6. crystal says:

    i have a son who is nearly 32 he got dianosed when he was two i have had a hard life with him he has done all sorts to me i am still here

  7. E says:

    My son is just starting the process of being statemented. I’m so worried about him generally. He is 7.

  8. anonymus says:

    I have a 11 year old brother that i love dearly! My mother lets him watch TV & be on his tablet all day every day. Obviously this isnt healthy for him but what can i do? How to entertain a child whos mind is always om cartoons?

    • ChArlotte says:

      My son is only two I have notice just doing things in am exaggerated voice or face. While I know you could not use aba therapy with him try looking into play project my sons does okay with it. My problem with play is it does not advance him and even dr Solomon said our son needed aba.

  9. donna says:

    My brother has autism and he is 6 he can say a few words,and can call mommy daddy,a few other words like that, but makes more nosies then talks.hes making great progress in school.does all kids with mild autism talk in the future or not?.

  10. Anonymous says:

    I’m actually autistic (asperger’s) and this is pretty terrifying for me because I’m 17 and I can barely read facial expressions as is… So if it gets worse, I do know how I’ll be able to function. On the bright side, I’ve been told I write well, although my speech is not as fortunate (it takes forever for me to process the fact that I need to respond to someone, so verbal conversations become awkward rather quickly). I hope there’s a way to prevent symptoms of autism from getting worse, but a cure? No… That would essentially be changing a child’s personality all together.

  11. edmund says:

    my son is autistic at an equal level to my father, my fathers autism is getting worse with age he’s 69 my son is 13, and he has particular fasination with one subject at such a deep level that he corrects his elders when they are wrong, where as me i’m finding that i interact with people at a higher level, so all of you, you need to know that to us this is just normal behaviour, dont worry we are just different

    • Alex says:

      Are you saying challenging authority is a somehow a bad thing or lower functioning level Edmund? It’s not a bad thing. It’s generations of parents teaching their children to obey!

      I recommend checking out Alfie Kohn: Unconditional parenting. 🙂

      I personally find it a compulsion to correct people and if I don’t, I feel guilty!

      Your son is still a child, he’ll probably discover tact as his brain fully develops and becomes aware of others outside himself (this is the same for NTs – look at your average “selfish” teenager, they’re not selfish they just havent had their brains fully develop).

      I am getting less blunt and more tactful. However I believe it should be more honesty than beat around the bush.

      I correct people on ALL subjects BTW ;P
      So we’re all different indeed 😉

      It’s a compulsion for me to correct, because I care too.

  12. Alex says:

    I could go on and on about this, which i did but removed due to lack of structure.

    Many things CAN improve symptoms, but the easiest and best for overall improvement of symptoms for self (not just ASD),

    For me, the ketogenic diet has allowed me to go from dysfunctional my whole life to giving me the opportunity to be a functional adult.

    So yes, I believe its possible that improvements can be made over time.
    (as long as not trying to be like NTs)

    With certain symptoms such as lack of “connection with others”, well ive found something even better, a pure honest not wanting anything in return, love.

    How many NTs do you know that arent usually after something on some level?

    Going by the rules or should be this of others has been one of the weaknesses of mankind for too long.

    We aren’t superficial and we shouldn’t act like it or want and get the same hugely flawed consequences of a living life, like NTs.

    I’m in a relationship with someone else who is most likely asd as well, and we’ve put all NT couples we know, to shame.

    You can’t really connect with someone who doesn’t understand. Why would you want, say, your child, if they have ASD, to act superficial and fake and generally avoid the truth, with niceties? Thats a good way to screw up your intelligence with illogical actions, turning into mental habits. You dont connect with someone from being fake.

    Highly recommend the Ketogenic diet.
    (may even improve word usage ability, it did for me whilst I was on keto. I put this down to ketones instead of glucose fuelling my brain, which many ASDers have gastrointestinal issues and don’t even know.

    The ketogenic diet also raised my stress tolerance level. Again I put this down to energy. We all can deal with and tolerate stress and others more when we have the energy to do so. Feeling depressed at the end of the day being tired is a known fact.

    Hope this helps someone.

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