What is autism? An expert explains
Some individuals with autism have challenges processing senses. Others struggle to communicate. Still, others might have a tough time socializing, thinking, physically moving or just going about daily living.
People with autism have their own ways of interacting with the world, because autism is a developmental disability that affects everyone who has it a little differently, according to , the Gordon and Virginia Macdonald distinguished professor of human genetics, neurology and psychiatry at UCLA.
Geschwind has spent 25 years studying autism and what causes it. To mark CNN talked with him about what autism is and what causes it.
This conversation has been lightly edited and condensed for clarity.
CNN: What is autism?
Dr. Daniel Geschwind: Autism refers to a broad range of conditions characterized by challenges with social skills and social and communication and repetitive behaviors, resistance to changes in routine, or restricted interests. I prefer to call it "the Autisms," because it's not one thing, and no two autistic children or adults are exactly alike even though they may share basic features. People with autism may also have some sensory-motor integration issues, especially sensory hypersensitivity.
CNN: How prevalent is autism today?
Geschwind: It isn't rare. The most recent statistics (from out in March, pulled data from 11 sites (in the United States) and reported 1 out of every 36 kids is autistic. The study before that estimated around 1 in 40. About 10 years ago, , or even lower.
It would be easy to look at this trend and say autism is increasing, but that's not really what is happening. The most recent data reflects that our ability to recognize autism and diagnose it early has improved dramatically. We're now able to diagnose people with autism who might have (previously) fallen through the cracks.
Everybody is neurodivergent to some extent. For example, if you look at a simple IQ test, a substantial portion of people will perform really badly on one specific item. That doesn't mean they have problems — it's just that it means we all have strengths and weaknesses.
If I were being tested on artistic ability, for example, or engineering ability, I would be far below what's called typical. I think we have to accept that intelligence is not just one thing, that cognition isn't one thing, that there's not just one way to behave.
CNN: What does it mean when people describe some as being "on the spectrum"?
Geschwind: About a decade ago, the term "autism spectrum disorder" was adopted to encompass everything that we called autism into one rubric. The intent was simply to describe the variability in how people with autism act and behave biomedically. There are some autistic individuals who just need accommodations and don't need treatment. There are other autistic individuals who need a lot of treatment. The spectrum was intended to include them all.
Over time, non-autistic people began referring to the spectrum in a linear fashion: high to low. That means some autistic individuals were categorized as "high-functioning," while others were categorized as "low-functioning." For many, the notion of a spectrum is now a loaded term. Many believe that instead of talking about autism in a linear fashion, we should talk about it as a wheel or pie, where each slice represents a different trait and every individual has different strengths and weaknesses.
CNN: Is there a cure for autism?
Geschwind: There is no cure. At the same time, we've come very far in understanding what autism is, and we're making progress on how to treat it. When I started researching autism 25 years ago, the autism rate was 1 in 1,000 or 1 in 2,000. To put it in deeper historical perspective, I think at that time there was only about being done that was funded (by the National Institutes of Health). And so, there was a huge disconnect between the research dollars, public awareness and the real needs of patients and families.
The notion of the term "curing" autism can be controversial. From my perspective, our true goal is to establish a kind of personalized medicine, or precision health in autism and other neuropsychiatric disorders, so that each autistic person is seen as the individual they are. We envision a world where individuals who are severely impacted by autism have the opportunity to get therapy and drugs that can help them — and those for whom a therapy is not warranted or who don't want it will have opportunities to live life the way they want to as well. Patient autonomy and societal accommodation are important aspects when considering these issues.
Video below: Brothers use TikTok to spread autism awareness
CNN: What causes autism?
Geschwind: Almost every medical condition has both genetic and environmental components. In autism, it seems that heritability is very high. The most recent large study suggested that heritable genetic factors — the things that you get from your parents that your parents have in their DNA — are probably somewhere around .
That leaves 20% that's nonheritable, and of that we know that at least 10% of autism is caused by rare mutations that are not inherited. And that sounds like a paradox, but it's not. If you think about Down syndrome, that's a genetic mutation that the parents don't have in their DNA. That's called a new, or de novo, mutation.
You can calculate a risk score for having autism based on genetics, (but) right now, the risk score for autism is not that predictive because we haven't done enough research. For other conditions like cardiovascular or certain cancers, risk scores are very predictive because very large numbers of people have been studied.
Even so, this autism risk score is strongly correlated with high educational attainment, or a high IQ, which again speaks to the strengths associated with being autistic and highlights that we need to be more aware of the strengths that autistic individuals may have as well to optimize their opportunities to achieve their goals or contribute to society.
There also are several environmental factors that have been shown to increase the risk of autism. One of them is maternal exposure to valproate, which is an anti-epilepsy medication. There are several maternal viral infections that have been associated with autism. And two other things: the interbirth interval — how quickly after one birth a mother has another — and the age of the father. The thought on the last point is that as a man ages, their DNA repair mechanisms are maybe less active, and there are more frequent mutations in sperm.
A key point is that all these known environmental factors act prenatally, so in most cases the tendency towards being on the spectrum is something that individuals are born with.
CNN: To what extent has research debunked the controversial notion that vaccines can cause autism?
Geschwind: The notion that vaccines cause autism has been entirely (disproved). There have been dozens of studies, using very different methodologies. There is absolutely no evidence that vaccines cause autism, and there's been much more harm than good done by purveyors of that fiction.
CNN: How do you treat autism?
Geschwind: It is imperative to have an early diagnosis, because we know that early identification and early intervention with behavioral therapies can be effective in up to 50% of kids. Some kids will respond so well that it's very hard to make a diagnosis of autism when they're 9 years old if the therapy is started early enough.
The problem is that for many autistic individuals, current therapies are not that effective. There's a lot of work being done developing more effective cognitive behavioral therapies, figuring out which therapy is the best for which child. There's also work being done to develop medications that can be helpful to treat certain symptoms such as injurious behavior, repetitive behavior or difficulty with changes in routines.
My colleagues and I want to use treatment to augment and improve people's symptoms, not change who they are fundamentally. We believe strongly in every individual's autonomy. We also believe in personalized medicine so that it's not one-size-fits-all. There will be some patients in whom we're trying to correct a severe genetic mutation that has profound consequences, and there'll be others that need only a handful of accommodations, just like we provide for folks who need wheelchairs.
CNN: What will your research focus on next?
Geschwind: There are two basic frontiers in my research. One recognizes that most of the work in neuropsychiatric disorders and autism has been done in primarily White European populations and focuses on a pressing need to be studying diverse populations. About seven or eight years ago, I started working with African American communities because certain aspects of genetics are population-specific, and we as researchers really need to understand that.
The frontier that is crosscutting across all of this is we need to be able to move from genetics in a population to genetics in an individual, so that by looking at somebody's genetic makeup, we can understand the mechanism of their autism. This is precision medicine.
My work is trying to understand how specific genetic variants, how specific mutations, impact brain development to eventually lead to the symptoms of autism. If my colleagues and I can understand that mechanism, just like we can understand the genetic mechanism in cancer, we can find a drug to target that and improve those symptoms over time.