Autism spike may reflect better diagnoses, and that’s a good thing

Autism diagnoses in children have increased steadily over a decade, according to CDC statistics.

E. Otwell

Ever-increasing numbers of autism diagnoses have parents worried about a skyrocketing epidemic, and this week’s news may only drive alarm higher. Perhaps it shouldn’t.

In 2010, 1 in 68 (or 14.7 per 1,000) 8-year-olds had an autism spectrum disorder, the Centers for Disease Control and Prevention now estimates. That number is a substantial increase from 2008, which had an estimate of 1 in 88 (or 11.3 per 1,000).

But the numbers might not reflect a spike in actual cases. Instead, the rise might be driven, at least in part, by an increase in diagnoses. The estimates are drawn from a collection of organizations that provide services to children with autism, including doctors, schools and social service agencies. As awareness builds and more people look for signs of autism, these numbers will keep going up.

Regional spottiness suggests that better autism detection is feeding the increase. The autism rate in Alabama is just one in 175, while the rate in New Jersey is one in 45, the CDC reports. It would be surprising, and scientifically really important, if children in Alabama were truly much more protected from the disorder. Instead, differences in diagnosis rates are probably at play.

If these alarmingly high numbers are driven by professionals and parents better spotting autism, that’s nothing to be alarmed at. On the contrary: This is good news. The earlier therapies begin, the better kids with autism do. That’s the idea behind CDC’s “Learn the Signs: Act Early” program to educate people about signs that something might be amiss with a child. So our best move is to find the kids who need help, and find them when they’re young. Most kids, including the ones in the new CDC survey, aren’t diagnosed with autism until about age 4 1/2. But whatever goes wrong happens long before then.

In my job covering neuroscience news, I’ve found myself writing more and more stories about studies that find differences in the brains of infants and even fetuses who go on to develop autism.

Autism risk can be inherited. And although many of the genes involved are still mysterious, scientists are now fairly certain that genes affecting the developing brain are involved (SN: 8/13/11, p. 20).  These genetic problems may contribute to disorganized patches of neural tissue, a study published in the March 27 New England Journal of Medicine suggests. During gestation, multiple layers of the brain’s cortex are laid down like an intricate layer cake. But the brains of children with autism harbor patches in which the layers are all mixed up, postmortem studies revealed.

Scientists have also spotted behavioral differences in babies just a few months old who go on to be diagnosed with autism. Sophisticated eye-tracking experiments revealed that these infants show less interest in looking at other people’s eyes (SN Online: 11/6/13).

Those are just a few examples of the changes that happen very early in the brains of children with autism. A better understanding of what goes wrong — and when — will help doctors and scientists in their search for ways to treat and prevent the disorder. Until then, the best we can do for these kids is to get them help early.

Follow me on Twitter: @lssciencenews

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