Autism increase may reflect greater awareness
■ Physicians say the developmental disorder is more commonly diagnosed as the definition broadens.
By Christine S. Moyer — Posted Jan. 4, 2010
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When developmental and behavioral pediatrician Raun Melmed, MD, started in the field 25 years ago, autism was a relatively unusual diagnosis. Today, his Scottsdale, Ariz., practice sees two to three new cases of autism spectrum disorder each week.
Like many physicians, Dr. Melmed isn't sure what has driven that rate upward. But he thinks broadening the definition of autism "accounts for at least half of new cases identified, and maybe more."
The Centers for Disease Control and Prevention reports that the autism rate is going up markedly. From 2002 to 2006, the rate of autism spectrum disorders among 8-year-olds jumped 40%, from one in 154 to one in 110, according to a study released Dec. 18, 2009, in the CDC's Morbidity and Mortality Weekly Report.
Researchers offered no firm explanation for the upward trend, nor did they evaluate risk factors or causes. However, the CDC report pointed to a number of factors, including improved community awareness, the widening of diagnostic criteria to include milder presentations, and earlier identification.
Some experts cautioned against interpreting the CDC's report to mean the occurrence of autism is rising as quickly as the numbers might show.
"My own feeling is there is an actual increase in incidence of autism, but it's not at an epidemic level. And we have to be careful we don't identify it as such," said Darold Treffert, MD, professor of psychiatry at the University of Wisconsin School of Medicine and Public Health in Madison.
Dr. Treffert has written for decades about autistic savants, and consulted on the 1988 film Rain Man.
Experts said autism might still be underdiagnosed. Early detection of autism spectrum disorders can be challenging for physicians. This is due to insufficient time to adequately assess children during visits, and difficulty in differentiating among the range of normalcy for common behaviors, said Susan Hyman, MD, division chief of neurodevelopmental and behavioral pediatrics at University of Rochester (N.Y.) Medical Center.
Researchers for the CDC report analyzed education and health evaluation records for 8-year-olds in 11 states that participated in the CDC-funded Autism and Developmental Disabilities Monitoring Network for 2006.
For the 2006 surveillance, 2,757 of the 307,790 8-year-olds living in the 11 participating states were identified as having an autism spectrum disorder, or 9 out of 1,000 children. That was up from 6.6 per 1,000 in 2002. Prevalence varied widely, from 4.2 per 1,000 children in Florida, to 12.1 in Arizona and Missouri.
Most concerning was the consistent rise in prevalence at each of the studied sites, said Jon Baio, CDC epidemiologist and education specialist.
Arizona saw the largest jump, with prevalence nearly doubling from the 2002 rate of 6.2 per 1,000 8-year-olds.
Yet that experience is an example why physicians should not attribute the rising numbers solely to environmental hazards or other theories as to why children are affected, said Craig Newschaffer, PhD, an investigator for the CDC study.
"When we see that variability ... it reminds us that a lot of what we see in these trends is probably due to how communities recognize, diagnose and document autism," Newschaffer said.
For example, Arizona is home to the Southwest Autism Research & Resource Center. Dr. Melmed is also co-founder and medical director of that nonprofit center, which works to advance research and provide support for people with autism and their families.
Primary care on the front line
Often, the primary care physician is the first to be asked by a parent about autism spectrum disorders, or to notice behaviors that might require follow-up. Physicians should screen children early and often, "because these are not rare disorders," said Dr. Hyman, chair of the American Academy of Pediatrics' autism subcommittee.
The AAP recommends screening children for autism at 18 months and 24 months, regardless whether a concern has been raised or a risk has been identified.
As physicians screen, Dr. Treffert said, it is crucial they remember that autism can be early-onset, which can be identified by 18 months, or late-onset, in which a child seems to develop normally and then suddenly regresses.
Dr. Hyman recommends physicians continue screening children for autism spectrum disorders throughout childhood and adolescence.
She encouraged doctors to listen to parents' concerns and answer all of their questions, even if that means scheduling additional appointments.
Physicians also have to strike a careful balance between sympathizing with families and not giving false hope, said Newschaffer, chair of the department of epidemiology and biostatistics at Drexel University School of Public Health in Philadelphia.
He recommended physicians stress the evidence of autism research to families.
When children are diagnosed with an autism spectrum disorder, medical experts urge physicians to arm families with resources about appropriate and effective interventions.
"Autism is probably one of the most devastating diagnoses a parent can hear. ... It's being seen as a life sentence," Dr. Melmed said. "It's never easy [to give parents this diagnosis]. There are often tears. But on the other hand, our job is to comfort them and to figure out how to provide the family with the best coping tool there is -- education."