May 2017, British Medical Journal: Autism spectrum disorder: updated prevalence and comparison of two birth cohorts in a nationally representative Australian sample
The higher prevalence of parent-reported and teacher-reported ASD diagnosis in the later-born cohort may be partially explained by identifying children with milder behavioural problems as ASD and a change in the use of diagnostic categories in schools. …
Previous research has suggested that increased ASD prevalence may be due to the identification of cases with milder impairment. …
CONCLUSIONS These longitudinal findings point to the changing nature of ASD between the late 1990s, when the first cohort were born, and today, with changes occurring before 2013, when the fifth edition of the Diagnostic and Statistical Manual for Mental disorders was launched, including for the first time ASD as a diagnosis. This study highlights the complexities involved in understanding changes in the reported prevalence of ASD that are likely to be multifactorial. It has provided evidence in Australia of changes in diagnostic preferences and a broadening of the spectrum and that differences in service requirements can influence prevalence estimates.
May 2, 2017, Community Voice: There’s an Autism Epidemic, or is There?
(“Leading voice of Kansas' African-American community)
An often overlooked alternative explanation for the epidemic: changes in diagnostic practices. Over time the criteria for a diagnosis of autism have loosened, resulting in the labeling of substantially more mildly afflicted individuals as autistic.
Swapped Diagnoses
A 2006 article by University of Wisconsin Madison psychologist Paul Shattuck cited diagnostic substitution: as the rates of the autism diagnosis increased from 1994 to 2003, the rates of diagnoses of mental retardation and learning disabilities decreased. It is possible that the overall pool of children with autism-like features has remained constant but that the specific diagnoses within this pool have switched.
Most experts will agree, it is still too early to exclude the possibility that autism's prevalence is growing, but it is unlikely that it is growing as swiftly as many have suggested.
Mar 3, 2017, Scientific American: The Real Reasons Autism Rates Are Up in the U.S.
A hard look at whether the rise comes from more awareness, better diagnosis—or something else
Theprevalenceof autism in the United States has risen steadily since researchers first began tracking it in 2000. The rise in the rate has sparked fears of an autism ‘epidemic.’ But experts say the bulk of the increase stems from a growing awareness of autism and changes to the condition’s diagnostic criteria. …
How has autism prevalence changed over time?
The latest estimate of autism prevalence—1 in 68—is up 30 percent from the1 in 88rate reported in 2008, and more than double the 1 in 150 rate in 2000. In fact, the trend has been steeply upward since the early 1990s, not only in the U.S. but globally, saysMaureen Durkin, who heads the network site in Wisconsin. …
Until the 1980s, many people with autism were institutionalized, rendering themeffectively invisible. Studies show that parents who are aware of autism’s presentation—by living near someone with the condition, for example—aremore likely to seek a diagnosis for their childrenthan parents with no knowledge of the condition. Living close to urban centers and having access to good medical care alsoboost the likelihood of diagnosis.
Greater awareness of autism is also likely to boost CDC estimates by increasing the chances that autism traits, such as lack of eye contact, show up in school and medical records, says Fombonne.
Policy changes may have also played a role. In 2006, the American Academy of Pediatrics recommendedscreening all children for autismduring routine pediatrician visits at 18 and 24 months of age. This move may have led to diagnoses for children who would otherwise have slipped under the radar.
Are there other factors thathaveinfluencedprevalence?
Many individuals diagnosed with autism may, in the past, have been misdiagnosed with other conditions, such as intellectual disability: As diagnoses of autism have risen, those of intellectual disabilityhave decreased.
What’s more, a diagnosis of autism gives children greater access to specialized services and special education than do diagnoses of other conditions. This benefit makes clinicians more likely to diagnose a child with autism, even those who are on the borderline of the clinical criteria.
Prior versions of the DSM did not allow for children to be diagnosed with both autism andattention deficit hyperactivity disorder. The DSM-5 allows multiple diagnoses, and most children with developmental delay are routinely screened for autism. …
Istherenorealincrease in autismrates,then?
Awareness and changing criteria probably account for the bulk of the rise in prevalence, but biological factors might also contribute, says Durkin. For example, having older parents,particularly an older father, may boost the risk of autism. Children born prematurely alsoare at increased riskof autism, and more premature infants survive now than ever before.
Sept 16, 2015, Wall St Journal: ‘Diagnostic Substitution’ Drives Autism Spike
Studies find increase in disorder’s prevalence is at least in part due to changes in diagnosing
The number of children diagnosed with autism has surged around the globe in the past two decades. But new research in Europe and the U.S. suggests much of the increase occurred on paper.
Jul 22, 2015, Science Magazine: Autism rates are up, but is it really on the rise?
The number of U.S. school children placed in special education programs due to autism more than tripled from 2000 to 2010, to nearly 420,000. But a new study argues much of that increase likely came as educators swapped one diagnosis for another. The overall percentage of kids diagnosed with a collection of brain development problems that includes autism remained unchanged, suggesting that children who used to be labeled with conditions such as “intellectual disability” were in fact autistic. …
In the new study, Girirajan and colleagues combed through data collected in each state for approximately 6.2 million U.S. school children with disabilities who are enrolled in special education programs. The information is collected each year under the federal Individuals with Disabilities Education Act. Based on his or her diagnosis, each child was assigned to one of 13 broader categories, ranging from autism to physical challenges such as blindness.
Between 2000 and 2010, the number of children in the autism category more than tripled from 93,624 in 2000 to 419,647 a decade later. Yet nearly two-thirds of that increase was matched by a decline in the rate at which children were labeled as having an “intellectual disability.” The number of kids in that category fell from 637,270 to 457,478.
The data indicate thatthe autism rise is partly the result of students being moved from one category to another, Girirajan says.
For him, one lesson is that autism encompasses a potpourri of symptoms. It can also occur hand-in-hand with other conditions including intellectual disabilities, epilepsy, and attention-deficit hyperactivity disorder. That mixture makes it hard to pin down how common autism really is, and lends itself to shifting diagnoses, he says.
May 6, 2015, PLOS: The ‘autism epidemic’: increasing cases or increasing diagnoses?
Bucking this ‘environmental causes’ line of thought, the authors of the current study hypothesised that the ‘autism epidemic’ may be due to how autism has been diagnosed and registered over time. They provide four reasons for this hypothesis:
The rise in prevalence was reported during the same time period that the diagnostic criteria widened;
Increasing awareness of autism spectrum disorder causes ‘diagnostic substitution’: when children who would have previously been diagnosed with a learning disability or other mental illness or retardation are now diagnosed with autism;
Patient referral and availability of services increases due to increasing awareness; and,
Differential availability of case records and the way in which cases are diagnosed between similar geographical regions leads to wide variation in measured and actual prevalence.
March 27, 2014, USA Today: Autism rates soar, now affects 1 in 68 children
Autism rates climbed nearly 30% between 2008 and 2010 and have more than doubled since the turn of the century, according to a new study from the U.S. Centers for Disease Control and Prevention. The condition is now believed to affect one of every 68 8-year-olds – up from one in 88 just two years earlier. …
What's still unknown is the driver of that increase. Many experts believe the rise is largely due to better awareness and diagnosis rather than a true increase in the number of children with the condition.
"We don't know the extent those factors explain in terms of the increase, but we clearly know they do play a role," said Coleen Boyle, director of the National Center on Birth Defects and Developmental Disabilities at the CDC. "Our system tells us what's going on. It (only) gives us clues as to the why."
March 20, 2013, New York Times: Parental Study Shows Rise in Autism Spectrum Cases
According to experts not involved in the report, the increase coincided with a period of soaring awareness of autism spectrum disorders among clinicians and schools, as well as parents.
The report emphasized that while the numbers changed from 1 in 86 children, ages 6 to 17, having received a diagnosis in a 2007 parent survey, to 1 in 50 children in the current report, most of the increase was because of previously undiagnosed cases.
“Our findings suggest that the increase in prevalence is due to improved recognition of autism spectrum disorders,” said Stephen J. Blumberg, a senior scientist with the centers’National Center for Health Statisticsand the lead author of the study, “as opposed to children with newly developed risks for them.”
July 11, 2012, Discover Magazine:Is Autism an “Epidemic” or Are We Just Noticing More People Who Have It?
To most experts in autism and autism epidemiology, the biggest factors accounting for the boost in autism prevalence are the shifting definitions and increased awareness about the disorder. Several decades after the introduction of autism as a diagnosis, researchers have reported that professionals are still engaging in “diagnostic substitution”:moving people from one diagnostic category, such as “mental retardation” or “language impairment,” to the autism category.
March 30, 2012, Salt Lake City Tribune: Utah has nation's highest autism rate, CDC report says
One out of 47 Utah children have been identified as having an autism spectrum disorder, the highest rate in the country, according to new data released Thursday by the Centers for Disease Control and Prevention. …
In Utah, boys are almost three times as likely to have autism than girls with one in 32 boys identified, according to the new data, versus one in 85 girls.
Yet there has been a nearly 1,200 percent increase in identified girls in Utah between 2002 and 2008, said Judith Zimmerman, a researcher at the University of Utah's Department of Psychiatry. …
Researchers say the spike is real in Utah and can't be attributed to over diagnosis or a different definition of autism. …
In 2012, researchers identified Utah as having the highest rate of children diagnosed with autism out of the 14 communities surveyed in the network, a revelation that many found alarming.
That report, which was based on data from 2008 and relied on the state autism database, found that 1 in 47 Utah children had been identified as having autism — almost twice that of the national average
The CDC's next report, released in 2014 and based on data collected in 2010, showed that Utah no longer led the nation in autism prevalence. Researchers that year estimated that about1 in 54Utah children had been identified with autism spectrum disorder — much closer to the national average of 1 in 68.
In an email, Zimmerman claims that "pervasive" errors were found in the diagnostic codes used for individual children that year.)
March 29, 2012, CNN: CDC: U.S. kids with autism up 78% in past decade
…However, according to the CDC report, most children were diagnosed between ages 4 and 5, when a child's brain is already more developed and harder to change.
"Doctors are getting better at diagnosing autism; communities are getting much better at [providing] services to children with autism, and CDC scientists are getting much better at tracking which kids in the communities we're studying have autism," Frieden says.
"How much of that increase is a result of better tracking and how much of it is a result of an actual increase, we still don't know. We know more about autism today than we have ever known," he says, "but there is still so much we don't know and wish that we knew."
May 23, 2011, U.S. News: U.S. Rates of Autism, ADHD Continue to Rise: Report
Study finds 1 in 6 kids now have a developmental disability, perhaps due to better diagnosis
So, are the number of children with developmental disabilities on the rise, or are parents and doctors getting better at detecting cases? According to Dr. Nancy Murphy, chair of the American Academy of Pediatrics' Council on Children with Disabilities, the increases in these conditions may signify a greater awareness on the part of parents, teachers and health care professionals to identify children with disabilities and get them help.
That could mean that kids that might have been dismissed as simply being "slow" or disobedient in the past may now be getting some extra help to realize their potential, Murphy said.
"It speaks to providers and educators and parents being attentive to when kids are struggling, and that attentiveness is bringing them into systems that can generate diagnoses," Murphy said. "There is a greater willingness to say, 'My kid is struggling -- not because he's a bad kid but he may need a different approach to learning or development or behavior than he or she is getting.'"
One unanswered question is whether greater awareness and efforts to diagnose kids is the only explanation, or if there actuallyarea greater percentage of kids who are being born with or developing disabilities such as autism and ADHD early in life.
Research has suggested that advanced maternal and paternal age, assisted reproductive technology and greater numbers of premature or late-preterm births, could all be factors in some developmental disabilities, Boyle said. However, those are areas that need much more research, she added.
May 23, 2011, MedPage Today: Reports of ADHD, Autism on the Rise
From 2006-2008, nearly 10 million children ages 3 to 17 had a developmental disability, according to parental reports. That's a 17% increase in the prevalence of disorders such as autism and attention deficit-hyperactivity disorder (ADHD) since 1997, according to Coleen A. Boyle, PhD, and colleagues.
The increase over the 12-year period "represents [about] 1.8 million more children with developmental disabilities in 2006-2008 from a decade earlier ... caused in large part by shifts in the prevalence of ADHD and autism," wrote the authors inPediatrics.
The investigators offered some possible factors for the general increase in ADHD and autism prevalence such as:
Advances in behavioral disorder classification
Efficacy of clinical and behavioral treatments for ADHD
Increase in services for children with developmental disabilities
Improvement in clinical, parental, and societal recognition of disorders