Diagnosed cases of autism are the rise. Estimates in the ‘80s put the number at roughly 1 in 2,500 American children. Today some say it's as high as 1 in every 200. One developmental pediatrician calls autism "the new epidemic." Autism is a collection of neurobiological conditions that lead to communication, social and behavioral disorders. While severe autism can leave children almost entirely unable to communicate with others, those with mild forms can lead near-normal lives. Nobody knows what has caused the enormous upsurge in diagnoses. There's speculation that the condition is brought on by some environmental toxin, possibly mercury. But no environmental theory has been substantiated and many medical professionals are reluctant to chalk autism up to environmental pollution. There's been a corresponding drop in rates of mental retardation diagnoses, leading some to claim that children who would previously have been classified as developmentally disabled are now diagnosed as autistic.
IT'S JUST MORE DIAGNOSED: CBC News "Rise in Autism Rate Misleading, Study Says"
The rise in the number of autism cases is not evidence of an epidemic, but shows that schools are diagnosing autism more frequently, researchers said Monday . . . The study showed that the number of children classified as mentally retarded or learning disabled declined between 1994 and 2003, the same time as the rise in autism cases.
The author of the study, appearing in Monday's issue of Pediatrics, said this suggests a switch in diagnoses, not an epidemic of autism.
Shattuck said his study does not disprove the existence of an epidemic of autism cases, but it does show that data from school special education program is not sufficient to prove one exists.
The average prevalence of autism among six- to 11-year-olds enrolled in special education programs increased to 3.1 per 1,000 in 2003 from 0.6 per 1,000 students in 1994.
At the same time, the prevalence of mental retardation fell by 2.8 per 1,000 pupils and the prevalence of learning disabilities fell by 8.3 per 1,000 pupils.
In states such as California, there was no drop in the number of children labelled mentally retarded to offset the rise in autism cases.
Research has suggested that the rise in autism could be largely explained by changes in diagnosis, with children who might have been classified as mentally retarded or speech impaired before the 1990s now being classified as autistic. Lead researcher Craig J. Newschaffer, PhD, says the Department of Education figures do not show this, but he adds that the increase in autism may never be fully understood.
The study does not answer the question as to why autism is increasing. But the national data don't show a decrease in other learning disabilities. Trends for mental retardation and speech and language impairment remained unchanged.
This suggests the increase in autism is not the result of an across-the-board increase in special education classification, say the researchers.
He says a change in 1997 that allowed children up to the age of 9 to be classified as "developmentally delayed" may explain the apparent leveling of autism cases. Before 1997 the diagnosis was used only for children 5 and under.
It is possible, Newschaffer explains, that children with this label who would have been reclassified as autistic after age 5 are now being diagnosed when they are older.
Developmental pediatrician Cecelia McCarton used to see one or two autistic children a year. These days, three or four new patients come into her Manhattan office every week.
"It's the new epidemic," McCarton says — and there's plenty of evidence she's right.
Just how many people have autism or a related disorder is unknown, but the federal government acknowledges the numbers are growing.
In the mid-1980s, the figure tossed around was 1 in 2,500. The Centers for Disease Control and Prevention estimates as many as 1 in 500 people have autism today.
First recognized in 1943, autism is a collection of communication, social and behavioral disorders. At its worst, it can leave a child trapped in an impenetrable shell. But many people with autism are high-functioning and others make tremendous strides through treatment.
The medical community now realizes it's a neuro-biological condition that is probably influenced by more than a dozen genes. Still, scientists don't know exactly what causes it — genetics alone, a virus or a toxin — or why the numbers are skyrocketing.
"Part of it could be due to changes in diagnostic criteria and better diagnosis," said Marie Bristol-Powers, coordinator of autism programs at the National Institute of Mental Health.
"Do we think that accounts for all of the increase? The answer is no."
One 1998 British study found a correlation between the MMR injection (measles, mumps, rubella) and the spike in autism cases, but a subsequent survey swiftly shot down those findings. The Centers for Disease Control and Prevention and the National Institute of Mental Health insist there is no evidence of a link, but that hasn't quieted speculation that the live viruses of mercury preservatives in the vaccines trigger autism in susceptible children.
IT MAY BE ENVIRONMENTAL: BBC "Autism Rise Blamed On Environment"Autism, the devastating childhood learning disorder now thought to affect one in 200 children in Britain , could be triggered by something in the environment.
It is widely believed that autism has a strong genetic component.
But genetic diseases cannot lead to an epidemic-like rise in cases unless outside factors are at play.
Better diagnosis is thought to account for some of the rise.
Dr Ron Huff, California 's most senior psychologist, who is in charge of the State's $1.8 billion autism budget, told Newsnight that he now believes that an as yet unidentified environmental factor is partly to blame.
To account for the difference between the 200 - 300 cases a year in the '70s and the 3000 today you would have to argue that in 2700 cases clinicians were making diagnoses which would have been missed before.
Dr Huff believes that the rise in autism cannot be put solely down to changing diagnostic practise.
He said: "I think we would be foolish to attribute that rise simply to one single factor, I think it's a combination of factors."
It also seems highly unlikely given that the Californian statistics only count the more serious so called Level One cases of autistic disorder.
The symptoms of Level One cases, such as severely impaired speech, repetitive self-stimulatory behaviour, lack of eye contact and socialisation skills, are usually hard to miss.
Autistic children have been shown to have problems getting rid of toxic metals — and those metals are increasingly polluting the environment, says Dr Richard Lathe.
But it is not just electronic products whose toxic metals are getting into our bodies via the air we breathe and plants and seafood we consume, he says.
"Every ship that sinks, every rusting car, every unsealed mine and every tin can in our refuse dumps contributes to a rise in the levels of metal in seawater. It's absolutely clear there is a rise in autism, pointing to an environmental factor, with mercury and other toxic metals playing a crucial role."
"Couple this with a study published last month showing a correlation between mercury release into the environment and autism rates in Texas , and yet another study showing that autistic children have a problem getting rid of mercury through their hair, and you have a substantial body of evidence."
Dr Lathe, a former professor at Edinburgh University, says that, although the affected are probably genetically susceptible, we should all be worried about these pollutants leaking into the environment.
"Chelation therapy, which removes the metals, can significantly improve behaviour in autistic children. It has become controversial since a death occurred in a boy in therapy in the US . But that is because the wrong drug was used. I stand behind the effectiveness of removing harmful metals from the body."
(Source: TMCnet, July 17, 2006)