Of all the whoppers told by the autism bio-med/conspiracy buffs, none may be easier to refute than that chestnut which tells us that the symptoms of mercury poisoning are “exactly the same” as autism. This line is repeated over and over with great certainty, as if it was as obvious as the setting sun.
The lie, and that’s exactly what it is, was jump started in 2000 when Medical Hypothesis, a fringe medical journal, published “Autism: A Novel Form of Mercury Poisoning”. The paper was widely quoted by parents who needed something to blame. Mercury seemed so obvious – it is known to attack the nervous system, and it’s present in thimerosal, and the symptoms of autism present right around the time that infants are immunized. So there ya go – case closed!
When somebody writes “Dandruff: A Novel form of Skin Cancer”, it will also find a home in Medical Hypothesis.
A comparison of the clinical symptoms of mercury poisoning and the diagnostic criteria for autism shows they are quite distinct.
First of all, this handy article in Pediatrics tells us the characteristic motor findings of mercury poisoning are ataxia (gross incoordination of muscle movements) and dysarthria (motor speech disorder). Fetal methyl mercury poisoning in severe form also causes spasticity.
In autism, the only common motor manifestations are repetitive behaviors (stereotypies) such as flapping, circling, or rocking. Persons with Asperger syndrome may be clumsy, and hypotonia has been noted in some infants with autism; the frequency of clumsiness and hypotonia in autism spectrum disorders is not established. No other motor findings are common in autism, and indeed the presence of ataxia or dysarthria in a child whose behavior has autistic features should lead to careful medical evaluation for an alternative or additional diagnosis.
Fetal exposure to mercury leads to microcephaly – a small head, as does prenatal exposure to lead, alcohol, PCBs and other neurotoxins. “In contrast”, says Pediatrics, “in autism increasing evidence indicates that head size and, as measured by volumetric magnetic resonance imaging, brain size tends to be larger than population norms.”
I guess that’s where the “novel” part comes in.