Controversies in autism

Epidemiology

Most recent reviews of epidemiology estimate a prevalence of one to two cases per 1,000 people for autism, and about six per 1,000 for ASD; because of inadequate data, these numbers may underestimate ASD's true prevalence. ASD averages a 4.3:1 male-to-female ratio. The number of children on the autism spectrum has increased dramatically since the 1980s, at least partly due to changes in diagnostic practice; it is unclear whether prevalence has actually increased; and as-yet-unidentified environmental risk factors cannot be ruled out. The risk of autism is associated with several prenatal factors, including advanced parental age and diabetes in the mother during pregnancy. ASD is associated with several genetic disorders and epilepsy. Autism is also associated with intellectual disability.

Genetics

There is evidence that autism has a genetic component, and ongoing research focuses on finding the biomarkers that determine autistic phenotypes.

Genetics is viewed as an underlying factor because there is a statistical pattern for a significantly high risk to have another autistic child in families with an already affected child. However, while some parents of autistic children are progressively also being diagnosed on the autism spectrum, at least some autistic children have apparently neurotypical parents. This suggests to some that genetics are either not a necessary cause or that they don't play a part in all cases of ASD, although it could also mean that the gene(s) responsible may be recessive or a spontaneous mutation. The spectrum of autistic disorders is notable for its significant gender disparity, with the incidence of autism in males greatly exceeding the incidence in females. Whilst this could be evidence for a genetic theory, it has also been argued that male brains may be more vulnerable during early development.

Vaccines

Several controversial claims have been made with regard to autism and vaccinations, leading notably to the MMR vaccine controversy, the thiomersal controversy, and the theory of vaccine overload. A 2011 journal article described the vaccine-autism connection as "the most damaging medical hoax of the last 100 years".

Vaccine overload

Vaccine overload is the notion that giving many vaccines at once may overwhelm or weaken a child's immune system and lead to adverse effects. The idea of vaccine overload is flawed, for several reasons. First, vaccines do not overwhelm the immune system; in fact, conservative estimates predict that the immune system can respond to thousands of viruses simultaneously. It is known that vaccines constitute only a tiny fraction of the pathogens already naturally encountered by a child in a typical year. Common fevers and middle ear infections pose a much greater challenge to the immune system than vaccines do. Second, studies have shown that vaccinations, and even multiple concurrent vaccinations, do not weaken the immune system or compromise overall immunity. Finally, autism is not an immune-mediated disease. The lack of evidence supporting the vaccine overload hypothesis, combined with these findings directly contradicting it, have led to the conclusion that currently recommended vaccine programs do not "overload" or weaken the immune system.

Thiomersal

In 1999, the Centers for Disease Control (CDC) and the American Academy of Pediatrics (AAP) asked vaccine makers to remove the organomercury compound thiomersal (spelled "thimerosal" in the U.S.) from vaccines as quickly as possible, and thiomersal has been phased out of U.S. and European vaccines, except for some preparations of influenza vaccine. Under the FDA Modernization Act (FDAMA) of 1997, the FDA conducted a comprehensive review of the use of thimerosal in childhood vaccines. Conducted in 1999, this review found no evidence of harm from the use of thimerosal as a vaccine preservative, other than local hypersensitivity reactions. The CDC and the AAP followed the precautionary principle, which assumes that there is no harm in exercising caution even if it later turns out to be unwarranted, but their 1999 action sparked confusion and controversy that has diverted attention and resources away from efforts to determine the causes of autism. Since 2000, the thiomersal in child vaccines has been alleged to contribute to autism, and thousands of parents in the United States have pursued legal compensation from a federal fund. A 2004 Institute of Medicine (IOM) committee favored rejecting any causal relationship between thiomersal-containing vaccines and autism. Autism incidence rates increased steadily even after thiomersal was removed from childhood vaccines. Currently there is no accepted scientific evidence that exposure to thiomersal is a factor in causing autism.

MMR vaccine

In the UK, the MMR vaccine was the subject of controversy after publication in The Lancet of a 1998 paper by Andrew Wakefield, et al. This article reported a study of 12 children mostly with onset autism spectrum disorders soon after administration of the vaccine. During a 1998 press conference, Wakefield suggested that giving children the vaccines in three separate doses would be safer than a single vaccination. This suggestion was not supported by his paper, nor by several subsequent peer-reviewed studies that failed to show any association between the vaccine and autism. It later emerged that Wakefield had received funding from litigants against vaccine manufacturers and that Wakefield had not informed colleagues or medical authorities of his conflict of interest. Had this been known, the paper would not have been published in The Lancet the way that it was. Wakefield has been heavily criticized on scientific grounds and for triggering a decline in vaccination rates, as well as on ethical grounds for the way the research was conducted. In 2004 the MMR-and-autism interpretation of the paper was formally retracted by 10 of Wakefield's 12 co-authors, and in 2010 The Lancet's editors fully retracted the paper.

The CDC, the IOM of the National Academy of Sciences, and the UK National Health Service have all concluded that there is no evidence of a link between the MMR vaccine and autism. In 2009, The Sunday Times reported that Wakefield had manipulated patient data and misreported results in his 1998 paper, creating the appearance of a link with autism. A 2011 article in the British Medical Journal described how the data in the study had been falsified by Wakefield so it would arrive at a predetermined conclusion. An accompanying editorial in the same journal described Wakefield's work as an "elaborate fraud" which led to lower vaccination rates, putting hundreds of thousands of children at risk and diverting energy and money away from research into the true cause of autism.

Celebrity Involvement

Some celebrities have spoken out on their views that autism is related to vaccination, including: Jenny McCarthy, Kristin Cavallari, Toni Braxton, Jim Carrey, and Robert F. Kennedy, Jr. Kennedy in particular published the book Thimerosal: Let the Science Speak: The Evidence Supporting the Immediate Removal of Mercury--A Known Neurotoxin--From Vaccines.

McCarthy, one of the most outspoken celebrities on the topic, has said her son Evan's autism diagnosis was a result of the MMR vaccine. She authored Louder than Words: A Mother's Journey in Healing Autism and co-authored Healing and Preventing Autism. She also founded an organization called Generation Rescue, which provides resources for families affected by autism. In a September 2015 CNN Presidential debate, Donald Trump claimed to know a 2-year-old who recently got a combined vaccine, developed a tremendous fever and now is on the Autism Spectrum.

Intelligence

The percentage of autistic individuals who also meet criteria for intellectual disability has been reported as anywhere from 25% to 70%, a wide variation illustrating the difficulty of assessing autistic intelligence. For PDD-NOS the association with intellectual disability is much weaker. The diagnosis of Asperger's excludes clinically significant delays in mental or cognitive skills.

A 2007 study suggested that Raven's Progressive Matrices (RPM), a test of abstract reasoning, may be a better indicator of intelligence for autistic children than the more commonly used Wechsler Intelligence Scale for Children (WISC). Researchers suspected that the WISC relied too heavily on language to be an accurate measure of intelligence for autistic individuals. Their study revealed that the neurotypical children scored similarly on both tests, but the autistic children fared far better on the RPM than on the WISC. The RPM measures abstract, general and fluid reasoning, an ability autistic individuals have been presumed to lack. A 2008 study found a similar effect, but to a much lesser degree and only for individuals with IQs less than 85 on the Wechsler scales.

Autism rights movement

The autism rights movement (ARM) is a social movement that encourages autistic people, their caregivers and society to adopt a position of neurodiversity, accepting autism as a variation in functioning rather than a mental disorder to be cured. The ARM advocates a variety of goals including a greater acceptance of autistic behaviors; therapies that teach autistic individuals coping skills rather than therapies focused on imitating behaviors of neurotypical peers; the creation of social networks and events that allow autistic people to socialize on their own terms; and the recognition of the Autistic community as a minority group.

Autism rights or neurodiversity advocates believe that the autism spectrum is genetic and should be accepted as a natural expression of the human genome. This perspective is distinct from two other likewise distinct views: (1) the mainstream perspective that autism is caused by a genetic defect and should be addressed by targeting the autism gene(s) and (2) the perspective that autism is caused by environmental factors like vaccines and pollution and could be cured by addressing environmental causes.

Anti-cure perspective

"Curing" or "treating" autism is a controversial and politicized issue. Doctors and scientists are not sure of the cause(s) of autism yet many organizations like Autism Research Institute and Autism Speaks advocate researching a cure. Members of the various autism rights organizations view autism as a way of life rather than as a disease and thus advocate acceptance over a search for a cure. Some advocates believe that common therapies for the behavioral and language differences associated with autism, like applied behavior analysis, are not only misguided but also unethical.

The "anti-cure perspective" endorsed by the movement is a view that autism is not a disorder, but a normal occurrence—an alternate variation in brain wiring or a less common expression of the human genome. Advocates of this perspective believe that autism is a unique way of being that should be validated, supported and appreciated rather than shunned, discriminated against or eliminated. They believe quirks and uniqueness of autistic individuals should be tolerated as the differences of any minority group should be tolerated and that efforts to eliminate autism should not be compared, for example, to curing cancer but instead to the antiquated notion of curing left-handedness. The ARM is a part of the larger disability rights movement, and as such acknowledges the social model of disability. Within the model, struggles faced by autistic people are viewed as discrimination rather than deficiencies.

John Elder Robison was a discussant for the Autism Social, Legal, and Ethical Research Special Interest Group at the 2014 International Meeting for Autism Research (IMFAR). He ended up taking the group to task, stating that the autism science community is headed for disaster if it does not change course on several factors – and noting for context the larger size of the US autistic community in proportion to other minority groups such as Jewish or Native American communities.

Robison asserted that autistic people need to be the ones providing oversight and governance for autism research. He condemned the use of words like "cure". He pointed out that researchers' explicit or implicit efforts to eradicate autistic people are a formula for disaster and need to stop. He also affirmed that memoirs and narratives written by autistic people are more trustworthy than writing about autism by nonautistics.

Diagnostic complications

Although the 2013 fifth revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) has more specificity, it also has reports of more limited sensitivity. Due to the changes to the DSM and the lessening of sensitivity, there is the possibility that individuals who were diagnosed with autistic spectrum disorders (ASD) using the fourth revision (DSM-IV-TR) will not receive the same diagnosis with the DSM-5.

From the 933 individuals that were evaluated, 39 percent of the samples that were diagnosed with an ASD using the DSM-IV-TR criteria did not meet the DSM-5 criteria for that disorder. Essentially, the DSM-5 criteria no longer classified them with having ASD, deeming them without a diagnosis. It was likely that individuals that exhibited higher cognitive functioning and had other disorders, such as Asperger's or pervasive developmental disorder not otherwise specified (PDD-NOS), were completely excluded from the criteria. Also, it is more probable that younger children who do not exhibit the entirety of the symptoms and characteristics of ASD are more at risk of being excluded by the new criteria since they could have Asperger's as Asperger's disorder does not usually show symptoms until later in childhood. Because the onset age is different in Asperger's from autism, grouping together the disorders does not typically allow or distinguish the differentiating ages of onset, which is problematic in diagnosing. It is evident, through the various studies, that the amount of people being diagnosed will be significantly diminished as well, which is prominently due to the DSM-5's new criteria.