Controversies in autism
Diagnoses of autism have become more frequent since the 1980s, which has led to various controversies about both the cause of autism and the nature of the diagnoses themselves. Whether autism has mainly a genetic or developmental cause, and the degree of coincidence between autism and intellectual disability are all matters of current scientific controversy as well as inquiry.
Scientific consensus holds that vaccines do not cause autism, but popular rumors and an article in a respected scientific journal, The Lancet, provoked concern among parents. The Lancet article was retracted for making false claims and because its author was found to be on the payroll of litigants against vaccine manufacturers.
The epidemiology of autism is the study of factors affecting autism spectrum disorders (ASD). 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 known to be autistic 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.
There is evidence that autism has a genetic component, and ongoing research focuses on finding the biomarkers that determine autistic phenotypes. One yet unproven theory is that there may be genes which contribute to a vulnerability to environmental triggers or have another role in the etiology of autism.
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.
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 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.
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. 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.
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.
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.
"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 is a formula for disaster and needs to stop. And he affirmed that memoirs and narratives written by autistic people are more trustworthy than writing about autism by nonautistics.
|This section may be confusing or unclear to readers. (July 2012)|
Joint attention is the shared focus of two individuals on an object. It refers to a cluster of behaviors in one of two classes: a child's response to someone else pointing or shifting eye gaze, and a child seeking another's attention. Many joint-attention behaviors differ in autistic children: for example, eye contact is relatively absent or atypical. These joint attention skills seem to be prerequisites for functional language development. It has also been hypothesized that autistic children initiate joint attention perhaps even as often as their neurotypical peers, albeit in atypical ways, and that a parent should join an autistic child's focus of attention and try harder to notice the child's atypical requests for attention rather than insist on typical behavior from the child. The empirical data supporting the latter hypothesis has been questioned.
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.[unreliable medical source?] 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 than it is in 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.
- The Editors Of The Lancet (February 2010). "Retraction—Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children". Lancet 375 (9713): 445. doi:10.1016/S0140-6736(10)60175-4. PMID 20137807. Lay summary – BBC News (2010-02-02).
- Newschaffer CJ, Croen LA, Daniels J et al. The epidemiology of autism spectrum disorders [PDF]. Annu Rev Public Health. 2007;28:235–58. doi:10.1146/annurev.publhealth.28.021406.144007. PMID 17367287.
- Caronna EB, Milunsky JM, Tager-Flusberg H. Autism spectrum disorders: clinical and research frontiers. Arch Dis Child. 2008;93(6):518–23. doi:10.1136/adc.2006.115337. PMID 18305076.
- Rutter M. Incidence of autism spectrum disorders: changes over time and their meaning. Acta Paediatr. 2005;94(1):2–15. doi:10.1111/j.1651-2227.2005.tb01779.x. PMID 15858952.
- Gardener H, Spiegelman D, Buka SL. Prenatal risk factors for autism: comprehensive meta-analysis. Br J Psychiatry. 2009;195(1):7–14. doi:10.1192/bjp.bp.108.051672. PMID 19567888.
- Zafeiriou DI, Ververi A, Vargiami E. Childhood autism and associated comorbidities. Brain Dev. 2007;29(5):257–72. doi:10.1016/j.braindev.2006.09.003. PMID 17084999.
- Levisohn PM. The autism-epilepsy connection. Epilepsia. 2007;48(Suppl 9):33–5. doi:10.1111/j.1528-1167.2007.01399.x. PMID 18047599.
- Chakrabarti S, Fombonne E. Pervasive developmental disorders in preschool children. JAMA. 2001;285(24):3093–9. doi:10.1001/jama.285.24.3093. PMID 11427137.
- Dunham, Will (2007-02-19). "International study finds new autism genetic links". Reuters. Retrieved 2008-02-29.
- Kimura, Doreen (2002-05-13). "Sex Differences in the Brain". Scientific American. Retrieved 2008-02-29.[dead link]
- Flaherty DK (October 2011). "The vaccine-autism connection: a public health crisis caused by unethical medical practices and fraudulent science". Ann Pharmacother 45 (10): 1302–4. doi:10.1345/aph.1Q318. PMID 21917556.
- Hilton S, Petticrew M, Hunt K (2006). "'Combined vaccines are like a sudden onslaught to the body's immune system': parental concerns about vaccine 'overload' and 'immune-vulnerability'". Vaccine 24 (20): 4321–4327. doi:10.1016/j.vaccine.2006.03.003. PMID 16581162.
- Gerber JS, Offit PA (2009). "Vaccines and autism: a tale of shifting hypotheses". Clin Infect Dis 48 (4): 456–461. doi:10.1086/596476. PMC 2908388. PMID 19128068. Lay summary – IDSA (2009-01-30).[dead link]
- Immune challenges:
- Murphy TF (1996). "Branhamella catarrhalis: epidemiology, surface antigenic structure, and immune response" (PDF). Microbiol Rev 60 (2): 267–79. PMC 239443. PMID 8801433.
- Sloyer JL, Howie VM, Ploussard JH, Ammann AJ, Austrian R, Johnston RB (1974). "Immune response to acute otitis media in children. I. Serotypes isolated and serum and middle ear fluid antibody in pneumococcal otitis media" (PDF). Infect Immun 9 (6): 1028–32. PMC 414928. PMID 4151506.
- Vaccine burden:
- Miller E, Andrews N, Waight P, Taylor B (2003). "Bacterial infections, immune overload, and MMR vaccine. Measles, mumps, and rubella". Arch Dis Child 88 (3): 222–223. doi:10.1136/adc.88.3.222. PMC 1719482. PMID 12598383.
- Hviid A, Wohlfahrt J, Stellfeld M, Melbye M (2005). "Childhood vaccination and nontargeted infectious disease hospitalization". JAMA 294 (6): 699–705. doi:10.1001/jama.294.6.699. PMID 16091572.
- Bonhoeffer J, Heininger U (2007). "Adverse events following immunization: perception and evidence". Curr Opin Infect Dis 20 (3): 237–246. doi:10.1097/QCO.0b013e32811ebfb0. PMID 17471032.
- Vaccine schedules and "overload":
- Gregson AL, Edelman R (2003). "Does antigenic overload exist? The role of multiple immunizations in infants". Immunol Allergy Clin North Am 23 (4): 649–664. doi:10.1016/S0889-8561(03)00097-3. PMID 14753385.
- Offit PA, Quarles J, Gerber MA, et al. (2002). "Addressing parents' concerns: do multiple vaccines overwhelm or weaken the infant's immune system?". Pediatrics 109 (1): 124–129. doi:10.1542/peds.109.1.124. PMID 11773551.
- Schneeweiss B, Pfleiderer M, Keller-Stanislawski B (2008). "Vaccination safety update". Dtsch Arztebl Int 105 (34–5): 590–5. doi:10.3238/arztebl.2008.0590. PMC 2680557. PMID 19471677.
- Offit PA (2007). "Thimerosal and vaccines—a cautionary tale". N Engl J Med 357 (13): 1278–1279. doi:10.1056/NEJMp078187. PMID 17898096.
- Sugarman SD (2007). "Cases in vaccine court—legal battles over vaccines and autism". N Engl J Med 357 (13): 1275–1277. doi:10.1056/NEJMp078168. PMID 17898095.
- Immunization Safety Review Committee (2004). Immunization Safety Review: Vaccines and Autism. The National Academies Press. ISBN 0-309-09237-X.
- Doja A, Roberts W (2006). "Immunizations and autism: a review of the literature". Can J Neurol Sci 33 (4): 341–6. doi:10.1017/s031716710000528x. PMID 17168158.
- Wakefield A, Murch S, Anthony A, et al. (1998). "Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children". Lancet 351 (9103): 637–641. doi:10.1016/S0140-6736(97)11096-0. PMID 9500320. Retrieved 2007-09-05. (Retracted, see PMID 20137807)
- National Health Service (2004). "MMR: myths and truths". Retrieved 2007-09-03.
- Deer B (2004-02-22). "Revealed: MMR research scandal". The Sunday Times. Retrieved 2007-09-23.
- Horton R (2004). "The lessons of MMR". Lancet 363 (9411): 747–749. doi:10.1016/S0140-6736(04)15714-0. PMID 15016482.
- "Doctors issue plea over MMR jab". BBC News. 2006-06-26. Retrieved 2007-11-23.
- "MMR scare doctor 'paid children'". BBC News. 2007-07-16.
- Murch SH, Anthony A, Casson DH, et al. (2004). "Retraction of an interpretation". Lancet 363 (9411): 750. doi:10.1016/S0140-6736(04)15715-2. PMID 15016483.
- "Concerns about autism". Centers for Disease Control and Prevention. 2010-01-15.
- MMR Fact Sheet, from the United Kingdom National Health Service. Accessed June 13, 2007.
- Deer B (2009-02-08). "MMR doctor Andrew Wakefield fixed data on autism". Sunday Times. Retrieved 2009-02-09.
- Deer B (2011). "How the case against the MMR vaccine was fixed". BMJ 342: c5347–c5347. doi:10.1136/bmj.c5347. PMID 21209059.
- Godlee F, Smith J, Marcovitch H (2011). "Wakefield's article linking MMR vaccine and autism was fraudulent". BMJ. 342:c7452: c7452–c7452. doi:10.1136/bmj.c7452. PMID 21209060.
- Dawson M, Mottron L, Gernsbacher MA (2008). "Learning in autism" (PDF). In Byrne JH (ed.-in-chief), Roediger HL III (vol. ed.). Learning and Memory: A Comprehensive Reference 2. Academic Press. pp. 759–72. doi:10.1016/B978-012370509-9.00152-2. ISBN 0-12-370504-5. Retrieved 2008-07-26.
- Chakrabarti S, Fombonne E (2001). "Pervasive developmental disorders in preschool children". JAMA 285 (24): 3093–3099. doi:10.1001/jama.285.24.3093. PMID 11427137.
- DSM-IV-TR Diagnostical and Statistical Manual of Mental Disorders Fourth edition text revision. American Psychiatric Association, Washington DC. 2000. p. 80.
- Dawson M, Soulières I, Gernsbacher MA, Mottron L (2007). "The level and nature of autistic intelligence". Psychol Sci 18 (8): 657–662. doi:10.1111/j.1467-9280.2007.01954.x. PMID 17680932. Lay summary – ScienceDaily (2007-08-05).
- Bölte S, Dziobek I, Poustka F (2008). "Brief report: the level and nature of autistic intelligence revisited". J Autism Dev Disord 39 (4): 678–682. doi:10.1007/s10803-008-0667-2. PMID 19052857.
- Solomon, Andrew (2008-05-25). "The autism rights movement". New York. Archived from the original on 27 May 2008. Retrieved 2008-05-27.
- Mission Statement. Autism Acceptance Project. Retrieved on 2008-11-24.
- Mission Statement. Aspies for Freedom. Retrieved on 2008-11-24.
- Autism Network International presents Autreat. (2008-05-23) AIN.
- "Declaration From the Autism Community That They Are a Minority Group" (Press release). PRWeb, Press Release Newswire. 2004-11-18. Retrieved 2007-11-07.
- Harmon, Amy. Neurodiversity Forever; The Disability Movement Turns to Brains. The New York Times, May 9, 2004. Retrieved on 2007-11-08.
- Dawson, Michelle. The Misbehaviour of Behaviourists. (2004-01-18). Retrieved on 2007-01-23.
- Gal L (2007-06-28). "Who says autism's a disease?". Haaretz. Archived from the original on 1 July 2007. Retrieved 2007-07-16.
- "In Support of Michelle Dawson and Her Work". Autistics.org. Retrieved 2012-03-21.
- Waltz, M (2013). Autism: A Social and Medical History. London: Palgrave Macmillan. ISBN 0-230-52750-7.
- John Robison at IMFAR: On Autism Rights, Ethics, & Priorities
- Bruinsma Y, Koegel RL, Koegel LK (2004). "Joint attention and children with Classic Autism: a review of the literature". Ment Retard Dev Disabil Res Rev 10 (3): 169–175. doi:10.1002/mrdd.20036. PMID 15611988.
- Johnson CP, Myers SM, Council on Children with Disabilities (2007). "Identification and evaluation of children with autism spectrum disorders". Pediatrics 120 (5): 1183–1215. doi:10.1542/peds.2007-2361. PMID 17967920. Lay summary – AAP (2007-10-29).
- Joint attention controversy:
- Gernsbacher MA, Stevenson JL, Khandakar S, Goldsmith HH (2008). "Why does joint attention look atypical in autism?". Child Dev Perspect 2 (1): 38–45. doi:10.1111/j.1750-8606.2008.00039.x.
- Burack JA, Russo N (2008). "On why joint attention might look atypical in autism: a case for a strong policy statement but more nuanced empirical story". Child Dev Perspect 2 (1): 46–48. doi:10.1111/j.1750-8606.2008.00040.x.
- Gernsbacher MA, Stevenson JL, Khandakar S, Goldsmith HH (2008). "Autistics' atypical joint attention: policy implications and empirical nuance". Child Dev Perspect 2 (1): 49–52. doi:10.1111/j.1750-8606.2008.00041.x.
- [non-primary source needed] Barton, M. L., Robins, D. L., Jashar, D., Brennan, L., & Fein, D. (2013). Sensitivity and specificity of proposed DSM-5 criteria for Autism spectrum disorder in toddlers. Journal Of Autism And Developmental Disorders, 43(5), 1184-1195. doi:10.1007/s10803-013-1817-8 PMID 23543293