Controversies in autism

Diagnoses of autism have become more frequent since the 1980s, leading to various controversies in autism about both its causes 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 scientific controversy and inquiry. There is also more sociopolitical debate as to whether autism should be considered a disability on its own.

Epidemiology

, the prevalence of autism spectrum disorder (ASD) is around 1%. ASD averages a 4.3:1 male-to-female ratio. The number of children diagnosed with autism has increased dramatically since the 1980s, at least partly due to changes in diagnostic practice; it is unclear whether prevalence has actually increased; and other unidentified environmental risk factors may exist. 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.

Genetics

The role of genetic influence on ASD has been heavily researched over the past few years. ASD is considered to have polygenic traits since there is not a single risk factor, but multiple ones.

Multiple twin and family studies have been conducted in order to observe any genetic influence in diagnosing ASD. The chance of both twins having ASD was significantly higher in identical twins than fraternal twins, concluding that ASD is heritable. A reoccurring finding is that de novo (new mutation) copy number variants (CNVs) are a primary cause of ASD – they alter synaptic functions; germ line mutations can produce de novo CNVs. These mutations can only be passed on to offspring; this explains the phenomenon that occurs when the child has symptoms of ASD, but the parents have no symptoms or history of ASD. De novo variants differ from person to person, i.e. one variant can cause ASD in one person, whereas another person would need multiple variants to cause the same disorder.

There is also controversy over the nature vs. nurture debate. According to family studies, genetic and environmental factors have an equal influence on the risk of ASD. Specifically, C. tetani and C. histolyticum are two species of this bacteria that affect people with ASD. C. tetani produces tetanus neurotoxin in the intestinal tract; C. histolyticum is a toxin producer that is abundant in people diagnosed with ASD. Both of these could contribute to neurological symptoms.

Vaccines

A later-retracted article from The Lancet making false claims provoked concern about vaccines among parents. Its author, Andrew Wakefield, was found to be on the payroll of litigants against vaccine manufacturers.

The idea of a link between vaccines and autism was extensively investigated and shown to be false. The scientific consensus is that there is no relationship, causal or otherwise, between vaccines and incidence of autism,

Nevertheless, the anti-vaccination movement continues to promote myths, conspiracy theories, and misinformation linking the two. A developing tactic appears to be the "promotion of irrelevant research [as] an active aggregation of several questionable or peripherally related research studies in an attempt to justify the science underlying a questionable claim."

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.

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 non-autistic 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.

Facilitated communication

Facilitated communication (FC) is a scientifically discredited technique that attempts to facilitate communication by people with severe educational and communication disabilities. The facilitator holds or gently touches the disabled person's arm or hand during this process and attempts to help them move to type on a special keyboard. It was used by many hopeful parents of autistic individuals when it was first introduced during the early 1990s by Douglas Biklen, a professor at Syracuse University.

There is widespread agreement within the scientific community and multiple disability advocacy organizations that FC is not a valid technique for authentically augmenting the communication skills of autistic people. Instead, research indicates that the facilitator is the source of the messages obtained through FC (involving ideomotor effect guidance of the arm of the patient by the facilitator). Thus, studies have consistently found that patients are unable to provide the correct response to even simple questions when the facilitator does not know the answers to the questions (e.g., showing the patient but not the facilitator an object). In addition, numerous cases have been reported by investigators where disabled persons were assumed by facilitators to be typing a coherent message while the patient's eyes were closed or while they were looking away from or showing no particular interest in the letter board. Despite the evidence opposing FC, many continue to use and promote this technique. These two paradigms are not fully exclusive, and many people hold a combination of these viewpoints.

Pathology paradigm

The pathology paradigm is the traditional view of autism through a biomedical lens, in which it is seen as a disorder characterized by various impairments, mainly in communication and social interaction. Those taking this perspective believe that autism is generally a harmful dysfunction. The atypical behaviors of autistic individuals are considered a detriment to social and professional success and should therefore be reduced or eliminated through autism therapies.

Advocates with this view include both a small but significant minority of autistic adults and large majority of parents of autistic children, but contain a higher percentage of parents when compared to those adopting the neurodiversity paradigm. These advocates believe that medical research is necessary to address the rapid rise in autism diagnoses (sometimes referred to as the "autism epidemic"),

Advocacy groups that focus or have focused primarily on medical research include Autism Speaks and its predecessor organizations, the Autism Coalition for Research and Education, the National Alliance for Autism Research and Cure Autism Now. They also include the Autism Science Foundation and the defunct Autism Research Institute.

Neurodiversity paradigm

The neurodiversity paradigm is a view of autism as a different way of being rather than as a disease or disorder that must be cured. Autistic people are considered to have neurocognitive differences, lobbying for the inclusion of autistic people when making decisions that affect them, and opposition to therapies that aim to make children "indistinguishable from their peers".

Advocacy groups that focus primarily on acceptance and accommodation include Autism Network International, the Autism National Committee, the Autistic Self Advocacy Network, and the Autistic Women & Nonbinary Network.