Theories of the etiology of autism
Brain testosterone theory
Simon Baron-Cohen proposes a model for autism based in his empathising-systemising (E-S) theory[12]. His team at the Autism Research Centre in Cambridge, UK, measured testosterone levels in the amniotic fluid of mothers while pregnant. This is presumed to reflect levels in the babies themselves. The team found that the babies with higher fetal testosterone levels had a smaller vocabulary and made eye contact less often when they were a year old.
His group has looked at the original 58 children again, at age four. The researchers found that the children with higher testosterone in the womb are less developed socially, and the interests of boys are more restricted than girls. The results are published in the Journal of Child Psychology and Psychiatry in a 2004 issue [13].
Baron-Cohen theorizes that high fetal testosterone levels push brain development towards an improved ability to see patterns and analyze systems. Males supposedly tend to be better at these tasks than females. But the high levels are thought to inhibit the development of communication and empathy, which are allegedly typical female skills. (New Scientist, 24 May 2003) [14].
However, there is still no demonstrable evidence that testosterone levels affect brain development or autism. Gender or biodeterminism is a fashionable explanation for many human behaviors, but has been challenged by other professionals[15].
Vaccine theory
Controversial research by Andrew Wakefield in the UK that was published in The Lancet in the February 1998 issue, dubbed the "Wakefield Study", suggested a possible link between autism and the MMR vaccine. The original research has come under criticism, largely due to a conflict of interest on Wakefield's part [16]. In February 2004 The Lancet described the research as "entirely flawed", said that it should never have been published, and 12 of the original 14 authors of the paper retracted their claims. Critics with statistical skills have claimed that Wakefield's study contains many obvious flaws, including an inability to recognize bias in his sample. Controversy continues, with Wakefield continuing to defend his theory.
Although the fact that the Wakefield study is flawed does not in itself prove that no autism-vaccine connection exists, further research suggests that the theory is most likely false. Several independent groups have conducted thorough investigations into the possible link, including the National Academy of Sciences, and concluded that the evidence does not support a link between the MMR vaccine and autism.
For further proof, a study by Gillberg and Heijbel in 1998 that examined the prevalence of autism in children born in Sweden from 1975 to 1984[17] found that there was no difference in the prevalence of autism among children born before the introduction of the MMR vaccine in Sweden and those born after the vaccine was introduced. Another study, conducted by Madsen and other researchers in 2002, studied all children born in Denmark from January 1991 through December 1998[18]. There were a total of 537,303 children in the study; 440,655 of the children were vaccinated with MMR and 96,648 were not. The researchers did not find a higher risk of autism in the vaccinated than in the unvaccinated group of children.
Research in the U.S. has suggested a similar link between autism and the DPT vaccine. However, unlike early claims from Wakefield, it is doubtful that a large majority of autism cases would come from this vaccine. Despite all the evidence to the contrary, controversy surrounding autism and vaccines continues to this day, and many polls, such as the autism coach poll[19], show vaccines as the most popular theory currently on the etiology of autism among parents of autistic children.
In a controversial article in June 2005, Robert F. Kennedy, Jr. described research suggesting that it is not the vaccines themselves, but a mercury-based preservative called Thimerosal, which is used in some vaccine preparations, that may be a cause of autism[20]. Kennedy argues that autism was first observed in children who were born around the time of introduction of thimerosal into mass-produced vaccines, and that the incidence of autism in the United States is well correlated with the amounts of thimerosal children receive during their first two years of life.
Brain trauma
Susan Bryson has claimed that some autistics have evidence of trauma to the brain stem in early development, and that a small portion of the thalidomide victims have become autistic. The victims' limbs were normal unless thalidomide use continued later in the pregnancy. The brain stem anomaly's most striking feature is inability to focus attention away from a stimulus in a short time like neurotypicals, as demonstrated in a psychological test.
Some people claim the inability to shift attention quickly interferes with the ability to read nonverbal language where fast attention shifts are needed (such as eye language), suggesting that being nonverbal is not a primary feature of autism. Strong and shiftless focus is, however, a benefit in some areas like science, programming, and advanced mathematics. This is supported by the monotropism hypothesis.
Dr. Bernard Rimland's influential research and his book Infantile Autism (1967) argued that autism was not caused by childhood trauma or abuse, but by damage to certain areas of the brain, particularly the reticular formation which associates present sensory input with memories of past experiences. Dr. Rimland is a foremost advocate of the theory that autism may be precipitated by mercury and heavy metal toxicity[21]. He also is prominent in increasingly common claims of successful treatment of autism in children—particularly regarding improvements in ability to comprehend the spoken word—with the gluten-free, casein-free diet and mercury chelation therapy.
Others claim Dr. Bernard Rimland's methods alleviate the symptoms of heavy metal poisoning, but not autism. Curing heavy metal poisoning when it is present is a worthy goal (it helps with IQ and other learning difficulties as well as general health), but claiming a cure for autism is a misrepresentation. Heavy metal poisoning may be more common among autistics due to a severe metallothionein deficiency, but more evidence is needed to substantiate the idea that heavy metals cause autism. It is still being studied. The presence of heavy metals, particularly mercury, might make an autism diagnosis more likely, however.
Viral or bacterial infection
A growing body of peer-reviewed studies published in mainstream journals has shown that many common diseases of unknown origin are in fact caused by the presence of slowly acting viruses. For example, cervical cancer is caused by the human papilloma wart virus; some cases of liver cancer are caused by hepatitis C or B; Schizophrenia may be caused by Borna virus. Paul W. Ewald, among others, argues that the available data on the origin of autism is consistent with it being caused by a virus or infection.
Increase in diagnoses of autism
For more details on this topic, see Autism epidemic.
The number of reported cases of autism has increased dramatically over the past decade. Statistics in graph from the National Center for Health Statistics.There has been an explosion worldwide in reported cases of autism over the last ten years, which is largely reminiscent of increases in the diagnosis of schizophrenia and multiple personality disorder in the twentieth century. This has brought rise to a number of different theories as to the nature of the sudden increase.
Epidemiologists argue that the rise in diagnoses in the United States is either partly or entirely attributable to changes in diagnostic criteria, reclassifications, public awareness, and the incentive to receive federally mandated services. A widely cited study from the M.I.N.D. Institute in California (17 October 2002), claimed that the increase in autism is real, even after those complicating factors are accounted for (see reference in this section below).
Other researchers remain unconvinced (see references below), including Dr. Chris Johnson, a professor of pediatrics at the University of Texas Health Sciences Center at San Antonio and cochair of the American Academy of Pediatrics Autism Expert Panel, who says, "There is a chance we're seeing a true rise, but right now I don't think anybody can answer that question for sure." (Newsweek reference below).
The answer to this question has significant ramifications on the direction of research, since a real increase would focus more attention (and research funding) on the search for environmental factors, while a consensus for little or no real increase would direct more attention to genetics. On the other hand, it is conceivable that certain environmental factors (vaccination, diet, societal changes) may have a particular impact on people with a specific genetic constitution. There is little public research on the effects of in vitro fertilization on the number of incidences of autism.
One of the more popular theories is that there is a connection between "geekdom" and autism. This is hinted, for instance, by a Wired Magazine article in 2001 entitled "The Geek Syndrome", which is a point argued by many in the autism rights movement[22]. This article, many professionals assert, is just one example of the media's application of mental disease labels to what is actually variant normal behavior—they argue that shyness, lack of athletic ability or social skills, and intellectual interests, even when they seem unusual to others, are not in themselves signs of autism or Asperger's syndrome.
Due to the recent publicity surrounding autism and autistic spectrum disorders, an increasing number of independent adults are choosing to seek diagnoses of high-functioning autism or Asperger's syndrome in light of symptoms they currently experience or experienced during childhood. Since the cause of autism is thought to be at least partly genetic, a proportion of these adults seek their own diagnosis specifically as follow-up to their children's diagnoses. Because autism falls into the category of pervasive developmental disorders, strictly speaking, symptoms must have been present in a given patient before age seven in order to make a differential diagnosis.
Remediation
There are many different therapies and treatments but the success they have varies dramatically from person to person. Remediation of the debilitating aspects of autism is also hindered by widespread disagreement over its nature and causes, and by a lack of recognized and effective therapies.
The behavioral and cognitive functioning of individuals with autism might improve with the help of psychosocial and pharmacological interventions. Among psychosocial treatments, intensive, sustained special education programs and behavior therapy early in life might increase the ability of children with autism to acquire language and the ability to learn. In adults with autism, some studies have found beneficial effects of the antidepressant medications clomipramine and fluoxetine. There is also evidence that the antipsychotic medication haloperidol can be helpful; however, the risk of serious side effects is significant in children. In many cases quite a few medications will have to be tried until a successful drug is found, and the drug may lose effectiveness later in the autistic's life, complicating matters further.
Dr. Bruno Bettelheim believed that autism was linked to trauma in early childhood, and his work was highly influential for decades. Parents, and especially mothers, of autistics were blamed for having caused their child's condition through the withholding of affection. Leo Kanner, who first described autism (Autistic disturbances of affective contact, 1943) originated the "refrigerator mother" hypothesis, which held that autism was at least partly caused by a lack of affection from the autistic child's mother. Although Kanner eventually renounced the concept and apologized publicly, Bettelheim took the theory further. These theories did nothing to address the fact that having more than one autistic child in a family is exceptional, not the rule. Treatments based on these theories failed to help autistic children.
Applied Behavior Analysis
A major breakthrough (in some respects) in the remediation of autistic behaviors came through work spearheaded by Ole Ivar Lovaas, who believed that success could be obtained by behavioral approaches.
Lovaas' approaches—often referred to as Discrete Trial, Intensive Behavior Intervention, and Applied Behavior Analysis—are some of the best known and most widely used in the field and focus on the development of attention, imitation, receptive or expressive language, and pre-academic and self-help skills. Using a one-to-one therapist-child ratio and the “antecedent-behavior-consequence” (ABC) model, interventions based on this work involve trials or tasks. Each consists of (a) an antecedent, which is a directive or request for the child to perform an action; (b) a behavior, or response from the child, which may be categorized as successful performance, noncompliance, or no response; and (c) a consequence, defined as the reaction from the therapist, which ranges from strong positive reinforcement to a strong negative response, “No!”(Autism Society of America, 2001)[23].
Lovaas' Applied Behavioral Analysis (ABA) methods were the first scientifically validated therapy for autism. Early intervention, generally before school-age, seems to be critical to achieving optimal outcomes.
ABA techniques based on B. F. Skinner's Verbal Behavior have succeeded in helping nonverbal children start to talk, typically going from zero words to several dozen. By allowing children to express their needs, even rudimentary speech can alleviate frustration and tantrums.
The scientific validity of Lovaas's methods is questioned by many professionals as well as parents and autistics themselves. Lovaas's initial studies looked promising but have not been reproduced by others with the same rate of success. There have not been any double-blind studies that validate ABA, so it is unclear if any improvements seen in children are simply due to their normal course of development.
Many also feel that there are serious ethical problems, and point out that early ABA was based around the use of aversives which could be experienced by an autistic person as confusing and painful [24]. Most contemporary behaviorist programs for autistics employ no aversiveness at all, and not all attempt to "extinguish" behaviors such as rocking or spinning that autistics use for calming purposes.
ABA may not be appropriate for every autistic or developmentally delayed child. ABA has come into widespread use only in the last decade and the demand is outstripping the supply of committed and experienced service providers. As a result, parents of children need to be extra vigilant in choosing appropriate treatments for their children and especially in choosing providers, who may be inexperienced, use questionable methods or even deceive parents that they are competent to run an ABA or any other program. Such problems have led to horror stories from some parents. [25] [26]
Relationship Development Intervention
Relationship Development Intervention (RDI) is a research-based treatment program developed by Dr. Steven E. Gutstein. Whereas ABA aims to teach social skills directly, RDI focuses on building the "dynamic intelligence" that underlies the acquisition of those social skills in neurotypical children. It also focuses on the building blocks of motivation by developing episodic memory (seen as impaired in autism) and filling it with the child's own personal stories of competence and mastery. RDI emphasizes declarative (as opposed to imperative) communication, and aims for an appropriate balance of verbal and nonverbal communication.
Dr. Gutstein claims that 70% of his patients improved their ADOS score within 18 months, which is unprecedented (it was previously thought that improvement on the ADOS was impossible), and that a similar proportion are able to enter school without a shadow teacher or other personal assistant.
Son-Rise
The Son-Rise program was developed by Samahria & Barry Neil Kaufman, who founded the Option Institute to promulgate their more general philosophy upon which the Son-Rise program is partially based, and to provide training in this treatment approach. It is a home-based program with emphasis on eye contact, accepting the child without judgment, and engaging the child in a noncoercive way. The Association for Science in Autism Treatment (ASAT)[27] maintains a Description of the Son-Rise Program[28].
Autism and computing
Many studies have shown that computers help calm autistic children and help them communicate,[29] and that often autistic children take to computers more quickly than non-autistic people. However, evidence suggesting that computers help autistic children communicate without computers is less promising, and autistic children are not immune to the effects of overuse of computers. One can deduce from this that autistic children often communicate better through e-mail than normal speech, but in rare cases the reverse can be true also.
Some groups have proposed more precise scientific reasons for why this happens. One such group, the nonprofit Autism and Computing[30], claims that autism is monotropism (as stated in an above section), and they argue that computers provide an easy way of joining attention tunnels (a.k.a. undivided attention) with minimal discomfort, circumventing some of the most disabling features of autistic spectrum disorders.
Gluten-free, casein-free diet
Dr. Karl Ludwig Reichelt claims to have found peptides from casein and gluten that worsen the symptoms of autistic children. These peptides are casomorphines and gluten exorphines, which influence the brain. According to Dr. Reichelt, significant improvement has been seen in the symptoms of some of his patients with autism, on a diet that omits these peptides, the diet is called the gluten-free, casein-free diet. Some physicians see diet as a central part of the treatment, but in addition to many other treatments at the same time[31].
Sociology
Due to the complexity of autism, there are many facets of sociology that need to be considered when discussing it, such as the culture possible with it. In addition, there are several communities being formed within the autistic community, and in recent times they have become a bit polarized.
Community
For more details on this topic, see Autistic community.
Much like many other controversies in the world, the autistic community itself has splintered off into several groups. Essentially, these groups are those who seek a cure for autism, dubbed pro-cure, those who do not desire a cure for autism and as such resist it, dubbed anti-cure, and the many people caught in the middle of the two. In recent history, with scientists learning more about autism and possibly coming closer to a cure, some members of the "anti-cure" movement sent a letter to the United Nations demanding to be treated as a minority group rather than a group with a mental disability or disease.
There are numerous resources available for autistics from many groups. Due to the fact that many autistics find it easier to communicate online than in person, many of these resources are available online. In addition, sometimes successful autistic adults in a local community will help out children with autism, much in the way a master would help out an apprentice, for example.
2002 was declared Autism Awareness Year in the United Kingdom—this idea was initiated by Ivan and Charika Corea, parents of an autistic child, Charin. Autism Awareness Year was led by the British Institute of Brain Injured Children, Disabilities Trust, National Autistic Society, Autism London and 800 organizations in the United Kingdom. It had the personal backing of British Prime Minister Tony Blair and parliamentarians of all parties in the Palace of Westminster.
Culture
For more details on this topic, see Autistic culture.
With the recent increases in autism rates, an autistic culture has begun to develop. Autistic culture is much akin to deaf culture, which says that autism is a unique way of being and not a disorder to be cured, i.e., "anti-cure". There are some commonalities which are specific to autism in general as a culture, not just "autistic culture".
It is a common misperception that people with autism do not marry; many do get married. Often, it is to another person with autism, although this is not always the case. Many times this is due to shared interests or obsessions, but more often than not it is due to more compatibility with personality types. Multigenerational autistic families have also recently become a bit more common.
Interests with autistic people and so-called "geeks" or "nerds" can often overlap as autistic people can sometimes become preoccupied with certain subjects much like the variant normal behavior geeks experience. However, in practice many autistic people have difficulty with working in groups, which impairs them even in the most "technical" of situations.
Adults with autism
Temple Grandin, one of the more successful adults with autism. Photograph courtesy Joshua Nathaniel Pritikin and William Lawrence Jarrold.Some autistic adults are able to work successfully in mainstream jobs, usually those with high-functioning autism or Asperger's syndrome. Nevertheless, communication and social programs often cause difficulties in many areas of the autistic's life.
Many other autistics are capable of employment in sheltered workshops under the supervision of managers trained in working with persons with disabilities. A nurturing environment at home, at school, and later in job training and at work, helps autistic people continue to learn and to develop throughout their lives.
In the United States, the public schools' responsibility for providing services ends when the autistic person is in their 20s, depending on each state. The family is then faced with the challenge of finding living arrangements and employment to match the particular needs of their adult child, as well as the programs and facilities that can provide support services to achieve these goals.
Autistic savants
The autistic savant phenomenon is sometimes seen in autistic people. The term is used to describe a person who is autistic and has extreme talent in a certain area of study. Although there is a common association between savants and autism (an association created by the 1988 film Rain Man), most autistic people are not savants. Calendar calculators and fast programming skills are the most common form. Some famous examples are Daniel Tammet, the subject of the documentary film The Brain Man [32], and Kim Peek, the inspiration for Dustin Hoffman's character in the film Rain Man.
Other pervasive developmental disorders
Autism and Asperger's syndrome are just two of the five pervasive developmental disorders (PDDs). The three other pervasive developmental disorders are Rett syndrome, Childhood disintegrative disorder, and Pervasive developmental disorder not otherwise specified. Some of the these are related to autism, while some of them are entirely seperate conditions.
Rett syndrome
Rett syndrome is relatively rare, affecting almost exclusively females, one out of 10,000 to 15,000. After a period of normal development, sometime between 6 and 18 months, autism-like symptoms begin to appear. The little girl's mental and social development regresses; she no longer responds to her parents and pulls away from any social contact. If she has been talking, she stops; she cannot control her feet; she wrings her hands. Some of these early symptoms may be confused for autism. Some of the problems associated with Rett syndrome can be treated. Physical, occupational, and speech therapy can help with problems of coordination, movement, and speech.
Scientists sponsored by the National Institute of Child Health and Human Development have discovered that a mutation in the sequence of a single gene causes Rett syndrome, and can physically test for it with a 80% accuracy rate [33]. Rett syndrome in the past was sometimes classified as an autistic spectrum disorder, however most scientists agree that Rett syndrome is a developmental disorder and not part of the autistic spectrum [34].
Childhood disintegrative disorder
Childhood disintegrative disorder (CDD, and sometimes abbreviated as CHDD also) is a condition appearing in 3 or 4 year old children who have developed normally until age 2. Over several months, the child will deteriorate in intellectual, social, and language functioning from previously normal behaviour. This long period of normal development before regression helps differentiate CDD from Rett syndrome (and in fact it must be differentiated from autism in testing). The cause for CDD is unknown (thus it may be a spectrum disorder) but current evidence suggests it has something to do with the central nervous system [35] [36].
Pervasive developmental disorder not otherwise specified
Pervasive developmental disorder not otherwise specified, or PDD-NOS, is referred to as a subthreshold condition because it is a classification which is given to someone who suffers from impairments in social interaction, communication, and/or stereotyped behaviour but does not meet the criteria for one of the other four pervasive developmental disorders. Unlike the other four pervasive developmental disorders, PDD-NOS has no specific guidelines for diagnosis, so the person may have a lot of characteristics of an autistic person, or few to none at all. Note that pervasive developmental disorder is not a diagnosis, just a term to refer to the five mentioned conditions, while PDD-NOS is an official diagnosis [37].
