| Autism spectrum | |
|---|---|
| Other names | Autism spectrum disorder (ASD), autism spectrum condition (ASC) |
 | |
| Repetitively stacking or lining up objects is associated with autism. | |
| Specialty | Psychiatry |
| Symptoms | Problems with communication, social interaction, restricted interests, repetitive behavior |
| Complications | Social isolation, employment problems, family stress, bullying |
| Usual onset | By the age of 3 years |
| Risk factors | Advanced parental age, exposure to valproate during pregnancy, low birth weight |
| Diagnostic method | Based on symptoms |
| Differential diagnosis | Intellectual disability, Rett syndrome, ADHD, selective mutism, childhood-onset schizophrenia |
| Treatment | Behavioral therapy, psychotropic medication |
| Frequency | 1% of people (62.2 million 2015) |
Autism spectrum, also known as autism spectrum disorder (ASD), is a range of mental disorders of the neurodevelopmental type. It includes autism and Asperger syndrome. Individuals on the spectrum often experience difficulties with social communication and interaction; and restricted, repetitive patterns of behavior, interests or activities. Symptoms are typically recognized between one and two years of age. Long-term problems may include difficulties in performing daily tasks, creating and keeping relationships, and maintaining a job.
The cause of autism spectrum is uncertain. Risk factors include having an older parent, a family history of autism, and certain genetic conditions. It is estimated that between 64% and 91% of risk is due to family history. Diagnosis is based on symptoms. The DSM-5 redefined the autism spectrum disorders to encompass the previous diagnoses of autism, Asperger syndrome, pervasive developmental disorder not otherwise specified (PDD-NOS), and childhood disintegrative disorder.
Treatment efforts are generally individualized, and can include behavioural therapy, and the teaching of coping skills. Medications may be used to try to help improve symptoms. Evidence to support the use of medications, however, is not very strong.
Autism spectrum is estimated to affect about 1% of people (62.2 million globally as of 2015). Males are diagnosed more often than females. The term "spectrum" can refer to the range of symptoms or their severity, leading some to favor a distinction between severely disabled autistics who cannot speak or look after themselves, and higher functioning autistics.
Classification
In the United States, a revision to autism spectrum disorder (ASD) was presented in the Diagnostic and Statistical Manual of Mental Disorders version 5 (DSM-5), released May 2013. The new diagnosis encompasses previous diagnoses of autistic disorder, Asperger syndrome,
childhood disintegrative disorder, and PDD-NOS. Compared with the
DSM-IV diagnosis of autistic disorder, the DSM-5 diagnosis of ASD no
longer includes communication as a separate criterion, and has merged
social interaction and communication into one category. Slightly different diagnostic definitions are used in other countries. For example, the ICD-10 is the most commonly-used diagnostic manual in the UK and European Union.
Rather than categorizing these diagnoses, the DSM-5 has adopted a
dimensional approach to diagnosing disorders that fall underneath the
autism spectrum umbrella. Some have proposed that individuals on the
autism spectrum may be better represented as a single diagnostic
category. Within this category, the DSM-5 has proposed a framework of
differentiating each individual by dimensions of severity, as well as
associated features (i.e., known genetic disorders, and intellectual
disability).
Another change to the DSM includes collapsing social and
communication deficits into one domain. Thus, an individual with an ASD
diagnosis will be described in terms of severity of social communication
symptoms, severity of fixated or restricted behaviors or interests,
hyper- or hyposensitivity to sensory stimuli, and associated features.
The restricting of onset age has also been loosened from 3 years of age
to "early developmental period", with a note that symptoms may manifest
later when social demands exceed capabilities.
Autism forms the core of the autism spectrum disorders. Asperger syndrome is closest to autism in signs and likely causes; unlike autism, people with Asperger syndrome usually have no significant delay in language development, according to the older DSM-IV criteria. PDD-NOS is diagnosed when the criteria are not met for a more specific disorder. Some sources also include Rett syndrome and childhood disintegrative disorder,
which share several signs with autism but may have unrelated causes;
other sources differentiate them from ASD, but group all of the above
conditions into the pervasive developmental disorders.
Autism, Asperger syndrome, and PDD-NOS are sometimes called the autistic disorders instead of ASD, whereas autism itself is often called autistic disorder, childhood autism, or infantile autism. Although the older term pervasive developmental disorder and the newer term autism spectrum disorder largely or entirely overlap, the earlier was intended to describe a specific set of diagnostic labels, whereas the latter refers to a postulated spectrum disorder linking various conditions. ASD is a subset of the broader autism phenotype (BAP), which describes individuals who may not have ASD but do have autistic-like traits, such as avoiding eye contact.
Signs and symptoms
Autism
is characterized by persistent deficits in social communication and
interaction across multiple contexts, as well as restricted, repetitive
patterns of behavior, interests, or activities. These deficits are
present in early childhood, and lead to clinically significant
functional impairment. There is also a unique form of autism called autistic savantism, where a child can display outstanding skills in music, art, and numbers with no practice.
Because of its relevance to different populations, self-injurious
behaviors (SIB) are not considered a core characteristic of the ASD
population however approximately 50% of those with ASD take part in some
type of SIB (head-banging, self-biting) and are more at risk than other
groups with developmental disabilities.
Other characteristics of ASD include restricted and repetitive
behaviors (RRBs) which include a large range of specific gestures and
acts, it can even include certain behavioral traits as defined in the
Diagnostic and Statistic Manual for Mental Disorders.
Asperger syndrome was distinguished from autism in the DSM-IV by the lack of delay or deviance in early language development. Additionally, individuals diagnosed with Asperger syndrome did not have significant cognitive delays. PDD-NOS
was considered "subthreshold autism" and "atypical autism" because it
was often characterized by milder symptoms of autism or symptoms in only
one domain (such as social difficulties).
The DSM-5 eliminated the four separate diagnoses: Asperger Syndrome,
Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS),
Childhood Disintegrative Disorder, and Autistic Disorder and combined
them under the diagnosis of Autism Spectrum Disorder.
Behavioral characteristics
Autism
spectrum disorders include a wide variety of characteristics. Some of
these include behavioral characteristics which widely range from slow
development of social and learning skills to difficulties creating
connections with other people. They may develop these difficulties of
creating connections due to anxiety or depression, which people with
autism are more likely to experience, and as a result isolate
themselves.
Other behavioral characteristics include abnormal responses to
sensations including sights, sounds, touch, and smell, and problems
keeping a consistent speech rhythm. The latter problem influences an
individual's social skills, leading to potential problems in how they
are understood by communication partners. Behavioral characteristics
displayed by those with autism spectrum disorder typically influence
development, language, and social competence. Behavioral characteristics
of those with autism spectrum disorder can be observed as perceptual
disturbances, disturbances of development rate, relating, speech and
language, and motility.
Developmental course
Autism
spectrum disorders are thought to follow two possible developmental
courses, although most parents report that symptom onset occurred within
the first year of life.
One course of development is more gradual in nature, in which parents
report concerns in development over the first two years of life and
diagnosis is made around 3–4 years of age. Some of the early signs of
ASDs in this course include decreased looking at faces, failure to turn
when name is called, failure to show interests by showing or pointing,
and delayed imaginative play.
A second course of development is characterized by normal or
near-normal development followed by loss of skills or regression in the
first 2–3 years. Regression may occur in a variety of domains, including
communication, social, cognitive, and self-help skills; however, the
most common regression is loss of language.
There continues to be a debate over the differential outcomes
based on these two developmental courses. Some studies suggest that
regression is associated with poorer outcomes and others report no
differences between those with early gradual onset and those who
experience a regression period.
While there is conflicting evidence surrounding language outcomes in
ASD, some studies have shown that cognitive and language abilities at
age 2 1⁄2 may help predict language proficiency and production after age 5. Overall, the literature stresses the importance of early intervention in achieving positive longitudinal outcomes.
Social skills
Social
skills present the most challenges for individuals with ASD. This leads
to problems with friendships, romantic relationships, daily living, and
vocational success.
Marriages are less common for those with ASD. Many of these challenges
are linked to their atypical patterns of behavior and communication. It
is common for children and adults with autism to struggle with social
interactions because they are unable to relate to their peers.
All of these issues stem from cognitive impairments. Difficulty in this
thought process is called "theory of the mind" or mind blindness which
means that the mind has difficulty with thought process as well as being
aware of what is going on around them. Theory of mind is closely related to the pragmatic difficulties children with autism experience.
Communication skills
Communication deficits are generally characterized by impairments regarding joint attention and social reciprocity, challenges with verbal language cues, and poor nonverbal communication skills such as lack of eye contact and meaningful gestures and facial expressions.
Language behaviors typically seen in children with autism may include
repetitive or rigid language, specific interests in conversation, and
atypical language development. ASD is a complex pragmatic language disorder which influences communication skills significantly.
Many children with ASD develop language skills at an uneven pace where
they easily acquire some aspects of communication, while never fully
developing other aspects. In some cases, individuals remain completely nonverbal throughout their lives, although the accompanying levels of literacy and nonverbal communication skills vary.
They may not pick up on body language or social cues such as eye
contact and facial expressions if they provide more information than the
person can process at that time. Similarly, they have trouble
recognizing subtle expressions of emotion and identifying what various
emotions mean for the conversation. They struggle with understanding the
context and subtext of conversational or printed situations, and have
trouble forming resulting conclusions about the content. This also
results in a lack of social awareness and atypical language expression.
It is also common for individuals with ASD to communicate strong
interest in a specific topic, speaking in lesson-like monologues about
their passion instead of enabling reciprocal communication with whomever
they are speaking to.
What looks like self-involvement or indifference toward others stems
from a struggle to recognize or remember that other people have their
own personalities, perspectives, and interests. The ability to be focused in on one topic in communication is known as monotropism, and can be compared to "tunnel vision" in the mind for those individuals with ASD.
Language expression by those on the autism spectrum is often
characterized by repetitive and rigid language. Often children with ASD
repeat certain words, numbers, or phrases during an interaction, words
unrelated to the topic of conversation. They can also exhibit a
condition called echolalia in which they respond to a question by repeating the inquiry instead of answering.
However, this repetition can be a form of meaningful communication, a
way that individuals with ASD try to express a lack of understanding or
knowledge regarding the answer to the question.
Causes
While specific causes of autism spectrum disorders have yet to be
found, many risk factors identified in the research literature may
contribute to their development. These risk factors include genetics,
prenatal and perinatal factors, neuroanatomical abnormalities, and
environmental factors. It is possible to identify general risk factors,
but much more difficult to pinpoint specific factors. Given the current
state of knowledge, prediction can only be of a global nature and
therefore requires the use of general markers.
Genetic risk factors
As
of 2018, understanding of genetic risk factors had shifted from a focus
on a few alleles, to an understanding that genetic involvement in ASD
is probably diffuse, depending on a large number of variants, some of
which are common and have a small effect, and some of which are rare and
have a large effect. The most common gene disrupted with large effect
rare variants appeared to be CHD8, but less than 0.5% of people with ASD have such a mutation. Some ASD is associated with clearly genetic conditions, like fragile X syndrome; however only around 2% of people with ASD have fragile X.
As of 2018, it appeared that somewhere between 74% and 93% of ASD
risk is heritable and that after an older child is diagnosed with ASD,
7–20% of subsequent children are likely to be as well.
If parents have a child with ASD they have a 2% to 8% chance of having a
second child with ASD. If the child with ASD is an identical twin the
other will be affected 36 to 95 percent of the time. If they are
fraternal twins the other will only be affected up to 31 percent of the
time.
Some of the alterations that contribute to the development of the
autistic spectrum: SNVs (single-nucleotide variations), indels
(insertions-deletions) and SVs (structural variants). These associations
have been identified through whole-genome studies, such as WGS
(whole-genome sequencing) and GWAS (genome-wide analysis association
studies).
In early onset disorders, such as autism, de novo mutations have
been identified as risk factors. One study has identified 64 SNVs and 5
indels de novo on average. By performing an analysis of these variants,
comparing cases and controls, considering SNVs and indels in 179 genes
associated with autism or close to them, studies observed that the
relative risk of missense mutations or variants in promoter regions and
UTR (untranslated region), increases versus controls.
The identification of SVs has been very useful too, since
structural alterations in the chromosomes are able to rearrange the
genome, altering its functionality, depending on the size and the region
they affect.
After the analysis, 98,785 SVs were identified, with an average of 5,843 variants per individual: 171 SVs were de novo,
more frequent in the germ line. Some of these variants affected genes
associated with autism, such as the GRIN2B gene, balanced translocation,
or the deletion of exons 8, 9, and 10 of the CHD2 gene.
No significant differences were observed regarding the size of
certain rearrangements in cases and controls, though a slight increase
in number was observed for cases relative to controls.
All these genetic variants contribute to the development of the
autistic spectrum, however, it can not be guaranteed that they are
determinants for the development.
Prenatal and perinatal risk factors
Several
prenatal and perinatal complications have been reported as possible
risk factors for autism. These risk factors include maternal gestational diabetes, maternal and paternal age over 30, bleeding after first trimester, use of prescription medication (e.g. valproate) during pregnancy, and meconium in the amniotic fluid.
While research is not conclusive on the relation of these factors to
autism, each of these factors has been identified more frequently in
children with autism, compared to their siblings who do not have autism,
and other typically developing youth. While it is unclear if any single factors during the prenatal phase affect the risk of autism, complications during pregnancy may be a risk.
Low vitamin D levels in early development has been hypothesized as a risk factor for autism.
Disproven vaccine hypothesis
In 1998 Andrew Wakefield led a fraudulent study that suggested that the MMR vaccine may cause autism. This conjecture suggested that autism results from brain damage caused either by the MMR vaccine itself, or by thimerosal, a vaccine preservative.
No convincing scientific evidence supports these claims, and further
evidence continues to refute them, including the observation that the
rate of autism continues to climb despite elimination of thimerosal from
routine childhood vaccines.
A 2014 meta-analysis examined ten major studies on autism and vaccines
involving 1.25 million children worldwide; it concluded that neither the
MMR vaccine, which has never contained thimerosal, nor the vaccine components thimerosal or mercury, lead to the development of ASDs.
Pathophysiology
In general, neuroanatomical studies support the concept that autism
may involve a combination of brain enlargement in some areas and
reduction in others.
These studies suggest that autism may be caused by abnormal neuronal
growth and pruning during the early stages of prenatal and postnatal
brain development, leaving some areas of the brain with too many neurons
and other areas with too few neurons.
Some research has reported an overall brain enlargement in autism,
while others suggest abnormalities in several areas of the brain,
including the frontal lobe, the mirror neuron system, the limbic system,
the temporal lobe, and the corpus callosum.
In functional neuroimaging studies, when performing theory of mind and facial emotion response tasks, the median person on the autism spectrum exhibits less activation in the primary and secondary somatosensory cortices of the brain than the median member of a properly sampled control population. This finding coincides with reports demonstrating abnormal patterns of cortical thickness and grey matter volume in those regions of autistic persons' brains.
Mirror neuron system
The mirror neuron system (MNS) consists of a network of brain areas that have been associated with empathy processes in humans. In humans, the MNS has been identified in the inferior frontal gyrus (IFG) and the inferior parietal lobule (IPL) and is thought to be activated during imitation or observation of behaviors.
The connection between mirror neuron dysfunction and autism is
tentative, and it remains to be seen how mirror neurons may be related
to many of the important characteristics of autism.
"Social brain" interconnectivity
A
number of discrete brain regions and networks among regions that are
involved in dealing with other people have been discussed together under
the rubric of the "social brain". As of 2012, there was a consensus
that autism spectrum is likely related to problems with
interconnectivity among these regions and networks, rather than problems
with any specific region or network.
Temporal lobe
Functions of the temporal lobe are related to many of the deficits observed in individuals with ASDs, such as receptive language, social cognition, joint attention, action observation, and empathy. The temporal lobe also contains the superior temporal sulcus (STS) and the fusiform face area
(FFA), which may mediate facial processing. It has been argued that
dysfunction in the STS underlies the social deficits that characterize
autism. Compared to typically developing individuals, one fMRI study
found that individuals with high-functioning autism had reduced activity in the FFA when viewing pictures of faces.
Mitochondrial dysfunction
It has been suggested that ASD could be linked to mitochondrial disease (MD), a basic cellular abnormality with the potential to cause disturbances in a wide range of body systems. A recent meta-analysis
study, as well as other population studies have shown that
approximately 5% of children with ASD meet the criteria for classical
MD. It is unclear why the MD occurs considering that only 23% of children with both ASD and MD present with mitochondrial DNA (mtDNA) abnormalities.
Serotonin
It has been hypothesized that increased activity of serotonin
in the developing brain may facilitate the onset of autism spectrum
disorder, with an association found in six out of eight studies between
the use of selective serotonin reuptake inhibitors
(SSRIs) by the pregnant mother and the development of ASD by the child
exposed to SSRI in the antenatal environment. The study could not
definitively conclude SSRIs caused the increased risk for ASDs due to
the biases found in those studies, and the authors called for more
definitive, better conducted studies.
Diagnosis
Evidence-based assessment
ASD can be detected as early as 18 months or even younger in some cases. A reliable diagnosis can usually be made by the age of two years.
The diverse expressions of ASD symptoms pose diagnostic challenges to
clinicians. Individuals with an ASD may present at various times of
development (e.g., toddler, child, or adolescent), and symptom
expression may vary over the course of development.
Furthermore, clinicians must differentiate among pervasive
developmental disorders, and may also consider similar conditions,
including intellectual disability not associated with a pervasive developmental disorder, specific language disorders, ADHD, anxiety, and psychotic disorders.
Considering the unique challenges in diagnosing ASD, specific practice parameters for its assessment have been published by the American Academy of Neurology, the American Academy of Child and Adolescent Psychiatry, and a consensus panel with representation from various professional societies.
The practice parameters outlined by these societies include an initial
screening of children by general practitioners (i.e., "Level 1
screening") and for children who fail the initial screening, a
comprehensive diagnostic assessment by experienced clinicians (i.e.
"Level 2 evaluation"). Furthermore, it has been suggested that
assessments of children with suspected ASD be evaluated within a
developmental framework, include multiple informants (e.g., parents and
teachers) from diverse contexts (e.g., home and school), and employ a
multidisciplinary team of professionals (e.g., clinical psychologists,
neuropsychologists, and psychiatrists).
After a child shows initial evidence of ASD tendencies,
psychologists administer various psychological assessment tools to
assess for ASD.
Among these measurements, the Autism Diagnostic Interview-Revised
(ADI-R) and the Autism Diagnostic Observation Schedule (ADOS) are
considered the "gold standards" for assessing autistic children.
The ADI-R is a semi-structured parent interview that probes for
symptoms of autism by evaluating a child's current behavior and
developmental history. The ADOS is a semistructured interactive
evaluation of ASD symptoms that is used to measure social and
communication abilities by eliciting several opportunities (or
"presses") for spontaneous behaviors (e.g., eye contact) in standardized
context. Various other questionnaires (e.g., The Childhood Autism
Rating Scale, Autism Treatment Evaluation Checklist)
and tests of cognitive functioning (e.g., The Peabody Picture
Vocabulary Test) are typically included in an ASD assessment battery.
In the UK, there is some diagnostic use of the Diagnostic Interview for Social and Communication Disorders (DISCO) which was developed for use at The Centre for Social and Communication Disorders, by Lorna Wing
and Judith Gould, as both a clinical and a research instrument for use
with children and adults of any age. The DISCO is designed to elicit a
picture of the whole person through the story of their development and
behavior. In clinical work, the primary purpose is to facilitate
understanding of the pattern over time of the specific skills and
impairments that underlie the overt behavior. If no information is
available, the clinician has to obtain as much information as possible
concerning the details of current skills and pattern of behavior of the
person. This type of dimensional approach to clinical description is
useful for prescribing treatment.
Comorbidity
Autism spectrum disorders tend to be highly comorbid with other disorders. Comorbidity
may increase with age and may worsen the course of youth with ASDs and
make intervention/treatment more difficult. Distinguishing between ASDs
and other diagnoses can be challenging, because the traits of ASDs often
overlap with symptoms of other disorders, and the characteristics of
ASDs make traditional diagnostic procedures difficult.
The most common medical condition occurring in individuals with autism spectrum disorders is seizure disorder or epilepsy, which occurs in 11-39% of individuals with ASD. Tuberous sclerosis,
a medical condition in which non-malignant tumors grow in the brain and
on other vital organs, occurs in 1-4% of individuals with ASDs.
Intellectual disabilities are some of the most common comorbid
disorders with ASDs. Recent estimates suggest that 40-69% of individuals
with ASD have some degree of an intellectual disability,
more likely to be severe for females. A number of genetic syndromes
causing intellectual disability may also be comorbid with ASD, including
fragile X syndrome, Down syndrome, Prader-Willi and Angelman syndromes, and Williams syndrome.
Learning disabilities
are also highly comorbid in individuals with an ASD. Approximately
25-75% of individuals with an ASD also have some degree of a learning
disability.
Various anxiety disorders tend to co-occur with autism spectrum disorders, with overall comorbidity rates of 7-84%. Rates of comorbid depression in individuals with an ASD range from 4-58%. The relationship between ASD and schizophrenia
remains a controversial subject under continued investigation, and
recent meta-analyses have examined genetic, environmental, infectious,
and immune risk factors that may be shared between the two conditions.
Deficits in ASD are often linked to behavior problems, such as
difficulties following directions, being cooperative, and doing things
on other people's terms. Symptoms similar to those of attention deficit hyperactivity disorder (ADHD) can be part of an ASD diagnosis.
Sensory processing disorder is also comorbid with ASD, with comorbidity rates of 42-88%.
Treatment
There is no known cure for autism, although those with Asperger syndrome and those who have autism and require little-to-no support are more likely to experience a lessening of symptoms over time. The main goals of treatment are to lessen associated deficits and family distress, and to increase quality of life
and functional independence. In general, higher IQs are correlated with
greater responsiveness to treatment and improved treatment outcomes.
Although evidence-based interventions for autistic children vary in
their methods, many adopt a psychoeducational approach to enhancing
cognitive, communication, and social skills while minimizing problem
behaviors. It has been argued that no single treatment is best and
treatment is typically tailored to the child's needs.
Intensive, sustained special education programs and behavior therapy early in life can help children acquire self-care, social, and job skills. Available approaches include applied behavior analysis, developmental models, structured teaching, speech and language therapy, social skills therapy, and occupational therapy.
Among these approaches, interventions either treat autistic features
comprehensively, or focus treatment on a specific area of deficit.
Generally, when educating those with autism, specific tactics may be
used to effectively relay information to these individuals. Using as
much social interaction as possible is key in targeting the inhibition
autistic individuals experience concerning person-to-person contact.
Additionally, research has shown that employing semantic groupings,
which involves assigning words to typical conceptual categories, can be
beneficial in fostering learning.
There has been increasing attention to the development of
evidence-based interventions for young children with ASD. Two
theoretical frameworks outlined for early childhood intervention include
applied behavioral analysis (ABA) and the developmental social-pragmatic model (DSP).
Although ABA therapy has a strong evidence base, particularly in regard
to early intensive home-based therapy, ABA's effectiveness may be
limited by diagnostic severity and IQ of the person affected by ASD.
The Journal of Clinical Child and Adolescent Psychology has deemed two
early childhood interventions as "well-established": individual
comprehensive ABA, and focused teacher-implemented ABA combined with DSP.
Another evidence-based intervention that has demonstrated efficacy is a parent training model, which teaches parents how to implement various ABA and DSP techniques themselves. Various DSP programs have been developed to explicitly deliver intervention systems through at-home parent implementation.
A multitude of unresearched alternative therapies have also been
implemented. Many have resulted in harm to autistic people and should
not be employed unless proven to be safe.
In October 2015, the American Academy of Pediatrics (AAP)
proposed new evidence-based recommendations for early interventions in
ASD for children under 3.
These recommendations emphasize early involvement with both
developmental and behavioral methods, support by and for parents and
caregivers, and a focus on both the core and associated symptoms of ASD.
Epidemiology
The U.S. Center for Disease Control's most recent estimate is that 1
out of every 68 children, or 14.7 per 1,000, are affected by some form
of ASD as of 2010. Reviews tend to estimate a prevalence of 6 per 1,000 for autism spectrum disorders as a whole,
although prevalence rates vary for each of the developmental disorders
in the spectrum. Autism prevalence has been estimated at 1-2 per 1,000,
Asperger syndrome at roughly 0.6 per 1,000, childhood disintegrative
disorder at 0.02 per 1,000, and PDD-NOS at 3.7 per 1,000. These rates are consistent across cultures and ethnic groups, as autism is considered a universal disorder.
While rates of autism spectrum disorders are consistent across
cultures, they vary greatly by gender, with boys affected far more
frequently than girls. The average male-to-female ratio for ASDs is
4.2:1, affecting 1 in 70 boys, but only 1 in 315 girls.
Girls, however, are more likely to have associated cognitive
impairment. Among those with an ASD and intellectual disability, the sex
ratio may be closer to 2:1. Prevalence differences may be a result of gender differences in expression of clinical symptoms, with women and girls with autism showing less atypical behaviors and, therefore, less likely to receive an ASD diagnosis.
History
Controversies have surrounded various claims regarding the etiology of autism spectrum disorders. In the 1950s, the "refrigerator mother theory"
emerged as an explanation for autism. The hypothesis was based on the
idea that autistic behaviors stem from the emotional frigidity, lack of
warmth, and cold, distant, rejecting demeanor of a child's mother.
Naturally, parents of children with an autism spectrum disorder
suffered from blame, guilt, and self-doubt, especially as the theory was
embraced by the medical establishment and went largely unchallenged
into the mid-1960s. The "refrigerator mother" theory has since continued
to be refuted in scientific literature, including a 2015 systematic
review which showed no association between caregiver interaction and
language outcomes in ASD.
Another controversial claim suggests that watching extensive
amounts of television may cause autism. This hypothesis was largely
based on research suggesting that the increasing rates of autism in the
1970s and 1980s were linked to the growth of cable television at this
time.
Caregivers
Families
who care for an autistic child face added stress from a number of
different causes. Parents may struggle to understand the diagnosis and
to find appropriate care options. Parents often take a negative view of
the diagnosis, and may struggle emotionally. In the words of one parent
whose two children were both diagnosed with autism, "In the moment of
diagnosis, it feels like the death of your hopes and dreams."
More than half of parents over the age of 50 are still living with
their child as about 85% of people with ASD have difficulties living
independently.
Autism rights movement
The autism rights movement is a social movement within the context of disability rights that emphasizes the concept of neurodiversity, viewing the autism spectrum as a result of natural variations in the human brain rather than a disorder to be cured.
The autism rights movement advocates for including greater acceptance
of autistic behaviors; therapies that focus on coping skills rather than
imitating the behaviors of those without autism; 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:
the medical perspective, that autism is caused by a genetic defect and
should be addressed by targeting the autism gene(s), and fringe theories that autism is caused by environmental factors such as vaccines. A common criticism against autistic activists is that the majority of them are "high-functioning" or have Asperger syndrome and do not represent the views of "low-functioning" autistic people.
Academic performance
The
number of students identified and served as eligible for autism
services in the United States has increased from 5,413 children in
1991-1992 to 370,011 children in the 2010-2011 academic school year. The United States Department of Health and Human Services
reported approximately 1 in 68 children at age 8 are diagnosed with
autism spectrum disorder (ASD) although onset is typically between ages 2
and 4.
The increasing number of students with ASD in the schools presents significant challenges to teachers, school psychologists, and other school professionals.
These challenges include developing a consistent practice that best
support the social and cognitive development of the increasing number of
students with ASD.
Although there is considerable research addressing assessment,
identification, and support services for children with ASD, there is a
need for further research focused on these topics within the school
context.
Further research on appropriate support services for students with ASD
will provide school psychologists and other education professionals with
specific directions for advocacy and service delivery that aim to
enhance school outcomes for students with ASD.
Attempts to identify and use best intervention practices for
students with autism also pose a challenge due to overdependence on
popular or well-known interventions and curricula.
Some evidence suggests that although these interventions work for some
students, there remains a lack of specificity for which type of student,
under what environmental conditions (one-on-one, specialized
instruction or general education) and for which targeted deficits they
work best.
More research is needed to identify what assessment methods are most
effective for identifying the level of educational needs for students
with ASD.
A difficulty for academic performance in students with ASD, is the tendency to generalize learning.
Learning is different for each student, which is the same for students
with ASD. To assist in learning, accommodations are commonly put into
place for students with differing abilities. The existing schema of
these students works in different ways and can be adjusted to best
support the educational development for each student.
Employment
About half of autistics are unemployed, and one third of those with graduate degrees may be unemployed.
Among those on the autism spectrum who find work, most are employed in
sheltered settings working for wages below the national minimum.
While employers state hiring concerns about productivity and
supervision, experienced employers of autistics give positive reports of
above average memory and detail orientation as well as a high regard
for rules and procedure in autistic employees. A majority of the economic burden of autism is caused by lost productivity in the job market. Some studies also find decreased earning among parents who care for autistic children.
Adding content related to autism in existing diversity training can
clarify misconceptions, support employees, and help provide new
opportunities for autistics.
