Autism spectrum disorder.pdf lecture notes

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Autism Spectrum Disorder (ASD) is a developmental condition that affects how a person communicates, interacts with others, and experiences the world. The term "autism" was first used by Eugen Bleuler in 1911 and was later described as a unique childhood condition by Leo Kanner in 1943 and Hans Asperger in 1944. Over time, what was once seen as several separate disorders is now understood as a spectrum that can range from mild to severe.

Currently, ASD includes what used to be called classic autism, Asperger’s syndrome, childhood disintegrative disorder, Rett syndrome, and pervasive developmental disorder–not otherwise specified. Today, all of these are categorized under the umbrella term "autism spectrum disorder," recognizing that every individual has a unique combination of strengths and challenges.

ASD is classified mainly by the degree of support a person needs:
- Level 1 (requiring support): Individuals may have difficulty starting social interactions but need minimal help.
- Level 2 (requiring substantial support): Individuals experience more pronounced issues with communication and flexibility.
- Level 3 (requiring very substantial support): Individuals have severe challenges in communication and behavior, often needing considerable assistance in daily life.

ASD typically shows up in early childhood and persists throughout life. Early signs may include limited eye contact, delayed speech, repetitive movements, and a strong preference for routines. While some people with ASD need significant support, others may live independently, and everyone with autism has their own strengths and ways of interacting with the world.

1. AUTISM SPECTRUM DISORDER
DEFINITION

Autism Spectrum Disorder (ASD) is a complex
neurodevelopmental disorder defined by deficits
in social interaction, communication, and the
presence of restricted interests and repetitive
behaviors. The "spectrum" emphasizes the wide
range of symptoms and presentations.
Historically, several subtypes (such as Asperger’s
Syndrome and PDD-NOS) were used, but these
have been merged under the single diagnostic
umbrella of ASD in major classification systems
(DSM-5, ICD-11).
Authoritative Definitions
DSM-5 Definition (American Psychiatric
Association):
ASD involves persistent deficits in social
communication and social interaction across
multiple contexts and restricted, repetitive
patterns of behavior, interests, or activities.
The criteria require symptoms to be present in
early development, cause clinically significant
impairment, and not be better explained by
intellectual disability or developmental delay.
ICD-11 Definition (World Health
Organization):
Autism Spectrum Disorder is characterized by
persistent deficits in the ability to initiate and
sustain reciprocal social interaction and social
communication, and by a range of restricted,
repetitive, and inflexible patterns of behavior,
interests, or activities that are clearly atypical
or excessive for the individual’s age and
sociocultural context. Symptoms typically
appear in early childhood but may manifest
later when social demands exceed capacities.
Historic Definitions and Key Authors
 Leo Kanner (1943):

The first systematic clinical description of
“autistic disturbances of affective contact.”
Kanner is credited as the founder of the
concept of “early infantile autism.”
In 1943, Leo Kanner published a landmark paper
titled "Autistic Disturbances of Affective
Contact," which is considered a seminal work in
the field of autism. This paper described 11
children with what Kanner termed "early infantile
autism," outlining key characteristics such as
social withdrawal, language difficulties, and a
strong desire for sameness. Kanner's work laid the
foundation for the understanding and diagnosis of
autism as a distinct neurodevelopmental
condition.

Here's a more detailed look at Kanner's 1943
paper:
Identification of "Early Infantile Autism":
Kanner's paper was the first systematic description
of what he called "early infantile autism," now
commonly known as autism spectrum disorder
(ASD).
Key Characteristics:
He identified several key features in the children
he studied, including:
1.Impairments in social interaction: A profound
lack of affective contact and an inability to relate
to others in the typical way.
2.Communication difficulties: Mutism or
language that did not seem intended for social
communication.
3. Obsessive desire for sameness: An intense
need to maintain routines and avoid changes in
their environment.
4. Fascination with objects: A strong focus on
objects rather than people.

Distinction from Schizophrenia:

2. While Eugen Bleuler had previously used the
term "autism" in relation to schizophrenia,
Kanner's work established autism as a separate
and distinct condition, not just a symptom of
another disorder.

Influence on Diagnostic Criteria:
Kanner's detailed descriptions formed the basis for
early diagnostic criteria for autism, influencing
how the condition has been understood and
diagnosed over time.
Legacy:
Kanner's work is considered a cornerstone of
autism research, paving the way for further
investigation into the causes, characteristics, and
potential interventions for individuals on the
autism spectrum.

Hans Asperger (1944): Described “autistic
psychopathy” in children (now generally included
under ASD in DSM-5 and ICD-11).

In 1944, Austrian pediatrician Hans Asperger
described a condition he called "autistic
psychopathy" in children, which is now largely
encompassed within the umbrella term
Autism Spectrum Disorder (ASD) as defined by
the DSM-5 and ICD-11. This condition
was characterized by social impairments,
repetitive behaviors, and specific, sometimes
intense, interests. While Asperger's work was not
widely recognized initially, it was later brought to
prominence by Lorna Wing and ultimately
integrated into the broader understanding of ASD.





Eugen Bleuler (1911):


A Swiss psychiatrist who first used the term
“autism” to describe symptoms of schizophrenia
— the term was later re-purposed.
Swiss psychiatrist Eugen Bleuler first introduced
the term “autism” in 1911 while describing a
symptom he observed in patients with
schizophrenia. He created the word from the
Greek “autos,” meaning “self,” to explain the
phenomenon where patients withdrew from
reality, becoming absorbed in their own internal
world and disconnected from external
surroundings.
In his landmark work, Bleuler described “autism”
as a core feature of schizophrenia, characterizing
it as a detachment from reality and a dominance of
inner fantasy life. It is important to note that
Bleuler’s use of the term was not intended to
indicate a childhood disorder, but instead a
symptom within severe adult psychiatric illness.
This meaning changed over time, as later
researchers began to notice a distinct
neurodevelopmental pattern in children. In the
early 1940s, Leo Kanner in the United States
described “early infantile autism,” focusing on
unique patterns of social withdrawal and
communication difficulties in children.

Around the same time, Hans Asperger in Austria
outlined a group of children with different but
related features, then called “autistic
psychopathy.” Their work shifted the meaning of
“autism” from a schizophrenia symptom to a
description of a developmental condition, which

3. has since evolved into the present-day diagnosis
of autism spectrum disorder.

This historical progression underscores how the
term “autism,” first coined for one psychiatric
context, was later redefined and re-purposed.
Today, “autism” and “autism spectrum disorder”
refer to a range of neurodevelopmental differences
that begin in childhood, centered on challenges in
social interaction, communication, and behavior,
with a highly variable presentation across
individuals.




History of Autism
 1943: Leo Kanner describes “autistic
disturbances of affective contact”.
 1944: Hans Asperger documents “autistic
psychopathy” in children.
 1980s–90s: Subtypes gain recognition in the
DSM.
 2013: DSM-5 unifies subtypes under ASD.


Etiology (Causes)
Genetic Causes
Genetic factors are currently considered the
predominant contributors to autism risk. Twin and
family studies consistently demonstrate a high
heritability rate for ASD, with estimates ranging
from about 64% to over 90%, and recent large
population-based studies place heritability around
80%. This means that roughly four-fifths of the
variation in autism risk in the population can be
attributed to inherited genetic influences.
Many genes—possibly over a thousand—have
been associated with autism risk. These include
both common variations that each exert small
effects and rare, sometimes syndromic, mutations
that have a larger impact. Examples of rare
genetic mutations linked to ASD include changes
in genes like SHANK3, CHD8, and ADNP,
among others. These mutations can sometimes
cause syndromes that have autism as part of a
broader clinical picture with intellectual disability
or distinctive physical features.
Twin studies find that identical twins (sharing
nearly all genes) have a very high concordance
rate (60–90%) for autism, whereas fraternal twins
(sharing about half their genes) show much lower
concordance, strongly supporting a genetic basis.
Additionally, having one autistic child in a family
increases the chances of autism in siblings by
about 25 times compared to the general
population, further reinforcing the genetic link.
Importantly, no single "autism gene" exists.
Instead, many genes contribute to risk, and in
most individuals with ASD, no single clear
genetic cause can be identified. The genetic
architecture involves complex interactions of
multiple gene variants, some inherited and some
arising de novo (new mutations not found in
parents).
Environmental Causes
While genetics carry the major share of risk,
environmental factors also play a significant role,
likely contributing to 10–40% of the variation in
ASD risk depending on the study. These are
mostly nonshared environmental influences,
meaning factors not common to all members of a
family.

Key environmental risk factors that have been
studied include:
 Parental Age: Advanced maternal and
paternal age at conception is associated
with increased autism risk. For example,
each 10-year increase in parental age may
increase risk by approximately 18–21%.
 Prenatal Exposures: Certain prenatal
conditions and exposures can modestly
increase risk. These include maternal
infections during pregnancy (e.g., rubella),

4. prenatal exposure to medications (like
valproate, used for epilepsy and bipolar
disorder), and potentially limited effects
from prenatal stress or toxic chemical
exposure.
 Birth Complications: Prematurity, low
birth weight, hypoxia (lack of oxygen) at
birth, and cesarean section delivery have
been linked, though these are less
consistent risk factors.
 Other Factors: Some studies examine
nutrition, environmental pollutants, and
maternal health conditions, but no causal
environmental factor has been definitively
proven to cause autism.
Importantly, extensive research has found no
credible evidence linking vaccines to autism, nor
support for factors like parenting style. The risk is
thought to arise primarily from genetic
predisposition interacting with specific prenatal
and perinatal environmental exposures.
Multifactorial and Idiopathic Nature
The current consensus is that autism arises
from a multifactorial etiology, meaning it
results from interactions between genetic
susceptibility and environmental influences
rather than a single cause. Many genetic
variants may increase sensitivity to
environmental factors, but the precise
mechanisms remain under active research.
Despite advances, for most individuals, the
exact cause of autism remains idiopathic—
unknown. This reflects the diverse genetic
backgrounds and environmental histories of
those with ASD.
Key Discoverers and Contributors to Etiology
Research
 Early genetic epidemiology and twin
studies in the late 20th century laid the
foundation for understanding autism’s
heritability.
 Researchers like Sir Michael Rutter
conducted seminal family and twin studies
that quantified genetic and environmental
contributions.
 Modern large-scale population studies
from collaborations involving Karolinska
Institutet (Sweden) and others have
employed extensive national registries to
refine heritability estimates and evaluate
maternal and environmental effects.
 Molecular genetics pioneers identified rare
mutations and copy number variations
associated with ASD (e.g., studies by
Christopher Walsh, Stephan Sanders).
 Epidemiologists such as Paul Chaste have
studied gene-environment interactions and
the impact of prenatal exposures.
Psychiatric genetics and neurodevelopmental
research continue to evolve, led by multi-
disciplinary teams worldwide integrating
genomics, epidemiology, and neuroscience.


Clinical Features, Characteristics, Signs,
and Symptoms
Autism typically involves persistent
challenges in interacting and communicating
with others. People with ASD often
experience difficulty with social-emotional
reciprocity, such as engaging in back-and-
forth conversation, sharing emotions, or
responding to social interactions. Nonverbal
communication may be affected, leading to
limited or unusual eye contact, facial
expressions, or gestures. Forming and
maintaining relationships may be
challenging, with individuals sometimes
struggling to make or keep friends or
showing little interest in their peers.

Repetitive patterns of behavior are often
seen, such as frequent hand-flapping,
rocking, or spinning. Some may repeat
words or phrases, a behavior known as
echolalia. Many people with autism insist on
routines and sameness in daily life,
becoming distressed by small changes.
Those with ASD may also develop highly
focused or unusual interests, sometimes
becoming absorbed by topics, objects, or
hobbies to the exclusion of others.

Sensory sensitivities are common: a child
or adult might be very sensitive or, in some
cases, largely unresponsive to certain
sounds, sights, textures, or other sensory
experiences.
Speech and language development can be
delayed or regress after a period of typical
development. Vocal tone may sound flat,
singsong, or otherwise unusual, and
imaginative play—like pretending—may be
limited or lacking.
Changes in environment or unfamiliar
experiences may be particularly hard to
tolerate, evoking strong emotional responses

5. or withdrawal. Motor skills might develop
more slowly, resulting in clumsy movement
or an awkward gait. Many display repetitive
play with objects, such as lining up items,
and some may injure themselves through
behaviors like head banging or self-biting
. Emotional responses may not always
match a situation, leading to unexpected
laughter, crying, or anxiety.
Some individuals have an uneven pattern of
abilities, with certain skills—such as
memory or calculation—much stronger than
others. It is not uncommon for people with
ASD to have other neurological or
psychiatric conditions, such as ADHD,
epilepsy, anxiety, or depression.
Characteristics Commonly Observed in ASD
Children and adults on the autism spectrum
may avoid or struggle to sustain eye contact.
Sometimes, they do not respond consistently
when their name is called.
Their facial expressions may be less varied
or seem disconnected from context.
Gestures like pointing or waving can be
limited, especially in early years. Many do
not readily share their interests or bring
items to show others.
Copying others’ actions or imitating
behaviors may occur less often.

Noticing when others are hurt, upset, or
seeking comfort might not come easily.
Playing with other children, especially
games that require cooperation or pretend
roles, can present unique challenges.
Solitary play is often preferred, with some
children repeatedly spinning, flapping their
hands, or playing in highly ritualized ways.
Fixed routines are very important to many,
and deviations can trigger distress. Toys
may be used repetitively, or focus may land
on just one part of a toy.

Intense interests are frequent, with topics or
collections commanding hours of attention.
Repetition often extends to speech,
including repeating favorite lines or phrases
from shows or people around them.
Uncommon attachments can develop toward
certain objects, which might need to
accompany the person everywhere. Sensory
processing may be heightened or
diminished, influencing reactions to loud
noise, certain clothing, or food textures.

Unusual eating behaviors might be noticed,
including strict preferences for food color,
temperature, or texture. Sleep does not
always come easily, and patterns may
become irregular. Physical development of
skills such as crawling, walking, or using
fine motor skills can be slower compared to
peers. Those on the spectrum may seem
unusually clumsy, or have difficulties with
actions that require coordination.
Behaviors sometimes include hyperactivity,
impulsiveness, or inattention. Reactions to
fear may differ; dangers may be overlooked
or benign things may cause disproportionate
alarm. Shifting from one activity or setting
to another can be tough and may result in
strong reactions.

Skills in reading social cues, such as
understanding tone or facial expressions, are
often underdeveloped. Mood shifts can be
frequent, and some experience notable
irritability. There may be overlapping
medical concerns, such as epilepsy or
gastrointestinal issues. Cognitive strengths
sometimes stand out—such as deep
memorization or advanced puzzle skills—
existing alongside areas of real challenge or
delay.
Diagnostic Investigations and Special
Tests
 Standardized diagnostic observation (e.g.,
ADOS-2, ADI-R, CARS, M-CHAT).

 Multidisciplinary psychological,
developmental, and medical assessment.
 Use of DSM-5 and ICD-11 criteria.

6.  Developmental, speech/language,
occupational therapy, and psychological
assessments.
 Ruling out genetic syndromes or metabolic
diseases when clinically indicated.
Expand with:
 Evidence supporting each tool, their
limitations, and interpretation.
 Discussion of differential diagnoses.



International Classification
Systems
 DSM-5 criteria: two domains (social
communication/interaction and
restricted/repetitive patterns).
 ICD-11: criteria matching DSM-5 in major
points.
 Discussion of past versions.
 How these systems are used in research,
clinical settings, and policy.
Include tables comparing key criteria.
Lifespan and Prognosis
 ASD is lifelong; symptom expression and
support needs shift with age.
 Early intervention, adaptive coping
strategies, and support improve quality of
life.
 Co-existing conditions (intellectual
disability, epilepsy, anxiety, depression)
affect prognosis.
 Transition to adulthood: employment,
relationships, independent living, and
community integration issues.
Discuss long-term studies and success
stories.
Assessment Forms/Tools
1. ADOS-2 (Autism Diagnostic Observation
Schedule, Second Edition)
2. ADI-R (Autism Diagnostic Interview –
Revised)
3. CARS (Childhood Autism Rating Scale)
4. M-CHAT (Modified Checklist for Autism
in Toddlers)
5. Social Communication Questionnaire
(SCQ)
6. Sensory processing, cognitive, adaptive
behavior scales
7. Detail the administration, scoring,
interpretation, and utility of each.

Treatment Modalities
Surgical
 No surgical treatment for ASD itself;
procedures may be necessary for unrelated
health issues.
Non-surgical
 Multimodal, individualized intervention
plans.
 Core: behavioral, developmental,
educational, and social interventions.
 Pharmacological for comorbidities (ADHD,
irritability, mood).
 Speech/language, occupational, social skills,
and physiotherapy.
Pharmacological
 Risperidone and aripiprazole for irritability.
 Off-label use: stimulants, SSRIs, melatonin,
antiepileptic drugs.
 No approved drug for core symptoms.
Educational and Therapy
Protocols
 Applied Behavior Analysis (ABA)
 TEACCH (Treatment and Education of
Autistic and Communication related
handicapped Children)
 PECS (Picture Exchange Communication
System)
 Early Start Denver Model (ESDM)
 Individualized Education Program (IEP)
process.

Physiotherapy, Speech, Occupational,
Cognitive Behavioral, Early Intervention
 Each protocol elaborated for age, symptom
profile, and outcome measurement.
 Protocols for assessment, goal-setting,
interventions, and monitoring.
 Parent- and teacher-implemented programs.
Do’s and Don’ts
 List common-sense and evidence-based
behavioral and environmental interventions,
daily routines, language strategies, and
family support approaches.
 Avoid controversial or disproven methods.
Government Schemes
 Outline principal schemes and disability
laws (India: RPwD, National Trust Act,
U.S.: IDEA, Medicaid, etc.).
 Coverage for education, therapy, disability
pensions, travel, inclusion.
 Achievements and areas needing advocacy.

7. References (APA Format)

 American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th
ed.). Washington, DC: Author.
 Volkmar, F. R., & Wiesner, L. A. (2017). A Practical Guide to Autism: What Every Parent, Family
Member, and Teacher Needs to Know. Wiley.
 Lord, C., Elsabbagh, M., Baird, G., & Veenstra-Vanderweele, J. (2018). Autism spectrum disorder.
The Lancet, 392(10146), 508-520. https://doi.org/10.1016/S0140-6736(18)31129-2
 Mohammadi, M.-R. (Ed.). (2011). A comprehensive book on autism spectrum disorders. InTech.
http://www.autismforthvalley.co.uk/files/7314/4595/7855/A_Comprehensive_Book_on_Autism_Spe
ctrum_Disorders_2011.pdf
 Matson, J. L. (Ed.). (2016). Handbook of autism and pervasive developmental disorders. Springer.
 National Institute for Health and Care Excellence. (2021). Autism spectrum disorder in under 19s:
recognition, referral and diagnosis (NICE guideline CG128).
1. http://www.autismforthvalley.co.uk/files/7314/4595/7855/A_Comprehensive_Book_on_Autism_Spe
ctrum_Disorders_2011.pdf
2. https://www.ncbi.nlm.nih.gov/books/NBK525976/
3. https://link.springer.com/book/10.1007/978-3-319-40904-7
4. https://directory.doabooks.org/handle/20.500.12854/129040