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Autism Spectrum Disorder & Schizophrenia are characterized by pervasive problems in social,
emotional, and cognitive functioning that have a basis in neurobiological abnormality
o These disorders in youth are now considered distinct from each other
A BIT OF HISTORY
Historically, these disorders were associated with adult psychoses—that is, severely disruptive
disturbances implying abnormal perceptions of reality.
Psychotic disturbances were noted in early 20 century classifications of mental disorders based on
Bleuler applied the term “schizophrenias” to these disorders, which involve disturbances in reality, such
as hearing voices and seeing images that do not exist.
Ideas about psychoses & other severe disturbances developed gradually over many years.
Some investigators described groups of children with early onset of schizophrenia, and others pointed to
syndromes that appeared similar, but not identical, to schizophrenia
o Various diagnostic terms were applied, such as disintegrative psychoses & childhood psychoses
Around 1930 and several yrs afterward, childhood schizophrenia served as a general label for many
severe early occurring disturbances
In 1943, Kanner described what he called “early infantile autism,” arguing that it was different from
other cases of severe disturbance, which generally had later onset. Shortly after, Hans Asperger
described a group of children whose symptoms overlapped with Kanner’s cases.
o These two men were unaware of each other—they believed they were writing about different
types of disturbances (Currently autism & Asperger’s disorder are viewed as similar
By early 1970, data from several countries showed that severe disturbances in youth were age related
o A large number of cases appeared before age 3, very few cases during childhood, and prevalence
increased in adolescence àthis suggested that different syndromes might underlie that earlier-
occurring & later-occurring disturbances.
Gradually (using symptoms & other features) a distinction was made btw schizophrenia and a group of
non-psychotic disturbances of youth.
o Schizophrenia affects a small number of children, rises in frequency in adolescence, and
increases more in early adulthood.
Autism & Asperger’s disorder are among non-psychotic disorders that appear early in life and have
pervasive affects on development.
o Both appear in the DSM-IV-TR category of Pervasive Developmental Disorders (PDD)
o Childhood Disintegrative Disorder, Rett’s Disorder, and PDD-NOS were also included
o These disorders display similar characteristics to varying degrees
o It has been argued that Rett’s Disorder stands out as notably different from the others
o Autism (most severe), Aperger’s, and PDD-NOS are now widely viewed as falling on a continuum
o Youth with any of these 3 diagnosis are said to display autism spectrum disorder (ASD), and they
are often considered together in research & clinical applications
AUTISTIC DISORDER (Autism)
DSM CLASSIFICATION AND DIAGNOSIS
Kanner’s early description of autism emphasized that the fundamental disturbance was an inability to
relate to people and situations from the beginning of life.
Although not all of Kanner’s observations proved accurate, most the characteristics described
(communication deficits, good but atypical cognitive potential, and behavioral problems such as
obsessiveness, repetitious actions, and unimaginative play).
The primary symptoms of autistic disorder (Table 12.1 pg 315) are impaired social interaction,
disturbed communication, and the presence of restrictive, repetitive behaviors and interests.
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Diagnosis requires a total of at least six items, w/ all 3 features (qualitative impairments in social
interaction, in communication, and restricted repetitive & stereotyped patterns of behavior, interests,
and activities) present. Onset must occur prior to age 3.
DESCRIPTION: PRIMARY FEATURES
Youngsters with the disorder can appear remarkably different from each other, in both the core
symptoms and in the severity of problems. Not all display all features, and there is variation in the extent
to which their behavior appears deviant from normal or disrupts their lives.
Children w/ autism show few symptoms at 6 months, but many show subtle differences from typically
developing infants before 12 months
Very young children are less likely to be visually responsive, less likely to respond to their names, and
more likely to show aversion to being touched by another person.
o They fail to track people visually, avoid eye contact, exhibit an “empty” gaze, fail to respond to
others with emotional expression and positive affect, and show little interest in being held.
6 months: Children with autism show few symptoms
Before 12 months: Many show subtle differences from typically developing infants
After 6 months: Deficits in joint attention interactions usually start developing.
Very young children: Less likely to be visually responsive, less likely to respond to their names, and more
likely to show aversion to being touched by another person. They fail to track people visually, avoid eye
contact, exhibit an “empty gaze”, fail to respond to others with emotional expression and positive affect,
and show little interest in being held.
Joint attention interactions involve gestures pointing & eye contact that center the child’s &
caregiver’s attention on an object/situation, in order to share an experience
Young children w/ autism imitate the actions of others and appear to miss out on the mutual connection
btw two people and the potential it holds for learning about themselves and others
o Such behaviors interfere with social interaction
o Meta analysis: slightly over 50% of these children showed secure attachment
o Another study: 2 yr olds with ASD were rated as less secure than other clinical (ID or language
delay) or non-clinical comparison groups
Secure. Insecure, and disorganized attachment have all been demonstrated in children w/ autism
Abnormal processing of social stimuli, notably of the face, is another component of atypical social
interaction Facial processing is considered crucial to development
o Children w/ autism often show impairment in recognizing faces, matching emotional faces,
memorizing faces, and may also visually process faces in unusual ways
o Ex. By focusing on the mouth/eyes in ways different from what typically developing children do
Delayed or atypical social behaviors occur early in at least 5 domains of social behavior:
Orienting to social stimuli Joint Attention Imitation
Emotion Face Processing
Many social abnormalities persist There is some symptom change over time
During Childhood: A variety of social deficits (understanding of social cues & inappropriate social
actions) are evident alongside certain aloofness, disinterest, and lack of social reciprocity & empathy
o They may ignore others, fail to engage in cooperative play, or seem overly content to be alone
Older Functioning Adolescents & Adults: seem “odd,” have difficultly w/ the subtleties of social
interaction, and have problems forming friendships as they move through life
Disturbed communication—both nonverbal & verbal—is the 2 aspect of the difficulties in autism
Nonverbal communication: gestures, visual gaze & facial expressions of emotions are atypical or
Verbal communication: 30% of these children never develop spoken language. Development is delayed &
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often abnormal for those who do acquire language.
Babbling & verbalizations may be abnormal in tone, pitch, and rhythm
Echolalia is also seen in dysfunctions such as language disorders, schizophrenia, and blindness
Pronoun reversal is more common in autism than in other disorders/normal development and may
persist into adulthood.
Difficulties in syntax (comprehension) & other structural forms of language exist These resemble BUT
ARE NOT identical to specific language impairments
Impairments in pragmatics = the communicative & social use of language
Conversations may be marked by irrelevant details, inappropriate shifts in topic, or disregard of normal
give-and-take of conversation—or there may be an overall failure to develop conversation
Within the wide range of symptoms of autism, some children do function at a higher level.
o They may be able to communicate better when given prompts, tell stories, and read
Some exhibit hyperlexia: single word reading is extraordinary but comprehension is problematic
RESTRICTED, REPETITIVE, STEREOTYPED BEHAVIOR AND INTERESTS (RRSBS)
Repetitious behaviors (kicking & rocking) in infancy and later preference for sameness are features of
typical development that mostly subside by school age
Younger & older youths w/ autism display odd behaviors, interests, and activities that are described as
restricted, repetitive, and stereotyped
o Subtypes of these heterogeneous behaviors are being researched, but only 2 categories of RRSBs are
1. Lower Level “Repetitive Sensorimotor Behaviors”—hand flapping, rocking, twirling, and toe walking,
repetitive use of objects, and some self-injurious behaviors
o Although seen in typically developing young children & in children with other disorders, they occur
in autism more frequently and with greater severity more common in younger children with
autism and those with lower intelligence
2. Higher Level “Insistence On Sameness”—they appear preoccupied w/ aspects of the environment
o They seem obsessed with numbers, compulsively collect articles, or overly absorbed in hobbies.
o They may adopt motor routines (rearranging objects) and insist on following rituals for eating and
going to bed.
o Minor changes in the environment (rearrangement of furniture/schedules) can upset them
o These obsessive behaviors may be more common in older children with ASD
Excessive arousal or anxiety may play a role in why RRSVS occur/how they’re maintained, or perhaps
some of the behaviors serve as self-stimulation that results from the child’s inability to engage the world
in other waysChildren from 2-9 w/ASD exhibit heterogeneity in patterns of change over time
DESCRIPTION: SECONDARY FEATURES
They’re not necessary for the diagnosis but several additional features are often associated with autism
and are meaningful in understanding the disorder…
The sensory organs are intact but abnormal responses to stimuli make sensation and perception suspect.
Both oversensitivity and undersensitivity occur significantly more than in typical development
Oversensitive to stimuli: Youths may be disturbed by the sound of a vacuum cleaner, seams on their
clothing, or a light embrace. Sensory input may thus be disliked, feared, or avoided almost like “an
overwhelming, drowning wave of stimulation” in response to being touched by another person.
Undersensitivity: The most common problem & exemplified by children’s failing to respond to voices or
other sounds or walking into things. Ex. A child may seem unaware of a loud noise but fascinated by the
quiet ticking of a watch. In some cases, a child’s failure to respond appears as deafness.
Overselectivity is also common. The individual focuses on a select portion of a stimulus array while
neglecting other components. It occurs typically in developing children & those w/ specific & general
learning problems. It has been variously conceptualized (Ex. as sensory overload/a deficit in attention),
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and is recognized as interfering with normal development & functioning.
o Neglecting specific aspects of a learning task obviously hinders overall performance.
o Social interaction is also affected and has social consequences. Ex. A child with ASD may pay
attention to a toy held by another child but not to the accompanying verbalization “let’s play”
INTELLECTUAL PERFORMANCE IN ASD
There’s a wide range of intelligence, but deficiency is common & includes severe & profound deficits
In past years, the prevalence of intellectual disability was often estimated at about 70% but is now
currently estimated as between 40 - 55%... lowed estimates may be due to:
o ASD symptoms affect measurement of IQ, diagnosis of the disorder in children who once wouldn’t
have met diagnostic criteria, or may reflect improved functioning due to early intervention
A distinction based on intelligence is made btw individuals functioning at a higher/lower level, with an
IQ of about 70 being the defining score. Higher IQ is associated with less severe autistic symptoms,
different educational needs & greater chance of normal functioning in later life.
Uneven cognitive development: Deficits exist in abstract & conceptual thinking, language and social
understanding. Strengths appear in rote learning & rote memory, and visual-spatial skills.
A small minority of youth exhibit splinter skills and savant abilities
Savant skills aren’t unique to autism. They displaying feats in memory, mathematics, calendar
calculations, word recognition, drawing, and music. Although often associated with high IQ levels, these
abilities have been seen in individuals w/ IQs as low as 55 & in children whose deficits preclude testing.
ADAPTIVE BEHAVIOUR IN ASD
Autism is characterized by difficulties in dealing with the comings & goings of everyday life
At high-functioning levels, these youths do less well on the VABS, the Vineland Adaptive Behavior Scales,
compared to ‘normal’ peers matched on IQ, and less well than would be expected based on IQ
Self-help & daily living skills are roughly what is expected on the basis of mental ability, communication
skills fall somewhat short of this, and social skills are most notably deficient. Impairments tend to
increase with age and the mismatch with intelligence is greater in high-functioning autism.
Family factors may help explain the enormous variability shown in adaptive behavior; Ex., in one study a
history of family depression & shyness was related to VABS scores, especially in the social domain
SOCIAL COGNITION: THEORY OF MIND
Children with ASD have an impairment in theory of mind (ToM), unable to understand that mental
states exist—that humans have desires, intentions, beliefs, and feelings—and that these mental states
are connected to action theory of mind guides our interaction with others
3-4 yr olds have developed first-order abilities—some understanding of people’s private mental states.
By 6 yrs children acquire second-order abilities—they can think about another person’s thinking about a
third person’s thoughts
The Sally-Anne Test determines whether a child understands that another person can hold a false
belief. The first-order task can be modified to evaluate second-order ability
o There is evidence that the majority of children with autism fails first-order tests and that a great
number fails second-order tests.
Language ability & executive functions do correlate with ToM, but false belief impairment in young
toddlers has been demonstrated in a task not requiring verbal ability.
Many measure of ToM have been developed
o ToM Storybooks presents several tasks so as to gain a comprehensive understanding of ToM
development in preschool children. It taps various aspects of ToM, such as emotions, desires, and
beliefs (Figure 12.1, pg 319: Emotional understanding and recognition)
More challenging tasks have been developed for older children or children who are able to pass second-
o In the faux pas test the child is told stories in which character A commits a faux pas—
unintentionally says something that might negatively impact character B. The child being evaluated
is asked to identify the faux pas. The child must understand that (1) the 2 characters have different
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knowledge and (2) the statement of character A emotionally affects character B
o Children with autism or a related disorder who were able to pass second-order ToM tests did less
well than typically developing children
Research shows that ToM deficits in autism exist across different ages and can be present in higher
functioning autism. It is hypothesized that such deficits—“mind blindness—may underline many of the
social and communication deficits of autism
COGNITION: CENTRAL COHERENCE AND EXECUTIVE FUNCTION
On the basis of performance on specific visual-perceptual tasks, Frith and Happe proposed that
individuals with autism are weak in central coherence and they tend to focus on parts of stimuli rather
than on integrating information into wholes. “They see the trees rather than the forest.”
Performance on perceptual tasks illustrates deficits in central coherence. Ex. Children with autism
perform better than controls on embedded figure tasks (recognizing a stimulus figure that is embedded
within a larger picture). The ability to break the block into segments helps on this task…
o Shah and Frith: Those with autism showed a superior performance in block design task of the
Wechsler intelligence test compared with their achievement on other IQ tasks and also
outperformed typically developing children & control children with intellectual disability.
Youths with autism have a bias to process info in a more analytic, less global and integrative way which
can lead to exceptional performance on some tasks and poor performance on others
It has been suggested that weak central coherence on some tasks may be accounted for by impaired
communication across the brain’s hemispheres.
Children & adolescents w/ autism perform more poorly than control groups on executive function tests
It seems that executive dysfunction is not a primary deficit but develops secondarily in autism
o Data has shown that executive dysfunctions do not seem to exist in late preschool-age children and
toddlers showed almost no differences from the performance of age-matched typical children
No single impairment accounts for all ASD symptoms; all persons with autism do not display deficits, nor
are all deficits specific to autism BUT these impairments are still of importance
Researchers are exploring early-occurring behaviorsface perception, joint visual attention & imitation
o Many of these are thought to be involved in the development of affective social development that is
so deviant in autism This interest harks back to a perspective in Kanner’s time--intersubjectivity
PHYSICAL AND OTHER FEATURES
Autistic children are often described as physically attractive, but higher than normal physical
abnormalities, including minor physical anomalies (MPAs), are associated with ASD
o Prominent forhead, a high narrow palate, and low set ears
MPAs are not medically/cosmetically of consequence, but do implicate genetic processes and disturbed
prenatal development The head/face, limbs, and brain develop from the same prenatal cell layers in
early gestation, and MPAs in these bodily areas may point to abnormal neuron migration affecting brain
Some are poise while others exhibit poor balance, uncoordination, impaired gross motor skills
Unusual eating preferences are observed, and rates of sleep problems (40-80%)
Youth with ASD exhibit a variety of maladaptive behaviors (aggression, uncooperativeness, withdrawal,
and self-injurious behaviors)
The coexistence of intellectual disability (ID) with ASD creates a varied clinical presentation of autism
Co-occurring emotional & behavioral problems engender even greater heterogeneity
Determining comorbidity is challenging bc language & cognitive problems of ASD hinder communication
Some ASD primary features & psychiatric disorders may be difficult to distinguish (OCD & social phobia)
o The extent of co-occurrence is unclear but is thought to be high in clinic samples (74%)
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o Symptoms & disorders that co-occur with ASD= anxiety, depression, hyperactivity & OD behaviors
An array of unknown factors might underlie the association of ASD and anxiety.
o Excessive sensitivity to stimuli is found in about 50% of children with ASD, raising the possibility
that oversensitivity might lead to some forms of anxiety, such as fear of loud noises
Older children & adolescents w/ ASD appear to experience greater levels of anxiety, as do those
functioning at higher cognitive levels suggesting that awareness of the social deficits of ASD generates
anxiety, which leads to worsening social interactions & social isolation and, in turn, increased anxiety
o Bi-directional effects may operate for ASD and anxiety
Level of intellectual functioning may be related to the co-occurrence of other symptoms as well
o Lower functioning may be especially associated with irritability and hyperactivity, whereas higher
functioning may be especially related to depression. Although many youths with ASD have
intellectual impairments, the effects of ID are often not separated from those of ASD
Totsika & colleagues; Emotional & behavioral problems: in representative samples of 5-16yr olds with
ASD, they found that both ASD & ID were associated with problems BUT difficulties were more likely
with ASD, with/without ID (intellectual disability)…pointing to the need to address comorbidity, which
impairs functioning in youths with ASD
Many epidemiological studies of autism or ASD spectrum disorders have been conducted over the years
An extensive report examined 43 studies from several countries that included a wide age range but
mostly school age children and these studies were published btw 1996-2008, with over half since 2000
o The best estimate of prevalence was about 20/10,000 for autistic disorder…
o PDD-NOS = 37/10,000 Childhood disintegrative disorder = 2/10,000
o Asperger Disorder = 6/10,000 Combined prevalence of all 4 = 60-70 youth/10,000
In the USA: Reported by parents prevalence at 110/10,000 for youth 3-18 yrs diagnosed with ASD
Centers for Disease Control & Prevention: 1/110 of 8yr olds in health departments in 11 states (2009)
o 2012: 1/88 are diagnosed with ASDconsiderable concern in the increase in prevalence over time
Epidemiological & Clinic Studies: Boys display autism more often than girls, generally btw 3-4.5: 1
o ID and severe symptoms are more likely in girls, so the gender ratio is 2:1 in lower functioning ASD
o Boys are at greater risk for several genetic disorders associated with autism which might explain the
differences in gender prevalence
o It’s been hypothesized that underlying autism is the tendency to systemize the world—to detail or
analyze in terms of underlying rules—a tendency more characteristic of the male bra(questionable)
There is evidence that ASD is diagnosed more in Caucasian children in the US, and rates are more rapidly
rising for African American and Hispanic children
Retrospective parental reports, videotapes of infants taken prior to diagnosis, and more recent
perspective study of the at-risk siblings of children with ASD provide an understanding of the onset and
early development of ASD ~Parents cite language delays and social abnormalities~
Parents become concerned about symptoms at age 2, but diagnosis doesn’t occur until a few years later
Three Patterns of onset have been described…
1. Occurs in most children and indicates that abnormalities become obvious in the first years of life or
2. Manifested by mild delays until about age 2 & then a gradual/abrupt developmental arrest & plateau
3. Involves regression, in which typical or near typical development is followed by arrested skill
acquisition and loss of previously acquired language, social, and/or motor skills.
Regression occurs in 15-40% of children with autism, frequently in the second year of life
o Children stop using meaningful words, orienting to their names, or spontaneously imitating others
Evidence has showed that regressed children show more severe autism symptoms and poorer outcome
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than children with other types of onset, despite relatively good early development.
Research has pointed to heterogeneous developmental pathways, from diagnosis to age 14
o Social and Communication behaviors: most children improved over time, but other trajectories
showed slower change and little improvement
o Children whose symptoms were less severe at diagnosis tended to improve more rapidly
o “Bloomers” began at low functioning & improved so rapidly that at adolescence it resembled a group
whose functioning had been consistently high
o In general: Children of white, well-educated mothers showed higher functioning at outcome
Other investigations indicate that from childhood onward, modest improvement occurs in social,
communication & self-help skills(Changes from early childhood into adulthood were examined longitudinally)
o Many individuals showed decreases in the core symptoms of ASD & in associated maladaptive
behavior as well. Overall, individuals with intellectual disability improved less and lower family
income also was related to less improvement, suggesting less availability of quality services.
Another study showed that improvement slowed after adolescents & young adults exited the secondary
school system, especially for those without intellectual disabiProbably due to the lack of stimulating
occupational & educational activities available for higher functioning indivi)uals with ASD
Symptoms generally persist into adulthood for most persons with ASD.
o 15% reach independence, with successful work placement and some social life
Long-term outcome is relatively poor when early general intelligence and communicative language is
impaired. Those with childhood IQs 70+ did notably better, suggesting that this IQ level is a good
predictor of adult independent living. Life may included typical achievements and rewards with some
difficulties Ex. Temple Grandin
Neurological soft signs, abnormal EEGs and epilepsy, high rates of MPAs, and co-occurring ID are
considered neurological anomalies in autism
o Various brain structures & regions have been examined with post-mortem examination, brain
imaging, and other types of research. The temporal lobe-limbic system, the frontal lobes, and the
cerebellum are the most studied and implicated. (These connected regions = “social brain”)
Altered brain growth is a consistent finding.
o Unusually large brain size (by 5-10%) is found in toddlers; At birth, brain size is small to normal, but
an atypical growth spurt occurs soon afterwards (as early as 6 months) and soon levels off
o One study found brain enlargement of the cortex at age 2, with white matter of the temporal lobe
Brain Volume Anomalies have been found in youths and adults with ASD
o Excessive volume of gray & white tissue has been found in the cerebrum & excessive white matter in
the cerebellum; compromises in many white matter tracts that connect different regions of the brain
to each other and connect the hemispheres have been found.
Abnormalities in Cell Structure & Organization have been in the social brain with microscopic studies
o Decreased number & size of cells, high cell density, less dendritic branching, and abnormal cell
migration. Some of the microscopic cell studies suggest that brain anomalies may develop prenatally
Brain Functioning: Reduced Activity has been shown in several regions, most notably the frontal lobes &
limbic system, particularly the amygdala
o Functioning during visual/auditory tasks—the use of the brain regions not typically employed to
process information & otherwise abnormal responses. Ex. Electrical activity showed slowed brain processing
Biochemical systems finding is high levels of serotonin in blood platelets in 25-50% of cases
o Very early in development, serotonin plays a role in the development of neurons, and brain
serotonin & its synthesis are implicated in the expression of autism symptoms.
o Dopamine, glutamate (excitation) &GABA (inhibition) are important neurotransmitters(roles unclear)
o Oxytocin & Vasopressin, which are implicated in social behavior, haven’t provided a clear picture
o Secretin & Melatonin give no support to their involvement as well
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Connecting brain structure & functioning to the clinical picture of ASD is important to understand the
neurobiology of autism.Ex. Enlargement of the amygdala in toddlers has been associated w/ more severe course of
development during the preschool period, and abnormal brain activity may occur during tasks such as face processing
Research findings & the mix symptoms of the disorder point to abnormalities of multiple brain regions
Overall: ASD may result from early brain overgrowth & neuron anomalies leading to a cascade of
biological aberrations, including atypical or decreased connections between brain regions.
Dominant among early etiological proposals: Inadequate, “refrigerator” (cold mechanical way) parenting
became implicated in causing autism, even though Kanner hypothesized an innate social deficit.
Bettelheim’s psychoanalytic theory was an especially influential psychosocial explanation—autism was
caused by parental rejection/pathology that resulted in the young child’s retreating into an autistic
“empty fortress”. This approach has been abandoned due to a lack of any evidence.
Today’s parents play important roles in advocacy & treatment for their children. Current etiology
emphasizes variables that might account for neurobiological abnormalities.
Twin and Family Studies
Higher concordance among MZ (identical) twins than in DZ twins.
o MZ twins of probands have about a 60% chance of having autism, and an even greater probability
(90%) when autism-like disorder is included. DZ cotwins have about a 4.5% chance.
Family studies of autism point to genetic influence
o The rate of autism in siblings of autistic children varies from 2-7% and about 8% of extended
families have an additional autistic member.
o Higher than expected rate of other pervasive developmental disorders is found in families
o 20-30% of family members exhibit impairments in social, communicative, and repetitive behaviors
that are similar to autism but not severe enough for diagnosis
o Some siblings of youth w/ASD can show very early differences Ex. Atypical pre-speech vocalizations
in their 1 year of life. Some siblings w/ early manifestationsgo on to be diagnosed with ASD
o Family members show characteristics that (not diagnosable symptoms of ASD) are observed in
those with autism, such as macrocephaly, elevated serotonin, and neuroanatomical abnormalities
Some problems found in families have been shown to increase as the genetic relationship becomes closer
Genetic influence was suggested in a study that found greater social, communication, and repetitive
behavior impairments in biological than adoptive families further supports the view that genetic
predisposition leads to autism, autism-like disorders, or milder related problems.
A dimensional conceptualization of autism is suggested rather than a category of disorder because what
is transmitted btw families is broader than the specific symptoms of the diagnostic criteria and because
autistic traits (social reciprocity & language skills) are continuously distributed in the general population
Chromosomes and Genes
Single gene syndromes and chromosomal abnormalities appear in less than 10-20% of cases, with
intellectual disability (ID) often present in these
Two genetic conditions notably associated with autism are (1) fragile X syndrome & (2) tuberose
sclerosis (caused by inherited gene mutations resulting in tumors of the brain & other organs)
A duplication of genes in a particular region of chromosome 15 has been observed in an estimated 1-3%
of cases of autism, and this region is linked to other developmental disorder
Genome-wide association studies revealed copy number variations Ex. Involving 30 genes of chromosome 16
The research on ASD reflects the usual strategies for identifying susceptibility chromosomes and genes
o Progress has identified several susceptibility genes & their implications for brain functioning Ex. the
RELN, MECP2, NLGN3, and NLGN4 susceptibility genes affect early brain development.
Some favor the idea that many interacting genes best explain most cases of ASD, which is suggested by
the continuum of the disorder, the varied clinical picture, and research finding.
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o Bc the concordance is less than 100% in MZ twins, it suggests that gene-environment interactions &
epigenetic processes may play some role in the development of autism (there is evidence for both).
PRENATAL AND PREGNANCY RISK
A recent meta-analysis found 6 prenatal factors to be risk factors for autism:
(1) Advanced paternal & maternal age (2) Maternal medication (3) Maternal bleeding (4) Gestational
diabetes (5) Birth order—being born 1 vs. 3 or later (6) Having a mother born abroad
There is also some evidence implicating uterine inflammation or abnormal maternal immune responses
MEDICAL CONDITIONS AND VACCINES
Medical conditions associated with autism: cerebral palsy, infections (meningitis), hearing impairment,
and seizure disorders(about 25% of those with autism, w/ onset disproportionate in early childhood & adolescence)
Controversial issue: Association btw ASD and vaccines given to prevent diseases otherwise unassociated
with ASD. The issue arose when parents in England associated their children’s onset of PDD* with the
measles, mumps, and rubella vaccine (MMR) they had received to prevent the diseases
o Several investigations in different countries have failed to find a connection btw MMR and autism
Another concern: Vaccines w/ thimerosal (mercury-containing preservative) put children at risk for PDD
o It is argued that (1) some children may be especially susceptible and (2) the amount of thimerosal
received by children has increased due to an increase in recommended vaccinations.
o The evidence in MMR studidoesn’t support a relationship btw PDDs & thimerosal-containing vaccines
Reviews by major government & professional groups in the US haven’t supported the role of vaccines as
causative, although some recognize a small number of children could be unusually susceptible to MMR
o Wakefield’s original article was retracted by the journal & he lost his British professional credentials
ENVIRONMENT AND SOCIAL INTERACTION
The search for etiology has focused on possible causes of early brain abnormalities to the relative neglect
of possible later-occurring environmental and psychosocial influences.
A Developmental Model of Autism, by Dawson & Faja:
Genetic & Environmental Factors lead to brain abnormalities Interactions btw the child & the
environment are altered Development of abnormal brain circuits and autism
o Altered interactions are hypothesized to disrupt input critical for further brain development
o The model proposes that individual pathways of altered interactions mediate the connection btw
initial brain abnormalities & later outcome ~ These developmental pathways, which involve
the context of the child’s environment, can vary & change to a limited extent, but the longer the child
travels a maladaptive pathway, normal development is less probable
AUTISM SPECTRUM DISORDER AND OTHER PDDs
Asperger’s disorder and PDD-NOS are referred to as “lesser variants” of Autism at times.
There are overlap of symptoms of the 3 disorders, but also distinguishes them from each other and other
PDDs of Childhood Disintegrative Disorder and Rett’s Disorder…
ASPERGER’S DISORDER (AS)
Asperger 1 wrote of this syndrome in 1944, but not recognized by the DSM & ICD until the early 1990s
Asperger’s disorder/syndrome is marked by qualitative deficits in social interaction & by restrictive,
repetitive, stereotyped interests and behaviors In these ways, it resembles autism
According to DSM, youths with AS display no significant delay in language, cognitive development,
adaptive behavior (except in the social domain), or curiosity about the environment.
Individuals with AS have difficulties in establishing friendships & other positive social bonds.
o Deficits in the use of nonverbal social gestures, emotional expression, and early sharing behaviors.
o Social awkwardness, inappropriate, lack of empathy, and insensitivity are apparent. They seem to
have some interest in other people, but their lives are often marked by loneliness.
Research indicates impairment in ToM skills & the perception of complex emotions The exact nature
of their social deficits is not fully understood
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Obsessive & restricted interests, the focus of which seems to know few bonds. The child may collect an
inordinate number of facts and recite them in a pedantic, egocentric, long-winded style.
Adults with AS are known for their meticulous work—whether in art/science, and youths and adults
often exhibit imagination, for example, in art.
Other problems not required for diagnosis have been observed: A variety of motor problems may exist,
as well as behavioral problems such as noncompliance, negativism, and aggression
The rate of AS is not established, although prevalence is less than for autism
o Boys are identified more often than girls & diagnosis occurs on average much later than for autism
Clinical impressions agree that outcome can be favorable in terms of living independently, finding
employment, and having a family. Social impairments, however, may persist over time.
“Is Asperger’s syndrome distinct from autism or a manifestation of autism?”
o Several studies found little consistent evidence of significant differences btw AS & high functioning
autism. AS may be viewed as a variant of autism diagnosed on the basis of verbal and/or cognitive
higher functioning, not a qualitatively separate disorder
o This is consistent with AS being conceptualized as an ASD, and may even suggest that the diagnosis
of AS in unnecessary
o Counter argument: qualitative differences in AS—later onset, verbal IQ greater than performance IQ,
more complex/different language, more noticeable restricted interests & fewer motor mannerisms
AS differs in the manner of communication, described as one-sided or pedantic and with stilted
expressions and excessive details. Ex. Social behavior in AS is often described as active and odd whereas
in autism it is described as aloof and passive
Distinct disorders lead to the search for different developmental course and outcome, neurobiology,
etiology, prognosis, intervention, and the life.
This category applies when symptoms appear related to but fail to meet the diagnostic criteria for autism
and other PDDs. The diagnostic criteria are only generally described, with no specific items.
Youths with PDD-NOS must display impaired reciprocal social interaction and either impaired
communication or stereotyped behavior and interest.
Cases in which the criteria for autistic disorder are not met due to late onset, atypical symptoms, milder
symptoms, or all of these fall into the PDD-NOS category
The diagnosis of PDD-NOS is the most common but also the least stable over time, whether due to the
vagueness of the diagnostic criteria, a tendency for diagnosticians to use the diagnosis in the face of
uncertainty, or other reasons.
CHILDHOOD DISINTEGRATIVE DISORDER (CDD)
Heller first described this syndrome in 1908, and termed it Heller’s Syndrome & Disintegrative Psychosis
DSM Criteria: Development must be normal for at least 2 yrs & symptoms must be present before age 10
o By this time, many acquired skills are lost. Loss of skills in CDD occurs later than in regressed autism
Diagnosis: Significant loss in at least 2 areas of the following: language, social skills, bowel or bladder
control, play, or motor skills. In addition, abnormal functioning must be present in 2 areas of the
diagnostic symptoms of autism, that is, social interaction, communication, and RRSBs.
It appears more often in males than females, with onset (gradual/abrupt) usually btw 3-4 years of age
Impairment remains fairly constant over time & after regression CDD appears similar to severe autism.
More children with CDD than with autism are mute, display loss of self-help skills, and have IQ scores les
than 40. These youths are among the lowest functioning of children with PDDs.
Rett, an Austrian physician, described this syndrome in 1966.
Children with classic Rett syndrome seem to develop normally during the first months of life, although
subtle abnormalities may be present.
6-18 months: Regression & deterioration develop in distinctive ways. Head growth decelerates, hand
10 CH 12: AUTISM SPECTRUM DISORDER & SCHIZOPHRENIA
skills are lost w/ subsequent stereotyped hand movements & the child walks w/ poorly coordinated gait
Social engagement is lost, language is severely impaired, physical growth slows, and severe or profound
retardation develops ~ There’s more variation in symptoms than what was once thought, the physical &
mental deterioration of the syndrome are pervasive and outcome is poorer than in autism.
Rett’s is categorized as a PDD due to autistic-like behavior, particularly during the preschool years.
This syndrome is notably different from ASD in its severity, very broad range of effects, and known
genetic cause in most cases. (Unclear how this genetic disorder should best be classified)
Mutations in the MECP2 gene on the X chromosome affects the regulation of other genesPrevalence is
higher in females (1/15,000). Rett’s found in many parts of the world & in different ethnic groups.
ASSESSMENT OF ASD
Broad-based assessment is required because ASD encompasses many areas of functioning and implicates
The clinician must involve the parents in order to obtain a unique picture of the child’s functioning and
also to lay the groundwork for possible treatment. It’s also important to take a history of prenatal, birth,
developmental, familial, and