Transcript Child and Adolescent Psychopathology

Autism Spectrum
Disorders
Chapter 20
Susan Faja and Geraldine Dawson
HISTORICAL CONTEXT
 Leo Kanner (1943)
 First characterized autism as a variety of behaviors
including lack of social reciprocity and emotional
awareness, delays in communication, atypical use of
language, and repetitive interests and behaviors.
 Hans Asperger (1943)
 Described a high-functioning form of autism that
characterized children as “little professors” with intense
interests and the ability to provide lengthy descriptions of
their interests.
TERMINOLOGICAL AND
CONCEPTUAL ISSUES
 Autism spectrum disorders include autistic
disorder, Asperger’s disorder, and pervasive
developmental disorder not otherwise specified
(PDD-NOS)
 DSM-IV diagnostic criteria include four types of
impairments in each of three domains:
 Social interaction, communication, and repetitive or
restricted behaviors or interests.
 These symptoms typically appear before age 3.
TERMINOLOGICAL AND
CONCEPTUAL ISSUES
 Comorbidities
 Most commonly, ASD is accompanied by developmental delay
or intellectual disability; however, a significant portion of
individuals with ASD has average to above average
intelligence.
 Medical comorbidities, include sleep disorders, gastrointestinal
disorders, psychiatric conditions, and seizures.
 Socioeconomic Considerations
 Affects individuals regardless of socioeconomic level (Fombonne,
1999, 2003).
 Parental education level, continues to be related to age of
diagnosis (Fountain, King, & Bearman, 2011).
 Diagnosis is also delayed for children in the Medicaid system
(Mandell et al., 2010).
PREVALENCE
 ASD affects approximately 1 in 110 children in the
United States (ADDM, 2009)
 Annual societal cost of more than $35 billion per year
and approximately $3.2 million per individual (Ganz, 2007)
 Affects males more commonly than females, with a
ratio of 4.5 to 1, and prevalence for boys is 1 in 70
(ADDM, 2009)
 Affected females are more likely than males to have
comorbid intellectual disability in the severe range (IQ
< 35)
ETIOLOGICAL FORMULATIONS
Experience-based risk processes in autism
Vulnerabilities
Susceptibility
genes
•Environmental
risk factors
Risk processes
Altered neural
circuitry
Altered
patterns of
interaction
between child
and
environment
Outcome
Full autism
syndrome
Broader autism
phenotype
GENETICS AND HERITABILITY
 Strong evidence for genetic influences in autism, yet
the role of susceptibility genes is complex.
 Multiple genes interact to increase susceptibility to
ASD by influencing gene expression or encoding
functional changes in proteins that are part of complex
regulatory networks.
 The expression and effects of many genes are
influenced by environmental factors, offering hope that
early intervention can alter genetic expression, brain
development, and behavioral outcomes.
ENVIRONMENTAL RISK
FACTORS
 Advanced parental age, low birth weight, prenatal
exposure to pollution and pesticides, maternal
infection, and use of certain medications (e.g.,
SSRIs) during pregnancy.
 Measles-mumps-rubella (MMR) vaccination
 Epidemiological studies have failed to confirm an
association between the MMR vaccine and autism.
 Thimerosal, a preservative containing ethyl mercury that
was added to many vaccines, has also been examined
and no evidence of increased risk has been found (Parker,
Schwartz, Todd, & Pickering, 2004).
DEVELOPMENTAL
PROGRESSION
 Behavioral Symptoms Apparent in Infancy
 6 and 12 eye contact declines
 8 to 10 months infants are less likely to respond to their name
 6-12 months directed vocalizations (e.g., babbling or crying
while looking at a person) decreased and spent longer fixating
on a single object and had less active spontaneous visual
exploration
 12 months there is reduced orienting when called by name,
less time spent looking at faces, and decreased social interest
 12 to 24 months stereotyped movements and repetitive
behaviors also emerge.
DEVELOPMENTAL
PROGRESSION
 Toddler-Preschool Period
 Cognitive, language, and behavioral difficulties
 Five key domains of social behavior are affected:
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•
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Social orienting
Joint attention
Attention to emotional cues
Motor imitation
Face processing
ABNORMAL NEURAL
DEVELOPMENT IN AUTISM
 Structural brain imaging in young children with autism
 2- to 4-year-olds with ASD have larger total cerebral volumes.
 Neuroimaging of structural and functional connectivity in
children with autism
 Differences in white matter (i.e., myelinated axons) abnormal
minicolumn width and cell numbers, particularly in regions
involved in higher-order behaviors, have led to understanding
the neurobiology of autism as a disorder of connectivity (Minshew &
Williams, 2007).
 Electrophysiology in young children with autism
 Impairments in brain response in children with ASD by 6 months
for processing eye gaze, and by age 3 for neural differentiation
between the face of each child’s mother and a stranger and
slower processing of emotional content conveyed by faces.
PROTECTIVE FACTORS
 Early comprehensive interventions
 Initiated during the preschool period and sustained for 2 to 4 years
 A significant impact on outcome in a large subset of children with
autism, including significant gains in IQ, language, and educational
placements (Rogers & Vismara, 2008).
 Parent-delivered, targeted interventions
 More targeted approach
 Provides training in specific domains for the caregivers of children
with ASD
 Interventions for older individuals with ASD
 Used with school-age children
 Group format
 Social skills interventions
SYNTHESIS AND FUTURE
DIRECTIONS
 Research focused on identifying autism
susceptibility indices, early identification, and early
intervention offer real hope for the future.
 As early identification and intervention become
increasingly effective, the new challenge will be
translating these scientific findings into social
policy.