What Is Autism?

What Is Autism? What is Autism
Spectrum Disorder?

Autism spectrum disorder (ASD)
and autism are both general terms
for a group of complex disorders of
brain development. These disorders
are characterized, in varying
degrees, by difficulties in social
interaction, verbal and nonverbal
communication and repetitive
behaviors. They include autistic
disorder, Rett syndrome, childhood
disintegrative disorder, pervasive
developmental disorder-not
otherwise specified (PDD-NOS) and
Asperger syndrome. ASD can be
associated with intellectual
disability, difficulties in motor
coordination and attention and
physical health issues such as
sleep and gastrointestinal
disturbances. Some persons with
ASD excel in visual skills, music,
math and art.

Autism appears to have its roots in
very early brain development.
However, the most obvious signs
of autism and symptoms of autism
tend to emerge between 2 and 3
years of age. Autism Speaks
continues to fund research on
effective methods for earlier
diagnosis, as early intervention
with proven behavioral therapies
can improve outcomes. Increasing
autism awareness is a key aspect
of this work and one in which our
families and volunteers play an
invaluable role.

How Common Is Autism?

Autism statistics from the U.S.
Centers for Disease Control and
Prevention (CDC) identify around 1
in 88 American children as on the
autism spectrum–a ten-fold
increase in prevalence in 40 years.
Careful research shows that this
increase is only partly explained by
improved diagnosis and
awareness. Studies also show that
autism is four to five times more
common among boys than girls.
An estimated 1 out of 54 boys and
1 in 252 girls are diagnosed with
autism in the United States.
By way of comparison, more
children are diagnosed with autism
each year than with juvenile
diabetes, AIDS or cancer,
combined.* ASD affects over 2
million individuals in the U.S. and
tens of millions worldwide.
Moreover, government autism
statistics suggest that prevalence
rates have increased 10 to 17
percent annually in recent years.
There is no established
explanation for this continuing
increase, although improved
diagnosis and environmental
influences are two reasons often
considered.

What Causes Autism?

Not long ago, the answer to this
question would have been “we
have no idea.” Research is now
delivering the answers. First and
foremost, we now know that there
is no one cause of autism just as
there is no one type of autism.
Over the last five years, scientists
have identified a number of rare
gene changes, or mutations,
associated with autism. A small
number of these are sufficient to
cause autism by themselves. Most
cases of autism, however, appear
to be caused by a combination of
autism risk genes and
environmental factors influencing
early brain development.
In the presence of a genetic
predisposition to autism, a number
of nongenetic, or “environmental,”
stresses appear to further increase
a child’s risk. The clearest
evidence of these autism risk
factors involves events before and
during birth. They include
advanced parental age at time of
conception (both mom and dad),
maternal illness during pregnancy
and certain difficulties during birth,
particularly those involving periods
of oxygen deprivation to the
baby’s brain. It is important to
keep in mind that these factors, by
themselves, do not cause autism.
Rather, in combination with
genetic risk factors, they appear to
modestly increase risk.
A growing body of research
suggests that a woman can reduce
her risk of having a child with
autism by taking prenatal vitamins
containing folic acid and/or eating
a diet rich in folic acid (at least
600 mcg a day) during the months
before and after conception.
Increasingly, researchers are
looking at the role of the immune
system in autism. Autism Speaks is
working to increase awareness and
investigation of these and other
issues, where further research has
the potential to improve the lives
of those who struggle with autism.