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Many headlines have warned of an “Autism Epidemic.” How big a problem is this mysterious disorder? What do you know about autism and how it may affect your family? |
Autism has long been a controversial topic. In the 1950s, many believed autism was the product of “refrigerator moms” who didn’t provide enough affection and bonding to their young children. While as a society we have made considerable progress in our attitudes about autism, controversy remains over the causes of autism and how we can prevent it.
What is Autism Spectrum Disorder?
Autism Spectrum Disorder (ASD) refers to a group of developmental disabilities caused by a problem with the brain. People with ASD often have problems with language, communication and social skills. People with ASD may display a certain set of behaviors, such as resisting change, repeating phrases or actions, not interacting with others in traditional conversation or play, or showing distress for unapparent reasons. Affected children and adults may exhibit any combination of these typical behaviors in varying degrees of severity. For example, one child diagnosed with ASD may have advanced analytical skills, yet avoid all social interaction, while another child with the same diagnosis may display mild language and social problems.
Autism Spectrum Disorder is typically diagnosed during the toddler or preschool years, although some children are diagnosed at older ages. As far as we know, race, ethnicity, family income and educational levels do not affect the chance of the disorder’s occurrence. However, boys are three to four times more likely to have an ASD than girls. It is estimated that between 2 and 6 in every 1,000 children born will eventually be diagnosed with an ASD. While it is clear that more children than ever before are diagnosed as having an ASD, it is unclear how much of this increase is due to changes in how we identify and diagnose ASDs, or whether this is due to a true increase in prevalence.
What causes Autism Spectrum Disorders?
No one knows exactly what causes Autism Spectrum Disorders, but scientists think that both genetic and environmental factors play a role. Many cases occur in families with a history of ASD or related disabilities. Research also suggests that some children may be born with a susceptibility to ASD, but a single “trigger” that causes the disorder to develop has not been identified. A variety of factors could be associated with some forms of ASD, including viral infections, problems during pregnancy or delivery, metabolic imbalances and exposure to environmental chemicals. It is clear that “bad parenting” does not cause ASD. Genetic factors and brain abnormalities at birth are considered to be the most recognized causes, but experts believe genetic and environmental factors probably interact in complex ways to contribute to the onset of the disorder.
One hypothesis about the cause of Autism Spectrum Disorder is that the disorder is caused by childhood immunizations; however, the weight of currently available scientific evidence does not support this hypothesis. In 2000, CDC and the National Institutes of Health asked the Institute of Medicine to establish an independent expert committee (the Immunization Safety Review Committee) to examine evidence related to the theory that MMR (measles-mumps-rubella) vaccine causes ASD, as well as a second theory that vaccines containing the preservative thimerosal cause neurodevelopmental disorders, including autism spectrum disorders, attention deficit hyperactivity disorder (ADHD) and speech or language delay. A report from the Immunization Safety Review Committee in May 2004 concluded that:
- neither thimerosal-containing vaccines or MMR vaccine are associated with ASDs.
- the hypotheses regarding a link between ASDs and the MMR vaccine and thimerosal-containing vaccines lack supporting evidence and are only theoretical.
- future research to find the cause of ASDs should be directed toward other promising lines of inquiry that are supported by current knowledge and evidence and offer more promise for providing an answer.
CDC is committed to protecting the health of children and to identifying the biological and environmental causes of autism and other developmental disabilities. CDC continues to further evaluate the role of vaccines in long-term health and urges parents to keep their child’s immunizations up to date to protect them from serious and preventable diseases.
The Importance of Early Intervention
Currently, the main research-based treatment for Autism Spectrum Disorder is intensive structured teaching of skills, often called behavioral intervention. The earlier a problem is identified, the more effective the intervention. No lab test currently exists for ASD and other developmental disabilities, so health care professionals rely on developmental screening to detect these disabilities. Developmental screening is a procedure that measures how a child plays, learns, speaks and acts compared to other children of the same age to help identify children who should receive more intensive assessment or diagnosis for potential developmental delays. A delay in any of these areas could be a sign of a developmental problem like ASD. In addition to regular visits to the pediatrician, parents and caregivers can use CDC’s developmental milestones growth chart (PDF) to help measure a child’s progress and take action early if needed.
The impact of ASD is immense for the families affected and for the community services that provide intervention and support for these families. It is important that families and communities do everything possible to identify children’s learning needs and to begin intervention as early as possible to enable all children to reach their full potential.
Helping CDC Do More, Faster
The CDC Foundation has developed a partnership with the National Alliance for Autism Research that will help CDC conduct a biomarker study. Results of the study could enhance early recognition of autism, provide objective criteria for its diagnosis and help identify possible strategies for prevention. To learn more about how the CDC Foundation builds partnerships to help CDC protect the health and well-being of children and families around the world, contact Julie Rodgers at (404) 653-0790 or jrodgers1@cdc.gov.