Why Is Autism on the Rise

Learn about autism statistics.

Why is autism on the rise? According to the Centers for Disease Control and Prevention (CDC), one in 110 children has autism. Other sources suggest that the prevalence is 1 in 67. The precise reason is unknown. However, the autism community has many possible answers to this controversial question.

Autism Rise Controversy

The rate of diagnosed cases of autism grows each year. The autism community of experts, affected individuals and family members has theories about why the autism rate is growing. So far, there is no known cause for the rise in autism just as the cause of autism remains a mystery.

The controversy deals with the argument over whether there is a rise in autism rates and possible causes. A number of experts fear that the rising autism rate is an epidemic that will continue to grow. Many experts who see the autism rate as an epidemic claim that the cause of autism must be environmental.

Other experts argue that the increased number of autism cases is not due to an epidemic but instead due to a better understanding of how to diagnose autistic people with symptoms that were previously missed. In fact, some experts claim that the rate of autism is not growing more now and would have been larger in the past if the current diagnostic criteria were in place.

Why Is Autism on the Rise?

Common Theories

The theories about why autism is on the rise vary. The most popular theories include the following:

  • DSM IV diagnostic criteria
  • Increased autism awareness
  • 1990 IDEA law change
  • Environmental factors
  • Vaccinations

DSM IV Diagnostic Criteria

In 1992 the American Psychiatric Association began implementing the Diagnostic and Statistical Manual of Mental Health Disorders, Fourth Edition (DSM IV) to identify autism symptoms and aid diagnosis. The DSM IV grouped the neurological conditions of autism, Asperger's syndrome, childhood disintegrative disorder, Rett syndrome and pervasive developmental disorder not otherwise specified as pervasive development disorders. After the introduction of the DSM IV, autism diagnosis tripled between 1993 and 2003. Many experts credited the new diagnostic guidelines as helping both doctors and parents recognize autism symptoms that were previously overlooked or mistaken for some other condition.

A 2008 University of Oxford Wellcome Trust study found that children who were diagnosed with language impairments in the 1980's and 1990's would now be diagnosed as autistic based on current diagnostic criteria. The study analyzed 38 adolescents and adults between the ages of 15 and 35, who were diagnosed with a developmental language disorder as children.

The researchers found that the study participants met the current diagnostic requirements for autism based on both childhood behavioral records and their current condition. This study supports the theory that changes in diagnostic criteria have significantly contributed to the rise in cases of autism. The study was published in the April 2008 edition of the Developmental Medicine & Child Neurology journal.

Increased Autism Awareness

Since the 1990's, autism awareness has grown. April is now autism awareness month, offering news stories and activities that inform the public about autism. Many active autism advocacy organizations are constantly educating the public about autism awareness through the media. Celebrities such as Jenny McCarthy, Jim Carey and Toni Braxton are public spokespeople and advocates for autism. Jenny McCarthy operates an autism advocacy organization, Generation Rescue and she has written two autism awareness books. The Internet is filled with autism awareness websites and blogs.The large number of autism awareness activities has created a general public knowledge of autism symptoms. The increased awareness of autism symptoms and resources such as online copies of the DSM IV, allow many parents to recognize the early signs of autism in their children, research autism and seek diagnosis. The resulting parent advocacy has significantly increased the number of diagnosed cases of autism.

1990 IDEA Law Change

When services for children and adolescents with autism were added to the 1990 Individuals with Disabilities Education Act, the number of diagnosed cases of autism in school-aged children increased dramatically. Some critics claim that some children were diagnosed with autism, even if they were not truly autistic, just to be able to benefit from the new IDEA requirements for schools to provide transition services and assistive technologies.

Possible Environmental Factors

A number of experts believe that the rising autism rate must have an environmental trigger. They argue that common environmental toxins can cause autism in some individuals and until the toxin is identified and dealt with, the autism rate will continue to grow.

A 2009 University of California Davis study, published in the journal Epidemiology, linked California's rising autism rate with environmental toxin exposures such as pesticides and household chemicals. The researchers rejected the idea that the growing autism rate was linked to diagnostic criteria or genetics.

The study was a response the state's growing autism rate, which grew from 205 reported cases of autism in 1990 to 3,000 reported cases in 2006. 6.2 of every 10,000 Californian children were diagnosed with autism in 1990. By 2001, 42.5 of every 10,000 Californian children were diagnosed with autism.

Vaccination Question

For years, many members of the autism community have argued that required childhood vaccinations may be linked with autism and the rising autism rate due to mercury exposure through the preservative, thimerosal. Conflicting studies have raised questions about vaccinations having a connection to autism. Recent studies and a landmark Vaccine Court ruling have argued against vaccinations as a possible autism cause. After thimerosal was removed from most of the childhood vaccines in 1999, the autism rate continued to grow. However, a significant portion of the autism community continues to believe there is a connection.


So why is autism on the rise? There are many possible answers yet there is hope in all of the controversy. The debates, advocacy and awareness activities can lead to more autism research to find the true answer. Ongoing research for the cause of autism can ultimately lead to treatments that are more effective and a future cure.

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Why Is Autism on the Rise