Frequency

How frequent is ASD?

In the 1970s the incidence rate was 1 in 10,000 in many U.S. cities. It has now increased nationally up to 1 in 200. Some towns like Brick, New Jersey experience a 1 in 150 rate.

In the first quarter of this year a child was diagnosed with autism every three hours in California. Last year, that rate was every six hours. The prevalence of autism in some elementary school districts is 1 in 132 children.

The following incident rates are being quoted by Dr. Marie Bristol-Powers, of the National Institute of Child Health and Human Development:

Within the autism spectrum, including classic autism, PDD and Asperger's Syndrome: 1 in 200 individuals.
Within the autism spectrum, including classic autism and PDD: 1 in 500 individuals.
With classic autism: 1 in 1,000 individuals.

The latest report from the California Department of Developmental Services states that during the 6 month period from January 6, 1999 to July 7, 1999, the Developmental Services System added 1,027 NEW CHILDREN who were diagnosed and qualified for lifetime services with DSM IV autism - one new child every 4 hours.

In April 1999 the California Department of Developmental Services already reported a 273% increase in the number of children with autism who had entered the developmental services system - 1,685 new cases in 1998 alone. This number also did NOT include children under age 3, which is also the fastest growing group of ASD children.
[ http://www.dds.ca.gov ]

According to the 1998 Maryland Special Education Census Data, Maryland has experienced a 513% increase in autism from 1993-1998. The 513% increase in cases of autism also do NOT include children age birth through three.

Autism spectrum disorder is 4-5 times more prevalent in males.