Autism is a pervasive developmental disorder: its symptoms include differences and disabilities in many areas including social communication skills, fine and gross motor skills, and sometimes even intellectual skills.

Autism is also a “spectrum disorder.” In basic terms, this means you can be a little autistic or very autistic. At the highest end of the spectrum is Asperger Syndrome, sometimes called “The Little Professor” syndrome. At at the lowest end of the spectrum is the disorder that’s most often called “classic autism,” which often includes mental retardardation. In between are a variety of pervasive developmental disorders including Rett syndrome, childhood disintegrative disorder, and pervasive developmental disorder not otherwise specified (PDD-NOS).

What Causes?

AutismThere is great disagreement on this question within the scientific and lay communities. You're likely to see media reports on many different theories, ranging from genetics to toxins to food allergies.

Despite the disagreements, most experts agree that autism is a difference in brain structure and/or function caused by a combination of genetic factors and some form of environmental "insult." To date, no one has been able to pinpoint the precise genes or external factors to blame for autism. In fact, pursuant to the "many autisms" theory, there may be many different sets of factors likely to cause autistic symptoms in different people.