Autism

Autism is often not physiologically obvious, in that outward appearance may not indicate a disorder, and diagnosis typically comes from a complete physical and neurological evaluation.

There have been large increases in diagnosed autism, for reasons that are heavily debated by researchers in psychology and related fields within the scientific community. Some believe this increase is largely due to changed diagnostic criteria and/or societal factors, while others think the reason is environmental. The United States Centers for Disease Control (CDC) estimate the prevalence of autism spectrum disorders to be between one out of every 500 to one out of every 166 births.The National Institute of Mental Health (NIMH) states the "best conservative estimate" as 1 in 1000.

Although the specific causes of autism are unknown, there is a large database of links between autism and genetic loci that span every chromosome.Further, observations and studies that autistic children have generally larger head circumferences are intriguing, but their roles in the disorder are unclear. One group of researchers claims to have found a link between autism, abnormal blood vessel function, and oxidative stress, with potential for new medical therapies should this line of evidence prove fruitful.

With early intervention, intense therapies (most notably Applied Behavioral Analysis), practice, and schooling, some children diagnosed with autism may improve on their skills to the point of neurotypical children. Some autistic children and adults are opposed to attempts to cure autism, because they see autism as part of who they are, and in some cases they perceive attempts of a cure to be intensive and unnatural.