Autism is a more common term used for Autism Spectrum Disorders (ASD).
Autism is a syndrome, which means it’s identified by a group of signs and symptoms that together are characteristic of the disorder. It is referred to as a spectrum disorder because children are affected by it in varying degrees that occur across a spectrum—from mild to moderate to severe in several different categories.
Not all children with autism have the same level of functioning.
There are two major forms of autism, depending upon when the disorder manifests itself. Infantile autism refers to those children who show signs of autism at birth and fail to meet few or any developmental milestones. Regressive autism refers to children who develop normally until they are about 18 months old, then progress is halted and they begin to regress. They may learn a few words and be socially interactive, then cut back or stop altogether.
Autism is defined by a set of behaviors that are developmentally delayed, including delays in socialization and communication along with repetitive and/or aggressive behaviors. Children may exhibit a lack of social skills and interest in playing with friends, limitations with regard to communication skills such as talking and pointing, excessive aggression and temper tantrums, as well as self-stimulating and repetitive behaviors like flapping or wringing the hands. Some or all of these behaviors may be present and occur at varying degrees.
Most children with autism are slow to acquire new knowledge or skills. Some kids have signs of lower than normal intelligence while others have average or high intelligence. Intelligent children with autism may learn quickly but have trouble communicating, applying what they know to everyday life, and adjusting to social situations. Again, each child is different with regard to how autism is expressed as well as how he or she progresses.