Autism is a neurodevelopmental condition that impairs the way a person relates to and communicates with other people. Persons with autism can also have unusual behaviors, such as insistence on sameness, obsessions, or stereotypic behaviors (for example, hand flapping, spinning, and toe walking). The condition varies greatly in the presenting symptoms, the timing of presentation, the range and severity of symptoms, and its association with other conditions. Although recognition of autism is increasingly common, the cause of autism and the reason for its increase remain unknown. With intensive early intervention, significant improvements in a large percentage of children with autism can be achieved.