Autism is a neurodevelopmental disorder characterized by impaired social interaction, verbal and non-verbal communication and restricted and repetitive behavior. Symptoms of Autism typically appear during the first three years of life. Some children show signs from birth, other seem to develop normally at first only to slip suddenly into symptoms when they are between 18 to 26 months old. 

Autism was first identified in 1943 by Dr. Leo Kanner of Johns Hopkins Hospital. At the same time, a German scientist, Dr. Hans Asperger, described a milder form of the disorder that is now known as Asperger Syndrome. The two disorders are listed in the DSM IV (Diagnostic and Statistical Manual of Mental Disorders) as two of the five developmental disorders that fall under Autism Spectrum Disorders. The others include Rett Syndrome, PDD NOS (Pervasive Developmental Disorder), and Childhood Disintegrative Disorder. All of these disorders are characterized by varying degrees of impairment in communication skills and social abilities, including repetitive behaviors.