MODEL RELEASED. Autism. Girl with tape over her mouth and covering her ears in a representation of autism. Autism is a severe disorder of communication and behaviour that develops before the age of three. Autistic children are unable to use language meaningfully or process information from the environment. About half of autistic children are mute with some developing an isolated special skill such as outstanding memory or musical ability. The causes of autism are uncertain but evidence suggests it may be a genetic disease. Special schooling and behavioural therapy may be required.