Autism is a developmental disorder characterised by poor social interaction and communication. Children generally show signs of autism by the time they are 3-years-old. Signs and symptoms can be subtle or marked.
Social Skills
Three-year-old children with autism often have a difficult time interpreting others' emotions, cannot hold conversations with other people, do not respond to their name, do not make eye contact with others, do not want to be held or hugged and/or play alone much of the time.
Language
Autism often causes young children to talk in a singsong or robotic voice. Sometimes they have trouble speaking or do not talk at all. They might use words they hear without understanding their meanings and/or scream at others because they do not know how to express themselves.
Behaviour
Children with autism often rock back and forth, bite themselves or others, bang their heads on objects, spin around, flap their arms, have trouble adapting to changes in routine, stare at objects for long periods of time, experience sensitivity to sights and sounds and/or become obsessed with certain topics.
Other Disorders
Autism Speaks says that children with genetic disorders, such as Fragile X syndrome, tuberous sclerosis or Angelman syndrome, sometimes also develop autism (see Reference 1). Children with autism might suffer from epilepsy, Tourette syndrome, gastrointestinal disorders, sleep disorders and/or eating disorders.
Treatment
Three-year old children with autism often can work with a therapist to learn social and language skills. Sometimes they are given prescription medications, such as antidepressants, anticonvulsant drugs or antipsychotic medications, all of which reduce symptoms of autism such as anxiety, depression and hyperactivity.