Autism is a developmental disorder in which a child fails to develop normal social skills, language skills and communication skills. Such children are often excessively preoccupied with a particular type of behavior and are very resistant to change or education. Repetitive habits are common.
Autism is thought to be an abnormality in the development of the brain, and may be due to brain damage during growth in the womb, at birth, or in the first years of life. The absolute cause is not yet known.
There are no blood tests to diagnose the condition, but CT scans sometimes show non-specific abnormalities. Electroencephalograms are usually normal, except in those who develop epilepsy, which may occur in up to 30% of cases.
Occasionally autistic children have exceptional talents in a particular area (e.g. maths or music - the 'idiot savant syndrome'), but unfortunately the majority remain mentally retarded and require care from responsible parents or institutions throughout their life. There is no effective treatment, and their life expectancy is close to normal.