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autism (ôˈtĭzəm), developmental disability resulting from a neurological disorder that affects the normal functioning of the brain. It is characterized by the abnormal development of communication skills, social skills, and reasoning. Males are affected four times as often as females. Children may appear generally normal until around the age of 24 to 30 months, although studies have identified signs of autism in children under a year of age.
Symptoms, which vary widely in severity, include impairment in social interaction, fixation on inanimate objects, inability to communicate normally, and resistance to changes in daily routine. Characteristic traits include lack of eye contact, repetition of words or phrases, unmotivated tantrums, inability to express needs verbally, and insensitivity to pain. Behaviors may change over time. Autistic children often have other disorders of brain function; about two thirds are mentally retarded; over one quarter develop seizures.
The cause of autism remains unclear, but a psychological one has been ruled out. Neurological studies indicate a primary brain dysfunction, perhaps related to abnormalities that appear to occur in the way the autistic child's brain develops. A genetic component is indicated by a pattern of autism in some families, and studies have suggested that a number of genes may be involved. Exposure in the womb to elevated levels of steroid hormones has been found to be associated with autism in boys in one study, but study compared the average levels of two groups of boys (one with, the without, autism) and individual levels in the two groups overlapped. The condition also appears to be more common in children born to older mothers or older fathers. Treatment in which autistic children are intensively and repetitively taught skills and behaviors from a young age appears to help some children with the disorder.
See T. Grandin, Emergence: Labeled Autistic (with M. M. Scariano, 1986, repr. 1996), Thinking in Pictures (1995), and The Autistic Brain (with R. Panek, 2013); L. Wing, ed., Aspects of Autism (1988); J. Donvan and C. Zucker, In a Different Key (2016). See also publications of the Autism Society of America.