Autism is a disorder of neural development, characterized by impaired social interaction and communication and by restricted and repetitive behaviour, which usually begins in childhood.

Autism spectrum disorders may range from individuals with severe impairments (who may be silent, mentally disabled, and locked into hand flapping and rocking behaviours) to high-functioning individuals who may have active but distinctly odd social approaches, narrowly-focused interests and verbose or pedantic communication. The three main disorders in the spectrum are autism itself, Asperger syndrome and pervasive development disorder.

Did You Know?
Savants are people who have a prodigious memory, but usually in a very narrow specialized field.

Although usually associated with autism (autistic savants), in fact only one in ten autistic people have savant skills, and only 50% of savants are autistic (the other 50% often have different disabilities, mental retardation, brain injuries or brain diseases).
Male savants out-number female savants by six to one.

The best-known savant was Kim Peek (on whom the 1988 film “Rain Man” was based), a “megasavant” with a reported savant memory for most information and not just specialized pieces. Peek, however, was not autistic and probably had a rare genetic disease called FG syndrome.

There is no known cure for autism, although some would argue that autism is actually a variation in functioning (neurodiversity) rather than a mental disorder to be cured. Some individuals with autism spectrum disorder may even show superior skills in perception and attention, relative to the general population.

In recent years, it has become increasingly apparent that autism affects the functioning of virtually the entire brain, not just those brain areas involved with social interactions, communication behaviours and reasoning abilities, as had been previously thought. It has been discovered that people with autism have difficulty in many other areas, including balance, movement, memory and visual perception skills, complex tasks which involve different areas of the brain working together. It is perhaps better seen, then, as a disorder in which the various parts of the brain have difficulty working together to accomplish complex (as distinct from basic) tasks.

Autism affects information processing in the brain by altering how nerve cells and their synapses develop, connect and organize, although exactly how this occurs is not well understood, and there does not appear to be a clear unifying mechanism at either the molecular, cellular or systems level. It appears to result from developmental factors that affect many or all functional brain systems and to disturb the timing of brain development.

One popular theory, known as executive dysfunction, hypothesizes that autistic behaviour results, at least in part, from deficits in working memory, planning, inhibition and other forms of executive function. Certainly, poor short-term memory(as opposed to long-term memory, which may actually be normal or better than normal) is a common complaint among autism sufferers, although to what extent this results from attention deficits is not clear.

Some studies have suggested that there may be selective damage to the limbic-prefrontal episodic memory system in some people with autism, especially in the self-conscious memory of personally experienced events.