
It is important to remember that every person with autism is an individual. It is a myth that all autistic people act the same. They simply don't (Rainman was a film!). They do however share problems in three key areas:
Autism is a disabling brain disorder.
It affects the way in which people understand and react to the world around
them. This causes them to act differently than others.
Many autistic people have a hard time using words to say what they want or need, where as others might end up repeating the same word or sentence over and over again.
The difficulty in understanding what others are saying can
cause great confusion. They may see or hear a person talking, and although
every word has been heard, they fail to grasp the meaning of what has been
said.
A child with autism may be perfectly happy one moment, but all of a sudden
become sad or angry, or even have a tantrum. This may be because they can't
tell people what they want.
Taking the wrong turning, or a certain noise could trigger this reaction, or simply parking the car on the wrong side of the road. The fact is it could be any number of things, For the parent or carer of the autistic person finding the cause can be a long slow process (if not at times impossible).
A lack of communication can lead to frustration and confusion
both for the autistic person and for the people around them.
Many people with autism have ritualistic behaviour, insistence on routine
and sameness.
An autistic person may be perfectly happy to go to a familiar shop, but take
them to a different shop to buy the same item, and they may become frustrated,
withdrawn, even fearful. An unfamiliar space or routine no longer feels safe
or secure. The autistic person can find it very difficult to relate from one
situation to another.

People with autism can often have accompanying learning disabilities but everyone with the condition shares a difficulty in making sense of the world.