Excessive hyperactivity or no signs of active life at all. Many children who suffer from autism demonstrate the unpredictable behavior. Their moods may change every hour or several minutes. One minute they want to dance and jump, the other one they are sitting silently without having any desire to interact with somebody. The movements of such patients have no basis; they may start flapping their hands without any reason. People with autism frequently do so to feel safe and calm down.
Getting wild, wild, wild. Children with autism may demonstrate both very shy condition and real wilderness. They may suddenly start behaving like some wild animals: shouting, screaming, crying, trying to beat someone, etc. It is almost impossible to calm them in such situations. The worst thing is that these kids may do harm to themselves without recognizing it. That is why their parents or health care professionals should be around to help control these consequences of anger.