At birth, a child with autism spectrum disorder often appears normal. Symptoms may appear as early as the first year of life, but it may not be until the child is 2 or 3 years old that the parents realize something is not quite right.
Infants with autism spectrum disorder may respond abnormally to being touched. Instead of cuddling when they are picked up, they may stiffen or go limp. In addition, they may not show normal developmental behaviors during the first year of life, such as smiling at the sound of their mother's voice, pointing out objects to catch someone's attention, reaching out to others with their hands or attempting one-syllable conversations. The child may not maintain eye contact, may appear unable to distinguish parents from strangers and typically shows little interest in others. Symptoms vary from mild to severe.
Some behaviors associated with autism include:
Disordered play — A toddler with autism spectrum disorder usually ignores other children and prefers to play alone. The child may spend hours repeatedly laying out objects in lines, sitting silently in an apparent trance-like state or concentrating on only one object or topic. Any attempt to divert the child can provoke an emotional outburst. Children with autism spectrum disorder usually do not engage in make-believe play.
Disordered speech — A child with autism spectrum disorder may not speak much or may remain silent. When the child does speak, the words may be an echo of what another person said. Speech patterns may be different. Instead of saying, "I want a sandwich," the child may ask, "Do you want a sandwich?"
Repetitive behaviors — A child with autism spectrum disorder may perform repetitive behaviors, such as repeating the same phrase or a particular motion. Clapping, finger snapping, rocking, swaying and hand flapping are common.
Abnormal behaviors — Children with autism spectrum disorder may develop obsessive routines, such as wanting to take the same route to school every day or turning around before entering a room, or may become intensely preoccupied with something, such as parts of objects or a particular activity. Some may become hyperactive, aggressive, destructive or impulsive. Others may intentionally injure themselves.