Most parents of autistic children suspect that something is wrong by the time the child is 18 months old and seek help by the time the child is age 2. Children with autism typically have difficulties in:
    * Pretend play
    * Social interactions
    * Verbal and nonverbal communication

Some children with autism appear normal before age 1 or 2 and then suddenly "regress" and lose language or social skills they had previously gained. This is called the regressive type of autism.

People with autism may:

    * Be overly sensitive in sight, hearing, touch, smell, or taste (for example, they may refuse to wear "itchy" clothes and become distressed if they are forced to wear the clothes)
    * Have unusual distress when routines are changed
    * Perform repeated body movements
    * Show unusual attachments to objects

The symptoms may vary from moderate to severe.

Communication problems may include:
    * Cannot start or maintain a social conversation
    * Communicates with gestures instead of words
    * Develops language slowly or not at all
    * Does not adjust gaze to look at objects that others are looking at
    * Does not refer to self correctly (for example, says "you want water" when the child means "I want water")
    * Does not point to direct others' attention to objects (occurs in the first 14 months of life)
    * Repeats words or memorized passages, such as commercials
    * Uses nonsense rhyming

Social interaction:
    * Does not make friends
    * Does not play interactive games
    * Is withdrawn
    * May not respond to eye contact or smiles, or may avoid eye contact
    * May treat others as if they are objects
    * Prefers to spend time alone, rather than with others
    * Shows a lack of empathy

Response to sensory information:
    * Does not startle at loud noises
    * Has heightened or low senses of sight, hearing, touch, smell, or taste
    * May find normal noises painful and hold hands over ears
    * May withdraw from physical contact because it is overstimulating or overwhelming
    * Rubs surfaces, mouths or licks objects
    * Seems to have a heightened or low response to pain

    * Doesn't imitate the actions of others
    * Prefers solitary or ritualistic play
    * Shows little pretend or imaginative play

    * "Acts up" with intense tantrums
    * Gets stuck on a single topic or task (perseveration)
    * Has a short attention span
    * Has very narrow interests
    * Is overactive or very passive
    * Shows aggression to others or self
    * Shows a strong need for sameness
    * Uses repetitive body movements

Reprinted from