Autism is the most common development disability, affecting 1 in every 150 people. Males are four times more likely to have autism than females. It is characterized by impaired social interaction, problems with verbal and nonverbal communication, and unusual, repetitive, or severely limited activities and interests.  These behaviors can range in impact from mild to disabling.

The hallmark feature of autism is impaired social interaction.  Parents are usually the first to notice symptoms of autism in their child.  As early as infancy, a baby with autism may be unresponsive to people or focus intently on one item to the exclusion of others for long periods of time.  A child with autism may appear to develop normally and then withdraw and become indifferent to social engagement. 
Children with autism may fail to respond to their name and often avoid eye contact with other people.  They have difficulty interpreting what others are thinking or feeling because they can’t understand social cues, such as tone of voice or facial expressions, and they don’t watch other people’s faces for clues about appropriate behavior.  They lack empathy. 

Many children with autism engage in repetitive movements such as rocking and twirling, or in self-abusive behavior such as biting or head-banging.  They also tend to start speaking later than other children and may refer to themselves by name instead of using “I” or “me.”  Most children with autism don’t play interactively with other children.  Some speak in a sing-song voice about a narrow range of favorite topics, with little regard for the interests of the person to whom they are speaking. 

Many children with autism have a reduced sensitivity to pain, but may be abnormally sensitive to sound, touch, or other sensory stimulation.  These unusual reactions may contribute to behavioral symptoms such as a resistance to being cuddled or hugged.