Autism is a spectrum of neurodevelopmental disorders characterized by deficits in social interaction and communication, as well as unusual and repetitive behaviors. Signs of autism typically appear by age 6 in three areas: social skills, language, and behavior. Effects can include poor eye contact, lack of response to one's name, preference for playing alone, abnormal speech patterns, repetitive behaviors, and sensitivity to stimuli. Asperger's syndrome is a related disorder affecting social skills, language, and behavior.