Autism is a developmental disability that typically affects a person's ability to communicate, form relationships with others, and respond appropriately to the environment. Although there is a broad range of symptoms in people with autism, they tend to share certain social, communication, motor, and sensory problems that affect their behavior in predictable ways. Symptoms of autism include impaired social interaction, problems with verbal and nonverbal communication and imagination, and unusual or severely limited activities and interests. The most severe cases of autism are marked by extremely repetitive, unusual, self-injurious, and aggressive behavior. The mildest forms of autism resemble a personality disorder associated with a perceived learning disability.
Asperger Syndrome, a neurobiological disorder, includes serious deficits in social and communication skills without delays in spoken language development, and obsessive/repetitive routines and preoccupations with a particular subject matter. Individuals with Asperger Syndrome may have problems with social interaction, nonverbal communication, or managing change. They appear to lack common sense. Other difficulties include motor skills, writing, math, abstract reasoning, or concept formation. People with Asperger Syndrome may have anxiety, depression, or behavioral problems.
Pervasive Developmental Disorder is used to describe delay or deviance in social/language/motor and/or cognitive development. PDD is not one disorder but a category that encompasses a wide range of delays of different magnitude in different domains. Developmental Disorders are severe, chronic disabilities which are attributable to a mental or physical impairment or combination of mental and physical impairments; are manifested before the person attains the age twenty-two; is likely to continue indefinitely; and results in substantial functional limitations in three or more of the following areas of major life activities.