Autism is a complex developmental disability that typically appears during the first three years of life. The result of a neurological disorder that affects the functioning of the brain, autism impacts the normal development of the brain in the areas of social interaction and communication skills. Children and adults with autism typically have difficulties in verbal and non-verbal communication, social interactions, and leisure or play activities.

Autism is one of five disorders coming under the umbrella of Pervasive Developmental Disorders (PDD), a category of neurological disorders characterized by "severe and pervasive impairment in several areas of development," including social interaction and communications skills (DMS-IV-TR). The five disorders under PDD are Autistic Disorder, Asperger's Disorder, Childhood Disintegrative Disorder (CDD), Rett's Disorder, and PDD-Not Otherwise Specified (PDD-NOS). Each of these disorders has specific diagnostic criteria as outlined by the American Psychiatric Association (APA) in its Diagnostic & Statistical Manual of Mental Disorders (DSM-IV-TR).

Prevalence of Autism

Autism is the most common of the Pervasive Developmental Disorders, affecting an estimated 2 to 6 per 1,000 individuals (Centers for Disease Control and Prevention, 2001). This means that as many as 1.5 million Americans today are believed to have some form of autism.

And that number is on the rise. Based on statistics from the U.S. Department of Education and other governmental agencies, autism is growing at a rate of 10-17 percent per year. At these rates, the ASA estimates that the prevalence of autism could reach 4 million Americans in the next decade.

The overall incidence of autism is consistent around the globe, but is four times more prevalent in boys than girls. Autism knows no racial, ethnic, or social boundaries, and family income, lifestyle, and educational levels do not affect the chance of autism's occurrence.

Common Characteristics of Autism

While understanding of autism has grown tremendously since it was first described by Dr. Leo Kanner in 1943, most of the public, including many professionals in the medical, educational, and vocational fields, are still unaware of how autism affects people and how they can effectively work with individuals with autism. Contrary to popular understanding, many children and adults with autism may make eye contact, show affection, smile and laugh, and demonstrate a variety of other emotions, although in varying degrees. Like other children, they respond to their environment in both positive and negative ways.

Autism is a spectrum disorder. The symptoms and characteristics of autism can present themselves in a wide variety of combinations, from mild to severe. Although autism is defined by a certain set of behaviors, children and adults can exhibit any combination of the behaviors in any degree of severity. Two children, both with the same diagnosis, can act very differently from one another and have varying skills.

Parents may hear different terms used to describe children within this spectrum, such as autistic-like, autistic tendencies, autism spectrum, high-functioning or low-functioning autism, more-abled or less-abled. More important than the term used is to understand that, whatever the diagnosis, children with autism can learn and function productively and show gains with appropriate education and treatment.

Every person with autism is an individual, and like all individuals, has a unique personality and combination of characteristics. Some individuals mildly affected may exhibit only slight delays in language and greater challenges with social interactions. The person may have difficulty initiating and/or maintaining a conversation. Communication is often described as talking at others (for example, monologue on a favorite subject that continues despite attempts by others to interject comments).

People with autism process and respond to information in unique ways. In some cases, aggressive and/or self-injurious behavior may be present. Persons with autism may also exhibit some of the following traits.

• Insistence on sameness; resistance to change
• Difficulty in expressing needs; uses gestures or pointing instead of words
• Repeating words or phrases in place of normal, responsive language
• Laughing, crying, showing distress for reasons not apparent to others
• Prefers to be alone; aloof manner
• Tantrums
• Difficulty in mixing with others
• May not want to cuddle or be cuddled
• Little or no eye contact
• Unresponsive to normal teaching methods
• Sustained odd play
• Spins objects
• Inappropriate attachments to objects
• Apparent over-sensitivity or under-sensitivity to pain
• No real fears of danger 
• Noticeable physical over-activity or extreme under-activity
• Uneven gross/fine motor skills
• Not responsive to verbal cues; acts as if deaf although hearing tests in normal range.

For most of us, the integration of our senses helps us to understand what we are experiencing. For example, our senses of touch, smell and taste work together in the experience of eating a ripe peach: the feel of the peach fuzz as we pick it up, its sweet smell as we bring it to our mouth, and the juices running down our face as we take a bite. For children with autism, sensory integration problems are common. Their senses may be over-or under-active. The fuzz on the peach may actually be experienced as painful; the smell may make the child gag. Some children with autism are particularly sensitive to sound, finding even the most ordinary daily noises painful. Many professionals feel that some of the typical autism behaviors are actually a result of sensory integration difficulties.

There are many myths and misconceptions about autism. Contrary to popular belief, many autistic children do make eye contact; it just may be less or different from a non-autistic child. Many children with autism can develop good functional language and others can develop some type of communication skills, such as sign language or use of pictures. Children do not "outgrow" autism but symptoms may lessen as the child develops and receives treatment.

One of the most devastating myths about autistic children is that they cannot show affection. While sensory stimulation is processed differently in some children with autism, they can and do give affection. But it may require patience on a parent's part to accept and give love in the child's terms.