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 behaviours, children and adults can exhibit any combination of the behaviours in any degree of severity. Two children, both with the same diagnosis, can act very differently from one another and have varying skills.
 

Traits
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.

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 (DSM-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).

For a diagnosis of autism, the main symptoms must be clear before the age of 3 years. The disabilities are lifelong and there is no known cure, though careful training and sensitive support can bring improvements. The autistic impairments may be associated with cognitive disabilities. Two-thirds of those with classic autism (or Kanner syndrome) are severely to mildly handicapped in cognition and intellect. Most people with Asperger’s have average to higher IQ. Across the autistic spectrum, perhaps 10 per cent have distinctive abilities—in such fields as art, music, mathematics or memory—and are called autistic savants. (The proportion of people with such special abilities in the whole population is only one per cent).

According to the Canadian Autism Research and Strategy Agendas released in White Paper from the Autism Society of Canada, autism now effects at least one in every 200 Canadian children. The reported number of cases has risen by 150% in the past 6 years. To view this paper in its entirety, please go to www.autismsocietycanada.ca  and follow the links.
Definition courtesy of the Autism Awareness Center .