2. What is Autism?. complex developmental disability Autism first described by Kanner (1943)typically appears during the first three years of lifemost severe childhood neuropsychiatric conditiontriad of impairmentssocialisationcommunicationimagination. 3. Prevalence of Autism. 2-6 cases per 1,000growing at a rate of 10-17 percent per yearboy:girl 4:1Usually identified before 30 monthsNo racial or socioeconomic differences.