To clarify this point, I asked Dr. Susan Levy, a top autism expert at Children's Hospital of Philadelphia:
If a person has "autism-like" symptoms, does he or she have an autism spectrum disorder? That is, if a person has, for example, fetal alcohol syndrome with "autism-like" symptoms, does that person have autism caused by FAS, or FAS with autism-like symptoms, or a dual diagnosis?
Here is how Dr. Levy answered the question:
- If they meet the criteria, they have autism. Those medical issues are the underlying cause. Autism is the end-product of different biological entities. FAS [fetal alcohol syndrome] may be a cause of autism. The medical issue may cause the problem. There could also be confounding issues that make diagnosis difficult. [It's also critical that] onset must be before age 3. if there are cognitive impairments after age 3, it's not autism - it's brain injury with autism-like symptoms.
Interview with Dr. Susan E. Levy, MD, Director, Regional Autism Center, Childrens Hospital of Philadelphia, December 2009.
Rice, Catherine. "Prevalence of Autism Spectrum Disorders." Autism and Developmental Disabilities Monitoring Network, United States, 2006.