Autism spectrum disorder (ASD) has spectrum in the name for a reason.
I don’t diagnose ASD, but I can typically look at and interact with a child for 2-3 hours and know whether they’re likely on the spectrum or not. However, because it’s a spectrum, to diagnose or not to diagnose seems to be getting blurrier and blurrier. Some kids I see have a lot of the stereotypical behaviors like hand-flapping, self-talking, and pacing back and forth, poor language development, lack of understanding about social norms, etc.
What about the kids that don’t have any of those behaviors?
For instance, a child who loves to play with others, craves and seeks attention, looks at me straight in the eyes and has a funny face contest trying with all her might to keep a straight face but can’t help but crack up! A child who loves to laugh and be silly, and loves telling jokes which really are funny for a 4 year old.
The spectrum is a broad one and sometimes hard to distinguish. Here is a great link that tells the signs of ASD and criteria for diagnosis. http://www.cdc.gov/ncbddd/autism/hcp-dsm.html
A lot of children have one or two of these symptoms and are typically developing. A child on the Autism spectrum must meet 6 of these criteria and from a variety of categories.