This is what really helped me feel confident in my hypothesis (bold is mine):
What Brain Scans Tell Us About Autism Spectrum Disorder
Anagnostou and her colleagues had set out to use neuroimaging to identify brain differences unique to ASD, as compared to other neurodevelopmental differences like ADHD, OCD, and intellectual disability. And they did find that brain differences clustered into different groups—but not by diagnosis. In fact, brain scans could not distinguish children who had been diagnosed with ASD from those who had been diagnosed with ADHD or OCD.
“Dr. Anagnostou reported data from multiple papers that looked at over 3,500 children,” Dr. Alycia Halladay, Chief Science Officer at the Autism Science Foundation, explained to me. “These studies looked at multiple structural and functional features of the brain—including cortical gyrification (the way the brain folds in the cortex), connectivity of different brain regions, and the thickness of the cortical area—and found no differences based on diagnosis.”New Research May Change How We Think About the Autism Spectrum | Psychology Today