McCabe and Tivers take bold aim at the continuing stigma surrounding the ADHD diagnosis, and, in particular, the stimulant medications most commonly used to treat the disorder. Some justified concern about over-prescription and abuse of the medications contribute to the unusual skepticism, including books, published as recently as 2016, with titles like “ADHD Does Not Exist,” and “A Disease Called Childhood.” But the net effect is discriminatory and harmful, ADHD advocates say.