I welcome people constructively criticizing the study, but this kind of anecdotal response is really not useful.
Edit: As an example the caption of Dr. Farah's photo reads "Dr. Martha Farah and colleagues found no cognitive benefit from Adderall taken by students." Finding no correlation to grade improvement is very, very far from finding "no cognitive benefit."
On the other hand, if they were sloppy, it could potentially argue for a multimodal distribution that when forced into being viewed as an average (or with other tools that assume a unimodal distribution) then the effect gets washed out. One possible case for this is the idea that ADD/ADHD is wildly over diagnosed and, thus the incorrectly diagnosed children might show no improvement while masking the improvement of those who actually have it.
Grade improvements (along with the possibility that over prescribing is skewing the data) are a terrible metric, and a better one would be interpersonal relationships and how they behave in the classroom, which is much harder to measure. If a child is diagnosed pretty late (late elementary or middle school) they might also have a LOT to really catch up on. Just because they can focus doesn't mean they are prepared to deal with the material given to them.
Here's an exercise: try translating your anecdotal experience into boring clinical language, e.g. "one 27 year-old male subject had a small statistically insignificant increase in grades, and self-reported feeling more focused."