What's the deal with Dihexa? (What are the downsides?)

So, I've seen various people talking about Dihexa on here. And it's usually wonderful things, saying it's similar to Adderall (to varying degrees) where it really helps you get interested in things. But I also see a lot of people talking about how they stopped using it because of it's side effects/dangers. But everything I have found on Dihexa says it's well tolerated as recommended dosages, with the only side effects I'm seeing being fairly typical. Headache, Nausea, Stomach Upset, etc...

Is there something else to it?