Methamphetamine is so strong, I honestly couldn't even tolerate small amounts of the stuff. The few times I've tried it just resulted in dehydration, headaches, and muscle aches, easily outweighing any cognitive effects it had (which weren't even really more noticeable than regular amphetamine's effects for me). Cocaine isn't as bad, but still a bit too much for me as well.
Regular amphetamine on the other hand, the compound this article is about, has given me quite a noticeable improvement in my quality of life. Results do vary even among us adhd people, but for me, I've never experienced anything worse than staying up a bit later than I would like from taking it. Otherwise it just feels like drinking a really strong cup of tea for me, cause even coffee makes me more jittery. So the research in this article doesn't surprise me too much, but it's always nice to have some extra reassurance against all the anti-adhd-medication propaganda that originally made me paranoid about even trying it back when I was first diagnosed.