Personally, I'm strictly on the pragmatic side of thing. As Scott Alexander says[0], "society is fixed; biology is mutable". If we can't on Earth figure out an effective social solution to a problem, but we have a pill that fixes it outright, maybe let's try the pill so that people don't have to go miserable all their lives. Calling something a disease is really about assigning blame[1]. If I'm ill, it's not (entirely) my fault and I need a cure. If it's not a disease, all I'll get from people is pep talks at best, at worst I'll be called lazy and told to get my shit together. We clearly know that latter doesn't work; depression is pretty much defined as a state where you can't just "get your shit together".
BTW. I always considered ADD, ADHD, etc. to be a bit of a fake disease, a product of environment, but I'm no longer sure. I've been struggling with depression and anxiety for many years and responded relatively well to SSRIs which stabilized my mood and helped me quit the recurring panic attacks. The problem is not gone, but with a little more stable emotional situation I managed to figure out that what really causes most of my problems now is total lack of focus. I can't hold my attention on any kind of work-related task (the task doesn't matter; what matters is that it's work) for more than 30 seconds without compulsively seeking something else to do. Be it HN or IMs. With no easy distraction source available, I'll get anxious and sleepy. I can be perfectly well-rested but will still occasionally get sleepy at work just because I refuse to distract myself with Hacker News. A considerable amount of my mental energy goes to fighting this and forcing myself to focus. Now that I've finally dug that up from underneath the layers of anxiety, it's going to be a topic of the next conversation with my doctor.
#HNTherapy
Also, this is what I got googling for ADD[2]. What the shit?
[0] - http://slatestarcodex.com/2014/09/10/society-is-fixed-biolog...
[1] - http://lesswrong.com/lw/2as/diseased_thinking_dissolving_que...
[2] - http://i.imgur.com/n5nhyWt.png