I was diagnosed with ADD as an adult. The criteria seemed to fit and I had always wondered what was "wrong" with me that I could never seem to settle on any one particular career path.
Some history: Out of college I worked in Silicon Valley in the late 70's and early 80's, moved to construction for the next 13 years, to programming in the mid-90's, and from 2000 on I "settled' on biomedical informatics. At least that discipline had enough dimensions that it kept me pretty much on the same career path.
So in 2004 I had that diagnosis. I started to take Adderall regularly and it did seem to help. I had always been a big coffee drinker so this just seemed like coffee on steroids. However last year I had a big crisis at work where everything seemed to fall apart. Talk about feeling like a total imposter! I had a complete meltdown, something I had not had since I was in high school. After I got a horrible review at work I decided I had to really get coaching for my ADD.
Luckily I went to see a neuropsychologist who wanted to give me a complete neurocognitive assessment before working with me. When she gave me the results she told me that, clinically speaking, I did not have ADD. Rather I was very bright and had multiple aptitudes. This meant that I didn't have anything wrong, I just needed some help in figuring out how to harness and filter all those things I'd like to do.
This was a huge relief for me since it removed the stigma I had placed on myself for most of my adult life. There wasn't anything wrong with me, I just could never be fully engaged by any one thing. Then I came across Emilie Wapnick's TED talk (http://goo.gl/Dc6fzu) on Multipotentialites and it was a revelation that not only was I okay, I was not alone. Here is a definition of the term from Wikipedia:
“An educational and psychological term referring to a pattern found among intellectually gifted individuals. [Multipotentialites] generally have diverse interests across numerous domains and may be capable of success in many endeavors or professions, they are confronted with unique decisions as a result of these choices.”Emilie's site, http://www.puttylike.com, is a continuing source of comfort and inspiration.
Since then I've come across something called T-shaped persons (see http://tsummit.org/ for some interesting information). This describes a person who has a particular strength (the upright part of the T) and connects with many other interests or disciplines (the crossbar at the top of the T). I think of myself as more crossbar than upright, but everyone is different. I find that I enjoy being at the crossroads between many disciplines - this is probably why I have lasted as long as I did in my current field. Biomedical Informatics covers a whole lot of territory!