I am somewhat skeptical of MB personality testing, but doing one of the online assessments linked through typologycentral (very interesting forums!) I am INFP (http://typelogic.com/infp.html), and I did feel that significant chunks of the description fit me really well. As a data point for the I/E ADD/ADHD conversation, I am ADHD-Combined (scoring pretty high in restlessness and impulsivity, as well as the inattention – I’m just a big old mess! , but I am most definitely an introvert.
For example, I am *really* busy, and my commuting time is some of my only “me” time to read a book or listen to music or watch TV on my iPod. Especially when I am stressed out, I need to apologize to my co-commuting classmates on the bus for being “rude” and burying my nose in a book – and if someone insists on trying to make conversation, I get really really annoyed. I have changed my commuting schedule, arriving at work early, so that I don’t wind up on the same bus as my coworkers, and lose my precious downtime. Now, most of the people I interact with are flabbergasted that I am an “I” – this line from the profile that I linked to – “INFPs can even masquerade in their ESTJ business suit, but not without expending considerable energy” *definitely* rings true, because I work with people, and I really do enjoy it – but my husband suffers when I get home and all I want to do is veg in front of the TV/computer/with my knitting.