For better or worse, I took a personality assessment last year, as a participant in a study that another student in my program is doing. The test told me I'm an INTJ, which I like to refer to as the "evil mastermind phenotype." The description tells me that I look to put the world into logical frameworks (and am not so great on the personal relationship side of life -- oh well).
While, yes, this lends itself to scientific thought and exploration, it also produces some problems within the study of medicine. Because medical problem solving is all about finding the logic behind the mysery -- but when push comes to shove, something is still unexplained. I would much rather be the person writing the textbook than reading it, because the authors have the liberty to pick what they know and gloss over what they don't.
Scientific study continues with an aim towards explaining the unexplained, but there's also a point of complacency -- a point at which physicians seem content to know that a symptom is caused by a certain disease, and know which treatment works. How exactly the symptom occurs may never be explained, and may never need to be explained, practically speaking.
But for the med student, particularly one who craves answers, this is a continual source of frustration. The structural framework for explaining the disease is almost complete, but is missing a few blocks in one corner. You can drive yourself crazy looking for answers that you'll never find, or trying to reconcile contradictory theories.
So, apparently, there's an additional skill you need to learn in med school: learning when to give up. When to accept that the answers aren't there, and be at peace with the ambiguity. The first battle is with the material, and the second with the frustrated brain. For an INTJ, the second may be harder to win.