I'll second whoever said INFJ - every one I've known has been very prone to getting all kinds of odd ideas about why I don't contact them, if I don't do so with military-like regularity! And every time I've tried to help them with any problem by presenting possible solutions, they piss all over them by confidently predicting that it will all go wrong, there's no point and we're all doomed.
Having said that, ISTJ's, with inferior Ne, can be very paranoid too. The guy I mentioned in the ISTJ's gone wrong thread won't get any help with his OCD because he believes that if he tells people then they'll use it as a weapon against him and start planting the objects of his fears in his path all the time just for laughs.
The same could be said though of ISTP's, most I've known have been quite cynical and very much into those conspiracy type books and the 'worst case' I've known is convinced that everyone in the world is an asshole that's not worth bothering with, and writes people off within seconds of knowing them if he even detects that they're at all insincere - he cooks up all kinds of 'reasons' why they are, when to anyone else it's plainly obvious that theyr'e just nervous or shy - maybe it's inferior Ni that does that.