I did not feel the PRITE was an accurate representation of the psychiatry boards. The questions were on the same material, but the questions had different styles if you know what I mean.
The only way I can describe it in a manner that you may feel that you "get" what I mean is this---
Ever study some USMLE questions from Kaplan and USMLE-WORLD, and feel the questions on your actual exam were very similar?
Compare that to questions from the Appleton and Lange books--yes questions based on the same material, but when you take the questions from Kaplan or USMLE-World, you see a lot of the same questions repeated while A&L's books you hardly see any questions repeated. You also feel as if it's a different mindset.
That's the only way I can describe it. The PRITE for several years, for example, almost asks the same mitochondrial-based questions, while the psychiatry board exam asks questions on mitochondrial disorders that aren't the same as the PRITE. There were several questions I saw on the PRITE based on data with little backing (e.g. Welbutrin does not affect the REM cycle--there's only 1 or 2 studies that back this, and with a small sample, IMHO not enough data to put on a standardized exam unless it's an experimental question). The psychiatry board exam puts questions based on better amounts of data.
Your score on the PRITE does correlate with the psychiatry boards because, no surprise, it's based on psychiatry material. That said, however, it's difficult to study for the PRITE. There are no real PRITE study materials other than old exams, and IMHO using that is like eating matzo for dinner (and nothing else--just matzo and water). It's pretty bland.
There are plenty of psychiatry board materials out there that are good. I'd focus on those materials instead of the PRITE. In fact, I'd just study for the psychiatry board exam, in a manner where it adds to your ability to be a good psychiatrist (BTB notes are arranged in this manner).
The Kaufmann notes work and are good, but those notes are more in a --"here's what you need to pass, but it won't make you a better psychiatrist" style. I'd focus on that type of studying if you have very limited time or it's the last stretch of the race.
Forget the PRITE except it may be a gauge on how much you need to study for the board exam.
I wouldn't worry about the board exam anywhere near as much as USMLE. The psychiatry written boards were a cakewalk IMHO compared to USMLE (well at least for me it was.) It's material you actually are using on an everyday basis vs. seeing surgery questions you hardly ever saw even when you did surgery.