I had a very formal psychiatric exam that was spread out over a week when I was admitted for what turned out to be for almost a year. I learned I was highly dissociative (DID with a psychotic part), had bipolar 1 disorder with psychosis tending toward severe mania, PTSD with psychosis, OCD, and a documented severe trauma history. A complete review of my medical history was included in the formal exam. They went back to childhood records. It was as thorough as any diagnostic exam could be. I've never needed another one. It has held up well.