Part of our psychiatry class involves interviewing a psychiatric patient. We know nothing about the patient when we start the interview.
I joined two classmates in interviewing one such patient. One classmate went first, and for his 15 minutes he did a good job laying a foundation. He got an overview of the patient's life story, social history, and medical history. The patient struck us as a bit odd, but his answers seemed credible and he seemed to be an ordinary guy who had fallen on hard times.
Then it was my turn, and my job was to assess his psychiatric state. I quickly managed to open the floodgates. He revealed his delusions about being the son of god, that within a few months everyone's eye color would change, that he was adopted but that his birth family is profoundly wealthy and runs the American government. His story contradicted itself, showing that his thoughts were not only unhinged from reality but disorganized as well.
It took longer than I expected for us to uncover this patient's profound psychiatric disorder, even though we knew he was a psychiatric patient. First impressions can be deceiving.