I doubt there will be much of a psychological element; it's mostly for how much you might cost for insurance? They're perhaps trying to make sure they don't hire anyone with too many ongoing issues. The psychological elements will probably only be behavioral; how much you smoke, drink, etc. They would not want to be surprised later with you then popping up to say, "Well, I've always had X, Y, or Z condition and now I need your help." They don't want you using them to get help/medical care or time off when they think they're hiring a "healthy" person who is able to do the job, isn't just mentally good for the job.

I had that a long time ago when I worked for a department store (but there was no insurance), had to go see their recommended doctor, etc.