Many programs and systems can deduce information about a person's personality traits from various sorts of data.

This will tend to put people at a disadvantage in dealing with whoever uses the techniques. Systematically, those with less power will suffer losses from this. We need to cancel that out or prevent it, but how?

I think that using software which monitors indications of whether you are about to enter a depressive phase is perfectly sensible, provided the software is free and runs on your own computer, and the data stays in that computer. But if any nonfree software is involved, you must expect it to spy on you.