As an INFP, I hate to see a person I care about having a psychological disorder (or being on the way to it) and not being able to help because I don't know what to do.
I know that most of us aren't professional psychiatrists or psychologists, but knowing how to help with what we know is better than doing nothing. And it also might help to type someone's personality, since some personalities are more prone to a certain disorder than others.
So, this is the place for you to share resources on this topic. I'll start:
(can't make links yet)