As someone who suffers from anxiety and depression, I would like to say - just asking someone if they are OK is usually little to no help. People respond to that question with generic answers and react in predictable ways to avoid confrontation. Too often we ask that question and move on, and all that does is trigger further frustration and feelings of solitude. If you want to help someone you care about with depression, you have to actually demonstrate that you care in a meaningful way or they will just close themselves off further. You have to find a way to break through the shell, and that can be different for everyone. Most of all though, be a friend - not a facebook friend, a real life, get dinner or take a hike or go on a roadtrip with, share and trust a piece of your life with, friend. More often than not, that's what someone suffering from depression needs first. The rest you can work out as you go.