Haven't read the whole thread here so I'm just cutting in, but I find for me it's more the pressure to reply that gets to me. It's okay if you send me a message as long as it's equilly okay (and expected) that I won't reply. It's an individual thing, but what's most important for me is that the friend is there for me when I come out of my depressed state, no matter what happend during. Again, ask. But maybe send a smily with a note "for support" or something, just to let them know you're not expecting a conversation just that you're supporting them and want them to be okay.

Hope that helps.