In a "comment a positive message on your facebook status" way? Sure, I'd do that. In a real, be-there-no-matter-what, show up consistently for them even when they're a drain and show no signs of improving for months on end? Some I would, some not.
Really, though, friendship isn't a commitment. I am friends with people I enjoy spending time with. I have plenty of people I am no longer friends with because we stopped having things in common or geography got in the way. That's not a failure on them or me as people. I've made new friends and so have they.
I don't feel bad about saying no to things I don't want to do. I don't want to spend time with someone who isn't fun to be around. With some close friends, I will, out of some sense of obligation or caring about that person. With most friends, I don't feel responsibility over their emotional state, and would rather support my own.
I would argue any "friends" you have that you wouldn't be there for when its not convenient or "fun" for you to be around are not real genuine friends. I cannot imagine a single one of the people I actually consider my friends being unwilling to be there for me if I was going through a depressive spiral and I can't imagine me not being there for them if they were. Friendships are a form of relationships and that means being together through thick and thin, when its easy and when its hard. If you are unwilling to be there for your "friends" when its hard only when it's "fun" then you are not friends as far as I am concerned, you are acquaintances.
Really, though, friendship isn't a commitment. I am friends with people I enjoy spending time with. I have plenty of people I am no longer friends with because we stopped having things in common or geography got in the way. That's not a failure on them or me as people. I've made new friends and so have they.
I don't feel bad about saying no to things I don't want to do. I don't want to spend time with someone who isn't fun to be around. With some close friends, I will, out of some sense of obligation or caring about that person. With most friends, I don't feel responsibility over their emotional state, and would rather support my own.