Singing out loud takes the edge off depression, at least a little bit. Just about any activity does, actually, but singing is near the top of the list. Merely listening to music is also good, but I don't think it is in the same league. It's not accidental that most worship involves singing, and even the quiet Eastern forms often involve chanting. Living in New England, we have had lots of people in the pews who come for the concert as non-participants. Eventually, that leads to very good musicians and empty churches, I think.
I approve of different groups singing as part of the worship. Heaven seems to be a series of concerts, in which we are sometimes participants and sometimes the audience (I imagine we will be allowed to hum along.* I hope so, because I seem to do that naturally. We went to a musical last night and the accompanist noticed my humming the bass line. Fortunately, she was pleased. Not everyone is.)
When one is depressed, sometimes it is hard to get up and do even small things that will help, because the depressed mind, in Eeyorish fashion says "It won't fix everything. So why bother?) Encouraging friends who are depressed to get up and do something is a great gift. there are those encouragers and coaches who are very good at persuading those who don't want to to get going and do a little. Thrice blessed are they.
Getting yourself to church to sing out loud does some good, even in the natural realm. As today's sermon mentioned, explicitly mentioning gratitude also seems to help us, so worhsip music has some extra effect.
*In my next life, I hope to be a cello.