I come at this first and foremost from a place of recovery. Because I am in recovery it is ingrained in me to help other people in the recovery community. It started because I suffered so much and would do anything to keep that from happening again but its not just addicts that can benefit from doing for others. This may not be the case for everyone but I feel very strongly that when we are in a dark place one of the best ways to take us out of our own heads is to do something helpful, nice or beneficial for others. Think about how isolating and lonely depression can be. When I am in that place I am very self absorbed. Not selfish or ego driven, nothing negative like that but absorbed by how I feel, what happened to me and how things affect me.
Doing volunteering helps pull you out of that. It doesnt have to be elaborate. For me, I get the opportunity to go into some of the women's jails and institutions. But I have also done soup kitchen work, giving rides for people that have disabilities, giving quarters to people who need a cart at the aldi. Sometimes I have picked up the tab for someone's coffee. At christmas time I buy a few wawa gift cards and give them away to random people. When they have collection efforts for the homeless like socks or coats I try and help. I buy toys for catholic charities for the kids who cant afford a christmas. There are so many ways to take us out of ourselves and it can be the tiniest act of goodwill. Think about how good it feels to do something nice for someone expecting nothing in return... I believe it can really help our moods.