Just being around someone who is suffering is a great help because when we interact with others, we produce the happy, healthy chemicals in the brain that make us nice, happy, coping, brave little souls. So we need to interact in a positive way, be active in a positive way and think in a positive way because when we do we produce patterns in the brain that give a constant flow of the good chemicals and get us feeling on top of the world.
Try talking. If they are not ready to talk about their challenges then do not force them. Just let them know that you are there for them. Talking goes a long way even if what you are talking about seems trivial. Don't be judgemental or tell them to snap out of it. Just listen with empathy.
Get outside. Exercise is great but depression and anxiety can drain your energy levels and leave you with no motivation. However, going for a stroll can do wonders. Sunlight releases serotonin. Serotonin is a really important chemical that gives us that mentally, healthy behaviour. Also, being in nature can increase energy levels, reduce depression and boost well being.
Do you have at least an hour a week to give up? Then why not volunteer at an animal rescue centre. Interaction with animals lowers the stress hormones. Stroking an animal can also lower your blood pressure.
Make plans. It's such a great feeling to have something to get excited about and to look forward to. It could be tickets to the cinema or to the football, a day window shopping, a walk in the park or a movie marathon.
Remember that it doesn't have to be big to be effective. A small step in the right direction is wonderful and you should take time out to congratulate yourself when you do this.