I've always been known as a helpful person. Ya know, that highly involved, teacher's pet type. This trait carries over to my friends and being there for them. Unfortunately, I am strongly influenced by other people's emotions. I also am going through my own mental health issues, so helping someone through theirs isn't always the easiest. Here are some things that we all need to remember when helping a friend through their mental illness, or any problem.
1. You can't "fix" anyone.
You can't magically make someone better. You are not a professional psychologist. Do as much as you can, and remember that you're not trained to do this. Be there for them: listen, bring them coffee when they're having a bad day, whatever will lift them up. Even things as simple as sending them a random text reminding them how much you love them is helpful. But they also need to help themselves, and you can't do that for them.
2. Remember your own mental wellness.
To me, this is directly linked to the idea that you can't "fix" anyone. If you are being heavily affected by someone else's mental illness to the point of it worsening your own mental health, it is okay to set some distance. Even if this is your best friend in the entire world, it is important to remember that you also need to take care of yourself.
3. Different people need different things.
It may be your instinct to run up and hug someone when they break down, but that could do more harm than good for people. Don't assume that everyone wants the same thing to feel better. Communicate to them that you want to help, and ask them what they need.
4. Try not to get annoyed with them.
Don't criticize them for having a breakdown, even if you think it's over the silliest thing in the world. Clearly, it's not silly to them. Keep your cool because often the calmer you stay the calmer they'll get. Outbursts are not fun to deal with on either side, but no matter how "good" the person is on any given day, they sometimes happen. Learning how to work through them will be infinitely helpful.
5. Encourage them to get help, but don't push.
If they're not already getting professional help, encourage them to do so. Even if they don't think their problems are "serious" enough, remind them that their feelings are still valid and they deserve to be helped just as much as anyone else. If they are against going to someone for help, remind them of other resources, such as meditation, journalling, and various hotlines. A quick Google search will bring up other ideas to suggest.