I understand every post in this thread is a long read. Mines a little more of a story.
I've had a friend since he was 2. Best friends up til middle school.. not because we fought or anything.. We just grew up and went to different schools. Occasionally I'd see him around Safeway(where he worked.) I didn't know it but during that time he went through an extremely deep depression. Not because of me, he just had a falling out with a lot of people in high school, did a lot of drugs, drank a lot. Eventually all of his friends basically were just like fuck you get outta here. So he didn't talk to anyone while he was in school and just went home right after and try to sleep.
I had no idea. Until one day I skated over to Safeway on the way to work and I saw him (about a year ago.) It was sick, haven't seen him in a while. We kicked it once. He told me that hes hating it over at Safeway. They just threw him around and took advantage (BTW he wouldn't advise that job to anyone.) I told him that he should work over at my place, which happened to be our old elementary school. I told him how much it kicked ass and how fun it is just to sit around watching movies and playing with the kids. He called in the next day. Instantly hired just because the owners and all of the teachers loved him back in the day.
We went out to lunch a few weeks after and basically unloaded this whole story on me and told me if I hadn't come around he might've done something drastic. He's gotten a lot better. I've been helping him out and giving him some remedies. He's extremely happy and livin life at the fullest. We're best friends again and we kick it everyday.
What I told him to do and how it helped:
He swims a lot - Contact with water is literally a natural high. Working out in this sort of environment is fantastic for you. The water works every muscle in the body. Physically you are hurting but you are mentally wanting more and feeling good.
He left his old job - A bad work place is one of the biggest contributors to depression. Leaving this job gives more 'you' time. You aren't being bossed around or constantly told that you are doing it wrong. Being put down does not help.
He got a job working with kids - This is the one that probably helped him the most. Smiles, laughter, and all out fun is contagious. When you see all of these kids sharing all of these traits, you just cant help it. It is literally the best job I've ever had.
He dropped the drugs and alcohol - Neither are helping. They just prolong the problem.
He bought himself things - If you have the money, allow yourself a big purchase. My friend bought his first car a couple of moths ago. There is nothing better to your self esteem as self accomplishments. And when something is truly yours and not your parents, it's pretty awesome.
He doesn't avoid contact with his ex girlfriends and friends: Don't go out of your way to try and rekindle old friendships. They aren't worth your time. If you happened to see them around town after 3 or 4 years, approach them and create small talk. Don't bring up anything negative, may be some good memories. Chances are, they've matured since that time and nostalgia is awesome. It's a hard thing to pass up. If they act like a bag of dicks, don't worry about it, you've got it better than he does.
Seeing a doctor - Taking matters in to your own hands is extremely hard to do. A doctor will help. They will set you in the right path and give you a better plan than I can.
Starting your life over in a newer setting is much better than ending it.
Hope this helps.