I've got some about Sam.

Needed (http://archiveofourown.org/works/930891) by noobieninja. (This is an AU where Adam has been raised with the Winchesters since he was young, but the story is 100% centred around Sam and his mental illness, he's extremely depressed and suicidal).
AngstyAly wrote and AU of this AU where Sam did commit suicide, there's time travel involved where Dean and Adam go back and stop him. This is one of my all-time favourite fics but sadly it is a WIP and the author hasn't updated it in over a year. Still, here it is if you want to check it out: A Second To Last Chance (https://www.fanfiction.net/s/10720156/1/A-Second-to-Last-Chance) by AngstyAly

Open Book (http://archiveofourown.org/works/7075096/chapters/16081192) is a WIP by pineapplefan, but they update regularly. Set pre-series and is about Sam suffering depression.


You Better Start Swimming (https://www.fanfiction.net/s/8130931/1/You-Better-Start-Swimming) by Alex L. Kerr. This is set pre-series and Sam was kidnapped, the story follows the aftermath after being rescued by Dean and John, Sam is suffering PTSD and is very depressed and suicidal.

^I hope you don't mind pre-series lol

And a non-preseries fic: Sea Story (http://archiveofourown.org/works/7662202/chapters/17447392) by Chakatai. It's about Sam and Dean taking time off in a seaside cottage. The fic is very mysterious and a lot is implied. There's a really interesting author's note at the end which explains how things are open to interpretation but I think this definitely deals with the topic of suicide (although in a very symbolic way)

How The Wild Things Start (http://archiveofourown.org/works/4754549) is and AMAZING story by foolscapper. It's a post season 9 AU where Sam was taken and forced to fight in these monster fighting rings. The result of his experiences leaves him in a poor mental state. It's not quite what you asked for but it's an amazing story which is nearly complete, the author updates regularly.

Jared fics:

Rivers Till I Reach You (http://archiveofourown.org/works/7408642) by ElenyasBlood. It deals with depression, mental illness and suicide, but the relationship formed between Jared and Jensen is really sweet. Jared is a patient in a mental hospital and Jensen is working there as part of his community service. When Jared sneaks out of hospital and follows Jensen home, Jensen ends up taking him as a plus-one to his brother's wedding rather than taking him back to hospital (these aren't spoilers, it's all in the summary :)). I don't read much rpf but I really enjoyed this.

I hope you find something you like, I went for a bit of a variety :)