I want to make a story of a twenty year old with depression and how he often finds himself in rage at the world and how everyone else seems to have a better life than him.
My first thought was Holden from A Catcher in the Rye. Lots of angst, depression, self loathing in there, but also fits of extreme anger. I seem to remembering him fantasizing about violently murdering a pimp.
Or you can have my type of story where you pulled your shit together and due to the confines of society the main character begins to crawl and drop under the pressure to reach the levels of madness. Slow, subtle and let it burn.
As a twenty-six-year-old with depression, who was a twenty-year-old with depression not super long ago, I might be a good resource. Though... it'd help if you asked specific questions.
You will probably need to to a lot of research to make this realistic. If you have no personal experience with the topic, it will be much harder to write.
You need to figure out why he/she is depredded - is it family/work/relationship end/ death/illness? Once you know that then you need to know how MC reacts - anger/isolate themselves/ violence. then how do others react? Fred lost his job and come how so angry he hit Brenda. The next day he came home from the bar having drunk away his trouble, Brenda was gone. She'd left him. I know that is oversimplified but I think you need a basic plot first, don't worry about it changes as you go.
