You should probably hang yourself. Everything would get simple in no time.
isn't it possible that both are feeding each other.
both. depression is a lot like fear; it causes itself. eg: you don't clean your house, so that makes you depressed. now you can't seem to clean up your house because you're so depressed, and it gets worse, so now you're even more depressed. you said it best yourself, when you're depressed it's like you're "sinking into a daily downward spiral of negative thoughts". and the worse it gets, the worse it gets. :p
drink some beer and listen to faith no more
i think, that ussually (other then in chemical imbalences) there is an event that starts it and then it's like a self fueling fire that grows. the depresion takes away your happiness and the lack of happiness makes the depresion even stonger and it eventually one by one it takes over all aspects of your life if aloud to continue. so your question in a way answers its self. yes depresion can cause your life to fall apart and yes, the more your life falls apart the more you will feel depressed. i like literaturegurls answere the best so far. get into a routine that involves some sort of exersize and try as best as you can not to focus all of your attention on negitive things (i know it's hard not to sometimes) also, make a list of goals you want to achieve and try your best to focus on them. good luck
what durban said.
studies have shown that depression is usually caused by an outside trigger. once the process begins it becomes a vicious circle.
enlist in the military and that takes care of all of your problems with money and location and you can get away from the people who are holding you back. it's an option and will give you a purpose.