Have to disagree there, Ryan. I'm going to take a guess here and say you're not actually depressed or have been yourself, and the only way to fully understand it is if you are and or have been. I was on anti-depressants for... let's see... 3, 4 years? They stopped working about 1 year in, and actually left me somewhat addicted (Okay, addiction isn't really the right term. more like fear of not taking them). Once your brain kicks in and you realize how ****ed up the situation you're in really is, you think to yourself "holy ****, maybe I really should be depressed".
Take an MAOI or first generation antidepressant and then tell me what you think

Seriously, modern SSRIs are a world of difference from the older medications, and the atypicals are even better (Buproprion is better known by its commercial name, Zyban, and it and Zoloft, which is a Generation 2 SSRI are two of the best on the market).
Not all depression itself is situational, but it is true that depression can be triggered by circumstances. However, "depression" that disappears just because circumstances improve isn't depression: it's called stress, and the two are often confused.
And given that your profile says you are 15, there is no way in hell you should EVER have been prescribed any sort of anti-depressant. They are not tested in adolescents, and they don't work on adolescents.
Now, I'm probably going to take a lot of flak for saying this, but I view depression as an early warning system of sorts. The bodies way of saying you need to change. Now I see a lot of you calling depressed people unmotivated, or lacking in willpower, but that could just as easily be diagnosed as a symptom of modern society.
Major depressive disorder creates a literal inability to utilize cognitive thinking and complex planning - this is extremely different to what you're referring to, which is apathy. And that is a falsehood anyway; people have been saying this crap about the downfall of modern society since language was invented, and prior to that they drew paintings.
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It occurs to me that it wouldn't hurt to have the DSM-IV-TR definition of depression in this thread. This is the best capture of it I could find open on the web (unfortunately, the DSM-IV is a copyrighted work which requires a subscription or purchase). http://counsellingresource.com/distress/mood-disorders/depression-symptoms.html Be sure to read the definition of major depressive episode as well.