Having suffered from depression on-off through the last couple of years I can also confirm this is a problem for many, since several of my friends have suffered depression too. There is a lot of hullaballo, since, yes, doctors are very quick to brand a case as depression and stick you on a years prescritption to citalopram or whatever. In my own experience, it seems like a warp in perception that comes from an underlying low mood, which therein influences your thinking. Like that shit feeling after a really hard night out, or the comedown, for those who use any kind of drug. One day I would think XYZ about a situation or life as a whole, and it would make me sink further and further down inside until I was feeling almost broken. Then my mood would change, and I'd be like 'why the fuck was THAT bothering me'? It really is the biggest anti-inner game condition you can find, and it's important to deal with it and understand it however you can.

Some of the things that I have found worked for me, have been reading philosophies, which can indeed make me feel better when the source is some kinf of 'spiritual' problem or whatever. But I have found myself naturally slumping back down for little to no reason. Citalopram certainly works and I believe it has been well verified to be more than a placebo. The same they say, with St. Johns Wort. My only problem is it comes and goes, so it's hard to be sure what's fixing it.

I would argue, from personal experience, that it's very important to keep a pleasant environment around you, and often, like a lot of PUAs say about girls, I find it's better to change my feelings, now my mind, which comes through doing things I enjoy as well as forcing myself to do the things I want to do that scare me. That's the basis behind CBT. I've recently tried a bit of meditation, which has variable effects for me, but it's been very much verified scientifically. A large amount of it is a kind of self acceptance too, like when you acknowledge you aren't feeling that great, and you accept it and work with it, but not submit to it, you lose a lot of the 'negative' tension it creates.