Nietzsche had some interesting theories about this. Like some kind of morbid deformity. For example the will to feel bad when listening to sad music.

If depression is at base pessimistic then an understanding of pessimism in terms of what a depression characterizes is an adequate reference point to understand depression as a whole.
Pessimism im terms of depression seems to be a pessimism of overcoming or changing; that is, living a life that is not chained to that pessimistic depression.
Depression is usually constitutive of an inability to overcome certain aspects about one's existence that have associated with them negative emotions or pain.
The pessimistic depression consists of an inability of not finding a way out but finding a way around, onto a different path atop different premises. These different premises would be what would be constitutive of happiness or positive emotions. Often a depression is because of an overwhelming number or magnititude of negative emotions and experiences, and the future seems to be determined by these experiences.
In order to find a different path and a different future, one must inevitably act and think and plan based on something else, which is extremely hard. Depression is often because one has a reason to be depressed: they will the depression. They will the depression because they do not want to let go and accept the indefinability of these negative emotions and experiences. People do not want to let go of how they feel because that would be departing from oneself... That is where the radical acceptance comes in.
It seems to me that the inability or unwanting to let go and accept completely the unchangeability of the past is because one is uncomfortable with that past. It is easy to accept having been happy, because one allows these happy experiences to lose their determining quality and add to their totality of personality. A negative experience, on the other hand... One does not often want negative experiences to be integrated into the personality. But this must happen. One must accept the darkness in order to not have a light that only exists in relation to such a darkness.
"A tree can only reach the heavens if its roots reach down to Hell." C G Jung

Nietzsche had some interesting theories about this. Like some kind of morbid deformity. For example the will to feel bad when listening to sad music. — Heiko

Yes, if you care to expand please do. I'm quite interested in his views on the will and mental ailments like depression. I'm not sure if he explicitly talked about depression though.

Nietzsche was interested in a radical acceptance of the human in terms of Ubermensch, the ideal human... The overhuman. Typically people look at sad experiences or depression in terms of something bad, something that needs to be expunged. Nietzsche would have disagreed. "To live is to suffer; to survive is to find meaning in the suffering." Friedrich Nietzsche

The meaning of life is reaching something, but in reaching that something the meaning will have been in the reaching.

Sadness would not exist if it were not juxtaposed with happiness. And thus it is that we base ourselves in how far we have reach down into the abyss but, consequently, we will know how deep we ourselves are.
"When you look into the abyss the abyss looks into you." Nietzsche

Depression is usually constitutive of an inability to overcome certain aspects about one's existence that have associated with them negative emotions or pain. — Blue Lux

So, again an issue of motivation, and the power of the will. Is that correct?

Depression is often because one has a reason to be depressed: they will the depression. — Blue Lux

Huh? How can one will one's self into depression? That would be extremely irrational, no? Unless this is an unconscious process, yes?

hey will the depression because they do not want to let go and accept the indefinability of these negative emotions and experiences. People do not want to let go of how they feel because that would be departing from oneself... — Blue Lux

I thought depression was remedied by realizing those feelings, and not suppressing them? Or are you talking about suppressing them and not realizing them? Perhaps, I got the reasoning wrong?

The realization of a negative emotion is inconsequential. What is important is not letting it remain in its determining configuration, as it will determine the future and it will chain you to it, because it is outside of you, not integrated, not accepted. Accepting an emotion is not suppressing it actively. But that is what would happen eventually, for the unsuppressed emotion is that which persists and characterizes the Will's inability to escape it.

In case anyone is interested in the modern day conception of 'willpower':

http://www.apa.org/helpcenter/willpower.aspx

Pretty good read. Seems intrinsically linked with motivation; but, motivation is more internal than willpower, which is more malleable and external facet of human nature.

Depression is willed because one does not want to free that emotion. One wants it to determine them because of its power and its individual meaning. One feels that this emotion is greater than the self and if one 'loses' it, one will lose themselves in the process. In a sense it is true, for a personality consists of emotions... But a personality is the integration of emotions. If one does not integrate then one will disintegrate as such. Is it a coincidence that depression is often characterized as a falling apart?

Realizing and accepting a negative emotion will inevitably deprive that emotion of its power--its power to determine.

The question is not to be a Stoic, non-emotional person... But to have power over one's emotions and have the Ubermensch as the ideal! To OVERcome.

The realization of a negative emotion is inconsequential. What is important is not letting it remain in its determining configuration, as it will determine the future and it will chain you to it, because it is outside of you, not integrated, not accepted. — Blue Lux

This is interesting. So, you're saying that a negative emotion is inconsequential insofar as it is not accepted? Therefore, the talk therapy of psychology is helpful, yes?

Accepting an emotion is not suppressing it actively. — Blue Lux

So, therefore you are talking about the unconscious process' of defence mechanisms or such?

But that is what would happen eventually, for the unsuppressed emotion is that which persists and characterizes the Will's inability to escape it. — Blue Lux

Unsuppressed or suppressed, not sure I'm understanding you here.

to survive is to find meaning in the suffering — Blue Lux

...and overcome it?
Depression, seems to me, to be a completely useless and destructive human-condition. Allmost like fear, but not quite. As fear can be a rational feeling, and warn us of dangers, yet be an irrational feeling that prevents us from thinking rational.

Depression itself is a condition... But I think, contrarily, it is very useful. It shows a person their depth. It also shows a person their power if they overcome. "That which does not kill you makes you stronger." Nietzsche @Posty McPostface

But if you dont overcome it, its self-destructive...a disease.

is depression rational?

Accepting an emotion is not suppressing it actively.
— Blue Lux

So, therefore you are talking about the unconscious process' of defence mechanisms or such? — Posty McPostface

Not necessarily. What I am referring to is the fact that, subsequently, down the line after accepting an emotion, the emotion's power over the will becomes suppressed. The accepting is not the will to a suppression but a will to allowing different emotions to come and influence and be accepted and integrated as well... And the more and more this happens... The more integrated emotions constitute the personality, and therefore the less power and influence each singular emotion could have. For the integration of an emotion does not completely strip the emotion of its power, it simply allows other emotions to materialize and show their significance, which is an aim of talk therapy or psychoanalysis.

Unsuppressed or suppressed, not sure I'm understanding you here.
13m — Posty McPostface

Sometimes people think that suppressing an emotion is not bringing awareness toward it, or remaining unconscious of it, allowing it to metastasize. This is the case prior to the acceptance of an emotion, which suppresses it in terms of its determining power and influence OVER the will.

What springs to mind: drunkenness of emotion (Dionysos), cultural decadence (noblesse of suffering) and the turning-backward of natural destructivity (will to power).
I could not summarize this along the lines of Nietzsche (as he is really hardcore), but the general statement would be it is not the inability to "lift (yourself) out of depression" but the inability to stop yourself sinking into it. The depression itself, the painful thought as uncontrolled will to effect, as exercise of power in the absence of power to effect the world.

That depends. Some people do not want to get rid of their depression for good reason. Some people, in this case, can only live depressed. They cannot live without their negative emotions, because there are simply too many of them. They hold on to them.
Or, perhaps, after the integration of so many negative emotions into the personality, one finds themselves still at a loss. One simply has too negative of a personality.
But this is not the end.
Creativity is the key. Creating new experiences. Creating new understandings for oneself. Living differently.
The true definition of insanity and furthermore irrationality is doing the same thing over and over again and expecting a different result.
But, what do you do if someone does not want a different life? What if someone does not want to change?
In that case...
Psychoanalysis could uncover a subjugated will that is, prior to anything else, not able to find meaning in changing.

...so people like being depressed? :meh:

What I am referring to is the fact that, subsequently, down the line after accepting an emotion, the emotion's power over the will becomes suppressed. — Blue Lux

What do you mean by this? Do you mean this in the manner that emotions that are suppressed are also affecting the will in a negative way?

I could not summarize this along the lines of Nietzsche (as he is really hardcore), but the general statement would be it is not the inability to "lift (yourself) out of depression" but the inability to stop yourself sinking into it. The depression itself, the painful thought as uncontrolled will to effect, as exercise of power in the absence of power to effect the world. — Heiko

So, it's an endless spiral out of control? Perhaps, the issue, then-past willpower-is control?

willpower and control seems to me to be the same in this scenario....

I personally, in my depression, have found myself wallowing in it, willing it further, in the past. It's not that I 'liked' it as much as I found meaning in it, aside from anything and everything else that seemed meaningless.

willpower and control seems to me to be the same in this scenario.... — Aleksander Kvam

Yes, there's certainly a causal relationship between the two. But, chicken or egg? When one has no willpower they feel out of control of their lives or some situation; but, not being out of control and having no willpower?

Yes, agreed! It is not so much an alleviation as it is a stopping of a sinking.

So, is it:

I have no willpower, therefore, I feel out of control? (The converse doesn't sound right.)

So willpower is the life-perserver in the ocean of depression. Low willpower could only mean that you are more likely to succomb to depression. But I fail to see the benefits of depresson, unlike fear, that I mentioned.

Changing away from depression is a realization of benefit. Thus changing from a depression is finding a way it benefits you.

So why "will it further" ?

It is a spiral out of control for the personality, for the personality which would be a lack of totality in relation to the negative emotions that have more power and more of a control on the personality. Nietzsche would say to empower the personality by all means... Which would be the integration of emotions into the totality of the personality, empowering not emotions themselves but that which they become a part of constituting, namely the personality.