Hi Desdemona,
Two ways of looking a psychosis/depression...
For me, psychosis (mania and depression) made me see that it is heavily connected to what we think of as 'dreams'. My mania was like a slow dissolving from reality, into a more loose mental state.
First - how does the brain work? From the first moments of our lives, our brains are storing away sense memories, and also storing away the relevance of each memory to other memories.
For example, if you think of an oven, and the experience of burning your hand. There's a whole string of identifiers in there - oven, white, metal, hard, hot, hand, pain etc.
And each of these has a connections to other sense memories - metal = oven, car, tin, spoon, gold, filing cabinet, bicycle frame etc etc.
So it's like one giant lattice of associations. Behaviours all come with socialised connections ie. sex = private etc.
I think of an analogy of a musical instrument like a guitar, with vibrating strings, that can resonate with each other.
So mania was like all the strings being in tune, and 'excitable' - everything that you sense, in turn vibrates into many other associations. Numbers with numbers, thoughts with other thoughts etc.
Depression is like someone has their hand resting on the guitar strings, so everything falls flat, with no connections with anything else - apart from fear - my theory is that depression is like the 'fear' node is overly dominant - so everything seems connected with blackness.
It's not rational - it's a dysfunctional brain state.
Like judasishmael said - suicide is like wanting to stop a traumatic mental state, much more than it is a rational response. There's many people in the world living in extremely desperate situations, but they won't be depressed unless their brain chemistry has become dysfunctional.
Even that is debatable - I think my brain knew that my mania was getting out of control, and my depression was it's attempt to 'put out a fire'.
The second part is about the connection to the 'dream state'. The dream state is very like mania - in fact I think mania is pretty much like your brain withdrawing slowly from reality - and the random association part of the brain starts to take over more and more. I think that's why people sleep less - the body is getting very confused about whether it asleep or awake.
When people ask about responsbility for bipolar actions, I often say to people - if you were held morally, and legally responsible for what you do in your dreams, would that be fair or reasonable?
Which leads to the conclusion - what if we're effectively always dreaming - even when awake. It's just that waking reality floods our senses with cue from the world that makes our brain process more stable.
Except in the case of mental illness, the sense stimulation is decreased, and our brain association process is increased - a sense of confusion, or unrealistic thoughts.
It's a theory that seems to fit a lot of different conditions.
Our kidneys sometimes are dysfunctional - we called it diabetes and there is no blame associated with it. Why people should think brains are perfect, but people's 'personalities' are flawed goes all the way back to mind/body Dualism, and organised religions idea of the 'soul' and 'being moral'.
Turns out these ideas are the ones which are highly flawed - and are the reason why life is hell for so many people with mental health conditions.