Hmmm so far i agree most with RSWells. i myself am also bi-polar and have been thinking about these questions since i was 14.
"why are poets more known to be in depression/bi-polar and/or easily descending into madness?"
that is a difficult question,my personal theories are far too long and far to tangled to really express though i would say that in my opinion,in general an artist is someone who seeks something. Visula artists seek the ideal form,they seek beauty,poets seek the ideal perfection of thought,musicians seek the profoundest most near perfection in melody that can be attained. I know each artist has their own ideas on their artistic creed,but personally i beleive artists are seekers,searchers for knowledge and for perfection. it kind of reminds me of what plato said about the human spirit coming from an ideal spirtual realm and bound inside an earthly body,plato said all things in the physical world were mere imitations of that perfect ideal spiritual realm,and therefore mankind could never be satisfied with earthly accomplishments,but would be always seeking for that ideal perfection. Though i don't completely agree with that i think he had a point. Anyways,what this has to do with anything: myself,i feel as if i am striving to attain some kind of perfection and since that's immpossible i often get quite frustrated with the whole mortality/imperfection thing. that's got to be my biggest GRRR!! in life.lol. it only fuels my chemicaly deficent disillusionment.
"can we be insane and not know it...what exactly is a state called-insanity?..."
i have heard it said that a person who is truely insane does not realize they are,and that a person who thinks they are insane is not truely.....that's an interesting thought,but perhaps not totally true. My own deffinition of insanity is a complete seperation from reality,there is an edge you cross,where something breaks and you no longer care about the world of reality,cease to care what people think completely,sometimes i think insanity is just to reject all social learning and requirements,on the other hard i think social perception of insanity is much differnt,as brad said it has a great deal to do with what you define as insanity and what you define as normality.
"are genius/deep thinkers more fond to this state called-insanity? "
I do think that many times and in many ways the lines of genius and insanity bleed almost into one. A close examination of a many of the greatest artists of the past reveals a state of genius and madness. Whether madness reaps genius of genius reaps madness is hard to tell,but if your interested in exploring the connection between manic-depression and artistic genius i suggest you look into a book,maybe your library would have it. it's called touched with fire by kay redfeild jamison and it is an EXCELLENT EXCELLENT book!! one of my personal favorites. it talks about alot of studies done by several doctors in several countries about the incredibly high percentage of artists with mental disorders and suicide compared to a "normal" control group of unartistic people. ah bosh i'll quit trying to explain it,just check it out if you get the chance,it also talks about particular writers and artists like van gogh,lord byron,shelly,etc. excellent book.
Fere libenter homines id quod volunt credunt~Julius Caesar