One of the more romantic reasons why intelligent/talented people get so depressed maybe consists of them asking questions like "Why is there so much sadness in the world", which presents itself like a sword of Damocles as an intractable problem to be solved, cured or debated away.

until perhaps you realize that depression is in no way correlated to intelligence or talent, simply that they had a more eloquent way of putting it across other than "sian", which is why they make such appealing case studies.

take, for example, nirvana's "all apologies"