Not sleeping can lead to mania. When manic, I feel motivated to stay up. I don't feel tired....I feel wired and as if there's just so many things running through my head: it can be new projects, etc. If it's mixed mania, it's usually related to things I'm delusional/paranoid about or fixation on really negative things. I don't experience the need for sleep during those phases, since I have excessive energy when manic. If you're simply just having trouble sleeping, then it's not automatically mania, but it's still important to get enough sleep, especially if you are prone to it.