I've been fighting my inner demons since I was 11 or 12. The feelings of despair seem to mellow with age.
If you look back are there no moments of happiness? I know from experience that they can be hard to recognize when you're in that dark place in your mind, but I know there have been times, even if they're just fleeting moments, where I was truly happy. And I strongly believe I have a few such moments ahead of me. Then again, where is the line between joy and happiness?