That would explain his utter fearlessness of dying, the complete lack of affect when he kills, the substance abuse, and the way he almost completely substitutes tradecraft and strategy with sex and showing up in fancy clothes until somebody explains things to him and then dies. He knows that's how his movies work (or, worse, he thinks it's the real world, and that this is how reality works), and it's driving him quite insane, but he wants to live, and that's how he gets to keep going, by being entertaining as defined by the rules of his world.
He might not have been an alcohol/pills/sex addict to begin with, and I wouldn't blame him for becoming one over time (how many movies has he lived through? how many faces, how many retcons? can he even keep count?)
(I don't believe this for a second, but the Bond movies as a nightmarish representation of the existential despair implicit in even the extraordinarily successful performance of fixed societal and gender roles — the prize and price of being James Bond is that you will only do things James Bond would do, and that everybody in your life will be a James Bond movie character — seems to me a bit funnier and more interesting than the surface reading. Also, it makes me feel empathy for James, who even when he's having a good time knows it's just another thing he has to do along his way to yet another traumatically painful confrontation with a villain and either a soul-crushing or a happy-seeming plot ending, neither of which will change his life in any significant way come the next turn of the wheel. He doesn't like pain, our Mr. Bond, and he tries his best to keep alive the characters he thinks might have a chance of making it to the credits, but it's no wonder he'll laugh at your face when you threaten him with death.)