Rav Chaim Shmulevitz says (in Sichos Mussar) that the reason why a metzora, someone without kids, a poor person and a blind person are choshuv kemais (considered as dead), is because they all have something in common which they are lacking.
Each one, in their own way, is lacking in the ability to give and interact with other people. The people we give most to are our kids, a poor person is obviously less able to give and to help people (monetarily), a metzora is secluded from people, and a blind person can't connect to people on the highest level (he quotes from the possuk where Moshe saw the suffering of the people, that the highest level of connection is through sight). In other words, the whole point of life is being able to give to others, share in their pain, try and help them out and connect with them. If you are unable to do this, you aren't truly alive and are therefore considered as dead.
The message I took from this in relation to our struggle, is that being absorbed in self pleasure and lust gratification is withdrawing from people and taking selfishly, it's the opposite of what life is for, and the whole time we do it, we are adding ourselves to the list of 'chosuv kemais' - we are behaving as if we are dead!
As a side point, I try to have kavonoh in shmoineh esrei when saying 'mechayey maisim' that Hashem should help me act alive instead of dead.
May we all be Zoche to 'chose life'!