It can be really any addiction. Although "Defines the meaning of their life" could be somebody he/she lives for. They could live for the person, and they are the only person that makes them continue life. Or it could be God, because (I don't believe in god) supposedly is WHY you are on the earth, it's the meaning of your life is to serve god (that's the super religious reason) which I don't agree with personally. I think its just about a person that he lives for and is practically addicted to the person.
It can be really any addiction. Although "Defines the meaning of their life" could be somebody he/she lives for. They could live for the person, and they are the only person that makes them continue life. Or it could be God, because (I don't believe in god) supposedly is WHY you are on the earth, it's the meaning of your life is to serve god (that's the super religious reason) which I don't agree with personally. I think its just about a person that he lives for and is practically addicted to the person.