I'm not sure it's right to say that all demons in possession cases are there by invitation
— I think the implication of that would be rather terrifying considering the numerous times the bible records Jesus/possession/children.
Also, though not exactly/explicitly related, when Jesus was asked about the man blind from birth (Who sinned, this man or his parents?
) the answer was Neither.
(John 9:1-5)
As he walked along, he saw a man blind from birth. His disciples asked him, “Rabbi, who sinned, this man or his parents, that he was born blind?”
Jesus answered, “Neither this man nor his parents sinned; he was born blind so that God’s works might be revealed in him. We must work the works of him who sent me while it is day; night is coming when no one can work. As long as I am in the world, I am the light of the world.”
Think about all the times that someone addicted to any substance want to quit, says they will quits, quits, and then falls off the wagon again and again.
The demon is always there.
I'm not sure it's wise to equate addiction with demonic influence.
While it's certainly possible that one impacts the other, this sort of thinking completely dismisses the fallen nature of the flesh.
And let's be honest, even without demons pushing towards something, we are perfectly capable of sending ourselves to our doom:
(James 1:12-16)
Blessed is anyone who endures temptation. Such a one has stood the test and will receive the crown of life that the Lord has promised to those who love him. No one, when tempted, should say, “I am being tempted by God”; for God cannot be tempted by evil and he himself tempts no one. But one is tempted by one’s own desire, being lured and enticed by it; then, when that desire has conceived, it gives birth to sin, and that sin, when it is fully grown, gives birth to death. Do not be deceived, my beloved.