Free-will in the most simple definition I can put it, is the capacity to learn from consequences.
Some people however seem to be lost this attribute, like for example an alcoholic, it is not like alcoholics are not a subject of all the negative consequences that come from drinking, they are actually experience the most negative consequences because they do the most drinking. Wake up every day with a hangover, cirrhosis etc.
However ass soon as they start to get a little better they just jump back in too drinking heavily, like nothing significantly bad just happen to them.
You could say that it is the result of extended abuse, that they received in the past, from what I read most if not all addicts have lived traumatic childhoods or have experience other traumatic events in their lives, that triggered their addictions.
However the abuse happen in the past, it is technically no longer an active threat in to their lives, why in some cases even if you remove those people form the abusive environments they continue to have no free-will!?
The purpose of all abuse is to eliminate free-will, if someone puts a gun to your temple does so to change your motivation from doing whatever you want, to what it is more in the benefit of the person with the gun. This doesn't completely eliminate free will, because you still have choice, you can chose to die or do what the person with the gun wants you to do. Free-will it is impossible to eliminate because it is part of self preservation.
You can't fully eliminate it but you can limit the amount of options and choice people will have, this means that everybody has free will and is responsible of their actions, including addicts.
Whenever you experience chronic abuse, your mind adapts to the abuse, you start controlling yourself to please your abuser in order to eliminate some of the external abuse.
And in this process you lose your autonomy, you no longer have the capacity to do whatever you want whenever you want. Because you associate this with pain.
And if your actions are heavily influenced by the abuser that is controlling you as a puppet, this can create the illusion that you are no longer in control of your actions or responsible of your actions. In order to restore your free will you have to first gain back your autonomy.
Which seems like a paradox to tell someone who is self destructive to do whatever they want whenever they want. But the reason why they are self destructive in the first place is because someone took their autonomy. Autonomous people simply follow self preservation, whenever you are free you won't hurt yourself intentionally.
Abuse is being forced by someone to do something you don't want for their benefit, mental illness is forcing yourself to do something you don't want because you think that you will benefit out of it.
One of the biggest lye ever told is that if you let people to act free, they will hurt themselves or hurt other innocent people. And that it is not so much that you need protection from the "bad" people, but is it you, that you need to be protected from.
I am not saying that not every human being on the planet has the capacity to become corrupted, off course we do. But most people under normal circumstances are good. What is spreading the virus of corruption is the abuse, attacking their autonomy to diminish their ability to have free-will. It is like a virus that attacks your immune system.