Gosh, Mentalist acer, I am so sorry. I so rarely check my "questions" on HP. I wholeheartedly agree with what other answerers have said.
The to a successful intervention is to get unanimous agreement from the addict's support network (usually immediate family, but could also be friends, coworkers, etc.) that they are drawing a line in the sand. Remember that the addict is being "enabled" in his/her self-destruction by well-meaning "enablers." Enabling behavior is anything the prevents the addict from feeling the consequence of his/her drinking/using. It might be paying their rent, letting them live with you, giving them money, covering up for them, even giving them your own prescriptions or alcohol in the mistaken belief that this will keep them safer than if they have to drive somewhere to get their supply.
Each person at the intervention writes a letter to the addict and you take turns reading your letters.
If you have watched the TV show "Intervention" it really is like that. However, you don't have to have a professional interventionist present.
The goal of the intervention is to get the addict to admit they have a problem and to accept help. If they refuse, then you HAVE to stick to your resolve -- as tough as it is (and trust me, it hurts you more than it hurts them). If they refuse to change their self-destructive, hurtful behavior, you have to cut them off.
With any luck, the addict soon realizes you mean business.
They hit what is called a "bottom" (where they realize they can't go any lower).
I do have to agree that even if the addict agrees to get help, it's often for the wrong reasons (usually to get you off their back). Unless THEY want to quit and are willing to do the work to live clean and sober, they will go back to drinking/using.
The sad truth is that MOST alcoholics/addicts take multiple tries to get clean. And MOST alcoholics/addicts never do.
Well, now that I've written a hub-length answer, perhaps I should go and write a hub about interventions!
Good luck. Feel free to contact me on or offline if you have further questions. MM