anybody who is really addicted to gambling knows himself because it is obvious enough when you keep losing money and keep coming back. so unless they start wanting to give it up on themselves i don't see any solution for their problem. they are the only ones who can help themselves.
Like you said they are getting back even if they have lost a lot in gambling who in their right minds would still be back when they have taste defeat on gambling? so why would you say that addicted gamblers should know on themselves that they are the only one who could help themselves if they don't know what exactly they are doing? I think if you know a person or you have a friend that are addicted with gambling you should help him in any help you can give!