Those people who are dependent on substances or activities that are negative to their well being need help whether they want to be honest or not. Most people who find themselves addicted to unsafe substances or activities simply affiliate themselves with people that have those identical issues, that will make it hard to try to advise these people in a helpful approach.
The best advice that can be given to an addict is advice which comes from goodwill. Advise addicts that you may worry about that there are physicians who can help them. Also, advising addicts to search for the aid of groups like Alcoholics Anonymous or Narcotics Anonymous is another great way to give those individuals hope.