I am ex heroin addict
My old man drank away half his life.
So, here's my two cents based on my somewhat limited experience
Rehabs
Think twice before you just send a loved one off to one of these places. Yes, its a nice time-out session where you are not allowed near your high of choice and is taught a bit of chemistry and psychology.
BUT...
Firstly, you usually end up with a group of people reminiscing about the old days. Secondly, most of these institutions are run by churches that condition you with the idea that you can't get better without accepting their ideology. To me this is morally corrupt behavior and creates a whole new range of psychological issues for the person. Lastly, remember the analogy of sending a car thief to jail. He goes in knowing how to steal VWs and comes out knowing how to steal Mercs and BMWs. Most of these centers have a mixed population of people with different addictions. This happened to me personally.
AA
I've never been to one of these and comment much. First thing that comes to mind is the first line of my rehab post. Yes, it can be good to talk about your addiction, but we have shrinks for that. Rest of the time, its the last damn thing that should be on your mind. If you are still with a group after 5 years, you have a problem. You should be long over your addiction after 2 years.
What worked for me
After walking out of rehab I left my job and moved in with the parentals for a year who became my support group. In that year I did not set a foot outside the gate. I did not have any contact with 'partners in crime'. In fact, I lost most of those 'friends'. I had a few sessions with a shrink, which helped with underlying issues.
All of these things helped a great deal, but in the end only one thing got me clean. WILLPOWER. You can take a horse to the water...