In Rat Park, all the rats obviously tried both water bottles, because they didn't know what was in them. But what happened next was startling.
The rats with good lives didn't like the drugged water. They mostly shunned it, consuming less than a quarter of the drugs the isolated rats used. None of them died. While all the rats who were alone and unhappy became heavy users, none of the rats who had a happy environment did." from http://www.huffingtonpost.com/johann-hari/the-real-cause-of-addicti_b_6506936.html
And from Bruce Alexander site linked to above Bruce tries to compare how we think of addiction and how we should.