One of the most interesting was that happy rats who had pleasant quarters and social interaction would choose not to take drugs (morphine, iirc) even if they had used them previously. Pretty interesting stuff.
I do not 100% agree with Hari, who focuses almost exclusively on environmental factors. They are important but not the complete picture, IMO - there are physiological components too; alcohol dependency to me appears to be a clear-cut malfunctioning of the brain's reinforcement-based learning system. Environment exacerbates this, yes, but is perhaps not the root cause, or at least is not the sole actor in what is a pretty complicated drama.
https://theoutline.com/post/2205/this-38-year-old-study-is-s...
And Johann Hari is universally understood to be an incorrigible charlatan.
Hungry, Angry, Lonely, Tired
Naltrexone has substantially resolved hundreds of thousands of alcohol addiction presentations worldwide. Pharmacological remedies do exist. Connection is important, yes, but it is far from the whole picture. I do like Hari, like I said, but I feel like he is interested in selling himself and his story more than any particular desire to actually help.