Gabor Mate’s full defination of addiction is any behavior that gives you temporary relief, temporary pleasure, but in the long term causes harm, has some negative consequences and you can’t give it up, despite those negative consequences.
This can be appreciated through a provocative question — what are you addicted to?
What do you do that may have long-term negative consequences but provides you short-term comfort? By this definition most of us have been or are addicts.
When we explore addiction we find it is a solution (albeit usually a poor one). It is a solution to the problem of physical and/or psychological pain. So it’s not so much what’s the addiction but what is the pain? Addiction starts with pain and ends with pain.
In my opinion addiction may be essential to understanding the nature of happiness. Because it is ultimately an attempt at happiness. It is a failed solution to what is many cases the problem of the human condition. Maybe happiness then lies in healing the part of us that is “not okay”.