As I understand it there are various forms of addiction emotional, chemical, behavioral, etc. Different people are probably more prone to one form of addiction than another. My theory is that we like to escape from stress, reality, a relationships, etc. and we become addicted to whatever form of escape we have chosen. Of course, there are different severity levels to addictions. Some additions are basic distractions and time wasters while others totally destroy peoples lives.
Our very thought patterns are addictive because as neural pathways are created our cells are set up to maintain and en-grain those patterns. Addictions are part of our natural programing which can serve us well in certain respects. Becoming aware of our mental addictions can be empowering because we learn how huge and underrated the power of choice is.