Self-control is a factor too. Some people might get a big rush but have strong frontal lobes, other people might get a smaller rush but have low self-control an

Self-control is a factor too. Some people might get a big rush but have strong frontal lobes, other people might get a smaller rush but have low self-control and still end up consuming a lot / having their behavior reinforced. I think susceptibility to negative emotion is relevant too. Not all of the addictive content feels good. Lots of companies have figured out how to make negativity addictive.