Glucocorticoid is what starts addiction. When your body is stressed, it releases glucocorticoid. When this substance is released, it directly affects the brain. The dopamine goes through a pathway towards the pleasure center or to the nucleus accumbens. The dopamine pathway is important when it comes to motivation and feeling good. Dopamine makes us have feelings like being excited, sad etc. One feeling that you have is that you want more of something. Overtime this feeling makes a person do more and more drastic things to get the thing they want. This is pretty much basic addiction. Inatic is what makes you want things. and that is what makes you want things and inatic thinks enough is never enough. To block addiction from happening, serotonin comes into hand to prevent dopamine from going too far. People with low serotonin need more of something to get enough. Pretty much somebody with low serotonin and hiper - sensitive to dopamine means you have addiction Scientists say addiction is a brain disease and its considered one because drugs change the structure of the brain and how it works. Video games are so additive because if a game is too easy then you get bored, but if its to hard you get frustrated and mad. But if its just right you start to like it because its challenging but not to hard.