Marc Kern has an excellent post on the nature of addiction. He basically breaks down the various addictions into active (e.g., gambling, smoking, shopping, drinking, etc) and passive (e.g., failing to exercise, inability to work or study, watching too much TV).
It is a subtle and seductive process, which occurs over the course of time. What seems to happen is this: In the early stages of our unhealthy behavior, we are sociologically introduced to a substance or an activity that gives us immediate positive feelings while masking the realities and responsibilities of everyday life.This is a theory that strikes a rare balance between neurological and consciousness-based ideas. I tend to shy away from molecular neurobiological explanations of addiction. Of course there are neurological underpinnings to any behavior, but the understanding of how and why an addiction takes place has to be seen in the context of an individual's life experience as well.
Through friends, acquaintances, advertising, or just plain accident, we are introduced to things like cigarettes, alcohol, street drugs, pornography, shopping, the advantages of being sick, certain types of food, or even the 'good old' work ethic.
Through the gradual use of these substances or behavior patterns our biological drives take over and we start to need or even crave this stimulus. Before we know it, the needs of our mind have taken control and through our psychological processes we can feel stimulated and relaxed at the same time.
We can feel powerful and friendly, or closeted and protected from the world. It is the FEELING that leads to the ACTION. The substance or behavior that seems to work the best becomes our "Elixir" of choice, our "secret thing" that we do that we think no one else recognizes in us.
For more, I take you to Walk Hard, the Dewey Cox Story: