"Gotta have it" is the thought process of an addicted person. A drink, a drag, a hit, a line, a pill, another piece of chocolate. "Gotta have it." What drives this powerful need known as addiction? The problem isn't with the abused substance or activity, contends Dr. Ruden. The problem lies in the brain. As a result of genetic, hormonal and environmental factors, dopamine and serotonin levels in the brain are altered, and this sets the stage for the...