Why do slot-machine and video poker gambling addicts gamble? A new book by MIT Professor Natasha Schull argues that they don't play to win, but they play in order to continue playing -- that is, to remain steeped in that immersive, almost narcotic "zone" that shuts out the world -- an important distinction when it comes to understanding and treating gambling addiction.

Schull thinks this point — that for machine gamblers, it’s not about the money, but the escape into the “zone,” as Mollie and other gamblers call it — has eluded politicians who wrangle over casino openings and expansions throughout the United States, where more than 30 states currently have some form of legalized machine gambling. 

“It’s a real stumbling block for policymakers to understand that,” Schull says. She adds: “Everyone believes the harm is how much money is spent, and that what’s driving the compulsive gamblers is a desire to make money. But … the ‘zone’ is really what’s driving this experience. The idea of winning money falls away when you get to the point of addiction.”