Jennifer Matthews: During breaks at work, Mattie Williams now reaches for a snack instead of a cigarette pack. And a soda now subs for a smoke

Mattie Williams: I never, you know, ate snacks or anything. I just used my break to smoke.

Jennifer Matthews: Mattie lit up for thirteen years. She says the stress of her two jobs fueled the fire.

Mattie Williams: Right before I decided to quit I was smoking almost two packs of cigarettes a day.

Jennifer Matthews: Trying to quit cold turkey didn't work.

Mattie Williams: I found myself pacing the floor. If I didn't have any at home I'd be looking around to see if I left one in the ashtray or something.

Jennifer Matthews: So Mattie enrolled in a study to compare the habit of smoking to the craving for nicotine. Participants smoked nicotine-free cigarettes. The studies showed the urge to light up can be stronger than the need for a nicotine fix.

Dr. Jed Rose: Most people think of craving and addiction as a craving for the drug effect per se, but it's really a craving for the whole behavior, especially with something like cigarette smoking that presents a rich context of sensory cues and habit components.

Jennifer Matthews: Researchers say when used with traditional nicotine -replacement therapies like patches and gum, nicotine-free cigarettes could help smokers quit for good. Mattie says it's worked for her.

Mattie Williams: I feel great. I feel great. My car smells better, my house, my clothes.

Jennifer Matthews: Not to mention - the health benefits of quitting. This is Jennifer Matthews reporting.