RALEIGH, N.C. — More teens now prefer electronic cigarettes over traditional cigarettes, according to an annual government drug use survey. Another study has now added to the evidence that electronic cigarettes can help stop or reduce smoking.

E-cigarettes are battery-powered devices that produce a vapor. Some contain nicotine. New research out of London says smokers who use them may be more likely to reduce their smoking or quit altogether.

Mark Foster recently picked up electronic cigarettes and says he's close to kicking his regular cigarette habit.

“Since I got to using these more powerful e-cigarettes, my cigarette consumption is 2 percent of what it used to be,” he said. “As a replacement for a cigarette, they’ve really, for me, they’ve taken over.”

Peter Hajek, a clinical psychologist and the study’s author, said the main finding is that e-cigarettes can more than double the chances of stopping a person’s smoking.

The study looked at data on more than 650 current smokers. Researchers found nearly 10 percent of people who used e-cigarettes were able to stop smoking within a year. About 36 percent of e-cigarette users cut the number of traditional cigarettes they smoked in half.

Still, experts say, more study is needed on the long-term safety of the devices.