Smokers who want to quit have all sorts of tools at their disposal: call lines, nicotine patches, medication, friends, doctors. And now, texts.

Getting counseling through text messages doubled the odds of kicking the habit compared with those who relied on Internet searches and basic information brochures, a study published Friday in the American Journal of Preventive Medicine found. It's one of the few long-term randomized trials looking at the effectiveness of texting as a method to help people quit smoking.

The participants were enrolled in Text2Quit , a publicly available Web-based program that sends personalized texts and emails to smokers to help them cut down as they approach a target quit date.

In moments of weakness, people could text keywords like "CRAVE" or "STATS" to receive tips about fighting cravings, an update on their progress or even a trivia game they could play to distract them.

"I was interested in helping people quit smoking with cognitive behavioral therapy, and given the widespread use of cellphones, I thought this was a neat opportunity," says Lorien Abroms , a professor at George Washington University's School of Public Health in Washington, D.C., and the brain behind the program.

Abroms got the idea about five years ago, when there weren't other options available for receiving counseling or medical advice via text. So she started developing a program herself. Since Text2Quit was licensed and launched in 2012, about 120,000 people have enrolled.

In the trial, Abroms and her colleagues recruited 503 people by posting an ad on Google that would appear when people searched phrases like "quitting smoking" or "how to stop smoking." They randomly assigned some to enroll in Text2Quit. The others received a brochure in the mail and were encouraged to search for self-help materials online.

The researchers checked in with participants, who tended to skew female and white, four times over the course of six months to monitor their progress. Those who couldn't be followed up with were classified as "smokers."

By the end of the six months, at least 11 percent of the participants using Text2Quit had successfully quit. Only 5 percent of the participants using self-help materials had quit. (The researchers verified the self-reports by taking saliva samples, which shaved the numbers down by about half.)

That may not seem like a big deal, but it means that even with a conservative estimate, texting doubled a participant's chances of quitting. And, Abroms points out, it's about as effective as other methods, including phone counseling.

"We have a number of proven therapies in the U.S. that are recognized," says Abroms, like calling a help line or using a nicotine replacement patch. "But now we're accruing more evidence that we can also use text messaging on mobile phones. So we have another tool to quit smoking."

In a small pilot study published in 2012, the researchers asked people who were getting counseling from both a call line and Text2Quit which one they liked better and why.

"They liked that the texts came in the daytime," says Abroms. "Rather than scheduling a 45-minute phone conversation, usually at night, they could just glance down at their phone during the day. It was a constant reminder that they were quitting smoking."

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