Past research has yielded conflicting evidence on the effectiveness of such aids since they seem to work in clinical trials, but less so in a real-life setting.

But the current researchers, whose findings appear in the journal Addiction, found that some quitting aids were linked to four-to-six-fold higher success rates.

"Smokers in the United Kingdom, Canada, Australia and the United States are more likely to succeed in quit attempts when they use (drugs) or nicotine patch," wrote study leader Karin Kasza, a statistician at Roswell Park Cancer Institute in Buffalo, New York, and colleagues.

Kasza and her team surveyed more than 7,400 adult smokers in the United States, the Britain, Canada and Australia on their quit attempts, including whether they even remembered every time they resolved to give up cigarettes.

They then tracked these people to see how many had succeeded in staying smoke-free for at least six months.

About 2,200 people used a prescription medication or nicotine replacement therapy, but the rest did not.

Among those who used no medication to quit, five percent managed to stay smoke-free for six months.

In comparison, 18 percent of nicotine patch users, 15 percent of people who used buproprion - an antidepressant - and 19 percent of people who used a medication called varenicline stayed off cigarettes for six months.

After taking into account factors that could affect people's success, such as how long and how heavily they had smoked, the researchers determined that buproprion and the nicotine patch were each tied to a four-fold increase in quitting success compared with those who used no medications, and varenicline to a nearly six-fold increase.

Eight percent of people who used oral nicotine replacement products, such as gum, stayed abstinent for six months.

Overall, the researchers found, people who tried to quit without any aids were likely to be younger, have lower incomes, be less addicted to nicotine and have higher confidence in their ability to break the smoking habit than those who used aids.

The study does not prove that the medications are responsible for the greater success in quitting, merely that people who use them are more likely to quit.

"The disappointing reality is that even when people use these medications to help them quit, relapse is still the norm. It's better than nothing, but it's by no means a magic bullet."

SOURCE: bit.ly/Q0U21C Addiction, online August 14, 2012.

(Reporting from New York by Kerry Grens at Reuters Health; Editing by Elaine Lies)

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