bad smell
Researchers found that aversion therapy with foul smell was highly effective in helping smokers quitSira Hanchana/Flickr

Aversion therapy during sleep may help smokers quit, a new study has claimed.

As part of the study, people exposed to a mixture of cigarette smoke and rotten eggs or fish during sleep experienced a considerable reduction in the number of cigarettes they smoked the next day.

"To conclude, a single night of olfactory aversive conditioning during sleep significantly reduced cigarette-smoking behaviour in a sleep stage-dependent manner, and this effect persisted for several days," the authors wrote.

The study included 66 people, including 23 women, who wanted to stop smoking. Researchers from Israel and US wanted to analyse whether associative learning during sleep can leave any positive influence on their behaviour the following day.

The participants were divided into three groups. The first group was exposed to cigarette smoke along with the stink of fish and eggs, during two different stages of sleep: Stage 2 and Rapid Eye Movement (REM), New York Daily News reported.

The second group smelled each item separately. The third group were exposed to the smells as the first group, not during sleep, but when they were fully awake. During the study, the participants kept a record of the total number of cigarettes they smoked daily, before and after the experiment.

The sleep process at night goes through four stages- -- the first 5 to 10 minutes is Stage 1; Stage 2 lasts for about 20 minutes; Stage 3 (delta sleep) involves slow brain waves and people tend to be least responsive to external stimuli; and Stage 4 involves REM. During REM, the brain and body systems become more active and muscles relax. It is in the fourth stage that we dream.

Researchers found that aversion therapy with foul smell was more effective during Stage 2 than REM.

"The reduction in smoking following aversive conditioning during Stage 2 was greater and longer lasting compared with the reduction following aversive conditioning during REM," the authors, wrote.

The study has been reported in The Journal of Neuroscience.

Previous research has shown that a combined therapy with two smoking cessation drugs -- Varenicline and Bupropion -- can help heavy smokers kick the butt. Similarly, a Delhi-based study reported that a simple breathing yoga exercise can help people quit smoking.

In another study reported in September, a team of American researchers found that a hallucinogenic agent found in magic mushrooms- psilocybin- helped long-time smokers quit.