Nov. 20, 2014 — Bad smells during sleep may teach smokers to dislike cigarettes and help them cut back, a new study hints.
Smokers who were exposed to the smell of cigarettes along with an unpleasant odor during a single night of sleep smoked less for days afterward, the researchers found.
This study shows that "sleep learning can influence later wake behavior," says Anat Arzi. She's a PhD student at the Weizmann Institute of Science in Rehovot, Israel.
She presented the study at the Society for Neuroscience 2014 Annual Meeting in Washington, D.C.
Subliminal Messages
"This research stems from recent findings suggesting that novel associations can be learned during human sleep and retrieved upon awakening," Arzi said during a media briefing.
The researchers chose this method because the brain’s reward system, which is activated during addictive behavior, shares traits with the olfactory system, or sense of smell.
The study involved 76 adult smokers who wanted to quit. During 1 night in the sleep lab, they were exposed to cigarette smells and the smell of rotten fish or rotten eggs during light sleep (known as stage 2 sleep) or during "rapid eye movement" (REM) sleep, when people tend to dream. The odors didn't wake up the participants, Arzi said.
The experiment was also done while the smokers were awake.
They kept a diary of how many cigarettes they smoked for 7 days before and 7 days after the experiment.
The linking of the cigarette smell to the rotten food smell is called aversive conditioning. The smokers who had aversive conditioning during stage 2 sleep reduced smoking by 34% in the following week. When conditioning was done during REM sleep, they cut back on smoking by 12%.
"The reduction in smoking was significantly larger and longer-lasting following conditioning during stage 2 sleep in comparison to REM sleep," Arzi said.
Aversive conditioning while smokers were awake did not lessen smoking.
"We know that behavioral approaches can help treat nicotine addiction, but none have been remarkably successful," Arzi said in a conference statement.
More study is needed to figure out whether the tactic could work as a quit-smoking aid and a potential treatment for addiction in general, she said during the briefing.
