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.
"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 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.
Marina Picciotto, PhD, from Yale University, said the findings "could be a very useful tool to both motivate and assist people in quitting who might not otherwise have even thought about quitting. This study used smokers, but you could imagine that this could be applied to any addiction."
"We don't know yet from this early study how long the effect lasts and how useful it will be to actually induce quitting, but … the potential as a treatment is there," Picciotto said.
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.