The study enrolled 76 smokers to receive one session of aversive conditioning by pairing the smell of cigarette smoke with the noxious smell of rotten eggs or rotten fish. The participants were divided into three groups—one received the conditioning while awake, the second received the conditioning during stage 2 sleep, and the third during deep REM sleep.
All the participants kept a smoking diary that tracked their behaviors one week before and one week after their aversive-conditioning session. The smokers who received their stimuli during stage 2 sleep reported a 34% reduction in smoking over the next week, while those who received the smells during REM sleep reported a more modest 12% reduction; the smokers who were awake reported no changes.
Previous studies have tested various forms of aversive conditioning such as bad smells, bad tastes, or mild electric shocks as a smoking cessation tool, though such trials have not been remarkably successful, possibly because the participants were awake and anticipating the stimuli. These new positive findings reinforce the idea that indirect behavioral therapy through sleep or hypnosis, for example, may offer more benefit.
To read more about why quitting smoking is important for mental well-being, see the Psychiatric News article, "Smoking Cessation Bestows Multiple Mental Health Benefits." Read more about smoking cessation treatment in the November American Journal of Psychiatry study, “Combination Treatment With Varenicline andBupropion in an Adaptive Smoking Cessation Paradigm.”