This research suggests that:
- Smokers who switch to cigarettes with very low nicotine content may experience mild and transient increases in some withdrawal symptoms.
- Cigarettes with reduced nicotine will be easier to quit than the cigarettes marketed at present.
Withdrawal Symptoms Assessed in the Study
- Depressed mood/sadness
- Desire or craving to smoke
- Difficulty in concentration
- Increased appetite/hunger/weight gain
- Insomnia/sleep problems/awakening at night
The U.S. Food and Drug Administration (FDA) is considering a policy to restrict the nicotine content of cigarettes to levels too low to cause addiction. Such a policy could reduce smoking’s toll on public health by reducing new cases of smoking addiction and smokers' exposure to the toxic ingredients in tobacco smoke. Its feasibility hinges in part on whether current smokers will be able to successfully transition to cigarettes with much lower nicotine content than those marketed at present. NIDA-supported research suggests that they can, and will experience only mild and short-lived increases in some symptoms of withdrawal during the switchover.
Dr. Sarah Dermody of Oregon State University and colleagues analyzed data from a clinical trial, led by Dr. Eric Donny, that randomly assigned 839 smokers to smoke investigational cigarettes or their usual brand for 6 weeks. The investigational cigarettes contained nicotine at sharply reduced levels (0.4–2.4 mg nicotine per gram of tobacco), a moderate level (5.2 mg/g), or a level comparable to that of regular cigarettes (15.8 mg/g). The participants reported their experience of eight withdrawal symptoms (see list below) in daily phone calls during the first week of the study and roughly once a week thereafter.
The participant groups' reports of most withdrawal symptoms did not differ throughout the course of the study. When first switching to reduced-nicotine cigarettes, smokers reported slight increases in anger, irritability, frustration, restlessness, appetite, and weight gain; however, none of these lasted longer than a few weeks. The only symptom that persisted after 6 weeks, and only with the lowest nicotine level, was increased sadness.
After 6 weeks, the study participants were asked to abstain from their assigned cigarettes overnight. In general, the smokers of reduced-nicotine cigarettes reported less-intense withdrawal symptoms the following morning than those smoking cigarettes with normal nicotine content (see Figure). Other factors also appeared to influence withdrawal symptom severity:
- Tar appeared to play a role in withdrawal: Smokers of a high-tar version of the lowest-nicotine content cigarette reported much more severe withdrawal symptoms during withdrawal than smokers of the same cigarette without added tar. Their withdrawal symptoms were comparable to those reported by the smokers of the standard-nicotine content cigarettes.
- Brand-specific expectations, tastes, or other aspects may have affected participants’ withdrawal experiences. Participants reported more severe withdrawal symptoms when they abstained from their usual brand than when they abstained from standardized cigarettes with the same nicotine content.
Dr. Dermody notes that previous studies also showed that reduced-nicotine cigarettes can help smokers quit. "We found that treatment-seeking individuals who switched to reduced-nicotine cigarettes were more successful in quitting smoking, and a follow-up study showed that greater reductions in nicotine content corresponded with the greatest cessation rates," she says.
Dr. Dermody adds, "The FDA has taken initial steps in support of reducing the nicotine content of cigarettes. It is important to continue to build upon this research to understand the public health impact of this potential policy."
This study was supported by NIH grant DA031659.
- Text Description of Figure
The bar chart shows the severity of withdrawal symptoms after overnight abstinence from cigarettes with different nicotine contents. The horizontal x-axis shows the different nicotine contents of the cigarettes tested. The vertical y-axis shows the effects of the study cigarettes relative to standardized normal nicotine–content cigarettes on a scale from -0.8 to +0.8. Negative values indicate reduced symptom severity compared with normal nicotine–content cigarettes, whereas positive values indicate increased symptom severity. The withdrawal symptoms analyzed include anger, represented by blue bars; craving, represented by red bars; difficulty concentrating, represented by green bars; and restlessness, represented by purple bars.
For users of cigarettes with a nicotine content of 0.4 mg/kg, withdrawal severity compared with standardized normal-nicotine cigarettes was about -0.65 for anger, about -0.5 for craving, about -0.7 for difficulty concentrating, and about -0.3 for restlessness. For users of cigarettes with a nicotine content of 0.4 mg/kg but high tar content, withdrawal severity compared with standardized normal-nicotine cigarettes was about +0.1 for anger, about -0.08 for craving, about +0.1 for difficulty concentrating, and about -0.01 for restlessness. For users of cigarettes with a nicotine content of 1.3 mg/kg, withdrawal severity compared with standardized normal-nicotine cigarettes was about -0.4 for anger, about -0.65 for craving, about -0.4 for difficulty concentrating, and about -0.25 for restlessness. For users of cigarettes with a nicotine content of 2.4 mg/kg, withdrawal severity compared with standardized normal-nicotine cigarettes was about -0.2 for anger, about -0.25 for craving, about -0.2 for difficulty concentrating, and about -0.3 for restlessness. For users of cigarettes with a nicotine content of 5.2mg/kg, withdrawal severity compared with standardized normal-nicotine cigarettes was about -0.35 for anger, about -0.3 for craving, about -0.4 for difficulty concentrating, and about -0.2 for restlessness. For participants who smoked their usual brand of cigarettes, withdrawal severity compared with standardized normal-nicotine cigarettes was about +0.65 for anger, about +0.6 for craving, about +0.3 for difficulty concentrating, and about +0.55 for restlessness.
- Dermody, S.S., McClernon, F.J., Benowitz, N., et al. Effects of reduced nicotine content cigarettes on individual withdrawal symptoms over time and during abstinence. Experimental and Clinical Psychopharmacology 26(3):223-232, 2018.