Withdrawal symptoms impair the ability to stop tobacco use. The symptoms after abstinence from tobacco are in large part due to nicotine deprivation. Symptoms are much more intense among individuals who smoke cigarettes or use smokeless tobacco than among those who use nicotine medications. This difference in symptom intensity is likely due to the more rapid onset and higher levels of nicotine with cigarette smoking. Tobacco withdrawal is common among daily tobacco users who stop or reduce but can also occur among nondaily users. Typically, heart rate decreases by 5-12 beats per minute in the first few days after stopping smoking, and weight increases an average of 4-7 lb (2-3 kg) over the first year after stopping smoking. Tobacco withdrawal can produce clinically significant mood changes and functional impairment.