Particularly in the industrialized countries, most people addicted to nicotine initiated smoking during adolescence.Since a typical smoker takes 10 puffs on each cigarette, a person who smokes a pack of cigarettes a day (20 cigarettes per pack) will receive 200 doses of nicotine daily. No other drug is dosed at such a high frequency. A Inhalation of nicotine in the form of smoke provides the quickest delivery, with nicotine reaching the brain in approximately 7 seconds. Nicotine stimulates the dopaminergic pathways of the mesolimbic system in the brain, an area that is involved in reinforcement for other drugs of abuse.
Nicotine treatment often includes replacement therapies combined with behavior change programs. Smoking rates varied among men, from 43.3% to 65.3% among the countries examined. Results showed that smoking among women remains uncommon in Armenia, Georgia, Kyrgyzstan, and Moldova (rates of 2.4%–6.3%). In Belarus, Ukraine, Kazakhstan, and Russia, rates were higher (9.3%–15.5%). Men start smoking at significantly younger ages than women, smoke more cigarettes per day, and are more likely to be nicotine dependent.Research into nicotine's most predominant metabolite, cotinine, suggests that some, if not most, of nicotine's psychoactive effects may actually be mediated by complex interactions with cotinine, or perhaps even by cotinine alone rather than strictly by nicotine as conventionally thought.