Addiction is defined as repeated use of a psychoactive substance or substances, to the extent. Nicotine addiction is the fundamental reason that individuals persist in using tobacco products, and this persistent tobacco use contributes to many diseases. Smoking is primarily practiced as a route of administration for nicotine through the lungs; it is a way of getting nicotine into your system rapidly. The first use of nicotine, physical effects increase the likelihood of repeated nicotine consumption. Nicotine binds to cholinergic receptors in the central nervous system. In response to repeated nicotine use, the receptors rapidly desensitize and increase in number, and both these phenomena conspire to increase the addictive power of nicotine. Dopaminergic neurons within the nucleus accumbens (a brain structure associated with rewards and reinforcement) are activated by projections from nicotine-stimulated neurons.
According to the American Heart Association, 23.1% of men (24.8 million) and 18.3% of women (21.1 million) are smokers. According to the CDC (Centers for Disease Control and Prevention) an estimated total of 443,000 deaths occur every year in the USA from cigarette smoking - almost 1 in every 5 deaths. That is more deaths than the combined total from HIV, illegal drug use, alcohol use, motor vehicle injuries, suicides and murders. In America, 57% of adults have never smoked, 22% are former smokers, and 21% are current smokers. Smokeless tobacco use is less than 5%, and smoking pipes/cigars is less than 1%. The 12-month prevalence is 13% among adults aged 18 years and older. Prevalence declines from 17% among 18- to 29-year-olds to 4% among adults aged 65 years and older.