Nicotine

Tobacco use is the leading cause of preventable mortality worldwide, and nicotine (a small tertiary amine consisting of a pyridine and pyrrolidine ring) is the primary psychoactive constituent in tobacco. When inhaled, nicotine reaches the brain within 7-10 s, with peak blood levels occurring within a few minutes. In the USA, the prevalence of smoking among adults is just under 20%, although over half of all ever-smokers have now quit. Nicotine dependence is characterized by tolerance, withdrawal symptoms (e.g., irritability, depression, restlessness, insomnia, anxiety, hunger and poor concentration, as well as craving), and compulsive use. Tobacco use and dependence are more prevalent among psychiatric patients and persons with certain medical conditions, including HIV and chronic pain. Smokers often report that cigarettes enhance both their mood state and their cognitive functioning (e.g., attention); however, it is difficult to determine if these are actual nicotine onset effects, relief of nicotine withdrawal effects, or psychological expectancy (i.e., placebo) effects. Treatments for tobacco use include seven FDA-approved pharmacotherapies (nicotine gum, patch, nasal spray, inhaler, and lozenge, plus bupropion, and varenicline) with roughly similar efficacies. In addition, behavioral counseling enhances efficacy rates. Even minimal counseling, such as brief physician advice, significantly increases the odds of cessation, but more intensive counseling produces greater effects. Other options include self-help and telephone quitlines.