Description

Nicotine addiction is characterized by the compulsive use of nicotine products coupled with a lack of control over using, withdrawal symptoms, and/or continued use despite knowledge of or experiencing adverse consequences.

Epidemiology

Prevalence

• In 2019, an estimated 50.6 million U.S. adults (20.8% of the adult population) used tobacco; 14% of the U.S. adult population are actively smoking cigarettes, and 4.5% are using e-cigarettes (1).
• In 2016, 7.2% of women who gave birth smoked cigarettes during their pregnancy.
• In 2020, 19.6% of U.S. high school students and 4.7% of U.S. middle school students—a total of 3.6 million youth—reported current use (use in the past 30 days) of e-cigarettes (2). E-cigarettes have been the most commonly used tobacco product annually among youth since 2014 and have been associated with nicotine addiction in adulthood.
• Sociodemographic factors: Smoking rates are particularly high in non-Hispanic American Indian/Alaska Native persons; lesbian, gay, or bisexual adults; adults whose highest level of educational attainment is a GED certificate; persons who are uninsured or those with Medicaid; adults with a disability; and persons with mild, moderate, or severe generalized anxiety symptoms (1).

Etiology and Pathophysiology

• Similar to other addictive drugs, nicotine affects neural pathways that control reward and pleasure.
• Nicotine exerts its biologic effects through nicotinic acetylcholine receptors (nAChRs), which modulate neurotransmission with acetylcholine and other chemical messengers including glutamate, GABA, dopamine, serotonin, acetylcholine, and norepinephrine. In this way, it induces euphoria, assists in information processing, reduces anxiety, and mitigates fatigue.
• Upregulation of these receptors occurs over time, leading to tolerance and dependence.
• Polymorphisms in neuronal nAChR genes are associated with increased susceptibility to dependence.
• Nicotine is metabolized by cytochrome P450 2A6 (CYP2A6). Individuals who are fast metabolizers tend to smoke more cigarettes, are more likely to suffer intense withdrawal symptoms, and have a lower probability of quitting than slow metabolizers.
• Nicotine withdrawal involves the release of corticotropin-releasing factor in the amygdala, which induces the perception of anxiety and stress.

Pregnancy Considerations

• Smoking is a risk factor associated with placenta previa, abruptio placentae, decreased maternal thyroid function, preterm premature rupture of membranes, and ectopic pregnancy.
• Carbon monoxide and nicotine interfere with fetal oxygen supply, resulting in decreased birth weights and intrauterine growth restriction.
• Maternal smoking adversely affects fetal lung development, with lifelong decreases in pulmonary function and increased risk of asthma.
• Maternal smoking is associated with increased risk for sudden infant death syndrome, learning and behavioral problems, and obesity.

Risk Factors

• Mental illness (depression, posttraumatic stress disorder, bipolar disorder, and schizophrenia)
• Low socioeconomic status, low educational status
• Early firsthand nicotine experience, home and peer influence
• Concurrent substance abuse

General Prevention

• The U.S. Preventive Services Task Force (USPSTF) strongly recommends the following:
  • Screening all adults for tobacco use, providing cessation interventions for those who screen positive
  • Screening all pregnant women for tobacco use and providing pregnancy-tailored counseling to those who screen positive
• The USPSTF recommends that clinicians provide interventions, including education or brief counseling to prevent initiation of tobacco use among school-aged children and adolescents.