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 2018, there were an estimated 47.8 million U.S. adults who currently used any tobacco products, of which 41.1 million smoked combustible tobacco products and 9.0 million used two or more tobacco products. This included 34.3 million who smoked cigarettes, 9.3 million who smoked cigars, 6.9 million who used electronic cigarettes, 5.1 million who used smokeless tobacco, and 2.6 million who smoked pipes and hookahs.
• In 2020, an estimated 3.57 million middle and high school students currently used e-cigarettes. E-cigarette use among youth has increased 10-fold for high school and middle school students from 2011 to 2015 and has been associated with nicotine addiction in adulthood, and e-cigarettes have been the most commonly used tobacco product among youth since 2014. However, from 2019 to 2020, “current use” has declined among middle and high school students.

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
• Concurrent substance abuse
• Home and peer influence

General Prevention

• The U.S. Preventive Services Task Force (USPSTF) strongly recommends:
  • 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-age children and adolescents.