Effects of nicotine on human brain development

[notes 1][3] The use of tobacco products, no matter what type, is almost always started and established during adolescence when the developing brain is most vulnerable to nicotine addiction.

[11] When nicotine enters the brain it stimulates, among other activities, the midbrain dopaminergic neurons situated in the ventral tegmental area and pars compacta.

[17] This indicated that exposure to e-cigarette components in a susceptible time period of brain development could induce persistent behavioral changes.

[17] Long-term nicotine use affects a broad range of genes associated with neurotransmission, signal transduction, and synaptic architecture.

[49] Nicotine is a parasympathomimetic stimulant[8] that binds to and activates nicotinic acetylcholine receptors in the brain,[9] which subsequently causes the release of dopamine and other neurotransmitters, such as norepinephrine, acetylcholine, serotonin, gamma-aminobutyric acid, glutamate, endorphins,[10] and several neuropeptides, including proopiomelanocortin-derived α-MSH and adrenocorticotropic hormone.

[10] Its physiological effects stem from the stimulation of nicotinic acetylcholine receptors, which are located throughout the central and peripheral nervous systems.

[11] When nicotine enters the brain it stimulates, among other activities, the midbrain dopaminergic neurons situated in the ventral tegmental area and pars compacta.

[9] These symptoms can include cravings for nicotine, anger, irritability, anxiety, depression, impatience, trouble sleeping, restlessness, hunger, weight gain, and difficulty concentrating.

[61] When trying to quit smoking with vaping a base containing nicotine, symptoms of withdrawal can include irritability, restlessness, poor concentration, anxiety, depression, and hunger.

[64] Limiting tobacco consumption with the use of campaigns that portray cigarette smoking as unacceptable and harmful have been enacted; though, advocating for the use of e-cigarettes jeopardizes this because of the possibility of escalating nicotine addiction.

[67] Chronic nicotine use causes a broad range of neuroplastic adaptations, making quitting hard to accomplish.

[71] Various organizations,[84] including the International Union Against Tuberculosis and Lung Disease, the American Academy of Pediatrics, the American Cancer Society, the Centers for Disease Control and Prevention, and the US Food and Drug Administration (US FDA), have expressed concern that e-cigarette use could increase the prevalence of nicotine addiction in youth.

[89] A 2017 review noted that "adolescents experience symptoms of dependence at lower levels of nicotine exposure than adults.

"[90] Adolescents are particularly susceptible to nicotine addiction: the majority (90%) of smokers start before the age of 18, a fact that has been utilized by tobacco companies for decades in their teen-targeted advertising, marketing and even product design.

[34] Such disruption of neural circuit development may lead to long-term cognitive and behavioral impairment and has been associated with depression and anxiety.

[34] Nicotine delivery may be affected by the device itself, for example, by increasing the voltage which changes the aerosol delivered, or by "dripping"—a process of inhaling liquid poured directly onto coils.

[34] In the US, the unprecedented increase in current (past-month) users from 11.7% of high school students in 2017 to 20.8% in 2018 would imply dependence, if not addiction, given what we know about nicotine and its effects on the adolescent brain.

[94] Preclinical animal studies have shown that in rodent models, nicotinic acetylcholine receptor signaling is still actively changing during adolescence, with higher expression and functional activity of nicotinic acetylcholine receptors in the forebrain of adolescent rodents compared to their adult counterparts.

[94] In rodent models, nicotine actually enhances neuronal activity in several reward-related regions and does so more robustly in adolescents than in adults.

[30] Concerns exist in respect to adolescence vaping due to studies indicating nicotine may potentially have harmful effects on the brain.

[28] Animal research indicates strong evidence that the limbic system, which modulates drug reward, cognition, and emotion, is growing during adolescence and is particularly vulnerable to the long lasting effects of nicotine.

[97] A short period of regular or occasional nicotine exposure in adolescence exerts long-term neurobehavioral damage.

[97] Risks of exposing the developing brain to nicotine include mood disorders and permanent lowering of impulse control.

[6] The rise in vaping is of great concern because the parts encompassing in greater cognitive activities including the prefrontal cortex of the brain continues to develop into the 20s.

[100] As indicated in the limited research from animal studies, there is the potential for induced changes in neurocognitive growth among children who have been subjected to e-cigarette aerosols consisting of nicotine.

[29] The US FDA stated in 2019 that some people who use e-cigarettes have experienced seizures, with most reports involving youth or young adult users.

[101] Inhaling lead from e-cigarette aerosol can induce serious neurologic injury, notably to the growing brains of children.

[102] A 2017 review states that "Because the brain does not reach full maturity until the mid-20s, restricting sales of electronic cigarettes and all tobacco products to individuals aged at least 21 years and older could have positive health benefits for adolescents and young adults.

[108] A 2017 review states, "because nicotine targets the fetal brain, damage can be present, even when birth weight is normal.

[17] This indicated that exposure to e-cigarette components in a susceptible time period of brain development could induce persistent behavioral changes.