Neuroscience for Kids - Nicotine Addiction

Nicotine -- The Danger of "Just One Cigarette"

By Ellen Kuwana
Neuroscience for Kids Staff Writer
November 2, 2001

"Just one," you think to yourself, "I'll try just one cigarette. What's the harm in just one cigarette? It's not like I'm going to get addicted."
If you are older than 45, you may be right -- but if you are between 15-24 years old, research shows that you would be wrong. A team of researchers led by psychologist Naomi Breslau analyzed data from a 1992 national survey on tobacco use. In addition to looking at how often the 4,414 people surveyed smoked, the researchers also examined nicotine dependence. This was defined by a group of three symptoms:

an inability to quit smoking
distress at not being able to quit
harsh withdrawal symptoms when the person attempted to quit smoking.
The results of this survey may surprise you.
For daily cigarette use, the youngest group (ages 15-24) used tobacco the least; approximately 36% of people in that age group used tobacco daily. In contrast, approximately 60% of the people in the older group (ages 45-54) smoked daily. The researchers found that the symptoms of nicotine addiction showed up within a year of starting smoking.
A surprising result was that fewer people in the older group were addicted to nicotine -- even though they had been smoking for longer than many people in the younger group. It seems that younger smokers get hooked more easily than older smokers:

60% of the smokers in the younger group who had smoked for six years were addicted.
10% of the smokers in the older group who had smoked for six years were addicted.
The good news is that each year, fewer teens take up smoking. Many teens are making educated decisions to ignore cigarette ads and peer pressure. The bad news is that those who start may find it harder to stop for reasons that scientists do not yet understand. Why is the young brain more susceptible to nicotine addiction? Part of the story may lie in the fact that some drugs affect brain circuits that are responsible for "reward." Receptors in these circuits respond to drugs, resulting in the release of the neurotransmitter dopamine.
Scientists Huibert Mansvelder and Daniel McGehee of the University of Chicago observed how nicotine affected nerve cells in the brain. Tissue from rat brains was cut into slices so that living nerve cells could be seen under a microscope. The brain tissue was bathed in nicotine for approximately two minutes, about the amount of time it takes to smoke a cigarette. The scientists observed lasting changes in the connections (synapses) between nerve cells. Specifically, they noted long-term potentiation (LTP) in the brain's reward areas. LTP results in stronger connections between nerve cells and leads to long-lasting changes in neuronal wiring between nerve cells. These changes in wiring are thought to be responsible for learning and memory.
Although human brains are not identical to rat brains, it is clear that nicotine is addictive, and for reasons not clearly understood at this time, younger people appear to be more susceptible to the addictive power of nicotine. The easiest way to avoid nicotine addiction is to avoid smoking that first cigarette. If you are addicted to nicotine and want more information on how to quit, see these tips from the American Lung Association.

References and further information about nicotine addiction:

Mansvelder, H.D. and McGehee, D.S. Long-term potentiation of excitatory inputs to brain reward areas by nicotine. Neuron, 27:349-357, 2000.
Breslau, N., Johnson, E.O., Hiripi, E. and Kessler, R. Nicotine addiction in the United States. Archives of General Psychiatry, 58:810-816, 2001.
Youthful nicotine addiction may be growing. Article by Bruce Bower, Science News, Vol. 160, No. 12, September 22, 2001.
The Peril of a Single Cigarette:Brief exposure can lead to nicotine addiction. Article by Edward Edelson, HealthScout, August 24, 2000.
The Dope on Nicotine - PBS/NOVA

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