News Article:
Cigarettes and Other Nicotine Products
NIDA Infofact
Nicotine is one of the most heavily used addictive drugs
in the United States. In 2002, 30 percent of the U.S. population 12
and older—71.5 million people—used tobacco at least once in the month
prior to being interviewed. This figure includes 3.8 million young people
age 12 to 17; 14 million people age 18 to 25; and 53.7 million age 26
and older.* Most of them smoked cigarettes.
Cigarette smoking has been the most popular method of
taking nicotine since the beginning of the 20th century. In 1989, the
U.S. Surgeon General issued a report that concluded that cigarettes
and other forms of tobacco, such as cigars, pipe tobacco, and chewing
tobacco, are addictive and that nicotine is the drug in tobacco that
causes addiction. The report also determined that smoking was a major
cause of stroke and the third leading cause of death in the United States.
Statistics from the Centers for Disease Control and Prevention indicate
that tobacco use remains the leading preventable cause of death in the
United States, causing more than 440,000 deaths each year and resulting
in an annual cost of more than $75 billion in direct medical costs.
(See www.cdc.gov/tobacco/issue.htm).
Health Hazards
Nicotine is highly addictive. Nicotine provides an
almost immediate “kick” because it causes a discharge of epinephrine
from the adrenal cortex. This stimulates the central nervous system,
and other endocrine glands, which causes a sudden release of glucose.
Stimulation is then followed by depression and fatigue, leading the
abuser to seek more nicotine.
Nicotine is absorbed readily from tobacco smoke in the
lungs, and it does not matter whether the tobacco smoke is from cigarettes,
cigars, or pipes. Nicotine also is absorbed readily when tobacco is
chewed. With regular use of tobacco, levels of nicotine accumulate in
the body during the day and persist overnight. Thus, daily smokers or
chewers are exposed to the effects of nicotine for 24 hours each day.
Addiction to nicotine results in withdrawal symptoms
when a person tries to stop smoking. For example, a study found that
when chronic smokers were deprived of cigarettes for 24 hours, they
had increased anger, hostility, and aggression, and loss of social cooperation.
Persons suffering from withdrawal also take longer to regain emotional
equilibrium following stress. During periods of abstinence and/or craving,
smokers have shown impairment across a wide range of psychomotor and
cognitive functions, such as language comprehension.
ADOLESCENT smokeless
tobacco users are more likely than nonusers to become cigarette smokers.
Behavioral research is beginning to explain how social influences, such
as observing adults or other peers smoking, affect whether ADOLESCENTs
begin to smoke cigarettes. Research has shown that teens are generally
resistant to anti-smoking messages.
In addition to nicotine, cigarette smoke is primarily
composed of a dozen gases (mainly carbon monoxide) and tar. The tar
in a cigarette, which varies from about 15 mg for a regular cigarette
to 7 mg in a low-tar cigarette, exposes the user to an increased risk
of lung cancer, emphysema, and bronchial disorders.
The carbon monoxide in the smoke increases the chance
of cardiovascular diseases. The Environmental Protection Agency has
concluded that secondhand smoke causes lung cancer in adults and greatly
increases the risk of respiratory illnesses in children and sudden infant
death.
Promising Research
Research has shown that nicotine, like cocaine, heroin,
and marijuana, increases the level of the neurotransmitter dopamine,
which affects the brain pathways that control reward and pleasure. Scientists
now have pinpointed a particular molecule (the beta 2 (b2) subunit of
the nicotine cholinergic receptor) as a critical component in nicotine
addiction. Mice that lack this subunit fail to self-administer nicotine,
implying that without the b2 subunit, the mice do not experience the
positive reinforcing properties of nicotine. This new finding identifies
a potential site for targeting the development of nicotine addiction
medications.
Other new research found that individuals have greater
resistance to nicotine addiction if they have a genetic variant that
decreases the function of the enzyme CYP2A6. The decrease in CYP2A6
slows the breakdown of nicotine and protects individuals against nicotine
addiction. Understanding the role of this enzyme in nicotine addiction
gives a new target for developing more effective medications to help
people stop smoking. Medications might be developed that can inhibit
the function of CYP2A6, thus providing a new approach to preventing
and treating nicotine addiction.
Another study found dramatic changes in the brain’s
pleasure circuits during withdrawal from chronic nicotine use. These
changes are comparable in magnitude and duration to similar changes
observed during the withdrawal from other abused drugs such as cocaine,
opiates, amphetamines, and alcohol. Scientists found significant decreases
in the sensitivity of the brains of laboratory rats to pleasurable stimulation
after nicotine administration was abruptly stopped. These changes lasted
several days and may correspond to the anxiety and depression experienced
by humans for several days after quitting smoking “cold turkey.” The
results of this research may help in the development of better TREATMENTs
for the withdrawal symptoms that may interfere with individuals’ attempts
to quit smoking.
Treatment
Studies have shown that pharmacological TREATMENT
combined with behavioral TREATMENT,
including psychological support and skills training to overcome high-risk
situations, results in some of the highest long-term abstinence rates.
Generally, rates of relapse for smoking cessation are highest in the
first few weeks and months and diminish considerably after about 3 months.
Behavioral economic studies find that alternative rewards
and reinforcers can reduce cigarette use. One study found that the greatest
reductions in cigarette use were achieved when smoking cost was increased
in combination with the presence of alternative recreational activities.
Nicotine chewing gum is one medication approved by the
Food and Drug Administration (FDA) for the TREATMENT
of nicotine dependence. Nicotine in this form acts as a nicotine replacement
to help smokers quit smoking.
The success rates for smoking cessation treatment with
nicotine chewing gum vary considerably across studies, but evidence
suggests that it is a safe means of facilitating smoking cessation if
chewed according to instructions and restricted to patients who are
under medical supervision.
Another approach to smoking cessation is the nicotine
transdermal patch, a skin patch that delivers a relatively constant
amount of nicotine to the person wearing it. A research team at NIDA’s
Intramural Research PROGRAM studied the safety, mechanism
of action, and abuse liability of the patch that was consequently approved
by FDA. Both nicotine gum and the nicotine patch, as well as other nicotine
replacements such as sprays and inhalers, are used to help people fully
quit smoking by reducing withdrawal symptoms and preventing relapse
while undergoing behavioral TREATMENT.
Another tool in treating nicotine addiction is a medication
that goes by the trade name Zyban. This is not a nicotine replacement,
as are the gum and patch. Rather, this works on other areas of the brain,
and its effectiveness is in helping to make controllable nicotine craving
or thoughts about cigarette use in people trying to quit.
Extent of Use
2003 Monitoring the Future Survey (MTF)**
Despite the demonstrated health risk associated with
smoking, young Americans continue to smoke. However, past-month smoking
rates among high school students are declining from peaks reached in
1996 for 8th-graders (21.0 percent) and 10th-graders (30.4 percent)
and in 1997 for seniors (36.5 percent). In 2003, rates reached the lowest
levels ever reported by MTF; 10.2 percent of 8th-graders, 16.7 percent
of 10th-graders, and 24.4 percent of high SCHOOL
seniors reported smoking during the month preceding their responses
to the survey.
The decrease in smoking rates among young Americans
corresponds to several years in which increased proportions of TEENs
said they believe there is a “great” health risk associated with cigarette
smoking and expressed disapproval of “pack-a-day” smokers. Students’
personal disapproval of smoking had risen for some years, but showed
no further increase in 2003 among 8th-graders and only small increases
among 10th- and 12th-graders. In 2003, 84.6 percent of 8th-graders,
81.4 percent of 10th-graders, and 74.8 percent of 12th-graders stated
that they “disapprove” or “strongly disapprove” of people smoking one
or more packs of cigarettes per day.
Find this information and more at www.drugabuse.gov
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