tobacco addiction (research reports)

8/2/2019 Tobacco Addiction (Research Reports)

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rom the director:Tobacco use kills approximately

440,000 Americans each year, with

one in every fve U.S. deaths the result

o smoking. Smoking harms nearly

every organ in the body, causes many

diseases, and compromises smokers

health in general. Nicotine, a compo-

nent o tobacco, is the primary reason

that tobacco is addictive, although

cigarette smoke contains many other

dangerous chemicals, including tar,

carbon monoxide, acetaldehyde,

nitrosamines, and more.

An improved overall understanding

o addiction and o nicotine as an

addictive drug has been instrumen-

tal in developing medications and

behavioral treatments or tobacco

addiction. For example, the nicotine

patch and gum, now readily avail-

able at drugstores and supermarkets

nationwide, have proven eective or

smoking cessation when combined

with behavioral therapy.

Advanced neuroimaging technolo-

gies make it possible or researchers

to observe changes in brain unction

that result rom smoking tobacco.

Researchers are now also identiy-

ing genes that predispose people to

tobacco addiction and predict their

response to smoking cessation treat-

ments. These fndingsand many

other recent research accomplish-

mentspresent unique opportunities

to discover, develop, and disseminate

new treatments or tobacco addiction,

as well as scientifcally based pre-

vention programs to help curtail the

public health burden that tobacco

use represents.

We hope this Research Reportwill

help readers understand the harmul

eects o tobacco use and identiy

best practices or the prevention and

treatment o tobacco addiction.

Nora D. Volkow, M.D.

Director

National Institute on Drug Abuse

TobaccoAddiction

What are

the medical

consequences

o tobacco use?

See page 4.

continued inside

According to the 2007 National Survey on Drug Use

and Health, an estimated 70.9 million Americans aged

12 or older reported current use o tobacco 60.1

million (24.2 percent o the population) were current cigarette

smokers, 13.3 million (5.4 percent) smoked cigars, 8.1 million

(3.2 percent) used smokeless tobacco, and 2 million (0.8 percent)

smoked pipes, conrming that tobacco is one o the most widely

abused substances in the United States. Although the numbers

o people who smoke are still unacceptably high, according

What Are the Extent and

Impact o Tobacco Use?


2/12

Research Report Series

to the Centers or Disease

Control and Prevention there

has been a decline o almost50 percent since 1965.

NIDAs 2008 Monitoring the

Future survey o 8th-, 10th-, and

12th-graders, which is used to track

drug use patterns and attitudes, has

also shown a striking decrease

in smoking trends among the

Nations youth. The latest results

indicate that about 7 percent o

8th-graders, 12 percent o

10th-graders, and 20 percent o

12th-graders had used cigarettes in

the 30 days prior to the surveythe lowest levels in the history o

the survey.

The declining prevalence o

cigarette smoking among the

general U.S. population, how-

ever, is not refected in patients

with mental illnesses. The rate o

smoking in patients suering rompost-traumatic stress disorder,

bipolar disorder, major depression,

and other mental illness is two- to

ourold higher than in the general

population; and among people

with schizophrenia, smoking

rates as high as 90 percent

have been reported.

Tobacco use is the leading

preventable cause o death in the

United States. The impact o

tobacco use in terms o morbidityand mortality to society is staggering.

Economically, more than

$96 billion o total U.S. health

care costs each year are

attributable directly to smoking.

However, this is well below the

total cost to society because it

does not include burn care romsmoking-related res, perinatal

care or low-birthweight inants o

mothers who smoke, and medical

care costs associated with disease

caused by secondhand smoke.

In addition to health care costs,

the costs o lost productivity due

to smoking eects are estimated

at $97 billion per year, bringing

a conservative estimate o the

economic burden o smoking to

more than $193 billion per year.

How Does

Tobacco Deliver

Its Eects?There are more than 4,000

chemicals ound in the smoke

o tobacco products. O these,

nicotine, rst identied in the

early 1800s, is the primary rein-

orcing component o tobacco.

Cigarette smoking is themost popular method o using

tobacco; however, there has also

been a recent increase in the

use o smokeless tobacco prod-

ucts, such as snu and chewing

tobacco. These smokeless prod-

ucts also contain nicotine, as

well as many toxic chemicals.

The cigarette is a very ecient

and highly engineered drug deliv-

ery system. By inhaling tobacco

smoke, the average smoker takes

in 12 mg o nicotine per ciga-

rette. When tobacco is smoked,

nicotine rapidly reaches peak

levels in the bloodstream and

enters the brain. A typical smoker

will take 10 pus on a cigarette

over a period o 5 minutes that

Tobacco

Addiction

2 NIDA Research Report Series

12th grade

10th grade

8th grade

20072008200620052004200320022001200019991998199719961995199419931992

Source: University of Michigan, 2008 Monitoring the Future Survey.

5

10

15

20

25

30

35

40

Percent

Reporting

Use

Trends in Prevalence o Cigarette Use

or 8th-, 10th-, and 12th-GradersPercentage of Students Using Cigarettes Over a 30-Day Period, 19922008


3/12

the cigarette is lit. Thus, a person

who smokes about 1 packs (30

cigarettes) daily gets 300 hits o

nicotine to the brain each day. In

those who typically do not inhale

the smokesuch as cigar and pipe

smokers and smokeless tobaccousersnicotine is absorbed

through the mucosal membranes

and reaches peak blood levels

and the brain more slowly.

Immediately ater exposure

to nicotine, there is a kick

caused in part by the drugs

stimulation o the adrenal glands

and resulting discharge o

epinephrine (adrenaline).

The rush o adrenaline stimu-

lates the body and causes an

increase in blood pressure,respiration, and heart rate.

Is Nicotine

Addictive?Yes. Most smokers use tobacco

regularly because they are addicted

to nicotine. Addiction is charac-

terized by compulsive drug seek-

ing and abuse, even in the ace

o negative health consequences.It is well documented that most

smokers identiy tobacco use

as harmul and express a desire

to reduce or stop using it, and

nearly 35 million o them want

to quit each year. Unortunately,

more than 85 percent o those

who try to quit on their own

relapse, most within a week.

Research has shown how nico-

tine acts on the brain to produce

a number o eects. O primary

importance to its addictive natureare ndings that nicotine activates

reward pathwaysthe brain cir-

cuitry that regulates eelings o

pleasure. A key brain chemical

involved in mediating the desire to

consume drugs is the neurotrans-

mitter dopamine, and research

has shown that nicotine increases

levels o dopamine in the reward

circuits. This reaction is similar to

that seen with other drugs o abuse

and is thought to underlie the plea-

surable sensations experienced by

many smokers. For many tobaccousers, long-term brain changes

induced by continued nicotine

exposure result in addiction.

Nicotines pharmacokinetic

properties also enhance its abuse

potential. Cigarette smoking

produces a rapid distribution o

nicotine to the brain, with drug

levels peaking within 10 seconds

o inhalation. However, the

acute eects o nicotine dissipate

quickly, as do the associated eel-

ings o reward, which causes thesmoker to continue dosing to

maintain the drugs pleasurable

eects and prevent withdrawal.

Nicotine withdrawal symp-

toms include irritability, craving,

depression, anxiety, cognitive

and attention decits, sleep dis-

turbances, and increased appe-

tite. These symptoms may begin

within a ew hours ater the last

cigarette, quickly driving people

back to tobacco use. Symptoms

peak within the rst ew days osmoking cessation and usually

subside within a ew weeks. For

some people, however, symp-

toms may persist or months.

Although withdrawal is related

to the pharmacological eects

o nicotine, many behavioral

actors can also aect the sever-

ity o withdrawal symptoms. For

some people, the eel, smell, and

sight o a cigarette and the ritual

o obtaining, handling, lighting,

and smoking the cigarette are all

associated with the pleasurable

eects o smoking and can make

withdrawal or craving worse.

Nicotine replacement therapies

such as gum, patches, and inhalers

may help alleviate the pharma-

cological aspects o withdrawal;however, cravings oten persist.

Behavioral therapies can help smok-

ers identiy environmental triggers

o craving so they can employ

strategies to prevent or circum-

vent these symptoms and urges.

Tobacco plants

Most smokers

identiy tobacco

use as harmul and

express a desireto reduce or stop

using it, and nearly

35 million want to

quit each year.

NIDA Research Report Series 3


4/12

Are There Other

Chemicals That

May Contribute

to Tobacco

Addiction?Yes, research is showing that nico-

tine may not be the only ingredient

in tobacco that aects its addictive

potential. Using advanced neuro-

imaging technology, scientists can

see the dramatic eect o cigarette

smoking on the brain and are nd-

ing a marked decrease in the levels

o monoamine oxidase (MAO), an

important enzyme that is respon-

sible or the breakdown o dop-

amine. This change is likely causedby some ingredient in tobacco

smoke other than nicotine, because

we know that nicotine itsel does

not dramatically alter MAO lev-

els. The decrease in two orms

o MAO (A and B) results in

higher dopamine levels and may

be another reason that smokers

continue to smoketo sustain the

high dopamine levels that lead to

the desire or repeated drug use.

Animal studies by NIDA-

unded researchers have shownthat acetaldehyde, another

chemical ound in tobacco

smoke, dramatically increases

the reinorcing properties o

nicotine and may also contribute

to tobacco addiction. The inves-

tigators urther report that this

eect is age-related: adolescent

animals display ar more sensi-

tivity to this reinorcing eect,

which suggests that the brains

o adolescents may be more vul-

nerable to tobacco addiction.

What Are

the Medical

Consequences

o Tobacco Use?Cigarette smoking kills an esti-

mated 440,000 U.S. citizens each

yearmore than alcohol, illegal

drug use, homicide, suicide, car

accidents, and AIDS combined.

Between 1964 and 2004, more

than 12 million Americans diedprematurely rom smoking, and

another 25 million U.S. smok-

ers alive today will most likely

die o a smoking-related illness.

Cigarette smoking harms nearly

every organ in the body. It has been

conclusively linked to cataracts and

pneumonia, and accounts or about

one-third o all cancer deaths. The

overall rates o death rom cancer

are twice as high among smokers

as nonsmokers, with heavy smok-

ers having rates that are our times

greater than those o nonsmok-

ers. Foremost among the cancers

caused by tobacco use is lungcancercigarette smoking has

been linked to about 90 percent o

all cases o lung cancer, the number

one cancer killer o both men and

women. Smoking is also associated

with cancers o the mouth, phar-

ynx, larynx, esophagus, stomach,

pancreas, cervix, kidney, bladder,

and acute myeloid leukemia.

In addition to cancer, smok-

ing causes lung diseases such as

chronic bronchitis and emphysema,

and it has been ound to exacerbateasthma symptoms in adults and

children. About 90 percent o all

deaths rom chronic obstructive

pulmonary diseases are attribut-

able to cigarette smoking. It has

also been well documented that

smoking substantially increases

the risk o heart disease, includ-

ing stroke, heart attack, vascular

Nicotine replacement

therapies such as gum,

patches, and inhalers

may help alleviate

the pharmacological

aspects o withdrawal.

Using advanced neuroimaging technology, scientists can see the dramatic eect o

cigarette smoking on the brain and body and are fnding a marked decrease in the

levels o monoamine oxidase (MAO B), an important enzyme that is responsible or

the breakdown o dopamine. (Source: Fowler et al., 2003)

NIDA Research Report Series4


5/12

disease, and aneurysm. Smok-

ing causes coronary heart dis-ease, the leading cause o death

in the United States: cigarette

smokers are 24 times more

likely to develop coronary heart

disease than nonsmokers.

Exposure to high doses o

nicotine, such as those ound in

some insecticide sprays, can be

extremely toxic as well, caus-

ing vomiting, tremors, convul-

sions, and death. In act, one

drop o pure nicotine can kill

a person. Nicotine poisoninghas been reported rom acci-

dental ingestion o insecticides

by adults and ingestion o

tobacco products by children

and pets. Death usually results

in a ew minutes rom respira-

tory ailure caused by paralysis.

Although we oten think

o medical consequences thatresult rom direct use o tobacco

products, passive or secondary

smoke also increases the risk or

many diseases. Environmental

tobacco smoke is a major source

o indoor air contaminants; sec-

ondhand smoke is estimated to

cause approximately 3,000 lung

cancer deaths per year among

nonsmokers and contributes to

more than 35,000 deaths related

to cardiovascular disease. Expo-

sure to tobacco smoke in thehome is also a risk actor or

new cases and increased sever-

ity o childhood asthma. Addi-

tionally, dropped cigarettes are

the leading cause o residential

re atalities, leading to more

than 1,000 deaths each year.

Sticky, brown tar coats the

lungs o tobacco smokers.

Along with thousands o

other damaging chemicals,

tar can lead to lung cancer

and acute respiratory

diseases.


Are There

Sae Tobacco

Products?

The adverse health eects o

tobacco use are well known,

yet many people do not want to

quit or have diculty quitting.

As a result, there has been a

recent surge in the development

o tobacco products that claim

to reduce exposure to harmul

tobacco constituents or to have

ewer health risks than conven-

tional products. These poten-

tially reduced exposure products

(PREPs), which include cigarettes

and smokeless tobacco (e.g.,

snu, tobacco lozenges), have not

yet been evaluated suciently

to determine whether they are

indeed associated with reduced

risk o disease. Recent studies

indicate that the levels o carcino-

gens in these PREPs range rom

relatively low to comparable to

conventional tobacco products.

These studies conclude that

medicinal nicotine (ound in the

nicotine patch and gum) is a saer

alternative than these modied

tobacco products.


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Smoking and

PregnancyWhat Are

the Risks?In the United States, it is esti-

mated that about 16 percent o

pregnant women smoke during

their pregnancies. Carbon mon-

oxide and nicotine rom tobacco

smoke may interere with the oxy-

gen supply to the etus. Nicotine

also readily crosses the placenta,

and concentrations in the etuscan be as much as 15 percent

higher than maternal levels.

Nicotine concentrates in etal

blood, amniotic fuid, and breast

milk. Combined, these actors

can have severe consequences

or the etuses and inants o

smoking mothers. Smoking

during pregnancy caused an

estimated 910 inant deaths

annually rom 1997 through 2001,and neonatal care costs related

to smoking are estimated to be

more than $350 million per year.

The adverse eects o smoking

during pregnancy can include etal

growth retardation and decreased

birthweight. The decreased birth-

weights seen in inants o mothers

who smoke refect a dose-depen-

dent relationshipthe more the

woman smokes during pregnancy,

the greater the reduction o inant

birthweight. These newbornsalso display signs o stress and

drug withdrawal consistent

with what has been reported in

inants exposed to other drugs.

In some cases, smoking during

pregnancy may be associated

with spontaneous abortions and

sudden inant death syndrome

(SIDS), as well as learningand behavioral problems and

an increased risk o obesity in

children. In addition, smoking

more than one pack a day dur-

ing pregnancy nearly doubles

the risk that the aected child

will become addicted to tobacco

i that child starts smoking.

There is clear evidence o high rates o psychiatric

comorbidity, including other substance abuse,

among adolescents and adults who smoke. For

example, it has been estimated that individuals

with psychiatric disorders purchase approximately44 percent o all cigarettes sold in the United States,

which undoubtedly contributes to the disproportion-

ate rates o morbidity and mortality in these popula-

tions. In addition, studies have shown that as many

as 80 percent o alcoholics smoke regularly, and that

a majority o them will die o smoking-related, rather

than alcohol-related, disease.

In young smokers, the behavior appears to be

strongly associated with increased risk or a variety

o mental disorders. In some casessuch as with

conduct disorders and attention-decit hyperactivity

disorderthese disorders may precede the onset osmoking, while in otherssuch as with substance

abusethe disorders may emerge later in lie.

Whether daily smoking among boys and girls is the

result or the cause o a maniest psychiatric condition,

it is troubling that so very ew adolescents have their

nicotine dependence diagnosed or properly treated.

Preventing the early onset o smoking and treating its

young victims are critical primary-care priorities, the

ulllment o which could have a dramatic impact on

our ability to prevent or better address a wide rangeo mental disorders throughout lie.

Among adults, the rate o major depressive epi-

sodes is highest in nicotine-dependent individuals,

lower in nondependent current smokers, and lowest

in those who quit or never started smoking. Further-

more, there is evidence showing that, or those who

have had more than one episode, smoking cessation

may increase the likelihood o a new major depres-

sive episode. Adult tobacco use also increases

risk or the later development o anxiety disorders,

which may be associated with an increased severity

o withdrawal symptoms during smoking cessationtherapy. But the most extensive comorbidity overlap

is likely the one that exists between smoking and

schizophrenia, since, in clinical samples, the rate o

smoking in patients with schizophrenia has ranged

as high as 90 percent.

Tobacco Use and Comorbidity



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Smoking and Adolescence

In 2007, more than 3 million American adolescents (aged 1217) reported

using a tobacco product in the month prior to the survey. In that same

year it was ound that nearly 60 percent o new smokers were under

the age o 18 when they rst smoked a cigarette. O smokers under 18,

more than 6 million will likely die prematurely rom a smoking-relateddisease.

Tobacco use in teens is not only the result o psychosocial infuences,

such as peer pressure; recent research suggests that there may be bio-

logical reasons or this period o increased vulnerability. There is some

evidence that intermittent smoking can result in the development o

tobacco addiction in some teens. Animal models o teen smoking pro-

vide additional evidence o an increased vulnerability. Adolescent rats

are more susceptible to the reinorcing eects o nicotine than adult

rats, and take more nicotine when it is available than do adult animals.

Adolescents may also be more sensitive to the reinorcing eects o

nicotine in combination with other chemicals ound in cigarettes, thusincreasing susceptibility to tobacco addiction. As mentioned above,

acetaldehyde increases nicotines addictive properties in adolescent,

but not adult, animals. A recent study also suggests that specic genes

may increase risk or addiction among people who begin smoking during

adolescence. NIDA continues to actively support research aimed

at increasing our understanding o why and how adolescents become

addicted, and to develop prevention and treatment strategies to meet

their specic needs.

Are There Gender

Dierences

in Tobacco

Smoking?Several avenues o research now

indicate that men and women

dier in their smoking behaviors.

For instance, women smoke ewer

cigarettes per day, tend to use

cigarettes with lower nicotine con-

tent, and do not inhale as deeply

as men. However, it is unclear

whether this is due to dierences

in sensitivity to nicotine or other

actors that aect women dier-

ently, such as social actors or

the sensory aspects o smoking.The number o smokers in the

United States declined in the 1970s

and 1980s, remained relatively

stable throughout the 1990s, and

Large-scale smoking

cessation trials show

that women are

less likely to initiate

quitting and may be

more likely to relapse

i they do quit.



8/12

declined urther through the early

2000s. Because this decline in

smoking was greater among men

than women, the prevalence o

smoking is only slightly higher or

men today than it is or women.

Several actors appear to be

contributing to this narrowing

gender gap, including women

being less likely than men to quit.

Large-scale smoking cessation

trials show that women are less

likely to initiate quitting and may

be more likely to relapse i they

do quit. In cessation programs

using nicotine replacement meth-

ods, such as the patch or gum, the

nicotine does not seem to reduce

craving as eectively or womenas or men. Other actors that

may contribute to womens di-

culty with quitting are that with-

drawal may be more intense or

women or that women are more

concerned about weight gain.

Although postcessation weight

gain is typically modest (about

510 pounds), concerns about this

may be an obstacle to treatment

success. In act, NIDA research

has ound that when womens

weight concerns were addressed

during cognitive-behavioral

therapy, they were more success-ul at quitting than women who

were in a program designed only

to attenuate postcessation weight

gain. Other NIDA researchers

have ound that medications

used or smoking cessation,

such as bupropion and naltrex-

one, can also attenuate postces-

sation weight gain and could

become an additional strategy

or enhancing treatment success.

It is important or treatment

proessionals to be aware thatstandard regimens may have to be

adjusted to compensate or gender

dierences in nicotine sensitivity

and in other related actors that

contribute to continued smoking.

Are There

Eective

Treatments

or TobaccoAddiction?Yes, extensive research has shown

that treatments or tobacco

addiction do work. Although

some smokers can quit without

help, many individuals need

assistance with quitting. This is

particularly important because

smoking cessation can have

immediate health benets. For

example, within 24 hours o

quitting, blood pressure andchances o heart attack decrease.

Long-term benets o smoking

cessation include decreased risk

o stroke, lung and other cancers,

and coronary heart disease.

A 35-year-old man who quits

smoking will, on average, increase

his lie expectancy by 5 years.

Nicotine Replacement

Treatments

Nicotine replacement therapies

(NRTs), such as nicotine gum and

the transdermal nicotine patch,

were the rst pharmacological

treatments approved by the Food

and Drug Administration (FDA)or use in smoking cessation ther-

apy. NRTs are used (in conjunction

with behavioral support) to relieve

withdrawal symptomsthey

produce less severe physiological

alterations than tobacco-based

systems and generally provide

users with lower overall nico-

tine levels than they receive with

tobacco. An added benet is that

these orms o nicotine have little

abuse potential since they do not

produce the pleasurable eectso tobacco products, nor do they

contain the carcinogens and gases

associated with tobacco smoke.

Behavioral treatments, even beyond

what is recommended on packag-

ing labels, have been shown to

enhance the eectiveness o NRTs

and improve long-term outcomes.

The FDAs approval o nicotine

gum in 1984 marked the avail-

ability (by prescription) o the rst

NRT on the U.S. market. In 1996,

the FDA approved Nicorette gum

or over-the-counter (OTC) sales.

Whereas nicotine gum provides

some smokers with the desired

control over dose and the ability to

relieve cravings, others are unable

to tolerate the taste and chewing

demands. In 1991 and 1992, the

FDA approved our transdermal

Smoking cessation can

have immediate health

benefts. For example,

within 24 hours o

quitting, blood pressureand chances o heart

attack decrease.



9/12

nicotine patches, two o which

became OTC products in 1996.

In 1996 a nicotine nasal spray,

and in 1998 a nicotine inhaler,

also became available by prescrip-

tion, thus meeting the needs o

many additional tobacco users.All the NRT products gum,

patch, spray, and inhaler appear

to be equally eective.

Additional Medications

Although the primary ocus o

pharmacological treatments or

tobacco addiction has been nico-

tine replacement, other treatments

are also available. For example,

the antidepressant bupropion was

approved by the FDA in 1997 to

help people quit smoking and ismarketed as Zyban. Varenicline

tartrate (Chantix) is a medica-

tion that recently received FDA

approval or smoking cessation.

This medication, which acts at

the sites in the brain aected by

nicotine, may help people quit

by easing withdrawal symptoms

and blocking the eects o nico-

tine i people resume smoking.

Several other nonnicotine

medications are being investigated

or the treatment o tobacco addic-

tion, including other antidepres-

sants and an antihypertensive

medication. Scientists are also

investigating the potential o a

vaccine that targets nicotine or

use in relapse prevention. The

nicotine vaccine is designed to

stimulate the production o anti-

bodies that would block access o

nicotine to the brain and prevent

nicotines reinorcing eects.

Behavioral Treatments

Behavioral interventions play an

integral role in smoking cessation

treatment, either in conjunction

with medication or alone. A vari-

ety o methods can assist smok-

ers with quitting, ranging rom

sel-help materials to individual

cognitive-behavioral therapy. These

interventions teach individuals to

recognize high-risk smoking situ-

ations, develop alternative coping

strategies, manage stress, improveproblemsolving skills, and increase

social support. Research has also

shown that the more therapy is

tailored to a persons situation, the

greater the chances are or success.

Traditionally, behavioral

approaches were developed and

delivered through ormal settings,

such as smoking cessation clin-

ics and community and public

health settings. Over the past

decade, however, researchers have

been adapting these approaches

or mail, telephone, and Internet

ormats, which can be more accept-

able and accessible to smokers

who are trying to quit. In 2004,

the U.S. Department o Health

and Human Services (HHS) estab-

lished a national toll-ree number,

800-QUIT-NOW (800-784-8669),

to serve as a single access point

or smokers seeking inormation

and assistance in quitting. Callersto the number are routed to their

States smoking cessation quitline

or, in States that have not estab-

lished quitlines, to one maintained

by the National Cancer Institute.

In addition, a new HHS Web site

(www.smokefree.gov) oers online

advice and downloadable inorma-

tion to make cessation easier.

Quitting smoking can be

dicult. People can be helped

during the time an intervention

is delivered; however, most inter-

vention programs are short-term

(13 months). Within 6 months,

7580 percent o people who try

to quit smoking relapse. Research

has now shown that extending

treatment beyond the typical

duration o a smoking cessation

program can produce quit rates

as high as 50 percent at 1 year.


Twin studies indicate

that approximately

4070 percent o

a persons risk o

becoming addicted

to nicotine depends

on his or her genes.


10/12

New Frontiers

in Tobacco

ResearchI so many smokers want to quit,

why are ew able to do so success-ully? To address this question,

scientists are increasingly ocusing

on the powerul role o genetics in

addiction. Twin studies indicate

that approximately 4070 percent

o a persons risk o becoming

addicted to nicotine depends on

his or her genes. Although complex

diseases like addiction involve large

numbers o genes interacting with

a wide variety o environmental

actors, the contribution o a

particular gene can be substantial:

Genetic variants associated with

nicotine metabolism, or example,

have been shown to infuence

how people smoke such that slow

metabolizers smoke ewer ciga-

rettes per day and have a higher

likelihood o quitting, and thatthere is greater abstinence among

individuals receiving nicotine

patch therapy. A recent NIDA-

unded study identied a variant

in the gene or a nicotinic receptor

subunit that doubled the risk or

nicotine addiction among smokers.

A subsequent study ound that this

gene variant also increased suscep-

tibility to the severe health con-

sequences o smoking, including

lung cancer and peripheral arterial

disease. NIDA is currently support-ing large-scale genome-wide associ-

ation studies to uncover additional

genetic risk actors in order to bet-

ter understand tobacco addiction

and its adverse eects on health.

In addition to predicting an

individuals risk or nicotine

addiction, genetic markers canalso help predict whether medica-

tions (like bupropion) will eec-

tively help a smoker quit. This

takes root in the emerging eld

o pharmacogenomics, which

investigates how genes infuence

a patients response to drugs and

medications. In the uture, genetic

screening could help clinicians

select treatments, adjust dosages,

and avoid or minimize adverse

reactions, tailoring smoking ces-

sation therapies to an individualsunique genetic inheritance.

Glossary

Addiction: A chronic, relapsing

disease characterized by compul-

sive drug seeking and abuse andby long-lasting neurochemical and

molecular changes in the brain.

Adrenal glands: Glands located

above each kidney that secrete

hormones, e.g., adrenaline.

Craving: A powerul, oten uncon-

trollable desire or drugs.

Dopamine: A neurotransmitter

present in regions o the brain thatregulate movement, emotion, mo-

tivation, and eelings o pleasure.

Emphysema: A lung disease in

which tissue deterioration results

in increased air retention and

reduced exchange o gases. The

result is difculty breathing and

shortness o breath.

Neurotransmitter: A chemical that

acts as a messenger to carry sig-

nals or inormation rom one nerve

cell to another.

Nicotine: An alkaloid derived rom

the tobacco plant that is primarily

responsible or smokings psycho-

active and addictive eects.

Pharmacokinetics: The pattern

o absorption, distribution, and

excretion o a drug over time.

Tobacco: A plant widely cultivated

or its leaves, which are used pri-

marily or smoking; the N. tabacum

species is the major source o

tobacco products.

Withdrawal: A variety o symp-

toms that occur ater chronic use

o an addictive drug is reduced

or stopped.



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NIH Publication Number 09-4342

Printed July 1998, Reprinted August 2001, Revised July 2006,

Revised June 2009

Feel ree to reprint this publication.

Where Can I Get More Scientifc Inormation on

Tobacco Addiction?

To learn more about tobacco and other drugs o

abuse, or to order materials on these topics ree

o charge in English or Spanish, visit the NIDAWeb site at www.drugabuse.gov or contact

the DrugPubs Research Dissemination Center

at 877-NIDA-NIH (877-643-2644;

TTY/TDD: 240-645-0228).

Whats New on the NIDA Web Site

Informationondrugsofabuse

Publicationsandcommunications(including NIDA Notes and Addiction

Science & Clinical Practice journal)

Calendarofevents

LinkstoNIDAorganizationalunits

Fundinginformation(includingprogram

announcements and deadlines)

Internationalactivities

LinkstorelatedWebsites(accesstoWebsites

o many other organizations in the eld)

NIDA Web Sites

drugabuse.gov

backtoschool.drugabuse.govsmoking.drugabuse.gov

teens.drugabuse.gov

For Physician Information

www.drugabuse.gov/nidamed

Other Web Sites

Inormation on tobacco addiction is also

available through these other Web sites:

CentersforDiseaseControlandPrevention:

www.cdc.gov/tobacco

NationalCancerInstitute:www.cancer.gov

U.S.DepartmentofHealthandHumanServices:

www.smokefree.gov

SubstanceAbuseandMentalHealthServices

Administration Health Inormation Network:

www.samhsa.gov/shin

SocietyforResearchonNicotineandTobacco:

www.srnt.org

NicNet:www.nicnet.org

TheRobertWoodJohnsonFoundation:

www.rwjf.org

JoinTogetherOnline:www.quitnet.org

AmericanLegacyFoundation:

www.americanlegacy.org

tobacco addiction (research reports)

Documents