Home  |  Ask Dr. NIDA  |  Nicotine

What Is Nicotine?

Nicotine, one of more than 4,000 chemicals found in the smoke from tobacco products such as cigarettes, cigars, and pipes, is the primary component in tobacco that acts on the brain. Smokeless tobacco products such as snuff and chewing tobacco also contain many toxins as well as high levels of nicotine. Nicotine, recognized as one of the most frequently used addictive drugs, is a naturally occurring colorless liquid that turns brown when burned and acquires the odor of tobacco when exposed to air.

Is Nicotine Addictive?

Yes, nicotine is addictive. Most smokers use tobacco regularly because they are addicted to nicotine. Addiction is characterized by compulsive drug-seeking and use, even in the face of negative health consequences, and tobacco use certainly fits the description. It is well documented that most smokers identify tobacco as harmful and express a desire to reduce or stop using it, and nearly 35 million of them make a serious attempt to quit each year. Unfortunately, less than 7 percent of those who try to quit on their own achieve more than 1 year of abstinence; most relapse within a few days of attempting to quit.

What Is the Extent and Impact of Tobacco Use?

According to the 2001 National Household Survey on Drug Abuse, an estimated 56.3 million Americans were current smokers and 7.3 million used smokeless tobacco, which means that nicotine is one of the most widely abused substances. In addition, in 1998 each day in the United States more than 2,000 people under the age of 18 began daily smoking. According to the Centers for Disease Control and Prevention (CDC), the prevalence of cigarette smoking among U.S. high school students increased from 27.5 percent in 1991 to 36.4 percent in 1997 before declining to 34.8 percent in 1999. NIDA's own Monitoring the Future Study, which annually surveys drug use and related attitudes of America's adolescents, also found the prevalence rates for smoking among youth declined from 1999 to 2002. Since 1975, nicotine in the form of cigarettes has consistently been the substance the greatest number of high school students use daily.

How Does Nicotine Deliver its Effect?

Nicotine can act as both a stimulant and a sedative. Immediately after exposure to nicotine, there is a "kick" caused in part by the drug's stimulation of the adrenal glands and resulting discharge of epinephrine (adrenaline). The rush of adrenaline stimulates the body and causes a sudden release of glucose as well as an increase in blood pressure, respiration, and heart rate. Nicotine also suppresses insulin output from the pancreas, which means that smokers are always slightly hyperglycemic. In addition, nicotine indirectly causes a release of dopamine in the brain regions that control pleasure and motivation. This reaction is similar to that seen with other drugs of abuse-such as cocaine and heroin- and it is thought to underlie the pleasurable sensations experienced by many smokers. In contrast, nicotine can also exert a sedative effect, depending on the level of the smoker's nervous system arousal and the dose of nicotine taken.

What Happens When Nicotine is Taken for Long Periods of Time?

Chronic exposure to nicotine results in addiction. Research is just beginning to document all of the neurological changes that accompany the development and maintenance of nicotine addiction. The behavioral consequences of these changes are well documented, however. Greater than 90 percent of those smokers who try to quit without seeking treatment fail, with most relapsing within a week.

Repeated exposure to nicotine results in the development of tolerance, the condition in which higher doses of a drug are required to produce the same initial stimulation. Nicotine is metabolized fairly rapidly, disappearing from the body in a few hours. Therefore some tolerance is lost overnight, and smokers often report that the first cigarettes of the day are the strongest and/or the "best." As the day progresses, acute tolerance develops, and later cigarettes have less effect.

Cessation of nicotine use is followed by a withdrawal syndrome that may last a month or more; it includes symptoms that can quickly drive people back to tobacco use. Nicotine withdrawal symptoms include irritability, craving, cognitive and attentional deficits, sleep disturbances, and increased appetite and may begin within a few hours after the last cigarette. Symptoms peak within the first few days and may subside within a few weeks. For some people, however, symptoms may persist for months or longer.

An important but poorly understood component of the nicotine withdrawal syndrome is craving, an urge for nicotine that has been described as a major obstacle to successful abstinence. High levels of craving for tobacco may persist for 6 months or longer. While the withdrawal syndrome is related to the pharmacological effects of nicotine, many behavioral factors also can affect the severity of withdrawal symptoms. For some people, the feel, smell, and sight of a cigarette and the ritual of obtaining, handling, lighting, and smoking the cigarette are all associated with the pleasurable effects of smoking and can make withdrawal or craving worse. While nicotine gum and patches may alleviate the pharmacological aspects of withdrawal, cravings often persist.

[Back to top]

Next Page >>

Are you in crisis?
Call 1-800-662-HELP or
visit findtreatment.samhsa.gov

Don't know what something means?
Look it up. 

Think you know what drugs do to
the brain and body?
Play. 

Make your own iron-ons, stickers,
buddy icons and other cool stuff!
Check it out. 

Explore the brain's response to drugs
with Sara Bellum.
Explore.