Nicotine is the chemical in cigarettes that makes them addictive. About 85% of smokers are addicted to nicotine. Higher levels of nicotine in a cigarette can make it harder to quit smoking. The amount of nicotine in cigarettes has steadily increased in the past decade. Higher nicotine levels have been found in all cigarette categories, including "light" brands.
Some researchers feel nicotine is as addictive as heroin. In fact, nicotine has actions similar to heroin and cocaine, and the chemical affects the same area of the brain.
Depending on the amount taken in, nicotine can act as either a stimulant or a sedative. Cigarette smoking has definite immediate positive effects. For example, it can:
- Boost mood and relieve minor depression
- Suppress anger
- Enhance concentration and short-term memory
- Produce a modest sense of well-being
Most smokers have a special fondness for the first cigarette of the day because of the way brain cells respond to the day's first nicotine rush. Nicotine, particularly taken in the first few cigarettes of the day, increases the activity of dopamine, a chemical in the brain that elicits pleasurable sensations. This feeling is similar to getting a reward.
Over the course of a day, however, the nerve cells become desensitized to nicotine. Smoking becomes less pleasurable, and smokers may be likely to increase their intake to get their "reward." A smoker develops tolerance to these effects very quickly and requires increasingly higher levels of nicotine.
Review Date: 09/08/2010
Reviewed By: Reviewed by: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.