In the United States, 21 percent of people ages 18 and over smoke cigarettes, according to the ]]>Centers for Disease Control and Prevention (CDC)]]>. Cigarettes contain the addictive drug nicotine. When you smoke, the nicotine affects multiple parts of your body, including your brain. The reason people become addicted to nicotine (and other types of drugs) is that nicotine affects the neurotransmitters in the brain, which are chemicals involved in neural communication. The neurotransmitter that nicotine affects is acetylcholine. Nicotine mimics acetylcholine and binds to the nicotinic receptors in the brain, which is a type of acetylcholine receptor. The ]]>Canadian Institutes of Health Research and the Canadian Institute of Neurosciences, Mental Health and Addiction]]> explain that when you smoke, the nicotine causes more dopamine to be released. Dopamine is another neurotransmitter, and it causes pleasure. Thus, people who smoke cigarettes become addicted to the nicotine because of the pleasure they receive.
When you stop smoking, the lack of nicotine causes withdrawal. Symptoms include emotional and behavioral changes, such as a depressed mood, irritability, anxiety, impatience, hostility, restlessness and difficulty concentrating. The ]]>American Heart Association]]> notes that nicotine withdrawal can also cause physical changes, such as an increased appetite and decreased heart rate.
But nicotine may be causing other changes as well. In a new study published in Biological Psychiatry, people who are smokers had a thinner part of the cerebral cortex than people who have never smoked. ]]>HealthDay News]]> reports that the study included 22 people who smoked and 21 people who never smoked, and using 3-D images of the brain, the researchers looked at differences in cerebral cortex thickness. They found that smokers had a thinner medial orbito-frontal cortex.