• Smoking
• Controlled Substances
• Teen Health

• Smoking Addiction
• Addiction
• Alcoholism

• Substance abuse
• Addiction
• Drug addiction
• Narcotic

BACKGROUND: A new vaccine to help smokers kick the habit is underway at the University of Maryland's Center for Health Behavior Research, which tests new therapies for overcoming addiction, especially smoking and behaviors that lead to obesity. Current methods for quitting smoking use smaller and smaller doses of nicotine to wean smokers' physical dependence on cigarettes.

HOW IT WORKS: Vaccines in general are designed to stimulate the body's immune system by exposing you to a killed or weakened form, or a derivative, of a virus. The anti-smoking vaccine is a bit different: it bonds nicotine molecules before they can reach the target receptors in the brain, reducing the positive feedback -- in the form of released endorphins -- that users get from smoking.

ABOUT ADDICTION: The anti-smoking vaccine is not a magical "silver bullet" that removes all desire to smoke. Like all addictions, tobacco dependence is complex, with both psychological and physiological factors. People must be motivated to quit. Physically speaking, when a substance like alcohol, tobacco, or drugs is ingested, it crosses the blood-brain barrier, and alters the natural chemical behavior of the brain temporarily. For example, endorphins -- chemicals that induce feelings of pleasure -- are released. A person can become physically dependent on that substance if used repeatedly, particularly since as his/her tolerance increases, so must the amount of the substance consumed to achieve the same desired effect. When a person stops taking the substance regularly, he or she will experience physical symptoms of withdrawal.

MENTAL DEPENDENCE: Breaking the cycle of dependence requires overcoming unconscious behavior patterns. What compels someone to continue abusing a substance even when it is clearly harmful to his or her health? The psychological aspect of addition is the answer. In fact, psychological dependence can persist even when the physical addiction is broken. The term "dry drunk" describes someone who exhibits addictive behavior even after being weaned from a physical dependency on a given substance, like drugs or alcohol. Such a state is most common in the early stages of addiction recovery.

Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.