Introduction
Addiction is a worldwide problem resulting in great economic, health, and social burdens. It is estimated that 4.7% of the global population ages 15–64, or 184 million people, consume illicit drugs annually. 1
Addiction to legal substances is also a problem. According to the Centers for Disease Control and Prevention (CDC), 20.8% of all adults smoke cigarettes, totaling 45.3 million people, 2 and smoking remains the leading preventable cause of death in the United States. 3 The National Epidemiological Survey on Alcohol and Related Conditions indicates that the prevalence of lifetime alcohol abuse is 17.8%, and the prevalence of lifetime alcohol dependence is 12.5% in the United States. 4
Addiction is a chronic condition in which there is an obsession and compulsion to seek and use a substance (or engage in a behavior) that induces a pleasant state or relieves distress. Continued use of the addictive substance (or engaging in the addictive behavior) induces adaptive changes in the brain that lead to tolerance, physical dependence, uncontrollable craving, and a characteristic set of signs and symptoms upon withdrawal.
Common addictive substances include alcohol, nicotine, barbiturates, benzodiazepines, opioids, and stimulants. Behavioral addictions, also known as process addictions, such as gambling, eating disorders, and sex, have also recently been included in the scope of true addiction as they have the same core components as substance abuse, including mood modification, tolerance, withdrawal, and relapse.
