Addiction is a condition that results when a person ingests a substance (e.g., alcohol, cocaine, nicotine) or engages in an activity (e.g., gambling, sex, shopping) that can be pleasurable but the continued use/act of which becomes compulsive and interferes with ordinary life responsibilities, such as work, relationships, or health.
People with an addiction do not have control over what they are doing, taking or using. Their addiction may reach a point at which it is harmful. Addictions do not only include physical things we consume, such as drugs or alcohol, but may include virtually anything, such abstract things as gambling to seemingly harmless products, such as chocolate - in other words, addiction may refer to a substance dependence (e.g. drug addiction) or behavioral addiction (e.g. gambling addiction).
The word addiction is used in several different ways. One definition describes physical addiction. This is a biological state in which the body adapts to the presence of a drug so that drug no longer has the same effect, otherwise known as a tolerance. Another form of physical addiction is the phenomenon of overreaction by the brain to drugs (or to cues associated with the drugs).
However, most addictive behavior is not related to either physical tolerance or exposure to cues. People compulsively use drugs, gamble, or shop nearly always in reaction to being emotionally stressed, whether or not they have a physical addiction.
Related Journals of Addiction
European Addiction Research, Journal of Addictive Diseases, Sexual Addiction and Compulsivity, Addiction Biology, American Journal on Addictions, Journal of Addiction Medicine