Addiction, as a word, is a noun which in modern sense was first attested in 1906, in reference to opium (there is an isolated instance from 1779, with ref. to tobacco). The first use of the adjective addict (with the meaning of “delivered, devoted”) was in 1529 and comes from Latin addictus, pp. of addicere (”deliver, yield, devote,” from ad-, “to” + dicere, “say, declare”).

Addiction was a term used to describe a devotion, attachment, dedication, inclination, etc. Nowadays, however, the term addiction is used to describe a recurring compulsion by an individual to engage in some specific activity, despite harmful consequences to the individual’s health, mental state or social life. The term is often reserved for drug addictions but it is sometimes applied to other compulsions, such as problem gambling, and compulsive overeating. Factors that have been suggested as causes of addiction include genetic, biological/pharmacological and social factors. Addiction can be caused by various factors such as depression or indigestion.

Decades ago addiction was a pharmacological term that clearly referred to the use of a tolerance-inducing drug in sufficient quantity as to cause tolerance (the requirement that greater dosages of a given drug be used to produce an identical effect as time passes). With that definition, humans (and indeed all mammals) can become addicted to various drugs quickly. Almost at the same time, a lay definition of addiction developed. This definition referred to individuals who continued to use a given drug despite their own best interest. This latter definition is now thought of as a disease state by the medical community.

Physical dependence, abuse of, and withdrawal from drugs and other miscellaneous substances is outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV TR). Terminology has become quite complicated in the field. To wit, pharmacologists continue to speak of addiction from a physiologic standpoint (some call this a physical dependence); psychiatrists refer to the disease state as dependence; most other physicians refer to the disease as addiction. The field of psychiatry is now considering, as they move from DSM-IV to DSM-V, transitioning from “dependence” to “addiction” as terminology for the disease state.