Addiction used to be predominantly 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. 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.
The medical community now makes a careful theoretical distinction between physical dependence (characterized by symptoms of withdrawal) and psychological dependence (or simply addiction). Addiction is now narrowly defined as "uncontrolled, compulsive use"; if there is no harm being suffered by, or damage done to, the patient or another party, then clinically it may be considered compulsive, but to the definition of some it is not categorized as "addiction". In practice, the two kinds of addiction are not always easy to distinguish. Addictions often have both physical and psychological components.
There is also a lesser known situation called pseudo-addiction. (Weissman and Gallagher, 1989) A patient will exhibit drug-seeking behavior reminiscent of psychological addiction, but they tend to have genuine pain or other symptoms that have been under treated. Unlike true psychological addiction, these behaviors tend to stop when the pain is adequately treated.
The obsolete term physical addiction is deprecated, because of its connotations. In modern pain management with opioids physical dependence is nearly universal. While opiates are essential in the treatment of acute pain, the benefit of this class of medication in chronic pain is not well proven. Clearly, there are those who would not function well without opiate treatment; on the other hand, many states are noting significant increases in non-intentional deaths related to opiate use. High-quality, long-term studies are needed to better delineate the risks and benefits of chronic opiate use.
This section is reserved for the elaboration and discussion of addiction in all its forms and labels.~