Basic Definitions: Addiction and Dependence

by : Jan Edward Williams

Basic Definitions: Addiction and Dependence
[References available on request]


The terms "addiction" and "dependence" are often used interchangeably. The American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, 4th Ed. (DSM-IV-TR) uses the term "dependence" to refer to the cluster of signs and symptoms that combine to produce the drug and alcohol problems addressed in this course. In an effort to arrive at some consistency, we will use the language adopted by the American Academy of Pain Medicine, the American Pain Society, and the American Society of Addiction Medicine.

I. Addiction

Addiction is a primary, chronic, neurobiologic disease, with genetic, psychosocial, and environmental factors influencing its development and manifestations. It is characterized by behaviors that include one or more of the following: impaired control over drug use, compulsive use, continued use despite harm, and craving.

II. Physical Dependence

Physical dependence is a state of adaptation that is manifested by a drug class specific withdrawal syndrome that can be produced by abrupt cessation, rapid dose reduction, decreasing blood level of the drug, and/or administration of an antagonist.

III. Tolerance

Tolerance is a state of adaptation in which exposure to a drug induces changes that result in a diminution of one or more of the drug's effects over time.

Addiction is often (but not always) accompanied by physical dependence, a withdrawal syndrome, and tolerance. In this course, use of the word "physical" before dependence or addiction signifies use of a drug to the point of development of tolerance and withdrawal syndrome, as explained below.

Physical dependence is a physiological state of adaptation to a substance, the absence of which produces symptoms and signs of withdrawal.

Withdrawal syndrome is a predictable group of signs and symptoms resulting from abrupt removal of, or a rapid decrease in the regular dosage of, a psychoactive substance. The syndrome is often characterized by overactivity of the physiological functions that were suppressed by the drug and/or depression of the functions that were stimulated by the drug.

It is possible to be physically dependent on a drug (with tolerance and withdrawal syndrome) without having addiction (as defined in the first paragraph, above), and conversely, it is possible to have an addiction without being physically dependent (developing tolerance and withdrawal syndrome).

There are many examples of physical dependence on drugs without development of addiction. One would be the patient with cancer who becomes tolerant to, and physically dependent on, opioids prescribed to control pain. Such a patient may experience withdrawal symptoms with discontinuation of the usual dose, but will not experience social, psychological, or physical harm from using the drug and would not seek out the drug if it were no longer needed for analgesia.

An example of addiction to opioids that can occur without physical dependence (tolerance/withdrawal) is a patient with an oxycodone addiction who has been recently detoxified from the drug. In this situation, the patient may no longer be suffering from withdrawal symptoms or tolerance but may continue to crave an opioid high and will invariably relapse to active opioid abuse without further treatment.