NAH Joint Replacement Program

The difference between addiction, tolerance and dependence


Drug addiction is a brain disorder known as “chemical dependence.” The major symptom of drug addiction is compulsive drug seeking behavior. It is characterized by a persistent pattern of dysfunctional opioid use that involves taking opioids when there is no pain; losing control over one’s opioid use; preoccupation with obtaining opioids despite the presence of adequate pain relief; and manipulating others to get doses beyond the amount needed to manage the pain.

Pain in the addicted patient presents two problems:

  1. The patient’s addictive disorder.
  2. The patient’s uncontrolled pain.


Tolerance is a form of neuro-adaptation to the effects of chronically administered opioids. The body becomes used to larger and larger amounts of the drug, so an increasing dosage is needed to continue to achieve the desired effect. 

Physical dependence

This is a physiologic state in which abrupt cessation (sudden stopping) of the opioid results in a withdrawal syndrome. This is an expected outcome of chronic opioid therapy. Other drugs that can produce physical dependence include beta blockers, caffeine, barbiturates, benzodiazepine, clonidine, and alcohol.