There is much confusion about these terms:
Dependence and tolerance are the results of our body’s natural process of adaptation to its environment.
Addiction is a bio-psycho-social behavioral disorder – a disease independent of the substance.
From the American Pain Society:
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.
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.
Here is an explanation from the head of NIDA (National Institute for Drug Abuse), Dr. Nora Volkow:
Here are several more blog posts that discuss the differences:
Opioid Dependence Confused with Addiction – long detailed article by pain-topics.org