substance dependence is defined as:
"When an individual persists in use of alcohol or other drugs despite problems related to use of the substance, substance dependence may be diagnosed. Compulsive and repetitive use may result in tolerance to the effect of the drug and withdrawal symptoms when use is reduced or stopped. This, along with Substance Abuse are considered Substance Use Disorders...."
Substance dependence can be diagnosed with physiological dependence, evidence of tolerance or withdrawal, or without physiological dependence.
The related concept of drug addiction has many different definitions. Some writers give in fact drug addiction the same meaning as substance dependence, others for example provide drug addiction a narrower meaning which excludes drugs without evidence of tolerance or withdrawal symptoms
