In addition to having abuse potential, most controlled substances are capable of producing dependence, either physical or psychological.
Physical dependence refers to the changes that have occurred in the body after repeated use of a drug that necessitates the continued administration of the drug to prevent a withdrawal syndrome. This withdrawal syndrome can range from mildly unpleasant to life-threatening and is dependent on a number of factors, such as:
• The drug being used
• The dose and route of administration
• Concurrent use of other drugs
• Frequency and duration of drug use
• The age, sex, health, and genetic makeup of the user
Psychological dependence refers to the perceived “need” or “craving” for a drug. Individuals who are psychologically dependent on a particular substance often feel that they cannot function without continued use of that substance. While physical dependence disappears within days or weeks after drug use stops, psychological
dependence can last much longer and is one of the primary reasons for relapse (initiation of drug use after a period of abstinence).