The ability to recognize signs of alcohol or drug addiction, dependence, and tolerance can enable you to help yourself or someone else. A drug, broadly defined, refers to any substance that, by its chemical nature, alters the structure or function of a living organism. To be considered addicted to a drug, the presence of an increased tolerance and dependence are necessary. Tolerance refers to the need for larger and larger amounts of a drug over time to produce the same effects.
Drug dependence is divided into two components, physical dependence and psychological dependence.
Physical dependence refers to the body's need for the drug, in order to remain chemically balanced. The presence of withdrawal symptoms are the only sure signs of a physical dependence on drugs. Psychological dependence is separate from the person's physical need for the drug. Rather, it refers to the person's belief that he or she needs the drug to function mentally, to feel normal, and to improve their mood. The need for the effects of these drugs ca range from mild to intense.