Psychological dependence: a mental attachment to a drug; the belief that the drug is needed to
relieve stress, anxiety, or another mental discomfort.
Physical Dependence: the regular use of a substance to function.
Physical withdrawal symptoms develop when a person stops using a drug.
Tolerance: reduced sensitivity to a drug so that increased amounts are needed to achieve the
Toxicity: the dosage level at which a drug becomes poisonous to the body.
Substance Use Disorder
A pattern of substance use that ranges from mild to severe and that is characterized by 2-3 of
the following within a one-year period:
Developing tolerance to the substance.
Using the substance in larger quantities or over a longer period than intended.
Becoming unable to cut down or control one’s use of the substance.
Spending an inordinate amount of time on activities aimed at obtaining the substance,
using it, or recovering from its effects.
Sacrificing important social, occupational, or recreational activities due to the substance
Continuing to use the substance despite knowledge that the substance has either caused